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Abstract
Adenocarcinoma of the prostate is the most common cancer in men in the Western Hemisphere. This diagnosis includes a clinicopathologically diverse collection of disease entities, encompassing a spectrum from early localized disease to advanced-stage castration-sensitive and ultimately metastatic, castration-resistant states. Although early-stage disease is treatable and potentially curable, treatment options for castration-resistant prostate cancer, the common pathway to prostate cancer death, remain limited and palliative in nature. Therapeutic resistance to androgen blockade, cytotoxic chemotherapy, and radiotherapy is underpinned by a number of cellular mechanisms. The upregulation of protective, antiapoptotic chaperone proteins is one of these mechanisms, and is exemplified by the protein clusterin in castration-resistant prostate cancer. Antisense oligonucleotide technology provides the potential to inhibit specific genes in cancer cells and with this the possibility of a vast impact in oncology, but no antisense drugs have been approved for use in cancer patients to date. Custirsen (OGX-011) is a novel antisense oligonucleotide drug which targets clusterin expression, and its application in prostate cancer is reviewed in this article.
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Affiliation(s)
- Sohaib Al-Asaaed
- Division of Medical Oncology, Department of Oncology, Western University, London, ON, Canada
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2
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Kadowaki Y, Chari NS, Teo AEK, Hashi A, Spurgers KB, McDonnell TJ. PI3 Kinase inhibition on TRAIL-induced apoptosis correlates with androgen-sensitivity and p21 expression in prostate cancer cells. Apoptosis 2011; 16:627-35. [PMID: 21437722 DOI: 10.1007/s10495-011-0591-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
TNF-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in many types of cancer cells. TRAIL is considered a therapeutic target, therefore, it was of interest to examine molecular mechanisms that may modulate sensitivity to TRAIL signaling in prostate cancer cells. LNCaP cells were found to be relatively resistant to TRAIL induced cell death while PC3 cells were sensitive. PI3-kinase (PI3 K) inhibitors were able to render LNCaP cells sensitive to TRAIL but conferred resistance to PC3 cells. PI3 K inhibitors were associated with an increase in p21(waf1, cip1) expression in PC3 cells where as p21 decreases in LNCaP cells suggesting that p21 may impart TRAIL resistance. Since androgen receptor (AR) signaling can be modulated by AKT, and p21 is an AR responsive gene, the impact of PI3 K inhibition on TRAIL sensitivity was evaluated in AR transfected PC3 cells (PC3AR). The expression of AR was significantly downregulated by PI3 K inhibition in LNCaP cells, which have an intact AR signaling axis. PC3AR cells expressed higher levels of p21 protein and were relatively resistant to TRAIL compared to control cells. Finally, using adenoviral p21 gene transfer we directly demonstrated that p21 can confer resistance to TRAIL-induced cell death. These results suggest that TRAIL resistance is not regulated simply by a PI3 K/AKT survival pathway associated with inactivating PTEN mutations but may also be modulated by downstream AR responsive targets such as p21. These findings may have significant clinical implications for the utility of TRAIL in the management of prostate cancer.
