Loss of ASAP1 in the MMTV-PyMT model of luminal breast cancer activates AKT, accelerates tumorigenesis, and promotes metastasis

Role of ADP ribosylation factor guanylate kinase 1 in the malignant biological behavior of gastric cancer

Aim

This study aims to investigate the influence of ASAP1 (ADP ribosylation factor guanylate kinase 1) on the malignant behavior of gastric cancer (GC) cells and to elucidate the potential molecular mechanisms involved in cancer development and progression.

Methods

We assessed the impact of ASAP1 overexpression and knockdown on GC cell malignancy using CCK8, colony formation, flow cytometry (Annexin V/propidium iodide), Transwell migration, invasion, and scratch assays. Western blot analysis was used to assess the effects of ASAP1 on angiogenesis, matrix metalloproteinases (MMPs), apoptotic proteins, epithelial-mesenchymal transition (EMT)-related proteins, as well as AKT and p-AKT. The influence of ASAP1 knockdown was also evaluated in nude mice bearing BGC823 cell-derived tumors.

Results

Our findings revealed that ASAP1 was significantly overexpressed in GC cells, enhancing their proliferation, invasion, and migration, while reducing apoptosis. Conversely, ASAP1 knockdown reversed these effects, markedly increasing the expression of cleaved-caspase 3 (Casp3), PARP, and the epithelial marker E-cadherin, and significantly decreasing MMP2, MMP9, VEGFA, and mesenchymal markers such as N-cadherin and vimentin. Additionally, it reduced AKT, and p-AKT levels (P < 0.01). Tumor growth in nude mice was suppressed following ASAP1 knockdown.

Conclusion

The overexpression of ASAP1 significantly promotes malignant behaviors in GC cells, whereas its knockdown diminishes these effects. This modulation is potentially through the downregulation of VEGFA, leading to reduced angiogenesis, Cleaved-Casp3 and Cleaved-PARP overexpression, and a decrease in MMPs, EMT, AKT, and p-AKT activity.

ASAP1 Expression in Invasive Breast Cancer and Its Prognostic Role

Breast cancer is a major global health burden with high morbidity and mortality rates. Previous studies have reported that increased expression of ASAP1 is associated with poor prognosis in various types of cancer. This study was conducted on 452 breast cancer patients who underwent surgery at Hanyang University Hospital, Seoul, South Korea. Data on clinicopathological characteristics including molecular pathologic markers were collected. Immunohistochemical staining of ASAP1 expression level were used to classify patients into high and low groups. In total, 452 cases low ASAP1 expression group was associated with significantly worse recurrence-free survival (p = 0.029). In ER-positive cases (n = 280), the low ASAP1 expression group was associated with significantly worse overall survival (p = 0.039) and recurrence-free survival (p = 0.029). In multivariate cox analysis, low ASAP1 expression was an independent significant predictor of poor recurrence-free survival in the overall patient group (hazard ratio = 2.566, p = 0.002) and ER-positive cases (hazard ratio = 4.046, p = 0.002). In the analysis of the TCGA dataset, the low-expression group of ASAP1 protein demonstrated a significantly poorer progression-free survival (p = 0.005). This study reports that low ASAP1 expression was associated with worse recurrence-free survival in invasive breast cancer.