Suppression of Tumorigenicity 5 Ameliorates Tumor Characteristics of Invasive Breast Cancer Cells via ERK/JNK Pathway

BackgroundSuppression of tumorigenicity 5 (ST5) has been considered as a tumor suppressor gene in HeLa tumor cells. However, its role in the progression of breast cancer remains vague.MethodsOnline database analysis was determined by Oncomine and Breast Cancer Gene-Expression Miner v4.4 (bc-GenExMiner v4.4). Tumor biology behaviors were measured by MTT assay, wound healing model, Transwell and Flow cytometry assays. Methylation-specific PCR (MSP) was employed to detect promoter methylation.ResultsLow level of ST5 was observed in breast cancer specimens, particularly in recurrent, invasive breast cancer cases compared to para-carcinoma tissue or non-invasive breast cancer. The downregulation of ST5 was also proved in MDA-MB-231 and SKBR3 cell lines with a high invasive capability as compared to MCF-7 cell with a low invasive capability. ST5 was negatively associated with pathological stages of breast cancer. ST5-downregulation promoted, while ST5-upregulation inhibited the progression of cell proliferation, cell cycle and migration of MDA-MB-231 cells. Additionally, ST5 knockdown inhibited, whereas ST5 overexpression promoted apoptosis of MDA-MB-231 cells. However, ST5 modification, either upregulation or downregulation, had no significant impact on tumor behaviors of MCF-7 cells. Mechanistically, ST5 protein ablation activated, while ST5-upregulation repressed the activities of phosphorylated ERK1/2 and JNK, and subsequently the expression of c-Myc. PD98059-mediated ERK1/2 inhibition abolished the stimulatory effects of ST5-depletion on ERK1/2/JNK/c-Myc signaling axis, and ST5 depletion-mediated cell over-proliferation and migration. Of note, ST5 reduction in invasive breast cancer cells should implicate in the hypermethylation of ST5 promoter region.ConclusionOur findings suggest that ST5 potentially acts as a tumor suppressor gene in invasive breast cancer through regulating ERK/JNK signaling pathway and provide a novel insight for breast cancer treatment.

Download Full-text

Suppression of Tumorigenicity 5 Ameliorates Tumor Characteristics of Invasive Breast Cancer Cells via Integrating ERK/JNK Pathway

10.21203/rs.3.rs-58828/v1 ◽

2020 ◽

Author(s):

Jianghong Cheng ◽

Mingli Li ◽

Chi-Meng Tzeng ◽

Xingchun Gou ◽

Shuai Chen

Keyword(s):

Breast Cancer ◽

Cell Cycle ◽

Tumor Suppressor ◽

Cell Viability ◽

Cancer Cells ◽

Invasive Breast Cancer ◽

Breast Cancer Cells ◽

Suppressor Gene ◽

Pathological Stages ◽

Mcf 7

Abstract Background: Suppression of tumorigenicity 5 (ST5) has been considered as a tumor suppressor gene in HeLa tumor cells. However, there is no report of ST5 expression or function in the progression of breast cancer.Methods: ST5 expression in different subtypes and pathological stages of breast cancer was determined by Oncomine database, Breast Cancer Gene-Expression Miner v4.4 (bc-GenExMiner v4.4) analysis and immunohistochemistry. Cell viability was measured by CCK8 assay and metastatic behavior was assessed using scratch wound model and Transwell. Flow cytometry was employed for cell cycle and apoptosis detection, and methylation-specific PCR (MSP) was used to detect methylation level.Results: ST5 was expressed at low level in different subtypes of breast cancer specimens compared to normal breast and there was a negative association between ST5 status and pathological stages of breast cancer patients. Additionally, ST5 was lower in cases of recurrent and invasive breast cancer than that in non-recurrent and non-invasive patients. In in vitro experiment, ST5 status was also negatively associated with the invasive capability of breast cancer cells, showing lower in MDA-MB-231 and SKBR3 cell lines than that in MCF-7 cells. ST5-downregulation promoted, while ST5-upregulation inhibited the tumour characteristics of MDA-MB-231 cells including cell viability, cell cycle and migration. And exogenous ST5 also elevated, but ST5 depletion limited the proportion of apoptotic cells in MDA-MB-231 cells. However, the alteration of ST5, no matter upregulation or downregulation, had no impact on tumour behaviors of MCF-7 cells. Mechanistically, ST5 protein ablation activated, while ST5-upregulation repressed the activities of phosphorylated JNK and ERK1/2, and subsequently the expression of c-Myc. Of note, low level of ST5 in breast cancer cells was possibly related with the aberrant methylation of ST5 promoter region.Conclusion: Our findings suggest that ST5 potentially acts as a tumor suppressor gene in invasive breast cancer through regulating ERK/JNK signaling pathway and provide a novel insight for breast cancer treatment.

Download Full-text