SH003 overcomes drug resistance and immune checkpoints by inhibiting JAK-STAT3 signaling in MCF7/ADR cells

• Main Authors: Jin Mo Ku, Se Hyang Hong, Hyo In Kim, Min Jeong Kim, Su-Jeong Ku, Kwang-Rok Bae, Hye Sook Seo, Yong Cheol Shin, Seong-Gyu Ko
• Format: Article
• Language: English
• Published: Elsevier 2021-11-01
• Series: Phytomedicine Plus
• Subjects: SH003; PD-L1; Drug resistance; STAT3; Doxorubicin
• Online Access: http://www.sciencedirect.com/science/article/pii/S2667031321000932

Background: Breast cancer has the most commonly diagnosed malignancy cancer worldwide in women and has a high mortality. Various anticancer drugs to treat breast cancer have been developed and tested but have failed because of drug resistance. Objectives: The efficacy of SH003 against doxorubicin-resistant MCF/ADR cells has not been evaluated. In this study, we aimed to examine whether SH003 could efficiently prevent the proliferation of MCF7/ADR cells. Methods: Cell viability was measured by an MTT assay. Analysis of cell cycle arrest was performed by flow cytometry. Induction of apoptosis by SH003 was measured by an annexin V-FITC/PI assay. Levels of p-STAT3, p-PD-L1, MDR and caspases were measured by western blot analysis. mRNA expression levels of MDR1, MRP1, -2, -3, -4, -5, -6, -9, BCRP and PD-L1 were measured by RT-PCR. Nuclear staining of STAT3 was measured by immunocytochemistry. The expression levels of VEGF, MMP-2 and MMP-9 were measured by ELISA. Results: SH003 inhibited the proliferation of MCF7/ADR cells and induced their sub-G1 cell cycle arrest. SH003 also induced apoptosis, regulated apoptotic molecules, caused morphological changes and inhibited colony formation in MCF7/ADR cells. Furthermore, SH003 suppressed STAT3 transcriptional activity and, more importantly, reduced the cytokine levels of VEGF, MMP-2 and MMP-9 in MCF7/ADR cells. SH003 decreased the protein expression of PD-L1 and MDR1. Additionally, SH003 reduced the mRNA expression of PD-L1; MDR1; MRP1, -2, -3, -4, -5, -6, and -9; and BCRP. Conclusion: Our results clearly demonstrate that SH003 inhibits cell growth and induces apoptosis by inhibiting STAT3 signaling. Additionally, SH003 decreased the levels of MDR1 and PD-L1 by inhibiting STAT3 signaling in MCF7/ADR breast cancer cells. These results support the possibility that SH003 could be useful as an herbal medicine to treat doxorubicin-resistant breast cancer.