Molecular circuits of solid tumors: prognostic and predictive tools for bedside use. Nat Rev Clin Oncol. 2010;7:367-380. [PMID: 20551944 DOI: 10.1038/nrclinonc.2010.84]

PTEN activation sensitizes breast cancer to PI3-kinase inhibitor through the β-catenin signaling pathway

Combination therapy is considered a promising therapeutic modality in enhancing treatment efficacy. The phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway is almost universally dysregulated in breast cancer, with specific occurrence of PTEN mutations; thus, it has become an attractive target for cancer treatment. However, the use of single targeted therapeutics against the PI3K/AKT pathway has demonstrated only modest clinical benefits. In this study, recombinant adenovirus-mediated gene transfer of PTEN (AD-PTEN) combined with treatment with LY294002 was utilized to evaluate the effects of suppression of breast cancer cell proliferation. Herein, we show that AD-PTEN significantly enhanced the sensitization of breast cancer cells to LY294002. The 50% inhibitory concentration (IC50) values of LY294002 were significantly decreased to a greater extent in cells transfected with combination therapy. In addition, treatment of AD-PTEN-transfected cells with LY294002 resulted in significantly reduced cell viability and invasion ability compared to single LY294002 treatment. Using western blotting, we found that combination treatment resulted in lower levels of phosphorylated AKTSer473 and GSK-3βSer9 than single treatment with LY294002. Furthermore, we showed a significant decrease in nuclear β-catenin, Fra-1, Tcf-4 and c-Myc by combination treatment. Our results indicate that AD-PTEN sensitization of breast cancer to LY294002 is achieved by increased GSK-3β activity, thus resulting in inhibition of the β-catenin signaling pathway.

Overexpression of high mobility group box 1 with poor prognosis in patients after radical prostatectomy

What's known on the subject? and What does the study add? Recent studies have indicated that high mobility group box 1 (HMGB1) is related to the development and progression of human carcinomas. However, further studies were required to confirm the roles played by HMGB1 in clinical prostate cancer treatment. We investigated the relationship between HMGB1 expression and the characteristics of prostate cancer, and also evaluated the significance of HMGB1 as a prognostic factor for biochemical recurrence-free survival after radical prostatectomy.

OBJECTIVE

• To investigate high mobility group box 1 (HMGB1) expression in human prostate cancer (PC) cell lines and its prognostic significance after radical prostatectomy (RP).

PATIENTS AND METHODS

• Quantitative reverse-transcription polymerase chain reaction and western blotting were used to detect HMGB1 mRNA and protein expression in PC cell lines. • Immunohistochemistry coupled with the tissue microarray technique was performed to evaluate HMGB1 protein expression in 168 primary prostatectomy tissue samples. • Clinicopathological features were compared between positive and negative HMGB1 protein expression groups. • Kaplan-Meier and multivariate Cox analyses were applied to determine the prognostic value of HMGB1 protein expression on biochemical recurrence (BCR) for patients with PC who were undergoing RP.

RESULTS

• There were three PC cells (DU145, PC-3 and LNCaP) with overexpression of HMGB1 mRNA and protein compared to the non-transformed immortalized prostate cell RWPE-1. • A total of 60.1% (101/168) of the PC samples appeared to have positive protein expression of HMGB1. • HMGB1 protein expression was correlated with some clinicopathological parameters, such as pathological stage (pT) (P= 0.011), Gleason score, preoperative prostate-specific antigen concentration and BCR (P < 0.001, respectively). • Positive HMGB1 immunostaining in patients with PC who were undergoing RP was significantly associated with poor median BCR-free survival (23.1 months vs 15.6 months) (P < 0.001). • Multivariate analysis indicated that HMGB1 protein expression was an independent prognostic factor for BCR-free survival after RP (hazard ratio = 2.348, 95% confidence interval = 1.373-6.361, P= 0.001).

CONCLUSIONS

• Up-regulation of HMGB1 mRNA and protein concentrations was confirmed in PC cells. • HMGB1 expression may contribute to the malignant progression of PC. • HMGB1 presents as a novel prognostic factor for BCR after RP.

