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Travis G, McGowan EM, Simpson AM, Marsh DJ, Nassif NT. PTEN, PTENP1, microRNAs, and ceRNA Networks: Precision Targeting in Cancer Therapeutics. Cancers (Basel) 2023; 15:4954. [PMID: 37894321 PMCID: PMC10605164 DOI: 10.3390/cancers15204954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023] Open
Abstract
The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a well characterised tumour suppressor, playing a critical role in the maintenance of fundamental cellular processes including cell proliferation, migration, metabolism, and survival. Subtle decreases in cellular levels of PTEN result in the development and progression of cancer, hence there is tight regulation of the expression, activity, and cellular half-life of PTEN at the transcriptional, post-transcriptional, and post-translational levels. PTENP1, the processed pseudogene of PTEN, is an important transcriptional and post-transcriptional regulator of PTEN. PTENP1 expression produces sense and antisense transcripts modulating PTEN expression, in conjunction with miRNAs. Due to the high sequence similarity between PTEN and the PTENP1 sense transcript, the transcripts possess common miRNA binding sites with the potential for PTENP1 to compete for the binding, or 'sponging', of miRNAs that would otherwise target the PTEN transcript. PTENP1 therefore acts as a competitive endogenous RNA (ceRNA), competing with PTEN for the binding of specific miRNAs to alter the abundance of PTEN. Transcription from the antisense strand produces two functionally independent isoforms (PTENP1-AS-α and PTENP1-AS-β), which can regulate PTEN transcription. In this review, we provide an overview of the post-transcriptional regulation of PTEN through interaction with its pseudogene, the cellular miRNA milieu and operation of the ceRNA network. Furthermore, its importance in maintaining cellular integrity and how disruption of this PTEN-miRNA-PTENP1 axis may lead to cancer but also provide novel therapeutic opportunities, is discussed. Precision targeting of PTENP1-miRNA mediated regulation of PTEN may present as a viable alternative therapy.
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Affiliation(s)
- Glena Travis
- Cancer Biology, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (G.T.); (E.M.M.)
| | - Eileen M. McGowan
- Cancer Biology, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (G.T.); (E.M.M.)
- Central Laboratory, The First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China
| | - Ann M. Simpson
- Gene Therapy and Translational Molecular Analysis Laboratory, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia;
| | - Deborah J. Marsh
- Translational Oncology Group, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia;
| | - Najah T. Nassif
- Cancer Biology, Faculty of Science, School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; (G.T.); (E.M.M.)
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Liu J, Pan Y, Liu Y, Wei W, Hu X, Xin W, Chen N. The regulation of PTEN: Novel insights into functions as cancer biomarkers and therapeutic targets. J Cell Physiol 2023; 238:1693-1715. [PMID: 37334436 DOI: 10.1002/jcp.31053] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/10/2023] [Accepted: 05/17/2023] [Indexed: 06/20/2023]
Abstract
This review summarizes the implications of the primary tumor suppressor protein phosphatase and tensin homolog (PTEN) in aggressive cancer development. PTEN interacts with other cellular proteins or factors suggesting the existence of an intricate molecular network that regulates their oncogenic function. Accumulating evidence has shown that PTEN exists and plays a role in the cytoplasmic organelles and in the nucleus. PTEN blocks phosphoinositide 3-kinases (PI3K)-protein kinase B-mammalian target of rapamycin signaling pathway by dephosphorylating phosphatidylinositol (PI)-3,4,5-triphosphate to PI-4,5-bisphosphate thus counteracting PI3K function. Studies have shown that PTEN expression is tightly regulated at transcriptional, posttranscriptional, and posttranslational levels (including protein-protein interactions and posttranslational modifications). Despite recent advances in PTEN research, the regulation and function of the PTEN gene remain largely unknown. How mutation or loss of specific exons in the PTEN gene occurs and involves in cancer development is not clear. This review illustrates the regulatory mechanisms of PTEN expression and discusses how PTEN participates in tumor development and/or suppression. Future prospects for the clinical applications are also highlighted.
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Affiliation(s)
- Jie Liu
- Department of Dermatology, Skin Research, Peking University Shenzhen Hospital, Shenzhen, Guangdong, China
| | - Yongli Pan
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Yuheng Liu
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Wei Wei
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Xiaoping Hu
- Department of Dermatology, Skin Research, Peking University Shenzhen Hospital, Shenzhen, Guangdong, China
| | - Wenqiang Xin
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Nan Chen
- Department of Gastroenterology, Liaocheng People's Hospital, Liaocheng, China
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Resistance to Molecularly Targeted Therapies in Melanoma. Cancers (Basel) 2021; 13:cancers13051115. [PMID: 33807778 PMCID: PMC7961479 DOI: 10.3390/cancers13051115] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 12/12/2022] Open
Abstract
Malignant melanoma is the most aggressive type of skin cancer with invasive growth patterns. In 2021, 106,110 patients are projected to be diagnosed with melanoma, out of which 7180 are expected to die. Traditional methods like surgery, radiation therapy, and chemotherapy are not effective in the treatment of metastatic and advanced melanoma. Recent approaches to treat melanoma have focused on biomarkers that play significant roles in cell growth, proliferation, migration, and survival. Several FDA-approved molecular targeted therapies such as tyrosine kinase inhibitors (TKIs) have been developed against genetic biomarkers whose overexpression is implicated in tumorigenesis. The use of targeted therapies as an alternative or supplement to immunotherapy has revolutionized the management of metastatic melanoma. Although this treatment strategy is more efficacious and less toxic in comparison to traditional therapies, targeted therapies are less effective after prolonged treatment due to acquired resistance caused by mutations and activation of alternative mechanisms in melanoma tumors. Recent studies focus on understanding the mechanisms of acquired resistance to these current therapies. Further research is needed for the development of better approaches to improve prognosis in melanoma patients. In this article, various melanoma biomarkers including BRAF, MEK, RAS, c-KIT, VEGFR, c-MET and PI3K are described, and their potential mechanisms for drug resistance are discussed.
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Tan AC. Targeting the PI3K/Akt/mTOR pathway in non-small cell lung cancer (NSCLC). Thorac Cancer 2020; 11:511-518. [PMID: 31989769 PMCID: PMC7049515 DOI: 10.1111/1759-7714.13328] [Citation(s) in RCA: 269] [Impact Index Per Article: 67.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/07/2020] [Indexed: 12/24/2022] Open
Abstract
The traditional classification of lung cancer into small cell lung cancer and non-small cell lung cancer (NSCLC) has been transformed with the increased understanding of the molecular alterations and genomic biomarkers that drive the development of lung cancer. Increased activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway leads to numerous hallmarks of cancer and this pathway represents an attractive target for novel anticancer therapies. In NSCLC, the PI3K/Akt/mTOR pathway has been heavily implicated in both tumorigenesis and the progression of disease. A number of specific inhibitors of PI3K, Akt and mTOR are currently under development and in various stages of preclinical investigation and in early phase clinical trials for NSCLC. Early evidence has yielded disappointing results. Clinical trials, however, have been performed on predominantly molecularly unselected populations, and patient enrichment strategies using high-precision predictive biomarkers in future trials will increase the likelihood of success. A greater understanding of the underlying molecular biology including epigenetic alterations is also crucial to allow for the detection of appropriate biomarkers and guide combination approaches.
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Affiliation(s)
- Aaron C. Tan
- Division of Medical OncologyNational Cancer Centre SingaporeSingapore
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Son JH, Chung BY, Jung MJ, Choi YW, Kim HO, Park CW. Cowden Disease: Case Report and Review of the Literature. Ann Dermatol 2019; 31:325-330. [PMID: 33911599 PMCID: PMC7992722 DOI: 10.5021/ad.2019.31.3.325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/22/2018] [Accepted: 06/07/2018] [Indexed: 11/25/2022] Open
Abstract
Cowden's disease is a rare autosomal dominant, multiple hamartoma syndrome with characteristic mucocutaneous lesions. It is associated with abnormalities of the breast, thyroid, and gastrointestinal tract; and is characterized by multiple hamartomas in the gastrointestinal tract and mucocutaneous lesions such as trichilemmomas, oral papillomatosis, facial papules, and acral keratosis. A 21-year-old male patient presented with erythematous facial papules, oral mucosal papillomatosis, and punctate palmoplantar hyperkeratosis indicating a definite case of Cowden's disease. This disease derives from variable expression resulting from a mutation in the PTEN gene. Gastrointestinal endoscopy and colonoscopy revealed multiple hamartomas in the stomach and colon. On thyroid ultrasonography, several probable benign nodules were noted in the right thyroid gland. He had no pertinent family history and no other systemic findings. Further regular laboratory and image studies will be planned for our patient, as well as his family members. Sporadic Cowden's disease is rarely observed. Herein, we report a case of Cowden's disease without known family history. Dermatologists should be aware of the possibility of Cowden syndrome based on its several dermatologic findings.
