ABSTRACT
Prostate cancer (PCa) is the second most frequently diagnosed cancer in men worldwide. Dialyzed Leukocyte Extracts (DLEs) are heterogeneous mixtures of low-molecular-weight peptides that improve clinical responses in various diseases. Here, we analyzed the effects of TransferonTM, a commercial DLE with characterized active pharmaceutical ingredient and proven batch-to-batch reproducibility, in preclinical models of PCa. We employed v-Src-transformed murine prostate epithelial (PEC-Src) cells, which recapitulate the transcriptional profiles in human PCa, can be grown in immunocompetent mice, and consistently form bone and brain metastases. In vitro, TransferonTM did not induce cytotoxicity nor alterations in migration /invasion of PEC-Src cells. In vivo, TransferonTM reduced metastatic dissemination after intracardiac injection of PEC-Src and inhibited tumor growth of subcutaneous isotransplants. The antineoplastic effect of TransferonTM correlated with changes in tumor infiltration, increased serum concentrations of IL-12 and CXCL1, and reduced levels of VEGF. Our results suggest that the antineoplastic effect produced by TransferonTM is due to its immunomodulatory activity and not by a direct effect on cancer cells, and indicate that TransferonTM could be beneficial as adjuvant therapy in PCa patients.
Subject(s)
Brain Neoplasms/secondary , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/pathology , Transfer Factor/therapeutic use , Animals , Antineoplastic Agents/pharmacology , Cell Death/drug effects , Cell Line, Tumor , Cell Movement/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Disease Models, Animal , Interleukin-1/metabolism , Interleukin-12/metabolism , Male , Mice , Neoplasm Invasiveness , Transfer Factor/pharmacology , Vascular Endothelial Growth Factor A/metabolismABSTRACT
BACKGROUND AND AIMS: Nuclear transcription factor kappa B (NF-κB) is associated with many types of refractory cancer. However, despite multiple strategies to treat cancer and novel target drugs, multidrug resistance still causes relapses. The best-characterized mechanism responsible for multidrug resistance involves the expression of the MDR-1 gene product, P-glycoprotein (P-gp). Because the direct inhibition of this protein is very toxic, other methods of multidrug resistance (MDR) regulation have been proposed. The MDR-1 promoter sequence contains a κB site, which is recognized by NF-κB. The aim of this work was to characterize whether NF-κB modulation changes the response of bone marrow-derived cells (BMDCs) to chemotherapy. RESULTS: We exposed BMDCs to etoposide and doxorubicin, two of the most used antineoplastic drugs. BMDCs presented high tolerance to these drugs, which correlated with high intrinsic P-gp activity and strong protein expression of NF-κB. To determine the mechanism behind the poor sensitivity of BMDCs to chemotherapy, we blocked the activity of the heterodimer protein NF-κB using the pharmacological inhibitor Bay 11-7085 and through the transfection of an adenovirus negative mutant of I kappa B alpha. The multidrug resistance phenotype of BMDCs was reversed by inhibiting the NF-κB pathway, and this change was accompanied by a decrease in P-gp activity. CONCLUSIONS: NF-κB is a possible target for improving the antineoplastic response.