Preclinical evaluation of destruxin B as a novel Wnt signaling target suppressing proliferation and metastasis of colorectal cancer using non-invasive bioluminescence imaging

In continuation to our studies toward the identification of direct anti-cancer targets, here we showed that destruxin B (DB) from Metarhizium anisopliae suppressed the proliferation and induced cell cycle arrest in human colorectal cancer (CRC) HT29, SW480 and HCT116 cells. Additionally, DB induced apoptosis in HT29 cells by decreased expression level of anti-apoptotic proteins Bcl-2 and Bcl-xL while increased pro-apoptotic Bax. On the other hand, DB attenuated Wnt-signaling by downregulation of β-catenin, Tcf4 and β-catenin/Tcf4 transcriptional activity, concomitantly with decreased expression of β-catenin target genes cyclin D1, c-myc and survivin. Furthermore, DB affected the migratory and invasive ability of HT29 cells through suppressed MMPs-2 and -9 enzymatic activities. We also found that DB targeted the MAPK and/or PI3K/Akt pathway by reduced expression of Akt, IKK-α, JNK, NF-κB, c-Jun and c-Fos while increased that of IκBα. Finally, we demonstrated that DB inhibited tumorigenesis in HT29 xenograft mice using non-invasive bioluminescence technique. Consistently, tumor samples from DB-treated mice demonstrated suppressed expression of β-catenin, cyclin D1, survivin, and endothelial marker CD31 while increased caspase-3 expression. Collectively, our data supports DB as an inhibitor of Wnt/β-catenin/Tcf signaling pathway that may be beneficial in the CRC management.

[Possibilities and limitations of stratified medicine based on biomarkers and targeted therapies in oncology]

Research over the past two decades has untangled the molecular heterogeneity of cancer at the cellular level. The molecular techniques that have been developed in the past 5 to 10 years are dramatically improving our understanding of the genomic aberrations that underlie the malignant transformation of normal cells. At the same time, however, advances in our understanding of the genetic basis of solid tumours and hematologic malignancies have revealed how complex cancer is, and consequently how much more challenging it is in many of the more common cancers to identify the right drug for the right patient in the adequate dose at the right time. Given the slow pace of translation from genome science to individualised medicine in oncology, this expert review, mainly taking into account recently published perspective articles and reviews, describes the molecular heterogeneity of cancer, the difficulties in developing novel molecularly targeted agents, and the need for developing biomarkers to optimise drug development and clinical use. Distinct types of biomarkers, breakthroughs as well as disappointments in the clinical implementation of biomarkers and targeted therapeutics into clinical practice are discussed by focusing on four targeted anti-cancer drugs. Finally, as clinical biomarker tests that predict response to particular therapies will play an important role in achieving stratified medicine in the near future, this article will conclude by giving some recommendations for effective biomarker evaluation and clinical trial designs for predictive biomarker validation.

Thyroid hormone is a MAPK-dependent growth factor for human myeloma cells acting via αvβ3 integrin

Experimental and clinical observations suggest that thyroid hormone [l-thyroxine (T(4)) and 3,5,3'-triiodo-l-thyronine (T(3))] can support cancer cell proliferation. T(3) and T(4) promote both tumor cell division and angiogenesis by activating mitogen-activated protein kinase (MAPK) via binding to a hormone receptor on the αvβ3 integrin, overexpressed on many cancer cells. We have studied the responsiveness of several MM cell lines to T(3) and T(4) and characterized hormonal effects on cell survival, proliferation, and MAPK activation. Overnight T(3) (1-100 nmol/L) and T(4) (100 nmol/L) incubation enhanced, up to 50% (P < 0.002), MM cell viability (WST-1 assay) and increased cell proliferation by 30% to 60% (P < 0.01). Short exposure (10 minutes) to T(3) and T(4) increased MAPK activity by 2.5- to 3.5-fold (P < 0.03). Pharmacologic MAPK inhibition blocked the proliferative action of T(3) and T(4). Antibodies to the integrin αvβ3 dimer and αv and β3 monomers (but not β1) inhibited MAPK activation and subsequent cell proliferation in response to thyroid hormone, indicating dependence upon this integrin. Moreover, tetraiodothyroacetic acid (tetrac), a non-agonist T(4) analogue previously shown to selectively block T(3)/T(4) binding to αvβ3 receptor site, blocked induction of MAPK by the hormones in a dose-dependent manner. This demonstration of the role of thyroid hormones as growth factors for MM cells may offer novel therapeutic approaches.

