Management of metastatic castration-resistant prostate cancer: recent advances

Feasibility of cabazitaxel in octogenarian prostate cancer patients

Background

To evaluate the effectiveness and safety of cabazitaxel in castration-resistant prostate cancer patients aged ≥80 years, we performed a retrospective study on a sample of patients from 11 Italian cancer centers.

Materials and methods

Fifty-seven patients aged ≥80 years were treated with cabazitaxel after previous failure with docetaxel; 39 completed a comprehensive geriatric assessment questionnaire (34 fit and 5 vulnerable) and 8 patients (14%) had an Eastern Cooperative Oncology Group performance status (PS) ≥2, while most had a PS of 0-1 (86%). Cabazitaxel was administered at a dose of 25 mg/m2 in 30 (52%) patients and 20 mg/m2 or adapted schedules in 27 (48%) patients. These schedules were adopted mainly in patients ≥85 years (75%), with a PS ≥2 (87.5%), and those classified as vulnerable (100%).

Results

The duration of treatment was 4.8 months and was comparable in all subgroups; disease control rate was reported in 36 patients (63%); prostate-specific antigen response was recorded in 18 patients (31.5%). Median overall survival was 13.1 months regardless of age (<85/≥85 years), but overall survival was reduced in vulnerable (7.2 months) and PS ≥ 2 patients (6.8 months). The most frequently documented grade 3-4 toxicities were neutropenia (14%) and diarrhea (10.5%). Six patients (10.5%) dropped out due to severe toxicity.

Conclusions

Octogenarian patients can be treated with cabazitaxel with reduced doses or alternative schedules that are associated with less toxicity and fewer treatment interruptions. Comprehensive geriatric assessment could facilitate more appropriate patient selection.

The importance of personalized medicine in urological cancers

A better understanding of key regulatory pathways involved in cancers has led to the development of molecularly targeted therapies. Molecular profiling based on genomics, proteomics, and metabolomics in tumors provides clinicians with the necessary information to maintain a personalized therapeutic regimen according to the patient's needs. for example, androgen deprivation therapy (ADT) for advanced prostate cancer is one of the earliest forms of targeted therapy and has remained a choice of treatment by physicians. Unfortunately, most patients will eventually become non-responsive to ADT and succumb to the disease. Since the emergence of ADT, the understanding of androgen receptor (AR) signaling and mechanisms driving the resistance to ADT has been significantly improved. Inactivation of the PTEN gene is a common occurrence in prostate cancers and is associated with metastatic potential, androgen independence, and poor prognosis. Several studies over personalized medicine for muscle-invasive and metastatic bladder cancer discussed potential molecular biomarkers which are currently under investigation and based on the excision repair cross-complementing group 1 (ERCC1) gene and its role in tumor development and therapeutic resistance to cytotoxic DNA-damaging chemotherapy and ionizing radiation. In this review, we consider personalized medicine for four urological cancers.

Basic Science and Molecular Genetics of Prostate Cancer Aggressiveness

Androgen receptor function, tumor cell plasticity, loss of tumor suppressors, and defects in DNA repair genes affect aggressive features of prostate cancer. Prostate cancer development, progression, and aggressive behavior are often attributable to function of the androgen receptor. Tumor cell plasticity, neuroendocrine features, and loss of tumor suppressors lend aggressive behavior to prostate cancer cells. DNA repair defects have ramifications for prostate cancer cell behavior.

Secretory Clusterin Mediates Oxaliplatin Resistance via the Gadd45a/PI3K/Akt Signaling Pathway in Hepatocellular Carcinoma

Purpose: Systemic therapy has often been used for patients with advanced hepatocellular carcinoma (HCC). However, due to drug resistance, the use of cytotoxic chemotherapy in the treatment of patients with advanced HCC has typically demonstrated low response rates. Secretory clusterin (sCLU) is expressed in aggressive late-stage tumors and associated with resistance to chemotherapy, including that in HCC cases. The present research aimed to investigate the biological role of sCLU in HCC.

Methods: sCLU expression in HCC and normal tissues was examined using immunohistochemical staining, followed by analysis of the correlation between sCLU expression and clinical indicators. In addition, the role and internal mechanism of sCLU in cell proliferation and apoptosis were investigated in HCC cells.