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Affiliation(s)
- Jee Hee Son
- Department of Dermatology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea
| | - Bo Young Chung
- Department of Dermatology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea
| | - Min Je Jung
- Department of Dermatology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea
| | - Yong Won Choi
- Department of Dermatology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea
| | - Hye One Kim
- Department of Dermatology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea
| | - Chun Wook Park
- Department of Dermatology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Korea
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Ijuin T. Phosphoinositide phosphatases in cancer cell dynamics-Beyond PI3K and PTEN. Semin Cancer Biol 2019; 59:50-65. [PMID: 30922959 DOI: 10.1016/j.semcancer.2019.03.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 03/18/2019] [Accepted: 03/18/2019] [Indexed: 12/16/2022]
Abstract
Phosphoinositides are a group of lipids that regulate intracellular signaling and subcellular biological events. The signaling by phosphatidylinositol-3,4,5-trisphosphate and Akt mediates the action of growth factors that are essential for cell proliferation, gene transcription, cell migration, and polarity. The hyperactivation of this signaling has been identified in different cancer cells; and, it has been implicated in oncogenic transformation and cancer cell malignancy. Recent studies have argued the role of phosphoinositides in cancer cell dynamics, including actin cytoskeletal rearrangement at the plasma membrane and the organization of intracellular compartments. The focus of this review is to summarize the impact of the activities of phosphoinositide phosphatases on intracellular signaling related to cancer cell dynamics and to discuss how the abnormalities in the activities of the enzymes alter the levels of phosphoinositides in cancer cells.
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Affiliation(s)
- Takeshi Ijuin
- Division of Biochemistry, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki, Chu-o, Kobe 650-0017, Japan.
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Kosmas K, Mitropoulou G, Provatas I, Stamoulas M, Marouga A. Expression of phosphatase and tensin homologue in imprint smears of endometrial carcinoma. Cytopathology 2018; 29:558-564. [PMID: 30007089 DOI: 10.1111/cyt.12612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/03/2018] [Indexed: 01/04/2023]
Abstract
OBJECTIVE The aims of this study were to determine the expression of phosphatase and tensin homologue (PTEN) in endometrial adenocarcinomas (as a potential prognostic indicator before treatment) in imprint smears and to correlate the results with clinicopathological parameters of primary untreated endometrial cancer patients. METHODS A total of 126 patients with endometrial carcinoma were evaluated with samples freshly resected after a total abdominal hysterectomy during a 29-month period. The expression of PTEN was assessed by immunocytochemistry. RESULTS In total, 102 cases were type I and 24 type II endometrial adenocarcinomas. High expression of PTEN was more frequent in type I (42/102) compared to type II (6/24) adenocarcinomas, to less advanced and aggressive clinical stage (stage I: 41/79, stage II: 5/13, stage III: 2/19, stage IV: 1/15) as well as in low grade (grade 1: 26/42, grade 2: 20/57) compared to high-grade (grade 3: 8/27) carcinomas. The nonaffected lymph nodes showed high expression of PTEN (in 43.3%) than the affected lymph nodes (in 5.9%). Also, in 45 out of 74 cases with myometrial invasion <50%, there was positive expression of PTEN in contrast to 12 out of 52 cases with depth of myometrial invasion >50%. CONCLUSIONS Immunocytochemical findings from PTEN stain, in addition to cytomorphological features, appeared to be a useful marker in the diagnosis and in the postoperative prognosis of endometrial carcinoma in endometrial cytology with imprint smears and that high PTEN expression is related to morphological features of less aggressiveness tumours.
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Affiliation(s)
- Konstantinos Kosmas
- Department of Cytopathology, General Chest Diseases Hospital of Athens "SOTIRIA", Athens, Greece
| | | | - Ioannis Provatas
- Pathology Department, General Hospital of Athens "Evaggelismos", Athens, Greece
| | - Marios Stamoulas
- Department of Obstetrics & Gynaecology, Chesterfield Royal Hospital, Derbyshire, UK
| | - Anna Marouga
- Department of Cytopathology, Athens University Medical School, "Attikon" University Hospital, Athens, Greece
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Brader S, Eccles SA. Phosphoinositide 3-Kinase Signalling Pathways in Tumor Progression, Invasion and Angiogenesis. TUMORI JOURNAL 2018; 90:2-8. [PMID: 15143962 DOI: 10.1177/030089160409000102] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Aims and background The PI3 kinase signalling pathway is now accepted as being at least as important as the ras-MAP kinase pathway in cell survival and proliferation, and hence its potential role in cancer is of great interest1. The purpose of this review is briefly to examine evidence for an involvement of PI3K in human cancers, discuss the mechanisms by which its activation promotes tumor progression, and consider its utility as a novel target for anticancer therapy. Methods and study design A Medline review of recent literature concerning the role of PI3 kinase in tumor progression -mechanisms of action and clinical implications. Results Evidence is presented that misregulation of the PI3 kinase pathway is a feature of many common cancers, either by loss of the suppressor protein PTEN, or by constitutive activation of PI3 kinase isoforms or downstream elements such as AKT and mTOR. This activation potentiates not only cell survival and proliferation, but also cytoskeletal deformability and motility; key elements in tumor invasion. In addition the PI3K pathway is implicated in many aspects of angiogenesis, including upregulation of angiogenic cytokines due to tumor hypoxia or oncogene activation and endothelial cell responses to them. These cytokines signal though receptors such as VEGF-R, FGF-R and Tie-2 and potentiate processes essential for neoangiogenesis including cell proliferation, migration, differentiation into tubules and “invasion” of these capillary sprouts into extracellular matrix (ECM). Conclusions A more complete understanding of the role of the PI3 kinase pathway in cancer will lead the way to the development of more potent and selective inhibitors which should be a useful adjunct to conventional therapies, potentially interfering with tumor progression at several pivotal points; in particular cell survival, invasion and angiogenesis.
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Affiliation(s)
- Sharon Brader
- Tumor Biology and Metastasis, Cancer Research UK Centre for Cancer Therapeutics, Institute of Cancer Research, McElwain Laboratories, Belmont, Surrey, UK
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Li H, Yuan SM, Yang M, Zha H, Li XR, Sun H, Duan L, Gu Y, Li AF, Weng YG, Luo JY, He TC, Wang Y, Li CY, Li FQ, Wang ZB, Zhou L. High intensity focused ultrasound inhibits melanoma cell migration and metastasis through attenuating microRNA-21-mediated PTEN suppression. Oncotarget 2018; 7:50450-50460. [PMID: 27391071 PMCID: PMC5226595 DOI: 10.18632/oncotarget.10433] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/28/2016] [Indexed: 12/14/2022] Open
Abstract
High intensity focused ultrasound (HIFU) technology is becoming a potential noninvasive treatment for solid tumor. To explore whether HIFU can be applied to treat melanoma and its metastasis, we investigated the effect of HIFU on murine melanoma model. While there was little influence on cell survival, viability or apoptosis, HIFU exposure suppressed melanoma cell migration in vitro and metastasis in vivo. The expression of microRNA-21(miR-21) was down-regulated and PTEN expression was up-regulated in response to HIFU exposure, which was in concomitant with the reduction of AKT activity. Furthermore, ectopic miR-21 expression suppressed this effect of HIFU. These results demonstrate that HIFU exposure can inhibit AKT-mediated melanoma metastasis via miR-21 inhibition to restore PTEN expression. Therefore, targeting the miR-21/PTEN/AKT pathway might be a novel strategy of HIFU in treatment of melanoma.
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Affiliation(s)
- Huan Li
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Shi-Mei Yuan
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Min Yang
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - He Zha
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Xue-Ru Li
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Hui Sun
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Liang Duan
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Yue Gu
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Ai-Fang Li
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Ya-Guang Weng
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Jin-Yong Luo
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
| | - Tong-Chuan He
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.,Molecular Oncology Laboratory, Department of Orthopaedic Surgery and Rehabilitation Medicine, The University of Chicago Medical Center, Chicago, IL 60637, USA
| | - Yan Wang
- State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and The Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016, China
| | - Chong-Yan Li
- State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and The Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016, China
| | - Fa-Qi Li
- State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and The Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016, China
| | - Zhi-Biao Wang
- State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and The Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016, China
| | - Lan Zhou
- Key Laboratory of Clinical Diagnosis of Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
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Agosto-Arroyo E, Rosa M, Chau A, Khazai L. Concurrent BRAF and PTEN mutations in melanoma of unknown origin presenting as a breast mass. SAGE Open Med Case Rep 2017; 5:2050313X17711064. [PMID: 28607685 PMCID: PMC5456025 DOI: 10.1177/2050313x17711064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/21/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Metastases represent a small percentage of the malignancies affecting the breast, and only 5% of melanomas originate from non-cutaneous sites. Multiple genetic aberrations have been associated with the development of melanocytic lesions, including BRAF V600E mutation. Mutations in PTEN gene have also been related to the pathogenesis of multiple malignancies. PURPOSE/METHOD This is the case of a 28-year-old female who presented with a tender, palpable mass in the upper outer quadrant of the right breast. Ultrasound showed a 1-cm solid mass, initially diagnosed as invasive ductal carcinoma on biopsy. During pre-operative workup, a second mass was identified and biopsied. Immunohistochemical stains performed on the second mass biopsy demonstrated that the neoplastic cells were positive for cytokeratin AE1/3, pan-melanoma, tyrosinase, and SOX-10 and negative for CK7, CAM5.2, and GATA-3. Subsequent workup showed widespread metastatic disease involving the liver, lungs, bones, and brain. The brain metastasis tested positive for BRAF p.V600E and PTEN p.R130Efs*4 mutations. Thorough skin and eye examination did not reveal a primary melanoma. CONCLUSION Only few reports have been published of melanoma presenting as a breast mass. This is an interesting case due to the clinical presentation, diagnostic challenges, and genetic mutations profile.