Molecular markers that can be utilized in diet and dietary supplement research

Prostate and other cancers have a multitude of potential markers that can be used in laboratory and clinical studies of diet and dietary supplement interventions. More overt clinical markers include imaging tests, biopsy samples, prostate-specific antigen kinetics, and urinary testing. Many molecular markers are currently available, including antiapoptotic and apoptotic proteins, cell adhesion molecules, cell cycle compounds, growth factors, angiogenic markers, and proliferative and inflammatory signals. Protein kinases and transcription factors should also be considered for diversity. Testing of numerous molecular markers has become critical in gaining preliminary insight into the potential impact of a novel diet and supplemental agents.

ERCC1 and XRCC1 as biomarkers for lung and head and neck cancer

Advanced stage non-small cell lung cancer and head and neck squamous cell carcinoma are both treated with DNA damaging agents including platinum-based compounds and radiation therapy. However, at least one quarter of all tumors are resistant or refractory to these genotoxic agents. Yet the agents are extremely toxic, leading to undesirable side effects with potentially no benefit. Alternative therapies exist, but currently there are no tools to predict whether the first-line genotoxic agents will work in any given patient. To maximize therapeutic success and limit unnecessary toxicity, emerging clinical trials aim to inform personalized treatments tailored to the biology of individual tumors. Worldwide, significant resources have been invested in identifying biomarkers for guiding the treatment of lung and head and neck cancer. DNA repair proteins of the nucleotide excision repair pathway (ERCC1) and of the base excision repair pathway (XRCC1), which are instrumental in clearing DNA damage caused by platinum drugs and radiation, have been extensively studied as potential biomarkers of clinical outcomes in lung and head and neck cancers. The results are complex and contradictory. Here we summarize the current status of single nucleotide polymorphisms, mRNA, and protein expression of ERCC1 and XRCC1 in relation to cancer risk and patient outcomes.

Novel PI3K/Akt inhibitors screened by the cytoprotective function of human immunodeficiency virus type 1 Tat

The PI3K/Akt pathway regulates various stress-related cellular responses such as cell survival, cell proliferation, metabolism and protein synthesis. Many cancer cell types display the activation of this pathway, and compounds inhibiting this cell survival pathway have been extensively evaluated as anti-cancer agents. In addition to cancers, several human viruses, such as HTLV, HPV, HCV and HIV-1, also modulate this pathway, presumably in order to extend the life span of the infected target cells for productive viral replication. The expression of HIV-1 Tat protein exhibited the cytoprotective effect in macrophages and a human microglial cell line by inhibiting the negative regulator of this pathway, PTEN. This cytoprotective effect of HIV-1 appears to contribute to the long-term survival and persistent HIV-1 production in human macrophage reservoirs. In this study we exploited the PI3K/Akt dependent cytoprotective effect of Tat-expressing CHME5 cells. We screened a collection of compounds known to modulate inflammation, and identified three novel compounds: Lancemaside A, Compound K and Arctigenin that abolished the cytoprotective phenotype of Tat-expressing CHME5 cells. All three compounds antagonized the kinase activity of Akt. Further detailed signaling studies revealed that each of these three compounds targeted different steps of the PI3K/Akt pathway. Arctigenin regulates the upstream PI3K enzyme from converting PIP2 to PIP3. Lancemaside A1 inhibited the movement of Akt to the plasma membrane, a critical step for Akt activation. Compound K inhibited Akt phosphorylation. This study supports that Tat-expressing CHME5 cells are an effective model system for screening novel PI3K/Akt inhibitors.

