Soyasapogenol-A targets CARF and results in suppression of tumor growth and metastasis in p53 compromised cancer cells

Amr Omar,Jayarani Putri,Ahmed Elwakeel,Rajkumar Singh Kalra,Renu Wadhwa,Sunil C. Kaul

doi:10.1038/s41598-020-62953-5

Abstract

We screened some phytochemicals for cytotoxic activity to human cancer cells and identified Soyasapogenol-A (Snol-A) as a potent candidate anti-cancer compound. Interestingly, Soyasapogenin-I (Snin-I) was ineffective. Viability assays endorsed toxicity of Snol-A to a wide variety of cancer cells. Of note, wild type p53 deficient cancer cells (SKOV-3 and Saos-2) also showed potent growth inhibitory effect. Molecular analyses demonstrated that it targets CARF yielding transcriptional upregulation of p21WAF1 (an inhibitor of cyclin-dependent kinases) and downregulation of its effector proteins, CDK2, CDK-4, Cyclin A and Cyclin D1. Targeting of CARF by Snol-A also caused (i) downregulation of pATR-Chk1 signaling leading to caspase-mediated apoptosis and (ii) inactivation of β-catenin/Vimentin/hnRNPK-mediated EMT signaling resulting in decrease in migration and invasion of cancer cells. In in vivo assays, Snol-A caused suppression of tumor growth in subcutaneous xenograft model and inhibited lung metastasis in tail vein injection model. Taken together, we demonstrate that Snol-A is a natural inhibitor of CARF and may be recruited as a potent anti-tumor and anti-metastasis compound for treatment of p53-deficient aggressive malignancies.

Highlights

Cancer chemotherapy has made a remarkable progress in last two decades
We investigated the molecular mechanism of such activity and found that Snol-A, but not Snin-I, targets CARF protein leading to cell cycle arrest, apoptosis, inhibition of migration and metastasis in p53-deficient cancer cells
In order to confirm such differential effect of Snol-A and Snin-I, we investigated dose-dependent response using more human cancer cells including osteosarcoma (U2OS; wild type p53 and Saos-2; null p53), ovarian adenocarcinoma (SKOV3; null p53), and breast adenocarcinoma (MDA-MB-231; mutant p53)

Summary

Introduction

Cancer chemotherapy has made a remarkable progress in last two decades. conventional chemotherapeutic drugs are known to produce serious health issues, by affecting the normal body functions, and QOL of patients during and after the treatment[1]. CARF was shown to act by multiple mechanisms viz., its (i) direct interactions with proteins including ARF, p53, HDM2, (ii) transcriptional repression of HMD2 and p21WAF131,36 and (iii) promote cancer cell invasion and malignant metastases via epithelial-mesenchymal transition (EMT)[37]. Consistent to these findings, diverse clinical tumors are marked by genomic amplification of CARF and its enriched protein levels endorsing its role in human carcinogenesis and progression to metastasis[37]. Inhibition of CARF expression by Snol-A in p53-deficient tumors restricted their growth and lung metastases in in vivo assays

Methods

Results

Conclusion