Zishen Qingre Lishi Huayu recipe promotes proliferation and inhibits apoptosis of GCs of PCOS via KLF4-C/EBPβ pathway

Abstract

Ethnopharmacological relevance: Zishen Qingre Lishi Huayu recipe (ZQLHR) is a herbal recipe created on the basis on the theory of traditional Chinese medicine and clinical practice, and is mainly used in the treatment of polycystic ovary syndrome (PCOS). However, the underlying mechanism for this fact has not been clearly elucidated.

Aim of the study: To verify whether ZQLHR regulates granulosa cells (GCs) proliferation and apoptosis through the Krüppel-like factor 4 (KLF4) - CCATT enhancer-binding proteinβ (C/EBPβ) pathway, and to provide in vitro molecular mechanism supporting for the effects of ZQLHR to enhance follicular development and treat patients with PCOS.

Materials and methods: Based on previous experiments, we performed the following experiments. Firstly, we treated KGN cells (a steroidogenic human granulosa-like tumor cell line) for 48 h using different concentrations of ZQLHR in order to observe apoptosis in each group. Secondly, the mRNA and protein expression levels of KLF4 and C/EBPβ in KGN cells after administrated with ZQLHR were examined by quantitative real-time PCR(q-PCR) and Western blot assay. Thirdly, after knocking down KLF4 and C/EBPβ using siRNAs, the relationship between KLF4 and C/EBPβ in KGN cells was detected. Further, cell counting kit-8 assay, colony formation assay and flow cytometry were used to verify whether ZQLHR promotes proliferation and facilitates apoptosis in KGN cells through the KLF4-C/EBPβ pathway. Finally, q-PCR and Western blot were used to test whether ZQLHR mediated proliferation and apoptosis-related factors such as B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X (BAX), proliferating cell nuclear antigen (PCNA) and cleaved caspase-3 to affect the proliferation and apoptosis of KGN cells through the KLF4-C/EBPβ pathway.

Conclusions: ZQLHR, containing 0.2% by volume, administered to KGN cells resulted in the lowest rate of apoptosis. The expression levels of KLF4 and C/EBPβ were increased in KGN cells following ZQLHR treatment. Additionally, ZQLHR promoted proliferation and inhibited apoptosis of KGN cells by modulating proliferation and apoptosis-related factors via the KLF4-C/EBPβ pathway. Furthermore, we confirmed that KLF4 and C/EBPβ regulate each other in KGN cells. These findings indicate that ZQLHR enhances the proliferation of GCs and suppresses their apoptosis, which constitutes a therapeutic mechanism for treating patients with PCOS.

Keywords: Apoptosis; C/EBPβ; PCOS; Proliferation; Zishen Qingre Lishi Huayu recipe.