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Updated: Jun 2, 2026
A Bioluminescent and Fluorescent Orthotopic Syngeneic Murine Model of Androgen-dependent and Castration-resistant Prostate Cancer
Published on: March 6, 2018
Molecular chemotherapy and chemotherapy: a new front against late-stage hormone-refractory prostate cancer
Preetiner Pal Singh1, Swapna Joshi, Pamela J Russell
1Oncology Research Centre, Prince of Wales Hospital, Randwick, Sydney, New South Wales 2031, Australia.
Purpose:
Stemming from its inherent heterogeneity, single-agent treatments are essentially ineffective against castration-resistant prostate cancer (CRPC). Thus, clinically relevant regimens that harness different modalities to maximize treatment efficacy without increasing cumulative toxicities are urgently needed. Based on this rationale, we investigated whether a novel combination of purine nucleoside phosphorylase-mediated, gene-directed enzyme-prodrug therapy (PNP-GDEPT) with docetaxel against CRPC has superior efficacy in comparison with individual treatments.
Methods:
The in vitro cell growth inhibition in differentially treated murine and human CRPC cell lines was established using a cell-viability assay. The extent of synergy, additivity, or antagonism between treatments was evaluated using CalcuSyn statistical analyses. The local and systemic effects of docetaxel and/or PNP-GDEPT were tested in both immunodeficient and immunocompetent mice against human and murine CRPC tumors, respectively. Subsequently, immunohistochemical analyses and an evaluation of serum cytokine and serum toxicity profiles were conducted to characterize the differential host responses to treatment.
Results:
The combined use of PNP-GDEPT and docetaxel led to strong synergistic cell killing in vitro. Compared with the individual modalities, a combination of the 2 led to a marked reduction in "local and distant" tumor growth in vivo, and importantly, with lowered doses and without additional toxicities. Immunomodulation was indicated by enhanced immune cell infiltration and altered serum cytokine levels. Furthermore, a lowering of T-helper type 2 cytokines, MCP-1, interleukin (IL)-4, IL-6, and IL-10 marked lower tumor burden and enhanced treatment efficacy.
Conclusion:
PNP-GDEPT and docetaxel are a potent combination against CRPC in immunocompetent and immunodeficient settings; these outcomes have implications of translational potential for improved treatment and management of CRPC patients.
Insights
Combining purine nucleoside phosphorylase-mediated, gene-directed enzyme-prodrug therapy (PNP-GDEPT) with docetaxel shows synergistic efficacy against castration-resistant prostate cancer (CRPC). This novel approach reduces tumor growth without increasing toxicity, offering a promising treatment strategy.
Area of Science:
- Oncology
- Cancer Therapy
- Prostate Cancer Research
Background:
- Castration-resistant prostate cancer (CRPC) exhibits heterogeneity, rendering single-agent treatments largely ineffective.
- There is an urgent need for combination therapies that enhance efficacy while minimizing cumulative toxicities in CRPC treatment.
Purpose of the Study:
- To investigate the efficacy of a novel combination therapy using purine nucleoside phosphorylase-mediated, gene-directed enzyme-prodrug therapy (PNP-GDEPT) alongside docetaxel for treating CRPC.
- To compare the efficacy of this combined treatment against individual modalities.
Main Methods:
- In vitro assessment of cell growth inhibition in CRPC cell lines using viability assays.
- Synergy evaluation via CalcuSyn statistical analyses.
- In vivo studies in immunodeficient and immunocompetent mice to assess local and systemic effects, followed by immunohistochemical and serum cytokine analyses.
Main Results:
- The combination of PNP-GDEPT and docetaxel demonstrated strong synergistic cell killing in vitro.
- In vivo studies showed a significant reduction in tumor growth with the combination therapy, using lower doses and without additional toxicity.
- Treatment induced immunomodulation, evidenced by increased immune cell infiltration and altered serum cytokine profiles, including reduced T-helper type 2 cytokines.
Conclusions:
- PNP-GDEPT combined with docetaxel presents a potent therapeutic strategy for CRPC in both immunocompetent and immunodeficient models.
- This combination holds significant translational potential for improving the treatment and management of patients with castration-resistant prostate cancer.
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