Neoadjuvant Treatment of High-Risk, Clinically Localized Prostate Cancer Prior to Radical Prostatectomy

Hormonal Agents in Localized and Advanced Prostate Cancer: Current Use and Future Perspectives

Prostate cancer (PC) is generally a hormone-dependent tumor. Androgen deprivation therapy ( has been the standard of care in metastatic disease for more than 80 years. Subsequent studies have highlighted the efficacy of ADT even in earlier disease settings such as in localized disease or in the case of biochemical recurrence (BCR). Improved knowledge of PC biology and ADT resistance mechanisms have led to the development of novel generation androgen receptor pathway inhibitors (ARPI). Initially used only in patients who became resistant to ADT, ARPI have subsequently shown to be effective when used in patients with metastatic hormone-naive disease and in recent years their effectiveness has also been evaluated in localized disease and in case of BCR. The objective of this review is to describe the current role of agents interfering with the androgen receptor in different stages of PC and to point out future perspectives.

The Molecular Biology of Prostate Cancer Stem Cells: From the Past to the Future

Prostate cancer (PCa) continues to rank as the second leading cause of cancer-related mortality in western countries, despite the golden treatment using androgen deprivation therapy (ADT) or anti-androgen therapy. With decades of research, scientists have gradually realized that the existence of prostate cancer stem cells (PCSCs) successfully explains tumor recurrence, metastasis and therapeutic failure of PCa. Theoretically, eradication of this small population may improve the efficacy of current therapeutic approaches and prolong PCa survival. However, several characteristics of PCSCs make their diminishment extremely challenging: inherent resistance to anti-androgen and chemotherapy treatment, over-activation of the survival pathway, adaptation to tumor micro-environments, escape from immune attack and being easier to metastasize. For this end, a better understanding of PCSC biology at the molecular level will definitely inspire us to develop PCSC targeted approaches. In this review, we comprehensively summarize signaling pathways responsible for homeostatic regulation of PCSCs and discuss how to eliminate these fractional cells in clinical practice. Overall, this study deeply pinpoints PCSC biology at the molecular level and provides us some research perspectives.

Role of prostate cancer stem-like cells in the development of antiandrogen resistance

Androgen deprivation therapy (ADT) is the standard of care treatment for advance stage prostate cancer. Treatment with ADT develops resistance in multiple ways leading to the development of castration-resistant prostate cancer (CRPC). Present research establishes that prostate cancer stem-like cells (CSCs) play a central role in the development of treatment resistance followed by disease progression. Prostate CSCs are capable of self-renewal, differentiation, and regenerating tumor heterogeneity. The stemness properties in prostate CSCs arise due to various factors such as androgen receptor mutation and variants, epigenetic and genetic modifications leading to alteration in the tumor microenvironment, changes in ATP-binding cassette (ABC) transporters, and adaptations in molecular signaling pathways. ADT reprograms prostate tumor cellular machinery leading to the expression of various stem cell markers such as Aldehyde Dehydrogenase 1 Family Member A1 (ALDH1A1), Prominin 1 (PROM1/CD133), Indian blood group (CD44), SRY-Box Transcription Factor 2 (Sox2), POU Class 5 Homeobox 1(POU5F1/Oct4), Nanog and ABC transporters. These markers indicate enhanced self-renewal and stemness stimulating CRPC evolution, metastatic colonization, and resistance to antiandrogens. In this review, we discuss the role of ADT in prostate CSCs differentiation and acquisition of CRPC, their isolation, identification and characterization, as well as the factors and pathways contributing to CSCs expansion and therapeutic opportunities.

Systemic treatments for high-risk localized prostate cancer

The majority of patients with prostate cancer who later develop lethal metastatic disease have high-risk localized disease at presentation, emphasizing the importance of effective treatment strategies at this stage. Multimodal treatment approaches that combine systemic and local therapies offer a promising strategy for improving the clinical outcomes of patients with high-risk localized prostate cancer. Combinations of neoadjuvant and adjuvant chemotherapy, hormonal therapy, or chemohormonal therapy are considered to be the standard of care in most solid tumours and should be investigated in the future for the treatment of prostate cancer to improve patient outcomes. However, although the combination of androgen deprivation therapy and radiotherapy is a standard of care in high-risk localized or locally advanced prostate cancer, the benefit of chemotherapy or chemohormonal therapy has yet to be demonstrated outside of the metastatic setting. Moreover, the benefit of neoadjuvant and/or adjuvant systemic therapies in combination with radical prostatectomy has not been proved. The development of next-generation hormonal agents, which have been approved for the treatment of castration-resistant prostate cancer, offers further therapeutic possibilities that are being assessed in early-phase clinical trials.