Results: sCLU expression was significantly upregulated in HCC tissues; and was associated with histological grade and poor overall survival. The levels of sCLU were significantly increased in Bel7402, SMMC7721 and resistant HCC cells (Bel7404-OR). Inhibiting the activity of sCLU enhanced the chemosensitivity of Bel7402 and SMMC7721 cells. Downregulation of sCLU could increase the expression of Gadd45a in HCC cells. Overexpression of sCLU contributed to drug resistance in Bel7402, SMMC7721 and Bel7404-OR cells; whereas, overexpression of Gadd45a alone overcame drug resistance in the cells above. No significant expression changes of sCLU and Gadd45a were observed in HCC cells after the interference of a selective inhibitor of the PI3K/Akt signaling pathway. However, regulation of the expression of Gadd45a could influence the phosphorylation level of Akt; and further regulate the expression of Bcl-2 and Bax proteins involved in the mitochondrial apoptosis pathways.

Conclusions: The results demonstrate that sCLU/Gadd45a/PI3K/Akt signaling represents a novel pathway that could regulate drug resistance in a one-way manner in HCC cells.

MicroRNA-212 Targets Mitogen-Activated Protein Kinase 1 to Inhibit Proliferation and Invasion of Prostate Cancer Cells

Prostate cancer (PCa) is the second most commonly diagnosed malignancy and the fifth leading cause of cancer-related deaths in males worldwide. MicroRNAs (miRNAs) may serve as important regulators in PCa occurrence and development. Therefore, understanding the expression and functions of PCa-related miRNAs may be beneficial for the identification of novel therapeutic methods for patients with PCa. In this study, miRNA-212 (miR-212) was evidently downregulated in PCa tissues and several PCa cell lines. Functional assays showed that the resumption of miR-212 expression attenuated cell proliferation and invasion and increased the apoptosis of PCa. In addition, mitogen-activated protein kinase 1 (MAPK1), a well-known oncogene, was identified as a novel target of miR-212 in PCa, as confirmed by bioinformatics, luciferase reporter assay, qRT-PCR, and Western blot analysis. Furthermore, MAPK1 expression was upregulated in PCa tissues and inversely correlated with miR-212 expression. Rescue experiments also demonstrated that restored MAPK1 expression reversed the tumor-suppressing effects of miR-212 on PCa cell proliferation, invasion, and apoptosis. In conclusion, miR-212 may exert tumor-suppressing roles in PCa by regulating MAPK1 and could be a novel therapeutic target for treatment of patients with this malignancy.

GP73 level determines chemotherapeutic resistance in human hepatocellular carcinoma cells

Objective GP73 is a new hepatocellular carcinoma (HCC) marker, which is highly expressed in hepatocellular carcinoma and closely relates to prognosis. This study was to investigate the effects of GP73 on cellular proliferation, apoptosis, oxaliplatin (OXA) resistance and secretory clusterin (sCLU) of HCC cells. Materials and Methods Western blot and immunofluorescence was used to detect the expression of GP73 in 8 types of commonly used HCC cell lines. Drug resistance was induced by increasing concentration gradient method. The drug-resistant human HCC cell lines underwent GP73 overexpression or inhibition. Flow cytometry were used to detect the proliferation and apoptosis of HCC cell lines. The changes of sCLU were detected by enzyme-linked immunosorbent assay (ELISA). Results The expression of GP73 in MHC-97H cells was the highest and in Hep3B cells the lowest. The expression of GP73 was found further elevated in OXA-resistant MHC-97H cells. After the knockdown of GP73 in OXA-resistant 97H cells, the IC₅₀ of OXA decreased and the ability of cell proliferation decreased significantly. After over-expression of GP73 in OXA-resistant Hep3B cells, the IC₅₀ of OXA increased and the cell proliferation ability increased, showing that GP73 is critical for OXA resistant in HCC cell lines; No significant change of sCLU level in GP73 overexpressed Hep3B and GP73 blocked MHCC-97H were identified. Conclusion The expression level of GP73 is critical for the resistance of OXA in HCC cell lines.

miR-539 inhibits prostate cancer progression by directly targeting SPAG5

Background

We conducted multiple microarray datasets analyses from clinical and xenograft tumor tissues to search for disease progression-driving oncogenes in prostate cancer (PCa). Sperm-associated antigen 5 (SPAG5) attracted our attention. SPAG5 was recently identified as an oncogene participating in lung cancer and cervical cancer progression. However, the roles of SPAG5 in PCa progression remain unknown.

