 Synergistic Anti-Cancer Activity of the Combination of Curcumin Analogue, MS13 (1,5-Bis(4-Hydroxy-3-Methoxyphenyl)-1,4-Pentadiene-3-One), and Gefitinib in Triple-Negative Breast Cancer

Cancer as the leading cause of morbidity and mortality is responsible for ∼ 10 million deaths in 2020 worldwide. Female breast cancer (BC), as the world’s most common cancer in 2020, stands first in terms of incidence and mortality among women worldwide (1,2). BC is a highly heterogeneous disease, classified according to hormone and growth factor receptor expression. Triple negative breast cancer (TNBC) accounting for 15–20% of breast cancer is clinically negative for the expression of estrogens receptor (ER) and progesterone receptor (PR), and lacks human epidermal growth factor receptor 2 (HER2) overexpression (ER-, PR-, HER2-). TNBC is the most aggressive BC subtype, prone to earlier relapses and often metastasis to the brain and lungs. It is not responsive to hormonal therapies or those targeting the HER2 receptors and chemotherapy is the only systemic modality available for TNBC patients. However, the clinical efficiency of chemotherapy-based treatment regimens is still limited due to tumor heterogeneity, chemoresistance and deleterious side effects (5-7). Consequently, new alternative therapies have become an urgent clinical need. The majority of TNBC cases are characterized by the overexpression of an epidermal growth factor receptor (EGFR) as a receptor tyrosine kinase, suggesting that anti-EGFR targeted therapies are likely to be beneficial in TNBC treatment (8-10). Gefitinib is a selective EGFR tyrosine kinase inhibitor currently approved in oncology for advanced or metastatic non-small-cell lung cancer (NSCLC). However, it has also been evaluated in TNBC patients showing that gefitinib enhanced the growth inhibitory effect of chemotherapies, but its usage alone failed to demonstrate significant efficacy which could be due to the molecular heterogeneity of TNBC. Therefore, combinational therapy may improve the efficacy of anti-EGFR targeted therapy in TNBC (11-13). In this regard, curcumin, a major bioactive compound from turmeric, and its derivatives have attracted particular attention in combinational therapy due to their multitargeting action and regulation of multiple signaling pathways (14-16). Of note, curcumin analogue- MS13 (1,5-Bis(4-hydroxy-3-methoxyphenyl)-1,4- pentadiene -3-one) has been found to exhibit greater inhibitory effect against various cancers compared to curcumin (17-19). Therefore, this study for the first time is conducted to investigate anticancer activity, synergistic interactions and the apoptosis induction ability of MS13 and gefitinib co-treatment in MDA-MB-231 cells as a well-known model for triple negative breast cancer (TNBC) research . To achieve these objectives, initially the anticancer potential of MS13 and gefitinib will be assessed alone and in combination through the cell viability and proliferation approaches. Then, following the assessment of combination effect, apoptosis induction will be evaluated for selected concentrations and time points via the investigation of morphological changes, occurrence of early and late apoptosis as well as caspase 3 activity. This research for the first time will reveal the potential anticancer activity of co-treatment of MS13 and gefitinib in TNBC which may be beneficial in anti-EGFR targeted therapy in TNBC. Therefore, the new findings obtained from this study may result in the submission/publication of at least one manuscript in ISI-indexed journal.