Nuclear Eg5 (kinesin spindle protein) expression predicts docetaxel response and prostate cancer aggressiveness

Novel biomarkers predicting prostate cancer (PCa) aggressiveness and docetaxel therapy response of PCa patients are needed. In this study the correlation between nuclear Eg5-expression, PCa docetaxel response and PCa aggressiveness was assessed. Immunohistochemical staining for nuclear Eg5 was performed on 117 archival specimens from 110 PCa patients treated with docetaxel between 2004 and 2012. Samples were histologically categorized as positive/negative. Median follow-up time from diagnosis was 11.6 years. Nuclear Eg5-expression was significantly related to docetaxel response (p=0.036) in tissues acquired within three years before docetaxel initiation. Nuclear Eg5-expression was not related to Gleason-score (p=0.994). Survival of patients after docetaxel initiation did not differ based on nuclear Eg5-expression (p=0.540). Analyzing samples taken before hormonal therapy, overall survival and time to docetaxel use were significantly decreased in patients with nuclear Eg5-expressing tumors (p<0.01). Eg5-positive nuclei were found more frequently in T4-staged tumors (p=0.04), Gleason 8-10 tumors (p=0.08), and in metastasized tumors (p<0.01). Multivariate analyses indicated that nuclear Eg5-expression may be an independent parameter for tumor aggressiveness. Limitations of a retrospective analysis apply. In conclusion, nuclear Eg5-expression may be a predictive biomarker for docetaxel response in metastatic castrate-resistant PCa patients and a prognostic biomarker for hormone-naive PCa patients. Prospective validation studies are needed

Liposomal nanomedicines in the treatment of prostate cancer

Prostate cancer is the most common cancer type and the second leading cause of death from cancer in males. In most cases, no curative treatment options are available for metastatic castration-resistant prostate cancer as these tumors are highly resistant to chemotherapy. Targeted drug delivery, using liposomal drug delivery systems, is an attractive approach to enhance the efficacy of anticancer drugs and prevent side effects, thereby potentially increasing the therapeutic index. In most preclinical prostate cancer studies, passive liposomal targeting of anticancer drugs (caused by enhanced permeability and retention of the therapeutic compound) leads to an increased antitumor efficacy and decreased side effects compared to non-targeted drugs. As a result, the total effective dose of anticancer drugs can be substantially decreased. Active (ligand-mediated) liposomal targeting of tumor cells and/or tumor-associated stromal cells display beneficial effects, but only limited preclinical studies were reported. To date, clinical studies in prostate carcinoma have been performed with liposomal doxorubicin only. These studies showed that long-circulating, PEGylated, liposomal doxorubicin generally outperforms conventional short-circulating liposomal doxorubicin, stressing the importance of passive tumor targeting for this drug in prostate carcinoma. In this review, we provide an overview of the (pre)clinical studies that focus on liposomal drug delivery in prostate carcinoma

Liposomal nanomedicines in the treatment of prostate cancer

Prostate cancer is the most common cancer type and the second leading cause of death from cancer in males. In most cases, no curative treatment options are available for metastatic castration-resistant prostate cancer as these tumors are highly resistant to chemotherapy. Targeted drug delivery, using liposomal drug delivery systems, is an attractive approach to enhance the efficacy of anticancer drugs and prevent side effects, thereby potentially increasing the therapeutic index. In most preclinical prostate cancer studies, passive liposomal targeting of anticancer drugs (caused by enhanced permeability and retention of the therapeutic compound) leads to an increased antitumor efficacy and decreased side effects compared to non-targeted drugs. As a result, the total effective dose of anticancer drugs can be substantially decreased. Active (ligand-mediated) liposomal targeting of tumor cells and/or tumor-associated stromal cells display beneficial effects, but only limited preclinical studies were reported. To date, clinical studies in prostate carcinoma have been performed with liposomal doxorubicin only. These studies showed that long-circulating, PEGylated, liposomal doxorubicin generally outperforms conventional short-circulating liposomal doxorubicin, stressing the importance of passive tumor targeting for this drug in prostate carcinoma. In this review, we provide an overview of the (pre)clinical studies that focus on liposomal drug delivery in prostate carcinoma