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Affiliation(s)
| | - Marilin Rosa
- Department of Anatomic Pathology, Moffitt Cancer Center, Tampa, FL, USA
| | - Alec Chau
- Department of Diagnostic Imaging, Moffitt Cancer Center, Tampa, FL, USA
| | - Laila Khazai
- Department of Anatomic Pathology, Moffitt Cancer Center, Tampa, FL, USA
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Beale G, Haagensen EJ, Thomas HD, Wang LZ, Revill CH, Payne SL, Golding BT, Hardcastle IR, Newell DR, Griffin RJ, Cano C. Combined PI3K and CDK2 inhibition induces cell death and enhances in vivo antitumour activity in colorectal cancer. Br J Cancer 2016; 115:682-90. [PMID: 27529512 PMCID: PMC5023777 DOI: 10.1038/bjc.2016.238] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/31/2016] [Accepted: 07/14/2016] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The phosphatidylinositol-3-kinase/mammalian target of rapamycin (PI3K/mTOR) pathway is commonly deregulated in human cancer, hence many PI3K and mTOR inhibitors have been developed and have now reached clinical trials. Similarly, CDKs have been investigated as cancer drug targets. METHODS We have synthesised and characterised a series of 6-aminopyrimidines identified from a kinase screen that inhibit PI3K and/or mTOR and/or CDK2. Kinase inhibition, tumour cell growth, cell cycle distribution, cytotoxicity and signalling experiments were undertaken in HCT116 and HT29 colorectal cancer cell lines, and in vivo HT29 efficacy studies. RESULTS 2,6-Diaminopyrimidines with an O(4)-cyclohexylmethyl substituent and a C-5-nitroso or cyano group (1,2,5) induced cell cycle phase alterations and were growth inhibitory (GI50<20 μM). Compound 1, but not 2 or 5, potently inhibits CDK2 (IC50=0.1 nM) as well as PI3K, and was cytotoxic at growth inhibitory concentrations. Consistent with kinase inhibition data, compound 1 reduced phospho-Rb and phospho-rS6 at GI50 concentrations. Combination of NU6102 (CDK2 inhibitor) and pictilisib (GDC-0941; pan-PI3K inhibitor) resulted in synergistic growth inhibition, and enhanced cytotoxicity in HT29 cells in vitro and HT29 tumour growth inhibition in vivo. CONCLUSIONS These studies identified a novel series of mixed CDK2/PI3K inhibitors and demonstrate that dual targeting of CDK2 and PI3K can result in enhanced antitumour activity.
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Affiliation(s)
- Gary Beale
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Emma J Haagensen
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Huw D Thomas
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Lan-Zhen Wang
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Charlotte H Revill
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Bedson Building, Newcastle NE1 7RU, UK
| | - Sara L Payne
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Bedson Building, Newcastle NE1 7RU, UK
| | - Bernard T Golding
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Bedson Building, Newcastle NE1 7RU, UK
| | - Ian R Hardcastle
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Bedson Building, Newcastle NE1 7RU, UK
| | - David R Newell
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Paul O'Gorman Building, Medical School, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK
| | - Roger J Griffin
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Bedson Building, Newcastle NE1 7RU, UK
| | - Celine Cano
- Newcastle Cancer Centre, Northern Institute for Cancer Research, School of Chemistry, Newcastle University, Bedson Building, Newcastle NE1 7RU, UK
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12
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Laugier F, Finet-Benyair A, André J, Rachakonda PS, Kumar R, Bensussan A, Dumaz N. RICTOR involvement in the PI3K/AKT pathway regulation in melanocytes and melanoma. Oncotarget 2016; 6:28120-31. [PMID: 26356562 PMCID: PMC4695048 DOI: 10.18632/oncotarget.4866] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 08/17/2015] [Indexed: 01/16/2023] Open
Abstract
Several studies have highlighted the importance of the PI3K pathway in melanocytes and its frequent over-activation in melanoma. However, little is known about regulation of the PI3K pathway in melanocytic cells. We showed that normal human melanocytes are less sensitive to selective PI3K or mTOR inhibitors than to dual PI3K/mTOR inhibitors. The resistance to PI3K inhibitor was due to a rapid AKT reactivation limiting the inhibitor effect on proliferation. Reactivation of AKT was linked to a feedback mechanism involving the mTORC2 complex and in particular its scaffold protein RICTOR. RICTOR overexpression in melanocytes disrupted the negative feedback, activated the AKT pathway and stimulated clonogenicity highlighting the importance of this feedback to restrict melanocyte proliferation. We found that the RICTOR locus is frequently amplified and overexpressed in melanoma and that RICTOR over-expression in NRAS-transformed melanocytes stimulates their clonogenicity, demonstrating that RICTOR amplification can cooperate with NRAS mutation to stimulate melanoma proliferation. These results show that RICTOR plays a central role in PI3K pathway negative feedback in melanocytes and that its deregulation could be involved in melanoma development.
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Affiliation(s)
- Florence Laugier
- INSERM, U976, Centre de Recherche sur la Peau, Hôpital Saint-Louis, Paris, F-75010, France.,Université Paris Diderot, Sorbonne Paris Cité, UMRS976, Paris, F-75010, France
| | - Adeline Finet-Benyair
- INSERM, U976, Centre de Recherche sur la Peau, Hôpital Saint-Louis, Paris, F-75010, France.,Université Paris Diderot, Sorbonne Paris Cité, UMRS976, Paris, F-75010, France
| | - Jocelyne André
- INSERM, U976, Centre de Recherche sur la Peau, Hôpital Saint-Louis, Paris, F-75010, France.,Université Paris Diderot, Sorbonne Paris Cité, UMRS976, Paris, F-75010, France
| | | | - Rajiv Kumar
- Division of Molecular Genetic Epidemiology, German Cancer Research Center, 69120, Heidelberg, Germany
| | - Armand Bensussan
- INSERM, U976, Centre de Recherche sur la Peau, Hôpital Saint-Louis, Paris, F-75010, France.,Université Paris Diderot, Sorbonne Paris Cité, UMRS976, Paris, F-75010, France
| | - Nicolas Dumaz
- INSERM, U976, Centre de Recherche sur la Peau, Hôpital Saint-Louis, Paris, F-75010, France.,Université Paris Diderot, Sorbonne Paris Cité, UMRS976, Paris, F-75010, France
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13
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Ribero S, Longo C, Glass D, Nathan P, Bataille V. What Is New in Melanoma Genetics and Treatment? Dermatology 2016; 232:259-64. [PMID: 27173969 DOI: 10.1159/000445767] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 03/16/2016] [Indexed: 11/19/2022] Open
Abstract
New therapies for advanced melanoma have led to major advances, which, for the first time, showed improved survival for patients with this very challenging neoplasm. These new treatments are based on gene-targeted therapies or stimulation of immune responses. However, these treatments are not without challenges in terms of resistance and toxicity. Physicians should be aware of these side effects as prompt treatment may save lives. Melanoma genetics is also unravelling new genetic risk factors involving telomere genes as well as new gene pathways at the somatic level which may soon become therapeutic targets. It is also shedding new light onto the pathology of this tumour with links to neural diseases and longevity.
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Affiliation(s)
- Simone Ribero
- Twin Research and Genetic Epidemiology Unit, King's College London, London, UK
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14
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Josephs DH, Sarker D. Pharmacodynamic Biomarker Development for PI3K Pathway Therapeutics. TRANSLATIONAL ONCOGENOMICS 2016; 7:33-49. [PMID: 26917948 PMCID: PMC4762492 DOI: 10.4137/tog.s30529] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 11/08/2015] [Accepted: 11/10/2015] [Indexed: 12/11/2022]
Abstract
The phosphatidylinositol 3-kinase (PI3K) signaling pathway is integral to many essential cell processes, including cell growth, differentiation, proliferation, motility, and metabolism. Somatic mutations and genetic amplifications that result in activation of the pathway are frequently detected in cancer. This has led to the development of rationally designed therapeutics targeting key members of the pathway. Critical to the successful development of these drugs are pharmacodynamic biomarkers that aim to define the degree of target and pathway inhibition. In this review, we discuss the pharmacodynamic biomarkers that have been utilized in early-phase clinical trials of PI3K pathway inhibitors. We focus on the challenges related to development and interpretation of these assays, their optimal integration with pharmacokinetic and predictive biomarkers, and future strategies to ensure successful development of PI3K pathway inhibitors within a personalized medicine paradigm for cancer.
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Affiliation(s)
- Debra H Josephs
- Department of Research Oncology, Division of Cancer Studies, King's College London, Guy's Hospital, London, UK
| | - Debashis Sarker
- Department of Research Oncology, Division of Cancer Studies, King's College London, Guy's Hospital, London, UK
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15
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Abstract
This article presents an overview of the PI3K/Akt/mTOR signaling pathway. As a central regulator of cell growth, protein translation, survival, and metabolism, activation of this signaling pathway contributes to the pathogenesis of many tumor types. Biochemical and genetic aberrations of this pathway observed in various cancer types are explored. Last, pathway inhibitors both in development and already approved by the Food and Drug Administration are discussed.
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16
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Brana I, Siu LL. Clinical development of phosphatidylinositol 3-kinase inhibitors for cancer treatment. BMC Med 2012; 10:161. [PMID: 23232172 PMCID: PMC3552942 DOI: 10.1186/1741-7015-10-161] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 12/11/2012] [Indexed: 01/21/2023] Open
Abstract
The phosphatidylinositol 3-kinase (PI3K) pathway is commonly deregulated in cancer. In recent years, the results of the first phase I clinical trials with PI3K inhibitors have become available. In comparison to other targeted agents such v-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitors in melanoma or crizotinib in anaplastic lymphoma receptor tyrosine kinase (ALK) translocated tumors, the number of objective responses to PI3K inhibitors is less dramatic. In this review we propose possible strategies to optimize the clinical development of PI3K inhibitors: by exploring the potential role of PI3K isoform-specific inhibitors in improving the therapeutic index, molecular characterization as a basis for patient selection, and the relevance of performing serial tumor biopsies to understand the associated mechanisms of drug resistance. The main focus of this review will be on PI3K isoform-specific inhibitors by describing the functions of different PI3K isoforms, the preclinical activity of selective PI3K isoform-specific inhibitors and the early clinical data of these compounds.