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Affiliation(s)
- Yoshihiko Kadowaki
- Department of Hematopathology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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3
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Patel S, Player MR. Small-molecule inhibitors of the p53-HDM2 interaction for the treatment of cancer. Expert Opin Investig Drugs 2009; 17:1865-82. [PMID: 19012502 DOI: 10.1517/13543780802493366] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND The hdm2 oncogene product, HDM2 (also known as MDM2), is an ubiquitin protein ligase that suppresses the transcriptional activity of the tumor suppressor p53 and promotes its degradation. Approximately 50% of all human tumors harbor mutations or deletions in the TP53 gene. In the remaining half of all human cancers that express the wild-type protein, aberrations of p53 regulators such as HDM2 account for p53 inhibition. Therefore, small-molecule inhibitors of the HDM2-p53 protein-protein interaction appear to offer an attractive strategy for cancer therapy. OBJECTIVE This review focuses on recent progress in the field of small-molecule inhibitors of the p53-HDM2 protein-protein interaction for the treatment of cancer. RESULTS/CONCLUSION The development of pharmacological inhibitors has been challenging. Although many small-molecule HDM2 inhibitors have shown potent in vitro activity, only a limited number of compounds have displayed acceptable pharmacokinetic properties for in vivo evaluation. To date, the most studied chemotypes have been cis-imidazolines (e.g., Nutlins), benzodiazepines (BDPs) and spiro-oxindoles. The cis-imidazolines were the first reported potent, selective small-molecule inhibitors of the p53-MDM2 interaction, and continue to show therapeutic potential. Additionally, p53-based strategies involving inhibition of MDM2-mediated p53 ubiquitylation and restoration of DNA-binding activity of mutant p53 protein, as well as combination therapies, will be briefly described. Finally, a structurally distinct chemotype currently in Phase I clinical trials will be presented.
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Affiliation(s)
- Sharmila Patel
- Johnson & Johnson Pharmaceutical Research and Development, Welsh and McKean Roads, Spring House, PA 19477, USA
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4
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Alexis F, Rhee JW, Richie JP, Radovic-Moreno AF, Langer R, Farokhzad OC. New frontiers in nanotechnology for cancer treatment. Urol Oncol 2008; 26:74-85. [PMID: 18190835 DOI: 10.1016/j.urolonc.2007.03.017] [Citation(s) in RCA: 221] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Nanotechnology is a field of research at the crossroads of biology, chemistry, physics, engineering, and medicine. Design of multifunctional nanoparticles capable of targeting cancer cells, delivering and releasing drugs in a regulated manner, and detecting cancer cells with enormous specificity and sensitivity are just some examples of the potential application of nanotechnology to oncological diseases. In this review we discuss the recent advances of cancer nanotechnology with particular attention to nanoparticle systems that are in clinical practice or in various stages of development for cancer imaging and therapy.
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Affiliation(s)
- Frank Alexis
- Department of Anesthesiology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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5
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Inoue T, Kobayashi T, Terada N, Shimizu Y, Kamoto T, Ogawa O, Nakamura E. Roles of androgen-dependent and -independent activation of signal transduction pathways for cell proliferation of prostate cancer cells. Expert Rev Endocrinol Metab 2007; 2:689-704. [PMID: 30736131 DOI: 10.1586/17446651.2.5.689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prostate cancer is one of the most frequently diagnosed cancers in the western world and this malignant neoplasm is the second-leading cause of cancer death among men in the USA. In the early 1940s, Huggins and Hodges demonstrated that growth and survival of prostate cancer depends on androgens. The mainstay of treatment for advanced prostate cancer is currently androgen ablation. Over the past few decades, several compounds, such as luteinizing hormone-releasing hormone analogues and anti-androgens, were developed and widely used in clinics. Then, the new treatment strategy, maximum androgen blockade (MAB) was introduced. In fact, MAB improved the prognosis of patients with advanced prostate cancer to some extent; however, most of those patients finally relapse after a period of initial response to this therapy, developing androgen-independent prostate cancer (AIPC). Once patients develop AIPC, effective therapeutic modalities are extremely limited and, therefore, the prognosis of this disease is very poor. It is strongly desirable to explore novel therapeutic concepts for AIPC, based on detailed molecular mechanisms for progression to androgen independency. As for the molecular mechanisms involved in the emergence of AIPC, mutations in the androgen receptor have been examined most extensively. These days, evidence is accumulating that demonstrates activation of signal transduction pathways, such as Src, PI3K and mTOR/S6K, are involved in the acquisition of the androgen-independent cell proliferation of prostate cancer cells. In addition, animal models using transgenic and gene-knockout techniques have confirmed these results. The development of therapies targeting against the signal transduction pathways is critical for the improvement of the prognosis of patients with AIPC. In this article, we review recent understandings on molecular mechanisms of androgen-dependent proliferation of prostate cancer cells, whose aberrant activation is proposed as a critical event for progression to AIPC.