Methods

SPAG5 expression level in clinical primary PCa, metastatic PCa, castration resistant PCa, neuroendocrine PCa, and normal prostate tissues was investigated. We established multiple in vivo xenografts models using patient-derived tissues and investigated SPAG5 expression trend in these models. We also investigated the functions of SPAG5 in vivo and in vitro studies. Luciferase reporter assays were performed to investigate potential miRNAs that can regulate SPAG5.

Results

We identified that SPAG5 expression was gradually increased in PCa progression and its level was significantly associated with lymph node metastasis, clinical stage, Gleason score, and biochemical recurrence. Our results indicated that SPAG5 knockdown can drastically inhibit PCa cell proliferation, migration, and invasion in vitro and supress tumor growth and metastasis in vivo. We identified that miR-539 can directly target SPAG5. Ectopic overexpression of miR-539 can drastically inhibit SPAG5 expression and the restoration of SPAG5 expression can reverse the inhibitory effects of miR-539 on PCa cell proliferation and metastasis.

Conclusion

Our results collectively showed a progression-driving role of SPAG5 in PCa which can be regulated by miR-539, suggesting that miR-539/SPAG5 can serve as a potential therapeutic target for PCa.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0337-8) contains supplementary material, which is available to authorized users.

Prostate cancer metastasis-driving genes: hurdles and potential approaches in their identification

Metastatic prostate cancer is currently incurable. Metastasis is thought to result from changes in the expression of specific metastasis-driving genes in nonmetastatic prostate cancer tissue, leading to a cascade of activated downstream genes that set the metastatic process in motion. Such genes could potentially serve as effective therapeutic targets for improved management of the disease. They could be identified by comparative analysis of gene expression profiles of patient-derived metastatic and nonmetastatic prostate cancer tissues to pinpoint genes showing altered expression, followed by determining whether silencing of such genes can lead to inhibition of metastatic properties. Various hurdles encountered in this approach are discussed, including (i) the need for clinically relevant, nonmetastatic and metastatic prostate cancer tissues such as xenografts of patients’ prostate cancers developed via subrenal capsule grafting technology and (ii) limitations in the currently available methodology for identification of master regulatory genes.

Radium-223 dichloride: a review of its use in patients with castration-resistant prostate cancer with symptomatic bone metastases

Radium-223 dichloride (Xofigo®; formerly Alpharadin™) [hereafter referred to as radium-223] is a first-in-class alpha particle-emitting radiopharmaceutical that has recently been approved for the treatment of patients with castration-resistant prostate cancer (CRPC) with symptomatic bone metastases and no known visceral metastatic disease. Radium-223 is a calcium mimetic, which targets bone, delivering cytotoxic radiation to the sites of bone metastases. In the recently reported Alpharadin™ in Symptomatic Prostate Cancer (ALSYMPCA) phase III study, radium-223 was associated with significantly improved overall survival compared with placebo, making it the first bone-targeted CRPC therapy for which an overall survival benefit has been demonstrated. The ALSYMPCA study also demonstrated the beneficial effects of radium-223 on disease-related symptomatic skeletal events, pain and health-related quality of life. Radium-223 was generally well tolerated, being associated with low rates of myelosuppression and generally mild gastrointestinal adverse events. Thus, radium-223 is a valuable addition to the treatment options for this poor-prognosis population.

Metastatic castration-resistant prostate cancer (CRPC): preclinical and clinical evidence for the sequential use of novel therapeutics

With five novel therapies shown to improve survival in metastatic castration-resistant prostate cancer (CRPC) in the last 3 years, patients are now living longer and experiencing better quality of life. Since docetaxel became standard of care for men with symptomatic metastatic CRPC, three artificial treatment "spaces" have emerged for prostate cancer drug development: pre-docetaxel, docetaxel combinations, and following docetaxel. Multiple therapies are currently under development in both early and late stage CRPC. Additionally, the novel agents abiraterone, radium-223, cabazitaxel, and enzalutamide have all been approved in the post-docetaxel setting. Strategies for patient selection and treatment sequencing are therefore urgently required. In this comprehensive review, we will summarize the preclinical and clinical data available with regards to sequencing of the novel treatments for CRPC.