Neoadjuvant chemohormonal therapy combined with radical prostatectomy and extended PLND for very high risk locally advanced prostate cancer: A retrospective comparative study

OBJECTIVE

Docetaxel has been shown to be an effective chemotherapy agent when combined with androgen deprivation therapy for hormone sensitive metastatic prostate cancer (CaP). Since very high risk CaP has a high rate of occult metastatic disease and early recurrence, we hypothesize that patients with very high risk locally advanced CaP may benefit from docetaxel-based neoadjuvant chemohormonal therapy (NCHT). Thus, we conducted a retrospective study to identify the outcome of these patients treated with NCHT followed by radical prostatectomy (RP).

PATIENTS AND METHODS

We retrospectively analyzed data from 177 consecutive patients who had very high risk locally advanced CaP between March 2014 and July 2017. Patients received 3 different therapies: (i) 60 men in NCHT group, (ii) 73 men in neoadjuvant hormonal therapy (NHT) group, and (iii) 44 men received immediate RP without neoadjuvant therapy (No-NT group). Surgical outcomes were analyzed and survival differences were compared by the Kaplan-Meier method.

RESULTS

The NCHT group had statistically significant higher preoperative Prostate-Specific Antigen (PSA) (P < 0.002), higher Gleason score (P < 0.002), and more advanced clinical stage (P < 0.001) than other groups. After RP, 81% (42/52) of patients in NCHT group, 73% (51/70) of patients in NHT group, and 48% (21/44) of patients in No-NT group achieved an undetectable PSA (P < 0.001). A total of 14% (6/42) patients achieving a postoperative undetectable PSA experienced biochemical recurrence in the NCHT group, with median biochemical progression-free survival (bPFS) time of 19 months; 47% (24/51) experienced biochemical recurrence in the NHT group, with median bPFS time of 13 months; 81% (17/21) experienced biochemical recurrence in the No-NT group, with median bPFS time of 9 months (P < 0.001). The median follow-up time of 3 groups was 12.5 months in the NCHT group, 18.3 months in the NHT group, and 22.8 months in the No-NT group (P = 0.01).

CONCLUSION

Despite having poorer prognostic factors, the NCHT group had better bPFS time after surgery compared to NHT and No-NT groups. Randomized controlled investigations are needed to validate these results and further follow-up is required for survival endpoints.

Radical Prostatectomy With and Without Neoadjuvant Chemohormonal Pretreatment for High-Risk Localized Prostate Cancer: A Comparative Propensity Score Matched Analysis

BACKGROUND

To investigate the clinical outcomes in patients with high-risk prostate cancer (PCa) treated with neoadjuvant chemohormonal therapy (NCHT) before radical prostatectomy (RP).

PATIENTS AND METHODS

Our NCHT protocol involved complete androgen blockade followed by 6 cycles of docetaxel (30 mg/m²) plus estramustine phosphate (560 mg). NCHT was provided to 60 patients with PCa before RP, and we compared the clinical and pathologic outcomes with those of 349 patients with high-risk PCa who underwent RP alone using propensity score matching. The data for those who underwent RP alone were obtained from the Michinoku Japan Urological Cancer Study Group database.

RESULTS

In the NCHT group, 10.0% experienced pathologic complete response, 3.3% had positive surgical margins, and 13.3% developed severe complications (Clavien-Dindo grade III or higher) after RP. The median follow-up duration was 42.5 months, and the 5-year biochemical recurrence (BCR)-free survival was 60.1%. In multivariate analysis, pN+ was an independent prognostic factor for BCR (hazard ratio = 5.251, 95%CI 1.300-21.201; P = .020). In propensity score matching, the BCR rate in the NCHT group was significantly lower than that in the RP alone group (P = .021). In subgroup analyses, the BCR rate in patients with a single high-risk factor was significantly lower in the NCHT group than in the RP-alone group (P = .027).

CONCLUSION

NCHT before RP can reduce the risk of BCR in patients with high-risk PCa, particularly if a single high-risk factor is present. However, the potential for perioperative complications should be considered.

The ethanol extraction of prepared Psoralea corylifolia induces apoptosis and autophagy and alteres genes expression assayed by cDNA microarray in human prostate cancer PC-3 cells

Prostate cancer is the most common male reproductive system cancer. The prevalence of prostate cancer in Europe and the United States is higher than that in the Asian region. However, the treatment of prostate cancer remains unsatisfactory. Psoralea corylifolia has been used to cure this disease as Chinese medicine in the Asian region. In this study, we analyzed the components of ethanol extraction of unprepared and prepared P. corylifolia by HPLC. Psoralen and isopsoralen content from the prepared P. corylifolia is twofold higher than that from unprepared, so we use the prepared extraction in this study. However, the effects of the ethanol extraction of P. corylifolia (PCE) on PC-3 human prostate cancer cells remain unclear. PC-3 cells were treated with PCE for different time periods and cells were examined for cell morphological change and total viable cells by using contrast phase microscopy and flow cytometer, respectively. Results indicated that PCE induced cell morphological changes and cytotoxic effect in PC-3 cells in dose-dependent manners. PCE induced chromatin condensation of PC-3 cells dose-dependently. PCE also induced apoptosis and autophagy in PC-3 by western blotting and acridine orange (AO) staining, respectively. Furthermore, a complementary DNA microarray analysis demonstrated that PCE treatment led to 944 genes upregulation and 872 genes downregulation. For example, the DNA damage-associated gene DNA-damage-inducible transcript 3 (DDIT 3) had a 62.1-fold upregulation and CDK1 2.68-fold downregulation. The differential genes were classified according to the Gene Ontology. Furthermore, GeneGo software was used for the key genes involved and their possible interaction pathways. Those genes were affected by P. corylifolia, which provided information for the understanding of the antiprostate cancer mechanism at the genetic level and provide additional targets for the treatments of human prostate cancer.