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Affiliation(s)
- Irene Brana
- Drug Development Program, Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University of Toronto, 610 University Avenue, Toronto, Ontario, M5G 2M9, Canada
| | - Lillian L Siu
- Drug Development Program, Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University of Toronto, 610 University Avenue, Toronto, Ontario, M5G 2M9, Canada
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17
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A New Insight into Structural and Functional Impact of Single-Nucleotide Polymorphisms in PTEN Gene. Cell Biochem Biophys 2012; 66:249-63. [DOI: 10.1007/s12013-012-9472-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Aguissa-Touré AH, Li G. Genetic alterations of PTEN in human melanoma. Cell Mol Life Sci 2012; 69:1475-91. [PMID: 22076652 PMCID: PMC11114653 DOI: 10.1007/s00018-011-0878-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 10/13/2011] [Accepted: 10/24/2011] [Indexed: 12/31/2022]
Abstract
The PTEN gene is one of the most frequently inactivated tumor suppressor genes in sporadic cancers. Inactivating mutations and deletions of the PTEN gene are found in many types of cancers, including melanoma. However, the exact frequency of PTEN alteration in melanoma is unknown. In this study, we comprehensively reviewed 16 studies on PTEN genetic changes in melanoma cell lines and tumor biopsies. To date, 76 PTEN alterations have been reported in melanoma cell lines and 38 PTEN alterations in melanoma biopsies. The rate of PTEN alterations in melanoma cell lines, primary melanoma, and metastatic melanoma is 27.6, 7.3, and 15.2%, respectively. Three mutations were found in both melanoma cell lines and biopsies. These mutations are scattered throughout the gene, with the exception of exon 9. A mutational hot spot is found in exon 5, which encodes the phosphatase activity domain. Evidence is also presented to suggest that numerous homozygous deletions and missense variants exist in the PTEN transcript. Studying PTEN functions and implications of its mutations and other genes could provide insights into the precise nature of PTEN function in melanoma and additional targets for new therapeutic approaches.
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Affiliation(s)
- Almass-Houd Aguissa-Touré
- Department of Dermatology and Skin Science, Vancouver Coastal Health Research Institute, Jack Bell Research Centre, University of British Columbia, Vancouver, BC, Canada
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19
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Pópulo H, Lopes JM, Soares P. The mTOR signalling pathway in human cancer. Int J Mol Sci 2012; 13:1886-1918. [PMID: 22408430 PMCID: PMC3291999 DOI: 10.3390/ijms13021886] [Citation(s) in RCA: 575] [Impact Index Per Article: 47.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/28/2012] [Accepted: 01/30/2012] [Indexed: 01/20/2023] Open
Abstract
The conserved serine/threonine kinase mTOR (the mammalian target of rapamycin), a downstream effector of the PI3K/AKT pathway, forms two distinct multiprotein complexes: mTORC1 and mTORC2. mTORC1 is sensitive to rapamycin, activates S6K1 and 4EBP1, which are involved in mRNA translation. It is activated by diverse stimuli, such as growth factors, nutrients, energy and stress signals, and essential signalling pathways, such as PI3K, MAPK and AMPK, in order to control cell growth, proliferation and survival. mTORC2 is considered resistant to rapamycin and is generally insensitive to nutrients and energy signals. It activates PKC-α and AKT and regulates the actin cytoskeleton. Deregulation of multiple elements of the mTOR pathway (PI3K amplification/mutation, PTEN loss of function, AKT overexpression, and S6K1, 4EBP1 and eIF4E overexpression) has been reported in many types of cancers, particularly in melanoma, where alterations in major components of the mTOR pathway were reported to have significant effects on tumour progression. Therefore, mTOR is an appealing therapeutic target and mTOR inhibitors, including the rapamycin analogues deforolimus, everolimus and temsirolimus, are submitted to clinical trials for treating multiple cancers, alone or in combination with inhibitors of other pathways. Importantly, temsirolimus and everolimus were recently approved by the FDA for the treatment of renal cell carcinoma, PNET and giant cell astrocytoma. Small molecules that inhibit mTOR kinase activity and dual PI3K-mTOR inhibitors are also being developed. In this review, we aim to survey relevant research, the molecular mechanisms of signalling, including upstream activation and downstream effectors, and the role of mTOR in cancer, mainly in melanoma.
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Affiliation(s)
- Helena Pópulo
- Institute of Molecular Pathology and Immunology of University of Porto (IPATIMUP), University of Porto, 4200-465, Porto, Portugal; E-Mails: (H.P.); (J.M.L.)
- Medical Faculty, University of Porto, 4200-465 Porto, Portugal
| | - José Manuel Lopes
- Institute of Molecular Pathology and Immunology of University of Porto (IPATIMUP), University of Porto, 4200-465, Porto, Portugal; E-Mails: (H.P.); (J.M.L.)
- Medical Faculty, University of Porto, 4200-465 Porto, Portugal
- Department of Pathology, Hospital São João, 4200-465 Porto, Portugal
| | - Paula Soares
- Institute of Molecular Pathology and Immunology of University of Porto (IPATIMUP), University of Porto, 4200-465, Porto, Portugal; E-Mails: (H.P.); (J.M.L.)
- Medical Faculty, University of Porto, 4200-465 Porto, Portugal
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20
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Abstract
It recently has become clear that multiple molecular subtypes of melanoma likely exist that may be associated with clinical response to defined therapeutic modalities. Gene expression profiling has revealed a signature that is associated with clinical benefit to melanoma vaccines, with preliminary work suggesting a correlation with response to other immunotherapy agents as well. Activating mutations in B-Raf and c-kit are associated with clinical response to the specific kinase inhibitors PLX4032 and imatinib, respectively. Several other signal transduction pathways have been found to be constitutively active or mutated in other subsets of melanoma tumors that are potentially targetable with new agents. Together, these emerging data suggest the evolution of a new paradigm in melanoma therapy in which molecular analysis of the tumor will be used to assign the most appropriate therapeutic modality for each individual patient, to maximize therapeutic success.
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Affiliation(s)
- Thomas F Gajewski
- Department of Pathology, The University of Chicago, Chicago, IL 60637, USA.
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21
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Hollander MC, Blumenthal GM, Dennis PA. PTEN loss in the continuum of common cancers, rare syndromes and mouse models. Nat Rev Cancer 2011; 11:289-301. [PMID: 21430697 PMCID: PMC6946181 DOI: 10.1038/nrc3037] [Citation(s) in RCA: 619] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PTEN is among the most frequently inactivated tumour suppressor genes in sporadic cancer. PTEN has dual protein and lipid phosphatase activity, and its tumour suppressor activity is dependent on its lipid phosphatase activity, which negatively regulates the PI3K-AKT-mTOR pathway. Germline mutations in PTEN have been described in a variety of rare syndromes that are collectively known as the PTEN hamartoma tumour syndromes (PHTS). Cowden syndrome is the best-described syndrome within PHTS, with approximately 80% of patients having germline PTEN mutations. Patients with Cowden syndrome have an increased incidence of cancers of the breast, thyroid and endometrium, which correspond to sporadic tumour types that commonly exhibit somatic PTEN inactivation. Pten deletion in mice leads to Cowden syndrome-like phenotypes, and tissue-specific Pten deletion has provided clues to the role of PTEN mutation and loss in specific tumour types. Studying PTEN in the continuum of rare syndromes, common cancers and mouse models provides insight into the role of PTEN in tumorigenesis and will inform targeted drug development.
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Affiliation(s)
- M Christine Hollander
- Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
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22
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Vidwans SJ, Flaherty KT, Fisher DE, Tenenbaum JM, Travers MD, Shrager J. A melanoma molecular disease model. PLoS One 2011; 6:e18257. [PMID: 21479172 PMCID: PMC3068163 DOI: 10.1371/journal.pone.0018257] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 03/01/2011] [Indexed: 12/18/2022] Open
Abstract
While advanced melanoma remains one of the most challenging cancers, recent developments in our understanding of the molecular drivers of this disease have uncovered exciting opportunities to guide personalized therapeutic decisions. Genetic analyses of melanoma have uncovered several key molecular pathways that are involved in disease onset and progression, as well as prognosis. These advances now make it possible to create a “Molecular Disease Model” (MDM) for melanoma that classifies individual tumors into molecular subtypes (in contrast to traditional histological subtypes), with proposed treatment guidelines for each subtype including specific assays, drugs, and clinical trials. This paper describes such a Melanoma Molecular Disease Model reflecting the latest scientific, clinical, and technological advances.