Inhibitor of differentiation-1 as a novel prognostic factor in NSCLC patients with adenocarcinoma histology and its potential contribution to therapy resistance

PURPOSE

High inhibitor of differentiation-1 (Id1) levels have been found in some tumor types. We aimed to study Id1 levels and their prognostic impact in a large series of stages I to IV non-small cell lung cancer (NSCLC) patients. Experiments in cell lines and cells derived from malignant pleural effusions (MPE) were also carried out.

EXPERIMENTAL DESIGN

A total of 346 NSCLC samples (three different cohorts), including 65 matched nonmalignant tissues, were evaluated for Id1 expression by using immunohistochemistry. Additional data from a fourth cohort including 111 patients were obtained for Id1 mRNA expression analysis by using publicly available microarrays. In vitro proliferation assays were conducted to characterize the impact of Id1 on growth and treatment sensitivity.

RESULTS

Significantly higher Id1 protein levels were found in tumors compared with normal tissues (P < 0.001) and in squamous carcinomas compared with adenocarcinomas (P < 0.001). In radically treated stages I to III patients and stage IV patients treated with chemotherapy, higher Id1 levels were associated with a shorter disease-free survival and overall survival in adenocarcinoma patients in a log-rank test. A Cox model confirmed the independent prognostic value of Id1 levels for both stages I to III and stage IV patients. In silico analysis confirmed a correlation between higher Id1 mRNA levels and poor prognosis for adenocarcinoma subjects. In vitro Id1 silencing in radio/chemotherapy-resistant adenocarcinoma cells from MPEs restored sensitivity to both therapies.

CONCLUSIONS

In our series, Id1 levels showed an independent prognostic value in patients with adenocarcinoma, regardless of the stage. Id1 silencing may sensitize adenocarcinoma cells to radiotherapy and chemotherapy.

Targeting continued androgen receptor signaling in prostate cancer

Prostate cancer is the most common cancer and the second leading cause of death from cancer in males in most Western countries. Prostate cancer has an exquisite sensitivity to androgen deprivation therapy and is the most endocrine-sensitive solid neoplasm, although advanced disease eventually progresses to castration-resistant prostate cancer (CRPC). Recent evidence has shown that cancer progression at the CRPC stage is often mediated by androgen receptor signaling, so that subsequent androgen receptor targeting may further contribute to disease control and, eventually, survival improvement. Abiraterone acetate, an androgen biosynthesis inhibitor, was tested in patients with CRPC pretreated with docetaxel in a phase III trial with demonstration of an overall survival benefit, confirming that CRPC remains hormone driven, even in advanced stages of the disease. Several novel agents also targeting androgen receptor signaling are currently being evaluated, including MDV3100 and orteronel (TAK-700). With the availability of newer endocrine treatments and also nonendocrine treatments (e.g., chemotherapy, immunotherapy, and bone-targeting agents), data supporting a more rational use of therapeutic agents are urgently required in patients with CRPC. It is likely that molecular characterization of prostate cancer will lead to the identification of different subsets of prostate cancer disease with a different natural history, sensitivity, and resistance to treatment; efforts to develop, validate, and implement predictive biomarkers in clinical trials and eventually in routine care should now be strongly supported.

Uptake of KRAS mutation testing in patients with metastatic colorectal cancer in Europe, Latin America and Asia

