Intermittent tri-weekly docetaxel plus bicalutamide in patients with castration-resistant prostate cancer: a single-arm prospective study using a historical control for comparison

The effect of Ganoderma lucidum polysaccharide extract on sensitizing prostate cancer cells to flutamide and docetaxel: an in vitro study

Ganoderma lucidum polysaccharide is the most widely used complementary therapy in cancer. The present study aims to investigate the possible interaction between Ganoderma lucidum polysaccharide and Docetaxel (a chemotherapy drug) and the first-line medication for prostate cancer treatment (Flutamide) and sensitizing the cells to these treatments. The cytotoxic effects of Ganoderma lucidum polysaccharide in combination with Docetaxel and Flutamide on prostate cancer cells were investigated by the MTT test, Hoechst staining, and flow cytometry. In addition, the expression of genes related to apoptosis, angiogenesis, Epithelial-Mesenchymal Transition pathway (EMT), and prostate cancer biomarkers by Real-Time PCR was investigated. The results demonstrated that IC50 values for Ganoderma lucidum polysaccharide (30 μM and 20 μM), Docetaxel (10 μM and 5 μM), and Flutamide (20 μM and 12 μM) with MTT were confirmed by flow cytometry in a dose and time-dependent manner. Regarding the high efficacy of Ganoderma lucidum polysaccharide in combination with Flutamide and Docetaxel, 10 μM and 5 μM Flutamide were used instead of 20 μM and 12 μM and 5 μM and 2 μM Docetaxel was used instead of 10 μM and 5 μM in PC3 and LNCap, respectively. Moreover, for the first time, it was shown that Ganoderma lucidum polysaccharide alone and in combination with Docetaxel and Flutamide significantly augmented apoptosis, reduced cell migration and colonization, and downregulated expression of KLK2 and EMT pathway genes in both PC3 and LNCap cell line (P < 0.01). Ganoderma lucidum polysaccharide synergistically increased the effect of Docetaxel and Flutamide and increased the sensitivity of the prostate cancer cell lines to these drugs. Therefore, it may provide a new therapeutic strategy against prostate cancer.

Docetaxel Rechallenge in Patients with Metastatic Prostate Cancer: A Comprehensive Review

BACKGROUND

Recent years have witnessed a huge shift in the management and prognosis of metastatic prostate cancer with the advent of new-generation anti-hormonal treatments. Docetaxel, which was initially approved in the castrate-resistant prostate cancer setting, has been approved in the earlier course of the disease as it is still castrate sensitive.

SUMMARY

Apart from cabazitaxel and in the absence of other effective chemotherapies, docetaxel rechallenge (DR) in patients with proved sensitivity to docetaxel in the earlier stage of the disease remains a possible option. Unfortunately, the pivotal trials rarely reported on the outcomes of docetaxel retreatment which seems a plausible option in patients initially responding to docetaxel and maintaining a minimum progression-free interval of 3-6 months. In this review, a summary of the clinical evidence and potential concerns for the use of DR in patients with metastatic prostate cancer will be presented. Key Messages: Pivotal trials of docetaxel in metastatic castrate-sensitive prostate cancer as well as metastatic castrate-resistant prostate cancer have not reported on the outcomes of DR except in the GETUG-AFU 15 trial where the outcomes were disappointing. Based on the published retrospective data, DR may be effective in patients who initially responded to docetaxel and maintained a progression-free interval exceeding 6 months.

Intermittent vs continuous docetaxel therapy in patients with metastatic castration-resistant prostate cancer - a phase III study (PRINCE)

OBJECTIVE

To investigate non-inferiority of intermittent docetaxel compared to continuous docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC).