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23
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Madhunapantula SV, Robertson GP. Therapeutic Implications of Targeting AKT Signaling in Melanoma. Enzyme Res 2011; 2011:327923. [PMID: 21461351 PMCID: PMC3065045 DOI: 10.4061/2011/327923] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 01/01/2011] [Indexed: 11/29/2022] Open
Abstract
Identification of key enzymes regulating melanoma progression and drug resistance has the potential to lead to the development of novel, more effective targeted agents for inhibiting this deadly form of skin cancer. The Akt3, also known as protein kinase B gamma, pathway enzymes regulate diverse cellular processes including proliferation, survival, and invasion thereby promoting the development of melanoma. Accumulating preclinical evidence demonstrates that therapeutic agents targeting these kinases alone or in combination with other pathway members could be effective for the long-term treatment of advanced-stage disease. However, currently, no selective and effective therapeutic agent targeting these kinases has been identified for clinical use. This paper provides an overview of the key enzymes of the PI3K pathway with emphasis placed on Akt3 and the negative regulator of this kinase called PTEN (phosphatase and tensin homolog deleted on chromosome 10). Mechanisms regulating these enzymes, their substrates and therapeutic implications of targeting these proteins to treat melanoma are also discussed. Finally, key issues that remain to be answered and future directions for interested researchers pertaining to this signaling cascade are highlighted.
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Affiliation(s)
- Subbarao V Madhunapantula
- Department of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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24
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Metz HE, Houghton AM. Insulin receptor substrate regulation of phosphoinositide 3-kinase. Clin Cancer Res 2010; 17:206-11. [PMID: 20966354 DOI: 10.1158/1078-0432.ccr-10-0434] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Insulin receptor substrates (IRS) serve as downstream messengers from activated cell surface receptors to numerous signaling pathway cascades. One of these pathways, phosphoinositide 3-kinase (PI3K), frequently displays aberrant function in the setting of cancer. IRS proteins are capable of both regulating and activating PI3K, depending on the cell of origin. As such, both prohost and protumor functions have been described for IRS proteins in human cancers. IRS proteins may eventually serve as biomarkers of PI3K activity, and serve a much-needed role as a guide to using targeted pathway therapy. Additionally, IRS-1 could be indirectly targeted in lung cancer, by inhibiting neutrophil elastase, which functions to degrade IRS-1 in lung tumor cells, thereby generating PI3K hyperactivity.
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Affiliation(s)
- Heather E Metz
- Department of Medicine, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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25
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King JA, Tan F, Mbeunkui F, Chambers Z, Cantrell S, Chen H, Alvarez D, Shevde LA, Ofori-Acquah SF. Mechanisms of transcriptional regulation and prognostic significance of activated leukocyte cell adhesion molecule in cancer. Mol Cancer 2010; 9:266. [PMID: 20929568 PMCID: PMC2958981 DOI: 10.1186/1476-4598-9-266] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 10/07/2010] [Indexed: 01/02/2023] Open
Abstract
Background Activated leukocyte cell adhesion molecule (ALCAM) is implicated in the prognosis of multiple cancers with low level expression associated with metastasis and early death in breast cancer. Despite this significance, mechanisms that regulate ALCAM gene expression and ALCAM's role in adhesion of pre-metastatic circulating tumor cells have not been defined. We studied ALCAM expression in 20 tumor cell lines by real-time PCR, western blot and immunochemistry. Epigenetic alterations of the ALCAM promoter were assessed using methylation-specific PCR and bisulfite sequencing. ALCAM's role in adhesion of tumor cells to the vascular wall was studied in isolated perfused lungs. Results A common site for transcription initiation of the ALCAM gene was identified and the ALCAM promoter sequenced. The promoter contains multiple cis-active elements including a functional p65 NF-κB motif, and it harbors an extensive array of CpG residues highly methylated exclusively in ALCAM-negative tumor cells. These CpG residues were modestly demethylated after 5-aza-2-deoxycytidine treatment. Restoration of high-level ALCAM expression using an ALCAM cDNA increased clustering of MDA-MB-435 tumor cells perfused through the pulmonary vasculature of ventilated rat lungs. Anti-ALCAM antibodies reduced the number of intravascular tumor cell clusters. Conclusion Our data suggests that loss of ALCAM expression, due in part to DNA methylation of extensive segments of the promoter, significantly impairs the ability of circulating tumor cells to adhere to each other, and may therefore promote metastasis. These findings offer insight into the mechanisms for down-regulation of ALCAM gene expression in tumor cells, and for the positive prognostic value of high-level ALCAM in breast cancer.
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Affiliation(s)
- Judy A King
- Center for Lung Biology, University of South Alabama, Mobile, AL 36688, USA
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26
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Nardella C, Carracedo A, Salmena L, Pandolfi PP. Faithfull modeling of PTEN loss driven diseases in the mouse. Curr Top Microbiol Immunol 2010; 347:135-68. [PMID: 20549475 DOI: 10.1007/82_2010_62] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A decade of work has indisputably defined PTEN as a pivotal player in human health and disease. Above all, PTEN has been identified as one of the most commonly lost or mutated tumor suppressor genes in human cancers. For this reason, the generation of a multitude of mouse models has been an invaluable strategy to dissect the function and consequences-of-loss of this essential, evolutionary conserved lipid phosphatase in tumor initiation and progression.In this chapter, we will summarize the mouse models that have allowed us to faithfully recapitulate features of human cancers and to highlight the network of connections between the PTEN signaling cascade and other oncogenic or tumor suppressive pathways.Notably, PTEN represents one of the most extensively modeled genes involved in human cancer and exemplifies the strength of genetic mouse modeling as an approach to gain information aimed to improve our understanding of and ability to alleviate human disease.
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Affiliation(s)
- Caterina Nardella
- Department of Medicine and Pathology, Harvard Medical School, Boston, MA 02215, USA
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27
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Markman B, Atzori F, Pérez-García J, Tabernero J, Baselga J. Status of PI3K inhibition and biomarker development in cancer therapeutics. Ann Oncol 2009; 21:683-691. [PMID: 19713247 DOI: 10.1093/annonc/mdp347] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The phosphatidylinositol 3-kinase (PI3K) signalling pathway is integral to diverse cellular functions, including cellular proliferation, differentiation and survival. The 'phosphate and tensin homologue deleted from chromosome 10' (PTEN) tumor suppressor gene plays a critical role as a negative regulator of this pathway. An array of genetic mutations and amplifications has been described affecting key components of this pathway, with implications not only for tumorigenesis but also for resistance to some classic cytotoxics and targeted agents. Emerging preclinical research has significantly advanced our understanding of the PI3K pathway and its complex machinations and interactions. This knowledge has enabled the evolution of rationally designed drugs targeting elements of this pathway. It is important that the development of suitable biomarkers continues in parallel to optimize use of these agents. A new generation of PI3K inhibitors is now entering early clinical trials, with much anticipation that they will add to the growing armamentarium of targeted cancer therapeutics.
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Affiliation(s)
- B Markman
- Medical Oncology Service, Vall d'Hebron University Hospital and Vall d'Hebron Institute of Oncology, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - F Atzori
- Medical Oncology Service, Vall d'Hebron University Hospital and Vall d'Hebron Institute of Oncology, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - J Pérez-García
- Medical Oncology Service, Vall d'Hebron University Hospital and Vall d'Hebron Institute of Oncology, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - J Tabernero
- Medical Oncology Service, Vall d'Hebron University Hospital and Vall d'Hebron Institute of Oncology, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - J Baselga
- Medical Oncology Service, Vall d'Hebron University Hospital and Vall d'Hebron Institute of Oncology, Universitat Autonoma de Barcelona, Barcelona, Spain.
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28
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Abstract
Melanocytes undergo extensive genetic changes during transformation into aggressive melanomas. These changes deregulate genes whose aberrant activity promotes the development of this disease. The phosphoinositide-3-kinase (PI3K) and mitogen-activated protein (MAP) kinase pathways are two key signaling cascades that have been found to play prominent roles in melanoma development. These pathways relay extra-cellular signals via an ordered series of consecutive phosphorylation events from cell surface throughout the cytoplasm and nucleus regulating diverse cellular processes including proliferation, survival, invasion and angiogenesis. It is generally accepted that therapeutic agents would need to target these two pathways to be an effective therapy for the long-term treatment of advanced-stage melanoma patients. This review provides an overview of the PI3 kinase pathway focusing specifically on two members of the pathway, called PTEN and Akt3, which play important roles in melanoma development. Mechanisms leading to deregulation of these two proteins and therapeutic implications of targeting this signaling cascade to treat melanoma are detailed in this review.
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Affiliation(s)
| | - Gavin P. Robertson
- Department of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Pathology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
- Department of Dermatology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
- The Foreman Foundation for Melanoma Research, The Pennsylvania State University College of Medicine, Hershey, PA 17033
- Penn State Melanoma Therapeutics Program, The Pennsylvania State University College of Medicine, Hershey, PA 17033
- Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA 17033
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29
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Madhunapantula SV, Robertson GP. The PTEN-AKT3 signaling cascade as a therapeutic target in melanoma. Pigment Cell Melanoma Res 2009. [DOI: 10.1111/j.1755-1471.2009.00585.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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30
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Evidence of ultraviolet type mutations in xeroderma pigmentosum melanomas. Proc Natl Acad Sci U S A 2009; 106:6279-84. [PMID: 19329485 DOI: 10.1073/pnas.0812401106] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
To look for a direct role of ultraviolet radiation (UV) exposure in cutaneous melanoma induction, we studied xeroderma pigmentosum (XP) patients who have defective DNA repair resulting in a 1000-fold increase in melanoma risk. These XP melanomas have the same anatomic distribution as melanomas in the general population. We analyzed laser capture microdissection samples of skin melanomas from XP patients studied at the National Institutes of Health. The tumor suppressor gene PTEN was sequenced and analyzed for UV-induced mutations. Samples from 59 melanomas (47 melanomas in situ and 12 invasive melanomas) from 8 XP patients showed mutations in the PTEN tumor suppressor gene in 56% of the melanomas. Further, 91% of the melanomas with mutations had 1 to 4 UV type base substitution mutations (occurring at adjacent pyrimidines) (P < 0.0001 compared to random mutations). We found a high frequency of amino-acid-altering mutations in the melanomas and demonstrated that these mutations impaired PTEN function; UV damage plays a direct role in induction of mutations and in inactivation of the PTEN gene in XP melanomas including in situ, the earliest stage of melanoma. This gene is known to be a key regulator of carcinogenesis and therefore these data provide solid mechanistic support for UV protection for prevention of melanoma.