Docetaxel in prostate cancer: a familiar face as the new standard in a hormone-sensitive setting

The increasing knowledge of prostate cancer is leading to many questions about its natural history and to reconsider conventional therapeutic strategies. Androgen ablation therapy has been the standard therapy in the advanced setting. Although docetaxel has demonstrated increased survival in patients with metastatic prostate cancer who had progressed to hormone treatments, due to its potential toxicity the role of chemotherapy has been relegated to patients who were symptomatic or who had high tumor burden. Several studies have assessed whether docetaxel could have a role in hormone-sensitive disease or even in earlier stages with no distant metastases. In the CHAARTED and STAMPEDE studies, docetaxel provides an unprecedented increase in overall survival (OS). This review summarizes the evidence behind the paradigm shift to strengthening docetaxel as a new standard of treatment that prolongs survival in earlier stages of prostate cancer.

Carbon nanomaterials sensitize prostate cancer cells to docetaxel and mitomycin C via induction of apoptosis and inhibition of proliferation

We have previously shown that carbon nanofibers (CNFs) and carbon nanotubes (CNTs) can sensitize prostate cancer (PCa) cells to platinum-based chemotherapeutics. In order to further verify this concept and to avoid a bias, the present study investigates the chemosensitizing potential of CNFs and CNTs to the conventional chemotherapeutics docetaxel (DTX) and mitomycin C (MMC), which have different molecular structures and mechanisms of action than platinum-based chemotherapeutics. DU-145 PCa cells were treated with DTX and MMC alone or in combination with the carbon nanomaterials. The impact of the monotreatments and the combinatory treatments on cellular function was then systematically analyzed by using different experimental approaches (viability, short-term and long-term proliferation, cell death rate). DTX and MMC alone reduced the viability of PCa cells to 94% and 68%, respectively, whereas a combined treatment with CNFs led to less than 30% remaining viable cells. Up to 17- and 7-fold higher DTX and MMC concentrations were needed in order to evoke a similar inhibition of viability as mediated by the combinatory treatments. In contrast, the dose of platinum-based chemotherapeutics could only be reduced by up to 3-fold by combination with carbon nanomaterials. Furthermore, combinatory treatments with CNFs led mostly to an additive inhibition of short- and long-term proliferation compared to the individual treatments. Also, higher cell death rates were observed in combinatory treatments than in monotreatments, e.g., a combination of MMC and CNFs more than doubled the cell death rate mediated by apoptosis. Combinations with CNTs showed a similar, but less pronounced impact on cellular functions. In summary, carbon nanomaterials in combination with DTX and MMC evoked additive to partly synergistic anti-tumor effects. CNFs and CNTs possess the ability to sensitize cancer cells to a wide range of structurally diverse chemotherapeutics and thus represent an interesting option for the development of multimodal cancer therapies. Co-administration of chemotherapeutics with carbon nanomaterials could result in a reduction of the chemotherapeutic dosage and thus limit systemic side effects.

Systemic GM-CSF Recruits Effector T Cells into the Tumor Microenvironment in Localized Prostate Cancer

Granulocytic-macrophage colony-stimulating factor (GM-CSF) is used as an adjuvant in cancer vaccine trials and has the potential to enhance antitumor efficacy with immunotherapy; however, its immunologic effects are not fully understood. Here, we report results from a phase I study of neoadjuvant GM-CSF in patients with localized prostate cancer undergoing radical prostatectomy. Patients received subcutaneous injections of GM-CSF (250 μg/m²/day) daily for 2 weeks (cohort 1; n = 6), 3 weeks (cohort 2; n = 6), or 4 weeks (cohort 3; n = 6). Treatment was well tolerated with all grade 1 or 2 adverse events. Two patients had a decline in prostate-specific antigen (PSA) of more than 50%. GM-CSF treatment increased the numbers of circulating mature myeloid dendritic cells, proliferating conventional CD4 T cells, proliferating CD8 T cells, and to a lesser magnitude FoxP3⁺ regulatory CD4 T cells. Although GM-CSF treatment did not augment antigen-presenting cell localization to the prostate, treatment was associated with recruitment of CD8⁺ T cells to the tumor. These results suggest that systemic GM-CSF can modulate T-cell infiltration in the tumor microenvironment. Cancer Immunol Res; 4(11); 948-58. ©2016 AACR.