Loss of Androgen-Regulated MicroRNA 1 Activates SRC and Promotes Prostate Cancer Bone Metastasis

Bone metastasis is the hallmark of progressive and castration-resistant prostate cancers. MicroRNA 1 (miR-1) levels are decreased in clinical samples of primary prostate cancer and further reduced in metastases. SRC has been implicated as a critical factor in bone metastasis, and here we show that SRC is a direct target of miR-1. In prostate cancer patient samples, miR-1 levels are inversely correlated with SRC expression and a SRC-dependent gene signature. Ectopic miR-1 expression inhibited extracellular signal-regulated kinase (ERK) signaling and bone metastasis in a xenograft model. In contrast, SRC overexpression was sufficient to reconstitute bone metastasis and ERK signaling in cells expressing high levels of miR-1. Androgen receptor (AR) activity, defined by an AR output signature, is low in a portion of castration-resistant prostate cancer. We show that AR binds to the miR-1-2 regulatory region and regulates miR-1 transcription. Patients with low miR-1 levels displayed correlated low canonical AR gene signatures. Our data support the existence of an AR-miR-1-SRC regulatory network. We propose that loss of miR-1 is one mechanistic link between low canonical AR output and SRC-promoted metastatic phenotypes.

GATA2 as a potential metastasis-driving gene in prostate cancer

Effective treatment for metastatic prostate cancer is critically needed. The present study was aimed at identifying metastasis-driving genes as potential targets for therapy (oncotargets). A differential gene expression profile of metastatic LTL-313H and non-metastatic LTL-313B prostate cancer tissue xenografts, derived from one patient's specimen, was subjected to integrative analysis using the Ingenuity Upstream Regulator Analysis tool. Six candidate master regulatory genes were identified, including GATA2, a gene encoding a pioneer factor, a special transcription factor facilitating the recruitment of additional transcription factors. Elevated GATA2 expression in metastatic prostate cancer tissues correlated with poor patient prognosis. Furthermore, GATA2 gene silencing in human prostate cancer LNCaP cells led to a marked reduction in cell migration, tissue invasion, focal adhesion disassembly and to a dramatic change in cell transcriptomes, indicating that GATA2 plays a critical role in prostate cancer metastasis. As such, GATA2 could represent a prostate cancer metastasis-driving gene and a potential target for therapy of metastatic prostate cancer.

AR-regulated TWEAK-FN14 pathway promotes prostate cancer bone metastasis

The recurrence of prostate cancer metastases to bone after androgen deprivation therapy is a major clinical challenge. We identified FN14 (TNFRSF12A), a TNF receptor family member, as a factor that promotes prostate cancer bone metastasis. In experimental models, depletion of FN14 inhibited bone metastasis, and FN14 could be functionally reconstituted with IKKβ-dependent, NFκB signaling activation. In human prostate cancer, upregulated FN14 expression was observed in more than half of metastatic samples. In addition, FN14 expression was correlated inversely with androgen receptor (AR) signaling output in clinical samples. Consistent with this, AR binding to the FN14 enhancer decreased expression. We show here that FN14 may be a survival factor in low AR output prostate cancer cells. Our results define one upstream mechanism, via FN14 signaling, through which the NFκB pathway contributes to prostate cancer metastasis and suggest FN14 as a candidate therapeutic and imaging target for castrate-resistant prostate cancers.