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31
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Werzowa J, Cejka D, Fuereder T, Dekrout B, Thallinger C, Pehamberger H, Wacheck V, Pratscher B. Suppression of mTOR complex 2-dependent AKT phosphorylation in melanoma cells by combined treatment with rapamycin and LY294002. Br J Dermatol 2008; 160:955-64. [PMID: 19120326 DOI: 10.1111/j.1365-2133.2008.08991.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND Inhibition of mTOR complex 1 (mTORC1) with rapamycin leads to phosphorylation of AKT in some cancer cells, with unknown biological consequences. The role of this phosphorylation in melanoma is unknown, although preliminary clinical data indicate poor activity of rapalogues in melanoma. OBJECTIVES We aimed at elucidating the role of AKT phosphorylation after mTORC1 inhibition in melanoma cells. METHODS Western blotting, apoptosis assays, cell cycle analyses and viability assays were performed to analyse the effects of rapamycin and LY294002 treatment on melanoma cells. For suppression of mTOR complex 2 (mTORC2) an siRNA directed against rictor was used. RESULTS Rapamycin showed limited effects on cell viability but resulted in strong and lasting AKT phosphorylation in melanoma cells. Combined PI3K/mTOR inhibition with LY294002 had pronounced effects on viability but also led to increased AKT phosphorylation after prolonged treatment. In contrast, combination of rapamycin plus LY294002 suppressed AKT phosphorylation. Suppression of AKT phosphorylation did not correlate with decreases in cell viability. Inhibition of mTORC2 led to reduced levels of phosphorylated AKT. CONCLUSIONS mTORC1 inhibition with rapamycin and with LY294002 can lead to AKT phosphorylation in melanoma cells via mTORC2. Combination of rapamycin and LY294002 suppresses AKT phosphorylation but without significant effect on treatment efficacy.
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Affiliation(s)
- J Werzowa
- Department of Dermatology, Division of General Dermatology, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
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32
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Palomero T, Dominguez M, Ferrando AA. The role of the PTEN/AKT Pathway in NOTCH1-induced leukemia. Cell Cycle 2008; 7:965-70. [PMID: 18414037 DOI: 10.4161/cc.7.8.5753] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Activating mutations in NOTCH1 are the most prominent genetic abnormality in T-cell acute Lymphoblastic Leukemia (T-ALL) and inhibition of NOTCH1 signaling with gamma-secretase inhibitors (GSIs) has been proposed as targeted therapy in this disease. However, most T-ALL cell lines with mutations in NOTCH1 fail to respond to GSI therapy. Using gene expression profiling and mutation analysis we showed that mutational loss of PTEN is a common event in T-ALL and is associated with resistance to NOTCH inhibition. Furthermore, our studies revealed that NOTCH1 induces upregulation of the PI3K-AKT pathway via HES1, which negatively controls the expression of PTEN. This regulatory circuitry is evolutionary conserved from Drosophila to humans as demonstrated by the interaction of overexpression of Delta and Akt in a model of Notch-induced transformation in the fly eye. Loss of PTEN and constitutive activation of AKT in T-ALL induce increased glucose metabolism and bypass the requirement of NOTCH1 signaling to sustain cell growth. Importantly, PTEN-null/GSI resistant T-ALL cells switch their oncogene addiction from NOTCH1 to AKT and are highly sensitive to AKT inhibitors. These results should facilitate the development of molecular therapies targeting NOTCH1 and AKT for the treatment of T-ALL.
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Affiliation(s)
- Teresa Palomero
- Institute for Cancer Genetics-Columbia University, New York, New York, USA
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Abstract
Understanding regulatory pathways involved in melanoma development and progression has advanced significantly in recent years. It is now appreciated that melanoma is the result of complex changes in multiple signaling pathways that affect growth control, metabolism, motility and the ability to escape cell death programs. Here we review the major signaling pathways currently known to be deregulated in melanoma with an implication to its development and progression. Among these pathways are Ras, B-Raf, MEK, PTEN, phosphatidylinositol-3 kinase (PI3Ks) and Akt which are constitutively activated in a significant number of melanoma tumors, in most cases due to genomic change. Other pathways discussed in this review include the [Janus kinase/signal transducer and activator of transcription (JAK/STAT), transforming growth factor-beta pathways which are also activated in melanoma, although the underlying mechanism is not yet clear. As a paradigm for remodeled signaling pathways, melanoma also offers a unique opportunity for targeted drug development.
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Affiliation(s)
- Pablo Lopez-Bergami
- Signal Transduction Program, Burnham Institute for Medical Research, La Jolla, CA, USA
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Mirmohammadsadegh A, Marini A, Nambiar S, Hassan M, Tannapfel A, Ruzicka T, Hengge UR. Epigenetic silencing of the PTEN gene in melanoma. Cancer Res 2006; 66:6546-52. [PMID: 16818626 DOI: 10.1158/0008-5472.can-06-0384] [Citation(s) in RCA: 195] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phosphatase and tensin homologue deleted from chromosome 10 (PTEN) seems to be an important tumor suppressor gene in melanoma. Because the PTEN gene is only infrequently deleted or mutated, and because the PTEN protein is low to absent in a significant number of melanomas, we investigated alternative methods of epigenetic silencing. We did quantitative positional methylation analysis (pyrosequencing) on 37 sera from melanoma patients and on 21 pairs of corresponding sera and melanoma specimens in addition to Taqman reverse transcription-PCR. We report significant positional PTEN promoter methylation in 62% of circulating DNA isolated from sera of patients with metastatic melanoma. The percentage of methylation of a selected CpG island in blood showed a correlation with methylation levels in the corresponding melanoma tissue. Moreover, high percentages of PTEN methylation were associated with low PTEN transcription levels. Using the demethylation agent 5-aza-2'-deoxycytidine, reduced methylation and a corresponding increase in PTEN protein were observed in BLM melanoma cells, leading to reduced AKT activity in an in vitro kinase assay. In summary, epigenetic PTEN silencing seems to be a relevant mechanism of inactivating this tumor suppressor gene in melanoma that may promote melanoma development by derepression of the AKT pathway.
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Engelman JA, Luo J, Cantley LC. The evolution of phosphatidylinositol 3-kinases as regulators of growth and metabolism. Nat Rev Genet 2006; 7:606-19. [PMID: 16847462 DOI: 10.1038/nrg1879] [Citation(s) in RCA: 2453] [Impact Index Per Article: 136.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Phosphatidylinositol 3-kinases (PI3Ks) evolved from a single enzyme that regulates vesicle trafficking in unicellular eukaryotes into a family of enzymes that regulate cellular metabolism and growth in multicellular organisms. In this review, we examine how the PI3K pathway has evolved to control these fundamental processes, and how this pathway is in turn regulated by intricate feedback and crosstalk mechanisms. In light of the recent advances in our understanding of the function of PI3Ks in the pathogenesis of diabetes and cancer, we discuss the exciting therapeutic opportunities for targeting this pathway to treat these diseases.
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Affiliation(s)
- Jeffrey A Engelman
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
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36
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Abstract
Metastatic melanoma is an aggressive skin cancer that is notoriously resistant to current cancer therapies. In human melanoma, nuclear factor-kappa B (NF-kappaB) is upregulated, leading to the deregulation of gene transcription. In this review, we discuss (i) the relationship between gene alteration in melanoma and upregulation of NF-kappaB, (ii) mechanisms by which activated NF-kappaB switch from pro-apoptotic to anti-apoptotic functions in melanoma and (iii) autocrine mechanisms that promote constitutive activation of NF-kappaB in metastatic melanoma.
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Affiliation(s)
- Yukiko Ueda
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Ann Richmond
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Veterans Affairs, Nashville, TN, USA
- Address correspondence to Ann Richmond, e-mail:
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37
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Haluska FG, Tsao H, Wu H, Haluska FS, Lazar A, Goel V. Genetic alterations in signaling pathways in melanoma. Clin Cancer Res 2006; 12:2301s-2307s. [PMID: 16609049 DOI: 10.1158/1078-0432.ccr-05-2518] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Alterations in the RAS signaling cascade are almost uniformly present in melanoma. RAS itself is only infrequently mutated in melanoma although downstream of RAS lie BRAF on the mitogen-activated protein kinase pathway and PTEN on the protein kinase B/Akt pathway. These genes are often altered in melanomas; indeed, the most frequent target of mutation in melanomas is BRAF, which is mutated in approximately 60% to 70% of superficial spreading melanomas. These mutations occur in a background that is not normal, with the CDKN2A locus also typically being mutated. We review herein the data that suggest that the distribution of the signaling mutations is important. In general, melanomas carry a mutated NRAS, a mutated BRAF, or concurrent BRAF and PTEN mutations. These data support the hypothesis that the biochemical functions of RAS are portioned by mutations in the pathways lying downstream. Moreover, these mutations have no apparent relationship to the patterns of alteration of CDKN2A and its downstream effectors. Thus, the data also suggest that successful exploitation of mutations in melanoma will be dependent on understanding not only mutations and their frequency but their genetic context as well.
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Affiliation(s)
- Frank G Haluska
- Division of Hematology/Oncology, Massashusetts General Hospital, Boston, Massachusetts, USA.
