SASH1 regulates proliferation, apoptosis, and invasion of osteosarcoma cell

Abstract

SASH1, a member of the SLY-family of signal adapter proteins, is a candidate tumor suppressor in breast and colon cancer. The SASH1 protein possesses both the SH3 and SAM domains, indicating that it may play an important role in intracellular signal transduction. Reduced expression of SASH1 is closely related to tumor growth, invasion, metastasis, and poor prognosis. However, the biological role of SASH1 remains unknown in osteosarcoma. To unravel the function of SASH1, we explored the expression of SASH1 in osteosarcoma tissues and its correlation to the clinical pathology of osteosarcoma and analyzed the relationship between SASH1 expression and cell cycle, apoptosis and invasion of osteosarcoma MG-63 cells, using the flow cytometry analysis and transwell invasion chamber experiments. Furthermore, the effect of SASH1 on the expression of cyclin D1, caspase-3, matrix metalloproteinase (MMP)-9 were observed by western blot. Our results showed that the expression rate of SASH1 mRNA in osteosarcoma tissues was significantly lower than that in normal bone tissue (p = 0.000), that the expression rate of SASH1 mRNA in the carcinoma tissues from patients with lung metastasis was significantly lower than that from patients without lung metastasis (p = 0.041), and that the expression rate of SASH1 mRNA also decreased with increasing Enneking stage (p = 0.032). However, the mRNA expression of SASH1 in osteosarcoma was independent of the patient's gender, age, and tumor size (p = 0.983, 0.343, 0.517, respectively). The SASH1 protein displayed a down-regulation in osteosarcoma tissues compared to normal bone tissue (p = 0.000), displayed a down-regulation in osteosarcoma tissues from patients with lung metastasis compared to from patients without lung metastasis (p = 0.000), and displayed a gradual decrease with increasing Enneking stage (p = 0.000). In addition, the MG-63 cells from pcDNA3.1-SASH1 group exhibited significantly reduced cell viability, proliferation, and invasive ability compared to the empty vector group and blank control group (p = 0.023, 0.001, respectively), and there was no difference between the empty vector group and blank control group. The pcDNA3.1-SASH1 group displayed significantly more apoptotic cells than the empty vector group and blank control group (p = 0.004). The expression of cyclin D1, MMP-9 displayed a down-regulation in MG-63 cells from pcDNA3.1-SASH1 group compared to the empty vector group and blank control group (p = 0.000, 0.001, respectively) and the expression levels of caspase-3 displayed an up-regulation in MG-63 cells from pcDNA3.1-SASH1 group compared to the empty vector group and blank control group (p = 0.000). Taken together, these data indicated that the overexpression of SASH1 might be associated with the inhibition of growth, proliferation, and invasion of MG-63 cells and the promotion of apoptosis of MG-63 cells.

Autosomal-recessive SASH1 variants associated with a new genodermatosis with pigmentation defects, palmoplantar keratoderma and skin carcinoma

“…6,7 Consistent with the onset of carcinoma in the affected individuals in this study, SASH1 was recently reported to be involved in the tumorigenesis of several cancers. [15][16][17][18][19][20] Cellular experiments showed that SASH1 localizes to the nucleus and cytoplasm of epithelial cells and might regulate cellular migration and adhesion, through its role in protruding membrane structures. 21 Through its central SH3 domain, SASH1 interacts with the actin cytoskeleton and especially cortactin, a major regulator of actin filament dynamics.…”

“…SASH1 encodes a candidate tumor suppressor from the SLY family of signal proteins. [15][16][17][18][19][20] This variant was absent from Exome Variant Server, dbSNP and local exomes, predicted as deleterious by Condel and possibly damaging by Polyphen2, and comes from a well-conserved sequence (GERP conservation score: 5090) (see Web Resources). Cosegregation analysis in all available relatives confirmed its presence in a homozygous state in both affected patients (III.6 and III.3), in a heterozygous state in both parents and an unaffected brother (III7) and absent in the unaffected sister (III4).…”

The pleiotropic effects of fisetin and hesperetin on human acute promyelocytic leukemia cells are mediated through apoptosis, cell cycle arrest, and alterations in signaling networks

“…In a recent study, exogenous overexpression of the MT1F gene increased apoptosis in colon cancer cells [37], which supports our data. SASH1, a potential tumor suppressor, may function in various signaling pathways due to its SH3 and SAM domains; thus, its downregulation is related to tumor growth [38]. Therefore, its increased expression after hesperetin treatment might induce apoptosis and growth suppression.…”

Downregulation of SASH1 correlates with tumor progression and poor prognosis in ovarian carcinoma

“…These results indicated that the down-regulation of SASH1 is at least in part due to gene deletion (13). Down-regulation of SASH1 expression was closely correlated with tumor invasion, metastasis, and poor prognosis (22)(23)(24). However, the specific role of SASH1 in ovarian carcinoma has not yet been reported in the literature.…”

“…Therefore, the study of suppressor genes and apoptosis-related genes in carcinogenesis and tumor progression in ovarian carcinoma has drawn increasing attention. A previous study indicated that SASH1 is a tumor suppressor gene, located on chromosome 6q24.3 (22). Zeller et al (13) demonstrated reduced or absent SASH1 expression in 6 breast cancer cell lines, which exhibit a chromosome 6q24.3 deletion.…”