Enzalutamide: a review of its use in metastatic, castration-resistant prostate cancer

Enzalutamide (MDV3100, XTANDI(®)) is an androgen receptor inhibitor that is indicated for the treatment of metastatic, castration-resistant, prostate cancer (mCRPC) that has progressed despite treatment with docetaxel. This article reviews the pharmacology, efficacy and tolerability of enzalutamide relevant to this indication. In a randomized, double-blind, placebo-controlled, multinational, phase III trial in patients with mCRPC progressing after docetaxel therapy, enzalutamide significantly prolonged overall survival (OS), delayed prostate specific antigen progression and prolonged radiographic progression-free survival and time to the first skeletal event. The median OS was 18.4 months in the enzalutamide group and 13.6 months in the placebo group, which represents a 37 % reduction in the mortality risk in the enzalutamide group. Enzalutamide was also associated with significant benefits in health-related quality of life and in pain palliation. Enzalutamide was generally as well tolerated as placebo during the trial, with most adverse events at a mild or moderate level of severity. Enzalutamide carries a small increased risk of seizures that appears to be dose-dependent. Enzalutamide is an efficacious and well tolerated treatment for this severe, rapidly progressive disease.

Estimating scenarios for survival time in men starting systemic therapies for castration-resistant prostate cancer: a systematic review of randomised trials

BACKGROUND

We sought to estimate worst-case, typical and best-case scenarios for survival in men starting systemic therapies for castration resistant prostate cancer (CRPC).

METHODS

We sought randomised phase 3 trials of systemic therapies for CRPC and recorded the following percentiles (represented scenario) from Kaplan-Meier overall survival (OS) curves: 90th (worst-case), 75th (lower-typical), 50th (median), 25th (upper-typical) and 10th (best-case). We determined the accuracy of using simple multiples of the median OS to estimate the other selected percentiles from each curve: 0.25 for 90th, 0.5 for 75th, 2 for 25th and 3 for 10th. Estimates were deemed accurate if within 0.75-1.33 times the actual value.

FINDINGS

We reviewed 23 trials (13,909 men) with 48 treatment groups including 28 of chemotherapy, and three of novel hormonal agents. In trials of first-line docetaxel, the mean (interquartile range) for median OS was 19 months (17-20), and for each scenario was: worst-case 7 months (6-8); lower-typical 12 months (11-13); upper-typical 29 months (27-31); and best-case 40 months (34-44). For trials of novel hormonal agents after chemotherapy the mean values were: median OS 17 months, worst-case 5 months, lower-typical 9 months, upper-typical 24 months and best-case not reported. Simple multiples of the median gave accurate estimates of the worst-case scenario in 72% of OS curves, lower-typical in 89%, upper-typical in 84% and best-case in 84%.

INTERPRETATION

Simple multiples of the median OS from randomised trials provided accurate estimates of worst-case, typical and best-case scenarios for survival time in men starting systemic therapies for CRPC.

Genomic, pathological, and clinical heterogeneity as drivers of personalized medicine in prostate cancer

Prostate cancer (CaP) is the most commonly diagnosed malignancy in men in the Western world. In North America, more than 275,000 men are diagnosed annually, whereby approximately 1 in 6 men will be diagnosed with CaP in their lifetime, and 1 in 34 men will die from castration-resistant metastatic disease. Unfortunately, current clinical prognostic factors explain only a proportion of the observed variation in clinical outcome from patient to patient. Furthermore, overtreatment of indolent and low-risk cancers leads to inappropriate morbidity following radiotherapy or surgery. As such, better predictors of individualized prognosis and treatment response are urgently needed to triage patients to customized and intensified CaP treatment. Recent developments in next-generation sequencing have made it possible to identify prognostic and predictive signatures based on genomic profiles. We discuss the genetic basis of CaP progression from localized to systemic disease (e.g., point mutations, copy-number alterations, and structural variants) in relation with unique features of CaP biology, including intraprostatic and interprostatic heterogeneity, multifocality and multiclonality, TMPRSS2:ERG, and other ETS-family gene fusions. Finally, we focus on the use of genomic markers as prognostic factors for local failure and for systemic disease, as novel risk-stratification tools, in triaging patients to existing treatment options, and ultimately the potential of genomics for the identification of molecular targets for therapy of CaP.

Targeting HOX transcription factors in prostate cancer

BACKGROUND

The HOX genes are a family of transcription factors that help to determine cell and tissue identity during early development, and which are also over-expressed in a number of malignancies where they have been shown to promote cell proliferation and survival. The purpose of this study was to evaluate the expression of HOX genes in prostate cancer and to establish whether prostate cancer cells are sensitive to killing by HXR9, an inhibitor of HOX function.