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38
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Abstract
Identification of specific genes or signaling pathways involved in development of melanoma could lead to new therapies that target and correct these defects. Recent studies have revealed deregulation of the Akt signaling pathway occurring in 43-67% of melanomas. Akt kinase family members, Akt1/PKBalpha, Akt2/PKBbeta and Akt3/PKBgamma, share extensive structural similarity and perform common as well as unique functions within cells. The Akt signaling cascade initiates at the cell surface when growth factors or other extracellular stimuli activate phosphoinositide 3-kinase (PI3K). Activated PI3K generates a lipid second messenger, phosphatidylinositol-3,4,5-trisphosphate (PIP3), causing translocation of Akt to the plasma membrane where it becomes phosphorylated and activated. The balance of cellular PIP3 is regulated primarily by a phosphatase called PTEN that reduces PIP3 levels thereby lowering Akt activity. In melanomas, decreased PTEN activity elevates PIP3 levels resulting in Akt activation. Active Akt then phosphorylates downstream cellular proteins that promote melanoma cell proliferation and survival. Recently, Akt3 was discovered to be the predominant isoform activated in sporadic melanomas. Levels of activity increased during melanoma progression with metastatic melanomas having the highest activity. Although mechanisms of Akt3 activation remain to be fully characterized, overexpression of Akt3 and decreased PTEN activity play important roles in this process. Targeted reduction of Akt3 activity decreased survival of melanoma tumor cells leading to inhibition of tumor development, which may be therapeutically effective for shrinking tumors in melanoma patients. This review surveys recent developments in Akt deregulation in melanoma and its potential as a selective therapeutic target in patients in the advanced stages of this disease.
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Affiliation(s)
- Gavin P Robertson
- Department of Pharmacology, The Pennsylvania State University College of Medicine, 500 University Dr., Hershey, Pennsylvania, 17033, USA.
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Abstract
Nuclear Factor-kappa B (NF-kappa B) is an inducible transcription factor that regulates the expression of many genes involved in the immune response. Recently, NF-kappa B activity has been shown to be upregulated in many cancers, including melanoma. Data indicate that the enhanced activation of NF-kappa B may be due to deregulations in upstream signaling pathways such as Ras/Raf, PI3K/Akt, and NIK. Multiple studies have shown that NF-kappa B is involved in the regulation of apoptosis, angiogenesis, and tumor cell invasion, all of which indicate the important role of NF-kappa B in tumorigenesis. Thus, understanding the molecular mechanism of melanoma progression will aid in designing new therapeutic approaches for melanoma. In this review, the association between NF-kappa B and melanoma tumorigenesis are discussed. Additionally, the potential of emerging selective NF-kappa B inhibitors for the treatment of melanoma is reviewed.
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Celebi JT, Ward KM, Wanner M, Polsky D, Kopf AW. Evaluation of germline CDKN2A, ARF, CDK4, PTEN, and BRAF alterations in atypical mole syndrome. Clin Exp Dermatol 2005; 30:68-70. [PMID: 15663508 DOI: 10.1111/j.1365-2230.2004.01656.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Atypical mole syndrome is a sporadic or an inherited condition with an increased risk of melanoma. Germline mutations in the CDKN2A, ARF, CDK4 and somatic mutations in the PTEN and BRAF genes have been associated with melanoma. In this study, we evaluated genes associated with familial and sporadic melanoma for mutations in 28 probands with the atypical mole syndrome. No sequence alterations in the coding regions or in the splice junctions of CDKN2A, ARF, CDK4, PTEN or BRAF were identified. These data suggest that genes evaluated in this study are unlikely to be candidate genes for atypical mole syndrome and support the notion that unknown susceptibility gene/s for this disease exist.
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Affiliation(s)
- J T Celebi
- Department of Dermatology, Columbia University, New York, USA.
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Lim MA, Yang L, Zheng Y, Wu H, Dong LQ, Liu F. Roles of PDK-1 and PKN in regulating cell migration and cortical actin formation of PTEN-knockout cells. Oncogene 2005; 23:9348-58. [PMID: 15531926 DOI: 10.1038/sj.onc.1208147] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mutations in the tumor suppressor protein PTEN (phosphatase and tensin homologue deleted on chromosome 10) enhance cell migration, yet the underlying molecular mechanisms remain largely uncharacterized. Loss of PTEN in mouse embryonic fibroblasts (MEFs) correlates with striking cortical actin accumulation. However, how loss of PTEN leads to cortical actin formation and whether the presence of cortical actin contributes to the increased cell migration are unclear. Here we show that overexpression of dominant-negative forms of (DN) PTEN, RhoA or its kinase-dead (KD) effector, PKN, inhibited cortical actin formation, indicating that cortical actin of Pten(-/-) MEFs is mediated by the PTEN/Rho/PKN pathway. However, neither DN RhoA nor KD PKN inhibited the enhanced migration of Pten(-/-) cells, in contrast to the inhibitory effect of DN Rac. In agreement with the previous observation that DN Akt inhibits migration of Pten(-/-) cells, we demonstrate here that overexpression of KD PDK-1, the Akt kinase, reduces Pten(-/-) cell migration. Furthermore, overexpression of DN forms of Akt, Rac, or PDK-1, all of which inhibit migration of Pten(-/-) cells, had no effect on cortical actin accumulation. Our findings suggest that PDK-1/Akt signaling pathway plays a major role in regulating cell migration induced by PTEN deficiency.
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Affiliation(s)
- Mei Ann Lim
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Kang S, Bader AG, Vogt PK. Phosphatidylinositol 3-kinase mutations identified in human cancer are oncogenic. Proc Natl Acad Sci U S A 2005; 102:802-7. [PMID: 15647370 PMCID: PMC545580 DOI: 10.1073/pnas.0408864102] [Citation(s) in RCA: 689] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Mutations in genes that encode components of the phosphatidyl-inositol 3-kinase (PI3-kinase) signaling pathway are common in human cancer. The recent discovery of nonrandom somatic mutations in the PIK3CA gene of many human tumors suggests an oncogenic role for the mutated enzyme. We have determined the growth-regulatory and signaling properties of the three most frequently observed PI3-kinase mutations: E542K, E545K, and H1047R. Expressed in chicken embryo fibroblasts, all three mutants induce oncogenic transformation with high efficiency. This transforming ability is correlated with elevated catalytic activity in in vitro kinase assays. The mutant-transformed cells show constitutive phosphorylation of Akt, of p70 S6 kinase, and of the 4E-binding protein 1. Phosphorylation of S6 kinase and of 4E-binding protein 1 is regulated by the target of rapamycin (TOR) kinase and affects rates of protein synthesis. The inhibitor of TOR, rapamycin, strongly interferes with cellular transformation induced by the PI3-kinase mutants, suggesting that the TOR and its downstream targets are essential components of the transformation process. The oncogenic transforming activity makes the mutated PI3-kinase proteins promising targets for small molecule inhibitors that could be developed into effective and highly specific anticancer drugs.
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Affiliation(s)
- Sohye Kang
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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Martinez SR, Hoon DSB. Molecular markers in malignant cutaneous melanoma: Gift horse or one-trick pony? J Cell Biochem 2005; 96:473-83. [PMID: 16088931 DOI: 10.1002/jcb.20556] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The management of malignant cutaneous melanoma is problematic. Current clinical prognostic factors do not adequately predict disease recurrence and overall survival in a significant subset of patients. Adjuvant therapies for melanoma are notoriously toxic and associated with significant morbidity. Furthermore, it has been difficult to predict which patients will respond best to these treatments, if at all. DNA and RNA biomarkers have been developed to help overcome these problems. Biomarkers have been shown to upstage patients with melanoma, but are the assays sensitive and specific enough for clinical use as predictors of disease outcome or treatment response? We review our experience with DNA and RNA biomarkers in terms of their prognostic and predictive capabilities in malignant melanoma and outline their likely role in the future of melanoma staging, surveillance, and treatment.
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Affiliation(s)
- Steve R Martinez
- Department of Molecular Oncology, John Wayne Cancer Institute, 2200 Santa Monica Boulevard, Santa Monica, California 90404, USA
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Gill M, Cohen J, Renwick N, Mones JM, Silvers DN, Celebi JT. Genetic similarities between Spitz nevus and Spitzoid melanoma in children. Cancer 2004; 101:2636-40. [PMID: 15503312 DOI: 10.1002/cncr.20680] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Melanoma in children is rare. Diagnosis of the subtype of melanoma known as Spitzoid melanoma can be extremely challenging in this age group. Spitzoid melanoma clinically and histopathologically resembles a benign melanocytic proliferation referred to as Spitz nevus. In some cases, distinction between the two is impossible. Initial misdiagnoses of Spitzoid melanomas as Spitz nevi, thus leading to fatal outcomes, have occurred. The genetic basis and biologic behavior of Spitzoid melanoma is unknown. Although melanoma specimens exhibit high rates of mutation in the B-RAF and N-RAS genes, the Spitzoid melanoma subtype has not been evaluated. Spitz nevi have been found to be associated with a low percentage of mutations in the H-RAS gene; however, the mutational profile of H-RAS in Spitzoid melanoma is unknown. METHODS The authors evaluated a unique series of melanomas occurring in prepubescent children that showed Spitz nevus-like histopathology (Spitzoid melanoma). All of the melanomas in the current series have metastasized to lymph nodes, confirming the diagnosis of melanoma. The authors examined these tumors, as well as age-matched Spitz nevi, for mutations in the B-RAF, N-RAS, and H-RAS genes. RESULTS Activating hotspot mutations in the B-RAF, N-RAS, and H-RAS genes were not identified in Spitzoid melanoma or Spitz nevus specimens. CONCLUSIONS There are genetic similarities with respect to the B-RAF, N-RAS, and H-RAS genes between Spitzoid melanoma and Spitz nevi. Such similarities further differentiate these two tumor types from other melanoma subtypes and from melanocytic nevi, respectively. However, mutation analysis of B-RAF, N-RAS, and H-RAS was not useful in differentiating between Spitzoid melanoma and Spitz nevus in children.
