Abstract B105: Antineoplastic effects and expression modulations in proliferation/apoptosis related genes by riproximin in breast cancer cells

Abstract

Abstract Background: Ribosomal inactivating proteins (RIPs) target the ribosomal machinery of target cells and stop the translational machinery irreversibly. Riproximin is a plant-based RIP which was extracted and purified from the plant “Ximenia americana”. Riproximin has demonstrated its anticancer effects against various in vitro and in vivo cancer models. In this study, the focus was to evaluate the effects of riproximin on proliferation and apoptosis of breast cancer cells at functional and molecular levels. Methods: MTT dye reduction assay and DAPI nuclear staining methodologies were used to highlight the riproximin mediated effects on proliferation and apoptosis in primary (MCF-7) and metastatic (MDA-MB-231) breast cancer cell lines. Afterwards, the two cell lines were used to investigate the expression modulations in genes related to PIK3/Akt and apoptosis pathways (84 genes/pathway) via real-time PCR methodology. The expression modulations were used to build the signalling pathways via Ingenuity Pathway Analysis supported by Qiagen software system. Results: Riproximin successfully halted the proliferation of the breast cancer cells with an average 50% inhibitory concentrations of 1.2 and 2.9 ng/ml after 72 hours exposure interval in MCF-7 and MDA-MB-231 cells, respectively. The protein also induced apoptotic effects in the two cell lines as reflected by shrinkage, blebbing and fragmentation of the nucleus/DNA content in a concentration dependant format. Substantial alterations (≥2fold) were observed in PIK3/Akt pathway genes (MCF-7: 49/84, MDA-MB-231: 28/84) in response to riproximin exposure. Similarly, the protein induced de-regulation (≥2fold) of apoptosis related 44/84 and 34/84 genes in MCF-7 and MDA-MB-231 cell lines, respectively. The Ingenuity Pathway Analysis revealed involvement of these genes at distinct positions in cell survival and death mechanisms. Conclusion: Riproximin demonstrated the substantial potential to induce the cytotoxic effects in breast cancer cells. The protein also de-regulated a significant number of proliferation and apoptosis related genes in breast cancer primary and metastatic cells. Further in vitro investigations are required to understand the fine molecular tuning being operated by this natural plant protein in cancer cells. Citation Format: Asim Pervaiz, Asma Khan, Kiran Umer, Martin R. Berger. Antineoplastic effects and expression modulations in proliferation/apoptosis related genes by riproximin in breast cancer cells [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B105.