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Affiliation(s)
- Takahiro Inoue
- a Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Takashi Kobayashi
- b Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Naoki Terada
- c Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Yosuke Shimizu
- d Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Toshiyuki Kamoto
- e Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Osamu Ogawa
- f Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Eijiro Nakamura
- g Department of Urology, University Graduate School of Medicine, Kyoto, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
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6
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Liu B, Han M, Wen JK, Wang L. Livin/ML-IAP as a new target for cancer treatment. Cancer Lett 2007; 250:168-76. [PMID: 17218055 DOI: 10.1016/j.canlet.2006.09.024] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 09/19/2006] [Accepted: 09/28/2006] [Indexed: 11/21/2022]
Abstract
Livin is a member of the inhibitors of apoptosis protein (IAP) gene family, which encodes negative regulatory proteins that prevent cell apoptosis. Livin is selectively expressed in the most common human neoplasms and appears to be involved in tumor cell resistance to chemotherapeutic agents. Several studies in vitro and in vivo have demonstrated that down-regulation of Livin expression increases the apoptotic rate, reduces tumor growth potential and sensitized tumor cells to chemotherapeutic drugs. This review will focus on the role of this protein during cancer development and progression and will demonstrate possible targets for cancer therapy.
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Affiliation(s)
- Bin Liu
- Hebei Laboratory of Medical Biotechnology, Institute of Basic Medical Science, Hebei Medical University, Shijiazhuang 050017, PR China
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7
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Knudsen BS, Miranti CK. The impact of cell adhesion changes on proliferation and survival during prostate cancer development and progression. J Cell Biochem 2006; 99:345-61. [PMID: 16676354 DOI: 10.1002/jcb.20934] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In the normal prostate epithelium, androgen receptor (AR) negative basal epithelial cells adhere to the substratum, while AR expressing secretory cells lose substratum adhesion. In contrast, prostate cancer cells both express AR and adhere to a tumor basement membrane. In this review, we describe the differential expression of integrins, growth factor receptors (GFRs), and AR in normal and cancerous epithelium. In addition, we discuss how signals from integrins, GFRs, and AR are integrated to regulate the proliferation and survival of normal and malignant prostate epithelial cells. While cell adhesion is likely of great importance when considering therapeutic approaches for treatment of metastatic prostate cancer, no data on integrin expression are available from tissues of prostate cancer metastasis. However, several drug targets that are upregulated after androgen ablative therapy regulate cell adhesion and thus novel targeted therapies indirectly interfere with cell adhesion mechanisms in prostate cancer cells.
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Affiliation(s)
- Beatrice S Knudsen
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
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8
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Abstract
Despite significant advances that have been made in recent years, there is still an urgent need for novel, more effective and less toxic therapeutics for human cancer. Among many new molecular therapeutics being explored for cancer therapy, antisense oligonucleotides are a promising nucleic acid-based approach, with numerous antisense agents being evaluated in preclinical studies and several anticancer antisense drugs in clinical trials. Although there are still a few problems facing the development of antisense strategies for cancer therapy, with progress made in chemical modifications, target selection and drug delivery systems, antisense oligonucleotides are emerging as a novel approach to cancer therapy used alone or in combination with conventional treatments such as chemotherapy and radiation therapy.