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Affiliation(s)
- Melissa Gill
- Department of Pathology, Columbia University Medical Center, New York, New York, USA
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45
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Tell G, Pines A, Arturi F, Cesaratto L, Adamson E, Puppin C, Presta I, Russo D, Filetti S, Damante G. Control of phosphatase and tensin homolog (PTEN) gene expression in normal and neoplastic thyroid cells. Endocrinology 2004; 145:4660-6. [PMID: 15231710 DOI: 10.1210/en.2004-0282] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The lipid phosphatase, phosphatase and tensin homolog (PTEN), is a key element in controlling cell growth and survival and has a well established role as tumor suppressor protein in many neoplasia. Several data indicate that silencing of PTEN gene expression may be relevant in follicular thyroid cell transformation. Thus, in the present study regulation of PTEN gene expression in thyroid cells was investigated. Cotransfection experiments indicated that in normal FRTL-5 rat thyroid cells, PTEN promoter activity was increased by overexpression of the transcription factor early growth response protein-1 (Egr-1). Moreover, Western blot experiments indicated that when Egr-1 expression was up-regulated by treating FRTL-5 cells with H2O2, an increase in PTEN expression was also observed. TSH induced opposite modifications on PTEN and Egr-1 protein levels. Moreover, acute or chronic TSH stimulation determined distinct effects. In fact, acute TSH stimulation (30 and 60 min) induced a decrease in PTEN, but an increase in Egr-1 protein levels. These effects were cAMP dependent; in fact, they were mimicked by forskolin. A chronic TSH treatment (5 d) stimulated PTEN protein expression, whereas Egr-1 protein was down-regulated. In contrast to normal thyroid cells, when the thyroid tumor cell lines ARO and BCPAP were exposed to H2O2, neither Egr-1 nor PTEN protein levels were increased. Acute stimulation of ARO and BCPAP cells with forskolin increased Egr-1, but not PTEN, protein levels. Therefore, thyroid tumor cell lines show alteration of PTEN gene expression regulation. RT-PCR experiments performed on human thyroid tumors showed that the absence of Egr-1 mRNA is always paralleled by the absence of PTEN mRNA. Thus, modification of the Egr-1-dependent mechanisms may play a role in the silencing of PTEN gene expression occurring during thyroid cell transformation.
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Affiliation(s)
- Gianluca Tell
- Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, Piazzale Kolbe 1, 33100 Udine, Italy
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46
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Chu EC, Chai J, Tarnawski AS. NSAIDs activate PTEN and other phosphatases in human colon cancer cells: novel mechanism for chemopreventive action of NSAIDs. Biochem Biophys Res Commun 2004; 320:875-9. [PMID: 15240129 DOI: 10.1016/j.bbrc.2004.06.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Indexed: 02/06/2023]
Abstract
Studies on chemoprevention of colorectal cancer have generated increasing interest. The mechanisms involved in NSAIDs chemopreventive action are not fully elucidated. In this study, we examined in human colon cancer cells the effect of indomethacin and NS-398 (a pre-clinical selective COX-2 inhibitor) on expression of 96 genes of the EGF/PDGF signaling pathways essential for cell proliferation, migration, and survival. We found that indomethacin and NS-398 treatment significantly upregulated expression of the tumor suppressor gene, PTEN, the MAP kinase phosphatase-3, MKP-3, and the protein tyrosine phosphatase, SHP2. Additionally, NS-398 treatment increased expression of apoptotic genes such as BAD, STAT1, and CASP3. These results suggest that as a consequence of increased expression of phosphatases such as PTEN and the resulting dephosphorylation of kinases, NSAIDs can negatively regulate the EGF/PDGF pathways in colon cancer cells-a novel mechanism for NSAIDs' chemopreventive actions.
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Affiliation(s)
- Eric C Chu
- Department of Medicine, Division of Gastroenterology, VA Long Beach Healthcare System and University of California, Irvine, USA
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47
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Abstract
Genetic alterations targeting the PTEN tumor suppressor gene are among the most frequently noted somatic mutations in human cancers. Such lesions have been noted in cancers of the prostate and endometrium and in glioblastoma multiforme, among many others. Moreover, germline mutation of PTEN leads to the development of the related hereditary cancer predisposition syndromes, Cowden disease, and Bannayan-Zonana syndrome, wherein breast and thyroid cancer incidence is elevated. The protein product, PTEN, is a lipid phosphatase, the enzymatic activity of which primarily serves to remove phosphate groups from key intracellular phosphoinositide signaling molecules. This activity normally serves to restrict growth and survival signals by limiting activity of the phosphoinositide-3 kinase (PI3K) pathway. Multiple lines of evidence support the notion that this function is critical to the ability of PTEN to maintain cell homeostasis. Indeed, the absence of functional PTEN in cancer cells leads to constitutive activation of downstream components of the PI3K pathway including the Akt and mTOR kinases. In model organisms, inactivation of these kinases can reverse the effects of PTEN loss. These data raise the possibility that drugs targeting these kinases, or PI3K itself, might have significant therapeutic activity in PTEN-null cancers. Akt kinase inhibitors are still in development; however, as a first test of this hypothesis, phase I and phase II trials of inhibitors of mTOR, namely, rapamycin and rapamycin analogs are underway.
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Affiliation(s)
- Isabelle Sansal
- Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA
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48
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Abstract
Melanoma incidence is rising worldwide. Early diagnosis is very important, as the most effective treatment for melanoma still consists of excision of the tumour before onset of the metastatic growth phase. Immunohistochemistry is a valuable tool for (dermato)pathologists to aid establishing diagnosis. Melanoma markers can be classified into two main categories: melanocytic differentiation markers and melanoma progression markers. Melanocytic differentiation markers are mostly used to distinguish poorly differentiated melanomas from non-melanocytic tumours and for staging of melanocytic proliferative lesions. Melanoma progression markers are most suitable to determine the level of malignancy and/or aggressiveness of tumour cells. This review describes the classification of melanoma markers, including commonly used and recently identified antigens with potential marker function. We characterize their expression profile in melanocytic proliferative lesions and their potential usefulness for diagnosis, prognosis, microstaging, immunotherapeutic purposes and evaluation of therapies.
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Affiliation(s)
- N J W de Wit
- Department of Pathology, University Medical Centre St Radboud, Nijmegen, The Netherlands.
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49
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Abstract
Phosphatase and tensin homolog deleted in from chromosome ten (PTEN), initially also known as mutated in multiple advanced cancers or TGF-beta-regulated and epithelia cell-enriched phosphatase, is a tumor suppressor gene that is mutated in a large fraction of human melanomas. A broad variety of human cancers carry PTEN alterations, including glioblastomas, endometrial, breast, thyroid and prostate cancers. The PTEN protein has at least two biochemical functions: it has both lipid phosphatase and protein phosphatase activity. The lipid phosphatase activity of PTEN decreases intracellular PtdIns(3,4,5)P(3) level and downstream Akt activity. Cell-cycle progression is arrested at G1/S, mediated at least partially through the upregulation of the cyclin-dependent kinase inhibitor p27. In addition, agonist-induced apoptosis is mediated by PTEN, through the upregulation of proapoptotic machinery involving caspases and BID, and the downregulation of antiapoptotic proteins such as Bcl2. The protein phosphatase activity of PTEN is apparently less central to its involvement in tumorigenesis. It is involved in the inhibition of focal adhesion formation, cell spreading and migration, as well as the inhibition of growth factor-stimulated MAPK signaling. Therefore, the combined effects of the loss of PTEN lipid and protein phosphatase activity may result in aberrant cell growth and escape from apoptosis, as well as abnormal cell spreading and migration. In melanoma, PTEN loss has been mostly observed as a late event, although a dose-dependent loss of PTEN protein and function has been implicated in early stages of tumorigenesis as well. In addition, loss of PTEN and oncogenic activation of RAS seem to occur in a reciprocal fashion, both of which could cooperate with CDKN2A loss in contribution to melanoma tumorigenesis.
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Affiliation(s)
- Heng Wu
- Department of Hematology/Oncology, Massachusetts General Hospital, GRJ1021, 55 Fruit Street, Boston, MA 02114, USA
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50
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Abstract
Impaired ability to undergo programmed cell death in response to a wide range of external stimuli acquires melanomas a selective advantage for progression and metastasis as well as their notorious resistance to therapy. Better understanding of mechanisms that govern apoptosis has enabled identification of diverse routes by which melanomas manage to escape stimuli of apoptosis. Changes at genomic, transcriptional and post-translational levels of G-proteins and protein kinases (Ras, B-Raf) and their transcription factor effectors (c-Jun, ATF2, Stat3 and NF-kappaB) affects TNF, Fas and TRAIL receptors, which play important roles in acquiring melanoma's resistance to apoptosis. Here, we summarize our current understanding of changes that alters the regulation of death receptors during melanoma development.
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Affiliation(s)
- Vladimir N Ivanov
- Ruttenberg Cancer Center, Mount Sinai School of Medicine, New York, NY 10029, USA
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