Influence of copper (I) nicotinate complex and autophagy modulation on doxorubicin-induced cytotoxicity in HCC1806 breast cancer cells

Purpose: Doxorubicin is regarded as the most therapeutic active agent available for triple-negative breast cancer (TNBC) treatment. However, the development of drug resistance and toxicity limits its effectiveness. Thus, developing novel strategies for TNBC treatment remains a significant challenge and doxorubicin-based combinations either by metal complexes (Copper I nicotinate complex) or with autophagy modulators could provide novel strategies and alternative strategies contributed to cancer cell death pathways, autophagy and apoptosis. Materials and methods: The viability of HCC1806 TNBC cells and IC50 values of Doxorubicin (DOX), Torin-1 (TOR), Chloroquine (CQ) and Copper (I) nicotinate complex (CNC) were assessed by MTT assay. ELISA was used for detecting microtubule-associated protein 1 light chain 3 (LC3) level. Real time PCR was used to determine (NBR1) gene expression. Cell cycle analysis and quantitative detection of acid vesicular organelles (AVOs) was performed by flow cytometry. TOR and CQ were used as autophagy modulators for induction and suppression of autophagy, respectively. Results: The half-maximal inhibition effect of TOR combination with DOX was revealed to the induction of autophagic cell death and apoptotic cell death. On the other hand, combination of CQ with DOX increased the growth inhibitory effect, induced accumulation of AVOs and suppressed apoptotic cell death. However, combination of CNC with DOX inhibited autophagy and induced cell cycle arrest. Conclusion: Doxorubicin drug based combinations either with TOR, CQ or CNC could positively affect DOX effectiveness and reduce DOX doses applied on HCC1806 cells through modulation of autophagy.