Abstract P3-06-06: Pg5 promotes breast cancer metastasis by activatingpi3k/akt/mtor signaling pathways
Authors: Xiang Kui , Yan Wang , Yanshan Hua , Xiaojia Yi , Chunmei Zhao , Minmin Guo 
Published: March 2022

Background: Breast cancer is the most common malignancy and the leading cause of cancer death among women. Glycoprotein V (GP V) is involved in thrombin-induced platelet activation and in other platelet responses. However, its roles and underlying mechanisms in the pathogenesis of breast cancer are still unclear. This study aimed at assessing GP V expression in breast cancer, its subsequent effects on cancer cell apoptosis, proliferation, invasion, and migration, and the underlying molecular mechanisms. Methods: GP V mRNA expression was analysed in total RNA samples obtained from tumor and adjacent normal tissue of 41 breast cancer patients and cell lines (MDA-MB-231, MCF-7 and MCF-10A). The correlation between the expression of GP V and clinicopathological features was analyzed by immunohistochemical (IHC) staining. Stable knockdown and overexpression MDA-MB-231 cell lines were generated by using the lentiviral system. Then, the cells were harvested for CCK-8 assay, flow cytometry, scratch healing experiments, and western blotting. Two samples each from the Stable knockdown and control groups were used for transcriptome sequencing and pathway analysis. Finally key molecules associated with the related signaling pathways were analyzed by RT-PCR and western blot. Results: The results showed that the mRNA (P&lt;0.0001) and protein expression (P&lt;0.001) of GP V in the breast cancer tissues was significantly increased compared with in the adjacent non-tumor tissues. The protein and mRNA expression of GP V were significantly higher in MDA-MB-231 and MCF-7cell lines compared with human normal breast epithelial cells (MCF-10A) (P&lt;0.01). GP V expression was positively correlated with higher histological grade and advanced TNM stage. (P&lt;0.05), but was not related to gender, age, menopausal status, tumor size, vascular invasion, ER, PR, Ki-67 and lymph node metastasis (P&gt;0.05). CCK-8 assay showed that cell viability was enhanced after GP V upregulation compared to the control group (P&lt;0.05). The in vitro scratch assay showed that the number of GP-V-overexpressing cells migrating to the scratch area was significantly higher than that of the control group at 24 h and 48 h, respectively (P&lt;0.001). Flow cytometric analysis demonstrated there was no significant difference in cell cycle distribution and apoptosis. Differential gene expression analysis showed 13 significantly down- and 141 upregulated mRNAs. The mRNA expression levels of PI3K and AKT were significantly increased after GP V upregulation compared with those in the control group (P&lt;0.001). N-cadherin, Vimentin and MMP2/9 were up-regulated after GP V upregulation compared with those in the control group (P&lt;0.05).Conclusion: GP5 is highly expressed in breast cancer tissues and may play an important role as a cancer-promoting gene in breast cancer. The high expression of GP5 was significantly associated with higher nuclear grade, TNM stage and Her-2 negativity. GP5 can promote the proliferation, invasion, and metastasis of breast cancer cells. GP5 may promote the proliferation, invasion, and metastasis by activating PI3K/AKT signaling pathway to upregulate MET, and is expected to become a potential target for clinic diagnosis and treatment.

Citation Format: Kui Xiang, Wang Yan, Hua Yanshan, Yi Xiaojia, Zhao Chunmei, Guo Minmin. Pg5 promotes breast cancer metastasis by activatingpi3k/akt/mtor signaling pathways [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-06-06.