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Affiliation(s)
- Elizabeth Rose Rayburn
- University of Alabama at Birmingham, Department of Pharmacology and Toxicology, Division of Clinical Pharmacology, VH 113, 1670 University Blvd., Birmingham, AL 35294, USA
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9
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Kidd LR, Coulibaly A, Templeton TM, Chen W, Long LO, Mason T, Bonilla C, Akereyeni F, Freeman V, Isaacs W, Ahaghotu C, Kittles RA. Germline BCL-2 sequence variants and inherited predisposition to prostate cancer. Prostate Cancer Prostatic Dis 2006; 9:284-92. [PMID: 16733517 DOI: 10.1038/sj.pcan.4500884] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Apoptosis is an essential physiological process that regulates cellular proliferation. Here, we explored the effect of DNA sequence variation within the BCL-2 gene on prostate cancer susceptibility in three clinical populations, consisting of 428 African Americans, 214 Jamaicans and 218 European Americans. We observed a 70% reduced risk for prostate cancer among the European Americans who had possessed two copies of a promoter variant -938C/A. Additionally, common BCL-2 haplotypes appeared to influence prostate cancer risk; however, studies in larger data sets are needed to confirm our findings. Our data suggest that inherited BCL-2 variants may be associated with a decrease in prostate cancer susceptibility.
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Affiliation(s)
- L R Kidd
- Cancer Prevention and Control Program, Department of Pharmacology and Toxicology, James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY, USA
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10
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Lamy S, Ruiz MT, Wisniewski J, Garde S, Rabbani SA, Panchal C, Wu JJ, Annabi B. A prostate secretory protein94-derived synthetic peptide PCK3145 inhibits VEGF signalling in endothelial cells: implication in tumor angiogenesis. Int J Cancer 2006; 118:2350-8. [PMID: 16331603 DOI: 10.1002/ijc.21615] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have previously observed that the synthetic peptide corresponding to amino acids 31-45 (PCK3145) of PSP94 can reduce prostate tumor growth in vivo. Moreover, a recently concluded phase IIa clinical trial with patients with hormone refractory prostate cancer indicated that PCK3145 down-regulates the levels of plasma matrix metalloproteinase (MMP)-9, a MMP involved in metastasis and tumor angiogenesis. The purpose of our study was to investigate the molecular mechanisms of action of PCK3145 and whether this peptide could antagonize tumor neovascularization. We show that, in a syngeneic in vivo model of rat prostate cancer, the expression of endothelial cell (EC) specific CD31, a marker of tumor vessel density, was decreased by 43% in PCK3145-treated animals. In vitro, PCK3145 specifically antagonized in a dose-dependent manner the VEGF-induced ERK phosphorylation as well as the phosphorylation of the VEGFR-2 in cultured EC (HUVEC). These anti-VEGF effects were partly reproduced by pharmacological inhibitors such as PD98059 and PTK787, suggesting that PCK3145 inhibits the tyrosine kinase activity associated to VEGFR-2, which in turn prevents intracellular signalling through the MAPK cascade. Moreover, PCK3145 was also found to inhibit the PDGF-induced phosphorylation of PDGFR in smooth muscle cells. Finally, PCK3145 inhibited in vitro EC tubulogenesis and VEGF-induced MMP-2 secretion suggesting its potential implication as an antiangiogenic agent. Our study demonstrates that PCK3145 interferes with the tyrosine kinase activity associated with VEGF signalling axis in EC. The antiangiogenic properties of this peptide could be highly beneficial and exploited in novel antiangiogenic therapies, for patients with various cancers.
