ROR2 promotes invasion and chemoresistance of triple-negative breast cancer cells by activating PI3K/AKT/mTOR signaling.

This study aimed to investigate the role of receptor tyrosine kinase-like orphan receptor 2 (ROR2) in triple-negative breast cancer (TNBC). ROR2 expression in primary TNBC and metastatic TNBC tissues was analyzed by immunohistochemical staining and PCR. ROR2 expression in TNBC cell lines was detected by PCR and Western blot analysis. The migration, invasion and chemosensitivity of TNBC cells with overexpression or knockdown of ROR2 were examined. ROR2 expression was high in metastatic TNBC tissues. ROR2 knockdown suppressed the migration, invasion and chemoresistance of TNBC cells. ROR2 overexpression in MDA-MB-435 cells promoted the migration, invasion, and chemoresistance. Moreover, ROR2 knockdown in HC1599 and MDA-MB-435 adriamycin-resistant cells enhanced chemosensitivity to adriamycin. ROR2 could activate PI3K/AKT/mTOR signaling in TNBC cells. ROR2 is upregulated and promotes metastatic phenotypes of TNBC by activating PI3K/AKT/mTOR signaling.

DA X ，Ge H ，Shi J ，Zhu C ，Wang G ，Fang Y ，Xu J ... -  《-》

Protective effect of hsa-miR-570-3p targeting CD274 on triple negative breast cancer by blocking PI3K/AKT/mTOR signaling pathway.

To find out the role of hsa-miR-570-3p targeting CD274 in triple negative breast cancer (TNBC) via PI3K/AKT/mTOR signaling pathway. Hsa-miR-570-3p and CD274 expressions in 175 TNBC patients were detected by qRT-PCR and immunohistochemistry respectively. The human TNBC cell lines (MDA-MB-468 and MDA-MB-231) were used to verify the targeting relationship between hsa-miR-570-3p and CD274 via dual-luciferase reporter gene assay. Then, MDA-MB-468 and MDA-MB-231 cells were divided into Blank, miR-NC, miR-570-3p mimics, NC siRNA, CD274 siRNA, and miR-570-3p inhibitors + CD274 siRNA groups. Next, the biological activities of cells were detected by MTT, Cell-Light EdU, Annexin-V-FITC/PI, wound healing and Transwell invasion assays. Western blotting was conducted to detect protein expressions.MiR-570-3p expression was lower in tumor tissues than that in adjacent normal tissues, which was more obvious in CD274-positive TNBC patients, which targeted CD274 in TNBC cell lines. MiR-570-3p inhibited cell proliferation, invasion and migration, but induced cell apoptosis accompanying the upregulation of apoptotic proteins and downregulation of anti-apoptotic protein. CD274 siRNA had the similar results of miR-570-3p mimics, which could be reversed by miR-570-3p inhibitors. Besides, both miR-570-3p mimics and CD274 siRNA blocked PI3K/AKT/mTOR signaling pathway in TNBC cell lines. Hsa-miR-570-3p was downregulated and CD274 was upregulated in TNBC patients. Besides, hsa-miR-570-3p targeted CD274 to inhibit cell proliferation, invasion, migration, and induce cell apoptosis, which may be related to the suppression of PI3K/AKT/mTOR pathway.

Wang LL ，Huang WW ，Huang J ，Huang RF ，Li NN ，Hong Y ，Chen ML ，Wu F ，Liu J ... -  《-》

Hsa_circ_0000199 facilitates chemo-tolerance of triple-negative breast cancer by interfering with miR-206/613-led PI3K/Akt/mTOR signaling.

Li H ，Xu W ，Xia Z ，Liu W ，Pan G ，Ding J ，Li J ，Wang J ，Xie X ，Jiang D ... -  《Aging-US》

Down-regulating GRP78 reverses pirarubicin resistance of triple negative breast cancer by miR-495-3p mimics and involves the p-AKT/mTOR pathway.

Due to the lack of known therapeutic targets for triple-negative breast cancer (TNBC), chemotherapy is the only available pharmacological treatment. Pirarubicin (tetrahydropyranyl Adriamycin, THP) is the most commonly used anthracycline chemotherapy agent. However, TNBC has a high recurrence rate after chemotherapy, and the mechanisms of chemoresistance and recurrence are not entirely understood. To study the chemoresistance mechanisms, we first screened compounds on a pirarubicin-resistant cell line (MDA-MB-231R) derived from MDA-MB-231. The drug resistance index of MDA-MB-231R cells was approximately five times higher than that of MDA-MB-231 cells. MDA-MB-231R cells have higher GRP78 and lower miR-495-3p expression levels than MDA-MB-231 cells. Transfecting MDA-MB-231R cells with a siGRP78 plasmid reduced GRP78 expression, which restored pirarubicin sensitivity. Besides, transfecting MDA-MB-231R cells with miR-495-3p mimics increased miR-495-3p expression, which also reversed pirarubicin chemoresistance. Cell counting kit-8 (CCK-8), EdU, wound healing, and Transwell assays showed that the miR-495-3p mimics also inhibited cell proliferation and migration. Based on our results, miR-495-3p mimics could down-regulate GRP78 expression via the p-AKT/mTOR signaling pathway in TNBC cells. Remarkably, chemo-resistant and chemo-sensitive TNBC tissues had opposite trends in GRP78 and miR-495-3p expressions. The lower the GRP78 and the higher the miR-495-3p expression, the better prognosis in TNBC patients. Therefore, the mechanism of pirarubicin resistance might involve the miR-495-3p/GRP78/Akt axis, which would provide a possible strategy for treating TNBC.

Liu M ，Yang J ，Lv W ，Wang S ，Du T ，Zhang K ，Wu Y ，Feng X ... -  《-》

WNT1/ROR2 pathway enhances the Triple-Negative breast cancer invasion, migration, and Epithelial-Mesenchymal transition.

It has been evidenced that ROR2 influences the growth of many tumors, including non-small cell lung cancer, osteosarcoma, and breast cancer. This research examined the effect of the WNT1/ROR2 signaling pathway on the progression of triple-negative breast cancer (TNBC). Bioinformatics analysis results demonstrated that ROR2 had a higher messenger RNA (mRNA) expression level in TNBC tissues and was positively correlated with poor patient prognosis. Western blot analysis (WB) and quantitative reverse transcription polymerase chain reaction demonstrated that TNBC cells had relatively higher ROR2 mRNA and protein levels than normal cell lines. Transwell and Cell Counting Kit-8 (CCK-8) assay further proved that downregulating ROR2 expression dramatically slowed the MDA-MB-231 cell progression. WB detection of epithelial-mesenchymal transition (EMT)-related proteins suggested that knocking down ROR2 could alleviate the EMT tendency of cancer cells. The WNT1/ROR2 signaling pathway could be inhibited by the WNT inhibitor pyrvinium pamoate (PP). Experiments on in vitro cell functional recovery have demonstrated that PP could restore malignant phenotypes caused by ROR2 overexpression. Finally, the mouse model experiments further validated the anticancer effect of PP on TNBC. Generally speaking, the malignant progression of TNBC could be stimulated by the WNT1/ROR2 signaling pathway which can be inhibited by PP, suggesting the potential value of PP in controlling TNBC.

Jin X ，Fu C ，Chen Y ，Jin C ，Jin G ，Yan J ... -  《-》