PATIENT AND METHODS

The investigator initiated randomised phase III study included 187 chemotherapy-naïve patients with mCRPC who were allocated to two treatment arms: intermittent docetaxel and continuous docetaxel. Docetaxel was applied in both arms as weekly (35 mg/m² ) or 3-weekly (75 mg/m² ). The primary endpoint was 1-year survival, which was tested for non-inferiority (margin δ = 0.125). The secondary endpoints were: overall survival (OS), progression-free survival (PFS), median time to treatment failure (TTF), and toxicity.

RESULTS

Of 156 eligible patients, 78 were allocated to each arm. The intermittent treatment met the non-inferiority criteria for 1-year survival (two-sided 95% confidence interval, -0.12, 18, P = 0.022), but not for OS, according to the result of a post hoc analysis. The differences between the study arms in PFS and TTF were not significant. The median (range) treatment holiday in the intermittent arm was 110 (13-486) days, or 38% of the overall treatment duration. Safety profiles of both study arms were comparable. The main limitation of this study was that the planned number of patients could not be recruited.

CONCLUSION

Intermittent docetaxel chemotherapy was non-inferior to continuous therapy for 1-year survival; non-inferiority in regard to OS was not reached.

Targeting MRP4 expression by anti-androgen treatment reverses MRP4-mediated docetaxel resistance in castration-resistant prostate cancer

It has been demonstrated that docetaxel (DTX) may improve the overall survival of patients with castration-resistant prostate cancer (CRPC). However, its effectiveness is limited with time, and tumor escape is eventually inevitable. DTX resistance is the main reason for the failure of chemotherapy for CRPC. In the present study, the expression status of multidrug resistance protein 4 (MRP4) in DTX-resistant prostate cancer cells was investigated, and it was explored whether anti-androgen treatment may inhibit MRP4 expression and overcome DTX resistance. DTX-resistant C4-2/D cells were established by exposing DTX-sensitive C4-2/S cells to gradually increasing concentrations of DTX. MRP4 gene expression and the effect of androgen signaling on its expression were assessed by reverse transcription-polymerase chain reaction and western blotting. Intracellular and extracellular concentrations of DTX were detected by high-performance liquid chromatography. Anti-androgen treatment effects on DTX sensitivity were determined by a clonogenic test and an MTT cytotoxicity assay. MRP4 was overexpressed in C4-2/D cells, while its expression was barely detectable in C4-2/S cells. MRP4 expression levels were elevated in C4-2/D cells by dihydrotestosterone, whereas they were blocked by anti-androgen bicalutamide (BKL) treatment. Intracellular and extracellular DTX concentrations in C4-2/D cells were associated with MRP4 levels. The downregulation of MRP4 by BKL increased the intracellular concentration of DTX in C4-2/D cells and re-sensitized C4-2/D cells to DTX. These results indicated that overexpression of MRP4 mediates acquired DTX resistance, and suggest that targeting MRP4 expression by anti-androgen treatment may reverse DTX-resistant prostate cancer cells to DTX chemotherapy.

Prostate cancer in East Asia: evolving trend over the last decade

Prostate cancer is now becoming an emerging health priority in East Asia. Most of our current knowledge on Prostate cancer has been generated from studies conducted in Western population; however, there is considerable heterogeneity of Prostate cancer between East and West. In this article, we reviewed epidemiologic trends, risk factors, disease characteristics and management of Prostate cancer in East Asian population over the last decade. Growing evidence from East Asia suggests an important role of genetic and environmental risk factors interactions in the carcinogenesis of Prostate cancer. Exposure to westernized diet and life style and improvement in health care in combination contribute substantially to the increasing epidemic in this region. Diagnostic and treatment guidelines in East Asia are largely based on Western knowledge. Although there is a remarkable improvement in the outcome over the last decade, ample evidence suggests an inneglectable difference in diagnostic accuracy, treatment efficacy and adverse events between different populations. The knowledge from western countries should be calibrated in the Asian setting to provide a better race-based treatment approach. In this review, we intend to reveal the evolving trend of Prostate cancer in the last decade, in order to gain evidence to improve Prostate cancer prevention and control in East Asia.