Cryptolepine: A naturally derived alkaloid inhibits breast cancer progression by blocking cell cycle progression and inducing apoptosis.

Abstract

e13151 Background: Triple Negative Breast cancer is an aggressive breast cancer subtype. TNBC has a more aggressive clinical course, an earlier age of beginning, a larger propensity for metastasis, and worse clinical outcomes as evidenced by a higher risk of recurrence and a shorter survival rate when compared to hormone receptor-positive or HER2-positive illness. Currently, the primary options for TNBC treatment are surgery, radiation, and chemotherapy. These treatments, however, remain ineffective due to recurrence. However, given that p53 mutations have been identified in more than 60–88% of TNBC, translating p53 into the clinical situation is particularly important in TNBC. Given the scope that some natural drugs can be used as specifically targeting prospective therapeutic in TNBC and to sensitize this aggressive malignancy while reducing side effects. In this study, we screened and evaluated the therapeutic potential of CRP in TNBC in-vitro models being an anti-malarial drug it could be repurposed as an anti-cancer therapeutic in TNBC. Moreover, the cytotoxicity activity of cryptolepine to TNBC cells and a detailed anti-tumor mechanism in mutant P53 has not been reported. Methods: MTT assays were used to examine the cytotoxicity and cell viability activity of Cryptolepine in TNBC, non-TNBC T47D and MCF-7 and non-malignant MCF10A cells. Scratch wound and clonogenic assay was used to evaluate cryptolepine’s effect on migration and colony forming ability of TNBC cells. Flow cytometry, MMP and DAPI was used to assess cell cycle arrest and cell apoptosis. The expression of proteins was detected by western blots. The differential expression of RNAs was evaluated by RT-PCR and the interaction between P53 and drug was evaluated computationally using in-silico approach and in-vitro using ChIP assay. Results: In this study, we found that cryptolepine has more preferential cytotoxicity in TNBC than non-TNBC cells. Notably, our studies revealed the mechanism that cryptolepine can induce intrinsic apoptosis and inhibit migration, colony formation ability, induce cell cycle arrest by inducing conformational change in the mutant P53 thereby increasing its DNA binding ability and also inducing its own transcriptional activation to synthesize new P53 protein and hence activating its tumor suppressing potential significantly. Conclusions: Our study revealed that CRP significantly reduced the proliferation, migration and colony forming ability of TNBC cells lines. Moreover, it was revealed that CRP induces cell cycle arrest and apoptosis by activating mutant P53 and enhancing its DNA binding ability to induce its tumor suppressing ability.