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Affiliation(s)
- Sylvie Lamy
- Centre de Cancérologie Charles-Bruneau, Hôpital Sainte-Justine-UQAM, Montreal, Quebec, Canada
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11
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Gennigens C, Menetrier-Caux C, Droz JP. Insulin-Like Growth Factor (IGF) family and prostate cancer. Crit Rev Oncol Hematol 2006; 58:124-45. [PMID: 16387509 DOI: 10.1016/j.critrevonc.2005.10.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 09/30/2005] [Accepted: 10/07/2005] [Indexed: 11/28/2022] Open
Abstract
There is abundant in vitro, animal and epidemiologic evidence to suggest that the Insulin-Like Growth Factor (IGF) family is a multi-component network of molecules which is involved in the regulation of both physiological and pathological growth processes in prostate. The IGF family plays a key role in cellular metabolism, differentiation, proliferation, transformation and apoptosis, during normal development and malignant growth. This family also seem essential in prostate cancer bone metastases, angiogenesis and androgen-independent progression. Therapeutic alternatives in men with progressive prostate cancer after androgen ablation are very limited. More effective therapies are needed for these patients. Pharmacologic interventions targeting the IGF family are being devised. Such strategies include reduction of IGF-I levels (growth hormone-releasing hormone antagonists, somatostatin analogs), reduction of functional IGF-I receptor levels (antisense oligonucleotides, small interfering RNA), inhibition of IGF-IR and its signalling (monoclonal antibodies, small-molecule tyrosine kinase inhibitors) and Insulin-Like Growth Factor Binding Proteins.
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Affiliation(s)
- C Gennigens
- Department of Medecine, Division of Hematology/Oncology, University Hospital of Liege, Belgium.
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12
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Scher HI, Sawyers CL. Biology of progressive, castration-resistant prostate cancer: directed therapies targeting the androgen-receptor signaling axis. J Clin Oncol 2005; 23:8253-61. [PMID: 16278481 DOI: 10.1200/jco.2005.03.4777] [Citation(s) in RCA: 776] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prostate cancers that are progressing on medical and surgical therapies designed to ablate the action of androgens continue to express androgen receptor (AR) and to depend on signaling through the receptor for growth. A more clinically relevant classification of castration-resistant disease focuses on the mechanisms of receptor activation, which include (1) changes in the level of ligand(s) in tumor tissue; (2) increased levels of the protein due to gene amplification or altered mRNA expression; (3) activating mutations in the receptor that affect structure and function; (4) changes in coregulatory molecules including coactivators and corepressors; and (5) factors that lead to activation of the receptor independent of the level of ligand or receptor allowing kinase cross talk. From an AR perspective, the term "hormone refractory" is inappropriate. On the basis of this schema, we discuss strategies that are focused on the AR either directly or indirectly, as single agents or in combination, that are in clinical development.
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Affiliation(s)
- Howard I Scher
- Genitourinary Oncology Service, Department of Medicine, Sidney Kimmel Center for Prostate and Urologic Cancers, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10021, USA.
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13
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Kulesz-Martin M, Lagowski J, Fei S, Pelz C, Sears R, Powell MB, Halaban R, Johnson J. Melanocyte and keratinocyte carcinogenesis: p53 family protein activities and intersecting mRNA expression profiles. J Investig Dermatol Symp Proc 2005; 10:142-52. [PMID: 16363065 DOI: 10.1111/j.1087-0024.2005.200405.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Melanocytes and keratinocytes were analyzed for potential roles of p53, p73, and p63 tumor suppressor family proteins and of malignancy-specific gene expression changes in the etiology of multi-step cancer. Melanocytes expressed deltaNp73alpha, two p63 isoforms and p53. Although p21 and Noxa mRNA levels increased following DNA damage, p53 family member binding to p21 and Noxa DNA probes was undetectable, suggesting p53 family-independent responses. In contrast, keratinocytes expressed multiple isoforms each of p73 and p63 that were induced to bind p21 and Noxa DNA probes after ionizing (IR) or after ultraviolet B (UVB) irradiation, correlating with p21 and Noxa mRNA induction and with apoptosis. Interestingly, IR-resistant malignant melanocytes and keratinocytes both exhibited Noxa mRNA induction after UVB treatment, correlating with DNA binding of p53 family proteins to the Noxa probe only in keratinocytes. To uncover other malignancy-specific events, we queried mouse initiated keratinocyte clones for early changes that were exacerbated in malignant derivatives and also differentially expressed in human advanced melanoma versus normal melanocytes. Using a new method for ranking and normalization of microarray data for 5000 probe sets, 27 upregulated and 13 downregulated genes satisfied our query. Of these, the majority was associated with late-stage human cancers and six were novel genes. Thus, clonal lineage mouse models representing early through late cancer progression stages may inform the focus on early, potentially causal events from microarray studies of human cancers, facilitating prognosis and molecular therapy.