METHODS

HOX function was inhibited using the HXR9 peptide. HOX gene expression was assessed by RNA extraction from cells or tissues followed by quantitative PCR, and siRNA was used to block the expression of the HOX target gene, cFos. In vivo modelling involved a mouse flank tumour induced by inoculation with LNCaP cells.

RESULTS

In this study we show that the expression of HOX genes in prostate tumours is greatly increased with respect to normal prostate tissue. Targeting the interaction between HOX proteins and their PBX cofactor induces apoptosis in the prostate cancer derived cell lines PC3, DU145 and LNCaP, through a mechanism that involves a rapid increase in the expression of cFos, an oncogenic transcription factor. Furthermore, disrupting HOX/PBX binding using the HXR9 antagonist blocks the growth of LNCaP tumours in a xenograft model over an extended period.

CONCLUSION

Many HOX genes are highly over-expressed in prostate cancer, and prostate cancer cells are sensitive to killing by HXR9 both in vitro and in vivo. The HOX genes are therefore a potential therapeutic target in prostate cancer.

An arranged marriage for precision medicine: hypoxia and genomic assays in localized prostate cancer radiotherapy

Prostate cancer (CaP) is the most commonly diagnosed malignancy in males in the Western world with one in six males diagnosed in their lifetime. Current clinical prognostication groupings use pathologic Gleason score, pre-treatment prostatic-specific antigen and Union for International Cancer Control-TNM staging to place patients with localized CaP into low-, intermediate- and high-risk categories. These categories represent an increasing risk of biochemical failure and CaP-specific mortality rates, they also reflect the need for increasing treatment intensity and justification for increased side effects. In this article, we point out that 30-50% of patients will still fail image-guided radiotherapy or surgery despite the judicious use of clinical risk categories owing to interpatient heterogeneity in treatment response. To improve treatment individualization, better predictors of prognosis and radiotherapy treatment response are needed to triage patients to bespoke and intensified CaP treatment protocols. These should include the use of pre-treatment genomic tests based on DNA or RNA indices and/or assays that reflect cancer metabolism, such as hypoxia assays, to define patient-specific CaP progression and aggression. More importantly, it is argued that these novel prognostic assays could be even more useful if combined together to drive forward precision cancer medicine for localized CaP.

Phytoestrogens selective for the estrogen receptor beta exert anti-androgenic effects in castration resistant prostate cancer

Prostate cancer is the leading cause of cancer death in men of the Western world. A castration-resistant prostate cancer (CRPC) eventually will arise when a local restricted prostate carcinoma was not cured duly by radical prostatectomy or radiation therapy. Although androgen ablation therapies are considered the gold standard for treatments of advanced prostate cancer there is no curative therapy available at present. In previous pre-clinical and clinical trials several phytoestrogens were investigated for their anticancer potential in various models for prostate cancer. Phytoestrogens feature tumour preventive characteristics and most probably are involved in the low incidence rate of hormone related cancers in Asian countries. Phytoestrogens such as isoflavones can have a marked impact on the most essential therapy target of CRPC i.e. the androgen receptor. Furthermore, functional analyses solidified the notion of such drugs as androgen antagonistic. Phytoestrogens commonly feature low toxicity combined with a potential of targeted therapy. Thus, these drugs qualify for conceivable implementation in prostate cancer patients under active surveillance. In addition, relapse prevention with these drugs after radical prostatectomy or radiation therapy might be considered. This article is part of a Special Issue entitled 'Phytoestrogens'.

Peptidomimetic targeting of critical androgen receptor-coregulator interactions in prostate cancer

The growth of advanced prostate cancer depends on androgen receptor signalling, however treatment options are limited. Here we report the disruption of specific protein-protein interactions involving LXXLL motifs in androgen receptor-coregulator proteins such as PELP1 using a novel, small molecule peptidomimetic (D2). D2 is stable, non-toxic and efficiently taken up by prostate cancer cells. Importantly, D2 blocks androgen-induced nuclear uptake and genomic activity of the androgen receptor. Furthermore, D2 abrogates androgen-induced proliferation of prostate cancer cells in vitro with an IC50 of 40 nM, and inhibits tumour growth in a mouse xenograft model. D2 also disrupts androgen receptor-coregulator interactions in ex vivo cultures of primary human prostate tumours. These findings provide evidence that targeting androgen receptor-coregulator interactions using peptidomimetics may be a viable therapeutic approach for patients with advanced prostate cancer.