The mutation status of the KRAS gene in the tumors of patients with metastatic colorectal cancer (mCRC) is a predictive biomarker for the efficacy of epidermal growth factor receptor monoclonal antibody therapy. The establishment of KRAS mutation testing in this setting represents a significant change to standard diagnostic procedures and a major advance in the personalization of cancer care. Against a changing regulatory background, three cross-sectional surveys of physicians in 14 countries in Europe, Latin America and Asia were conducted in 2008, 2009, and 2010 to investigate the uptake and outcome of KRAS testing for patients with mCRC. Physicians in each year answered questions on four patients (last patient seen and last seen in first-, second- and third-line settings). Fieldwork was carried out February-May 2008, January-April 2009, and January-April 2010. Data from 3,819, 3,740 and 3,820 anonymized, uncoded patient records were collated. The frequency of KRAS testing in patients with mCRC increased from 3% in 2008 to 47% in 2009 and 69% in 2010. The 2010 survey revealed that test results were available within 15 days for 82%, 51% and 98% of the 1679, 679, and 261 tested patients in the European, Latin American and Asian regions, respectively. Cetuximab was the most commonly administered targeted agent in tested patients with KRAS wild-type mCRC (798/1607 patients; 50%) and bevacizumab was the most commonly administered targeted agent in tested patients with KRAS mutant tumors (396/893; 44% overall). In conclusion, KRAS testing is now widely established as a routine diagnostic procedure for patients with mCRC and is used increasingly to guide treatment selection.

Tumor cell group via phospholipase A₂ is involved in prostate cancer development

BACKGROUND

Prostate cancer (PCa) is one of the most common malignancies among men in the United States. Further understanding of the molecular mechanisms underlying PCa tumorigenic development is critical for advancing treatment strategies for PCa. The role of Group VIA phospholipase A₂β (iPLA₂β) in cancers has recently emerged. However, the biological functions of iPLA₂β in PCa development have been minimally investigated and only in vitro studies have been reported.

METHODS

We tested the role of iPLA₂β in host cells using an iPLA₂β deficient mouse model and the role of iPLA₂β in tumor cells by comparing the proliferation, migration, and invasion in vitro and tumorigenesis in vivo.

CONCLUSIONS

iPLA₂β deficiency did not affect tumor development in C57BL/6 mice injected with syngeneic PCa cell line TRAMP-C1P3 in any of three models (subcutaneous, orthotopic, or intratibia injection) tested, suggesting that host cell iPLA₂β is not required for PCa tumorigenesis and metastasis. In contrast, when iPLA₂β was down-regulated in TRAMP-C1P3 cells, cell proliferation was reduced in vitro and tumor growth was suppressed in vivo compared to control cells. In particular, iPLA₂β was required for lysophosphatidic acid (LPA)-induced migration and invasion in TRAMP-C1P3 cells. We compared human and mouse PCa cells and showed that they shared high similarities in LPA-stimulated effects and signaling pathways. LPA stimulated cell migration and/or invasion via a PI3K-dependent pathway. Together, our results suggest that the tumor cell iPLA₂β-LPA axis may represent a novel target for PCa.

Translational Medicine is developing in China: a new venue for collaboration

Translational Medicine is an emerging area comprising multidisciplinary Research from basic sciences to medical applications well summarized by the Bench-to-Beside concept; this entails close collaboration between clinicians and basic scientists across institutes. We further clarified that Translational Medicine should be regarded as a two-way road: Bench-to-Bedside and Bedside-to-Bench, to complement testing of novel therapeutic strategies in humans with feedback understanding of how they respond to them. It is, therefore, critical and important to define and promote Translational Medicine among clinicians, basic Researchers, biotechnologists, politicians, ethicists, sociologists, investors and coordinate these efforts among different Countries, fostering aspects germane only to this type of Research such as, as recently discussed, biotechnology entrepreneurship. Translational Medicine as an inter-disciplinary science is developing rapidly and widely and, in this article, we will place a special emphasis on China.

Possible role of autophagy in the treatment of pancreatic cancer with histone deacetylase inhibitors

Pancreatic cancer is a lethal disease and notoriously difficult to treat. Only a small proportion is curative by surgical resection, whilst standard chemotherapy for patients with advanced disease has only a modest effect with substantial toxicity. Clearly there is a need for the continual development of novel therapeutic agents to improve the current situation. Currently, there is a bulk of data indicating the important function of autophagy in cancer. While genetic evidence indicates that autophagy functions as a tumor suppressor, it is also apparent that autophagy can promote the survival of established tumors under stress conditions and in response to chemotherapy. This review provides a spectrum of potential pharmacological agents and autophagic approaches to enhance cell killing in pancreatic cancer.