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Affiliation(s)
- Molly Kulesz-Martin
- Department of Dermatology, Oregon Health & Science University, Portland, Oregon 97239, USA.
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14
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Smith MR, Nelson JB. Future therapies in hormone-refractory prostate cancer. Urology 2005; 65:9-16; discussion 17. [PMID: 15885273 DOI: 10.1016/j.urology.2005.03.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Revised: 03/02/2005] [Accepted: 03/07/2005] [Indexed: 11/21/2022]
Abstract
Hormone-refractory prostate cancer (HRPC) remains true to its name: it is largely refractory to attempts to delay its progression. Although the number of men presenting with metastatic prostate cancer has decreased significantly over the last several years, the death rate for those men is essentially unchanged. To alter the currently inevitable progression of HRPC to death, new targets and new therapies are needed. This article reviews investigational therapies directed against standard targets (eg, the hypothalamic-pituitary-gonadal axis) as well as novel targets (eg, the endothelin axis).
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Affiliation(s)
- Matthew R Smith
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts, USA
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15
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Strother JM, Beer TM, Dreicer R. Novel cytotoxic and biological agents for prostate cancer: Where will the money be in 2005? Eur J Cancer 2005; 41:954-64. [PMID: 15808961 DOI: 10.1016/j.ejca.2005.02.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Revised: 02/07/2005] [Accepted: 02/08/2005] [Indexed: 11/23/2022]
Abstract
In 2004, docetaxel-based chemotherapy became the first treatment capable of extending life in androgen-independent prostate cancer. The era of therapeutic nihilism in this disease has thus been put to rest and a broad range of agents is being tested with the goal of improving on the successes of 2004. Lessons learned from other tumour types will need to be applied to prostate cancer in order to harness the bounty of available ideas. Target amplification or activating mutations and not merely the presence of a target are likely to be important to the success of targeted agents. Thus, the promise of the current crop of targeted agents is most likely to be realised when pursued in the context of well-credentialed targets and tested in highly translational clinical trials that are capable not only of assessing tumour response, but also of evaluating the status of the targeted pathway. The most promising agents in clinical development are reviewed.
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Affiliation(s)
- John M Strother
- Division of Hematology and Medical Oncology, Oregon Health and Science University, Mail Code CR-145, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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16
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McCarty MF. Targeting multiple signaling pathways as a strategy for managing prostate cancer: multifocal signal modulation therapy. Integr Cancer Ther 2005; 3:349-80. [PMID: 15523106 DOI: 10.1177/1534735404270757] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The aberrant behavior of cancer reflects upregulation of certain oncogenic signaling pathways that promote proliferation, inhibit apoptosis, and enable the cancer to spread and evoke angiogenesis. Theoretically, it should be feasible to decrease the activity of these pathways-or increase the activity of pathways that oppose them-with noncytotoxic agents. Since multiple pathways are dysfunctional in most cancers, and cancers accumulate new oncogenic mutations as they progress, the greatest and most durable therapeutic benefit will likely be achieved with combination regimens that address several targets. Thus, a multifocal signal modulation therapy (MSMT) of cancer is proposed. This concept has already been documented by researchers who have shown that certain combinations of signal modulators-of limited utility when administered individually-can achieve dramatic suppression of tumor growth in rodent xenograft models. The present essay attempts to guide development of MSMTs for prostate cancer. Androgen ablation is a signal-modulating measure already in standard use in the management of delocalized prostate cancer. The additional molecular