Antitumor potential of plant protein (Riproximin) against breast and colorectal cancer: Facts from functional and molecular investigations

Abstract

Background: Ribosomal inactivating proteins comprise a big domain and inactivate the ribosomal machinery of the target cells irreversibly and induce toxic effects. Riproximin is a type II ribosomal inactivating protein which has been found lethal against various cancer cells originating from different tissues including breast and colorectal. The purpose of this study was to evaluate the effects of riproximin exposure on cell cycle relevant genes in breast and colorectal cancer cells.

Methods: Toxic effects of riproximin in breast (MDA-MB-231, MCF-7) and colorectal cancer cell lines (SW480, SW620) were identified by MTT assay. AT molecular levels, the cell lines were treated with riproximin separately and expressional levels of the three S-phase cell cycle related genes (CDC6, MCM3, MCM5) were evaluated to identify the effects of riproximin. Untreated samples were used as controls throughout the study.

Results: Riproximin induced toxic effects in breast and colorectal cancer cells (IC₅₀<1.2ng/ml, 24 hours). Exposure of the cells with different concentrations of riproximin showed concentration dependent effects on expressional profile of the selected S-phase related genes. The selected genes were continuously down regulated by the protein in the breast and colorectal cancer cell lines. The riproximin associated effects were statistically significant.

Conclusion: Riproximin imposed significant cytotoxic and gene modulation effects in breast and colorectal cancer cells. Further studies are required to understand the molecular features affected by riproximin in cancer cells.