Improving Taxane-Based Chemotherapy in Castration-Resistant Prostate Cancer

Currently, the clinical utility of taxane-based drug formulations in castration-resistant prostate cancer (CRPC) is severely limited by acquired chemotherapy resistance, dose-limiting toxicities, and nonresponders. Therefore, approaches to improve taxane-based chemotherapy are desperately required. In this review, we highlight the strategies that aim to overcome these limitations, such as bypassing therapy resistance, targeted drug delivery, and adequate prediction of therapy response. The involvement of the apoptotic pathway, ABC transporters, the glucocorticoid receptor (GR) axis, androgen receptor (AR) splicing, epithelial plasticity, and cancer stem cells in mediating taxane-resistance are outlined. Furthermore, passive and active targeted nanomedicinal drug delivery strategies and the use of circulating tumor cells in predicting docetaxel responses are discussed. Finally, recent advances towards clinical translation of these approaches in CRPC are reviewed

Osteolytic cancer cells induce vascular/axon guidance processes in the bone/bone marrow stroma.

Prostate and breast cancers frequently metastasize to bone. The physiological bone homeostasis is perturbed once cancer cells proliferate at the bone metastatic site. Tumors are complex structures consisting of cancer cells and numerous stroma cells. In this study, we show that osteolytic cancer cells (PC-3 and MDA-MB231) induce transcriptome changes in the bone/bone marrow microenvironment (stroma). This stroma transcriptome differs from the previously reported stroma transcriptome of osteoinductive cancer cells (VCaP). While the biological process "angiogenesis/vasculogenesis" is enriched in both transcriptomes, the "vascular/axon guidance" process is a unique process that characterizes the osteolytic stroma. In osteolytic bone metastasis, angiogenesis is denoted by vessel morphology and marker expression specific for arteries/arterioles. Interestingly, intra-tumoral neurite-like structures were in proximity to arteries. Additionally, we found that increased numbers of mesenchymal stem cells and vascular smooth muscle cells, expressing osteolytic cytokines and inhibitors of bone formation, contribute to the osteolytic bone phenotype. Osteoinductive and osteolytic cancer cells induce different types of vessels, representing functionally different hematopoietic stem cell niches. This finding suggests different growth requirements of osteolytic and osteoinductive cancer cells and the need for a differential anti-angiogenic strategy to inhibit tumor growth in osteolytic and osteoblastic bone metastasis

Differential expression of TGFbeta-stimulated clone 22 in normal prostate and prostate cancer

The transforming growth factor-beta (TGFbeta) superfamily and its downstream effector genes are key regulators of epithelial homeostasis. Altered expression of these genes may be associated with malignant transformation of the prostate gland. The cDNA array analysis of differential expression of the TGFbeta superfamily and functionally related genes between patient-matched noncancerous prostate (NP) and prostate cancer (PC) bulk tissue specimens highlighted two genes, namely TGFbeta-stimulated clone-22 (TSC-22) and Id4. Verification of their mRNA expression by real-time PCR in patient-matched NP and PC bulk tissue, in laser-captured pure epithelial and cancer cells and in NP and PC cell lines confirmed TSC-22 underexpression, but not Id4 overexpression, in PC and in human PC cell lines. Immunohistochemical analysis showed that TSC-22 protein expression in NP is restricted to the basal cells and colocalizes with the basal cell marker cytokeratin 5. In contrast, all matched PC samples lack TSC-22 immunoreactivity. Likewise, PC cell lines do not show detectable TSC-22 protein expression as shown by immunoblotting. TSC-22 should be considered as a novel basal cell marker, potentially useful for studying lineage determination within the epithelial compartment of the prostate. Conversely, lack of TSC-22 seems to be a hallmark of malignant transformation of the prostate epithelium. Accordingly, TSC-22 immunohistochemistry may prove to be a diagnostic tool for discriminating benign lesions from malignant ones of the prostate. The suggested tumour suppressor function of TSC-22 warrants further investigation on its role in prostate carcinogenesis and on the TSC-22 pathway as a candidate therapeutic target in PC