Real-world cabazitaxel safety: the Italian early-access program in metastatic castration-resistant prostate cancer

AIM

Cabazitaxel is a novel taxane that is approved for use in metastatic castration-resistant prostate cancer based on the Phase III TROPIC study, which showed improved overall survival with cabazitaxel/prednisone versus mitoxantrone/prednisone. A global early-access program was initiated in order to provide early access to cabazitaxel in docetaxel-pretreated patients and to obtain real-world data.

PATIENTS & METHODS

We report interim safety results from an Italian prospective, single-arm, multicenter, open-label trial of 218 patients receiving cabazitaxel 25 mg/m2 every 3 weeks plus prednisolone 10 mg/day, until disease progression, unacceptable toxicity, investigator's decision or death.

RESULTS

Patients completing treatment received a median of six cabazitaxel cycles. The most common grade 3/4 adverse events were neutropenia (33.9%), leukopenia (15.6%), anemia (6%) and asthenia (6%). No peripheral neuropathy or nail disorders were observed.

CONCLUSION

These results confirm that cabazitaxel has a manageable safety profile in daily clinical practice and support its use in patients with prostate cancer who progress during or after a docetaxel-based therapy.

IGF2 revs the steroidogenesis engine

Molecular understanding of how prostate cancers evade hormone therapy greatly increased over the last several years, and the realization that de novo steroidogenesis plays a significant role in tumor progression and therapeutic bypass has led to development of promising new therapeutics. In the April 2013 issue of Endocrine-Related Cancer, Lubik et al. revealed a new molecular pathway by which the IGF2 can ignite the de novo steroidogenesis engine and promote molecular events associated with tumor progression.

Secretory clusterin contributes to oxaliplatin resistance by activating Akt pathway in hepatocellular carcinoma

Secretory clusterin (sCLU) is expressed in numerous cancers and is associated with the resistance to chemotherapy. However, the role of sCLU in the resistance of hepatocellular carcinoma (HCC) to oxaliplatin (OXA), a recently used third-generation platinum agent, remains unclear. The stable transfectants that are depleted of or overexpress sCLU and OXA-resistant cells were generated using human HCC cells. Overexpression of sCLU abrogated OXA-induced inhibition of cell growth and cell apoptosis, but depletion of sCLU synergized with OXA to inhibit cell growth and enhance cell apoptosis, by regulating proteins involved in mitochondrial apoptosis pathways, such as Bcl-2, Bax, Bcl-xL and caspase-9, and affecting phosphorylation of Akt and GSK-3β. Overexpression of sCLU in either OXA-resistant cells or stable transfectants that overexpress sCLU significantly increased phosphorylated Akt. However, specific inhibition of Akt enhanced sensitivity of sCLU-overexpressing cells to OXA, but had no effect on sCLU expression, suggesting that the regulatory effects between sCLU and pAkt may be in a one-way manner in HCC cells. The expression levels of sCLU affected the therapeutic efficacy of OXA to treat HCC tumors established in immunodeficiency mice. The results have demonstrated that sCLU contributes to OXA resistance by activating Akt pathway, indicating that sCLU may be a novel molecular target for overcoming OXA resistance in HCC.

Adaptation or selection--mechanisms of castration-resistant prostate cancer

Men with advanced prostate cancer are typically treated with hormonal therapy, which leads to tumour shrinkage. However, tumours relapse and develop into the lethal form of the disease, termed castration-resistant prostate cancer (CRPC). Two distinct, but not mutually exclusive, models have been proposed in the literature to describe the onset of CRPC: adaptation and selection. Although some studies indicate that tumour cells acquire new alterations that enable them to survive in the castrated state (adaptation), other research points to the outgrowth of rare, pre-existing cells capable of surviving hormonal therapy (selection). Targeting the cells that survive hormonal therapy--by either adaptation or selection--is necessary to prevent the development of CRPC. Current research is focused on not only understanding the cellular mechanisms of CRPC, but also defining critical pathways that can be targeted with combinatorial therapies in castration-resistant cancer cells.