targets considered here include the type 1 insulin-like growth factor receptor, the epidermal growth factor receptor, mammalian target of rapamycin, NF-kappaB, hypoxia-inducible factor-1alpha, hsp90, cyclooxygenase-2, protein kinase A type I, vascular endothelial growth factor, 5-lipoxygenase, 12-lipoxygenase, angiotensin II receptor type 1, bradykinin receptor type 1, c-Src, interleukin-6, ras, MDM2, bcl-2/bclxL, vitamin D receptor, estrogen receptor-beta, and PPAR-. Various nutrients and phytochemicals suspected to have potential utility in prostate cancer prevention and therapy, but whose key molecular targets are still unknown, might reasonably be incorporated into MSMTs for prostate cancer; these include lycopene, selenium, green tea polyphenols, genistein, and silibinin. MSMTs can be developed systematically by testing various combinations of signal-modulating agents, in concentrations that can feasibly be achieved and maintained clinically, on human prostate cancer cell lines; combinations that appear promising can then be tested in xenograft models and, ultimately, in the clinic. Some signal modulators can increase response to cytotoxic drugs by upregulating effectors of apoptosis. When MSMTs fail to raise the spontaneous apoptosis rate sufficiently to achieve tumor stasis or regression, incorporation of appropriate cytotoxic agents into the regimen may improve the clinical outcome.
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17
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Rye PD, Stigbrand T. Interfering with cancer: a brief outline of advances in RNA interference in oncology. Tumour Biol 2005; 25:329-36. [PMID: 15627900 DOI: 10.1159/000081403] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Accepted: 09/13/2004] [Indexed: 12/28/2022] Open
Abstract
RNA interference (RNAi) is a potent and ubiquitous gene-silencing mechanism that is generating considerable excitement in the fields of molecular biology and gene therapy. It is now in widespread use for loss-of-function analysis in many diseases including cancer. Nevertheless, RNAi is still in its infancy, with new discoveries appearing on a monthly basis. This article presents a brief outline of the history and recent advances in RNAi with a specific focus on its potential in oncology.
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Affiliation(s)
- P D Rye
- Axis Shield ASA, Ulvenveien 87, NO-0581 Oslo, Norway.
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18
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Funasaka Y, Sato H, Chakraborty AK, Ohashi A, Chrousos GP, Ichihashi M. Expression of proopiomelanocortin, corticotropin-releasing hormone (CRH), and CRH receptor in melanoma cells, nevus cells, and normal human melanocytes. J Investig Dermatol Symp Proc 1999; 4:105-9. [PMID: 10536983 DOI: 10.1038/sj.jidsp.5640192] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Proopiomelanocortin (POMC) is a 31 kDa prohormone that is processed to various bioactive peptides, including adrenocorticotropin (ACTH), melanotropins (alpha, beta, gamma-MSH), lipotropins, and endorphins. POMC is expressed not only in the pituitary gland but also in a variety of nonpituitary organs and tumors, including melanomas. We previously showed that normal human melanocytes produce and secrete alpha-MSH and ACTH, and furthermore, that advanced melanoma cells generally produce higher amounts of POMC peptides that correlate with tumor progression. To elucidate the mechanism of this upregulation, the expression of genes encoding corticotropin-releasing hormone (CRH) and its receptor, CRH-R, as well as POMC and the MSH receptor (MC1-R), was evaluated by reverse transcriptase-polymerase chain reaction using cultured human melanoma cells, nevus cells, and normal melanocytes. Our results show that all melanocytic cells express CRH, CRH-R, POMC, and MC1-R, with highest intensities in melanoma cells. Furthermore, immunohistochemistry shows that CRH as well as POMC is strongly expressed in advanced melanomas, such as vertically growing lesions of acral lentiginous, nodular and metastatic melanomas, in contrast to negative expression in nevus cells. These results indicate that tumor progression accentuates CRH, CRH-R, and POMC expression by melanoma cells.
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Affiliation(s)
- Y Funasaka
- Department of Dermatology, Kobe University School of Medicine, Japan.
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