8678

BECN1

beclin 1, autophagy related;BECN1;beclin 1, autophagy related

ATG6 autophagy related 6 homolog|beclin 1 (coiled-coil, moesin-like BCL2 interacting protein)|beclin 1 (coiled-coil, moesin-like BCL2-interacting protein)|beclin-1|coiled-coil myosin-like BCL2-interacting protein

17q21

protein-coding

The influence of the autophagy-related gene Beclin1 on proliferation, invasion and metastasis of the cervical cancer CaSki cells and its possible mechanism in vitro were here targeted. After the overexpression vector pcDNA3.1-Beclin1 and RNA interference vector pSUPER-Beclin1 were transfected into CaSki cells in vitro, stable expression cell lines demonstration Beclin1 expression was upregulated, and VEGF and MMP-9 expression were decreased, leading to cell arrest in the G0/G1 phase of the cell cycle. MTT assays further revealed proliferation of cells was significantly inhibited in Beclin1-overexpressing transfectant cells, with invasion and metastasis also being inhibited in Transwell chamber assays. The present results suggest that Beclin1 inhibits invasion and metastasis of cervical cancer CaSki cells in vitro. Mechanisms probably involve Beclin1 inhibition of cell proliferation, and decreased expression of VEGF and MMP-9 proteins.

Autophagy can be tumor suppressive as well as promotive in regulation of tumorigenesis and disease progression. Accordingly, the prognostic significance of autophagy key regulator Beclin 1 was varied among different tumors. Here, we detected the clinicopathological and prognostic effect of Beclin 1 in the subtypes of intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC). Beclin 1 expression level was detected by immunohistochemistry staining in 106 ICC and 74 ECC patients. We found that Beclin 1 was lowly expressed in 126 (70%) cholangiocarcinoma patients, consist of 72 ICC and 54 ECC. Moreover, the cholangiocarcinoma patients with lymph node metastasis (N1) had a lower Beclin 1 level than that of N0 subgroup (P=0.012). However, we did not detect any correlations between Beclin 1 and other clinicopathological features, including tumor subtypes, vascular invasion, HBV infection, liver cirrhosis, cholecystolithiasis and TNM stage. Survival analysis showed that, compared with the high expression subset, Beclin 1 low expression was correlated with a poorer 3-year progression-free survival (PFS, 69.1% VS 46.8%, P=041) for cholangiocarcinoma. Importantly, our stratified univariate and multivariate analysis confirmed that Beclin 1 lowly expressed ICC had an inferior PFS as well as overall survival than ECC, particularly than that of Beclin 1 highly expressed ECC patients. Thus, our study demonstrated that Beclin 1low expression, correlated with lymph node metastasis, and might be a negative prognostic biomarker for cholangiocarcinoma. Combined Beclin 1 level with the anatomical location might lead to refined prognosis for the subtypes of ICC and ECC.

Beclin 1, an important autophagy-related protein in human cells, is involved in autophagy, differentiation, anti-apoptosis, and cancer progression, which is increased during periods of cell stress and extinguished during the cell cycle. In order to clarify the role of Beclin 1 in gastric carcinogenesis and subsequent progression, its expression was examined by immunohistochemistry and in situ hybridization (ISH) on tissue microarrays containing gastric carcinomas, adjacent non-neoplastic mucosa, and metastatic lymph node. Gastric carcinoma tissue and cell lines were studied for Beclin 1 expression by Western blot or RT-PCR, respectively. The results demonstrated that Beclin 1 was distinctively expressed in GES-1, AGS, BGC-823, GT-3 TKB, HGC-27, KATO-III, MGC-803, MKN28, MKN45, SCH, SGC-7901, or STKM-2 at both mRNA and protein levels. However, Beclin 1 mRNA was highly expressed in gastric carcinoma than matched mucosa by real-time PCR and ISH (P < 0.05). Beclin 1 expression was negatively related to distant metastasis and poor prognosis of gastric carcinoma (P < 0.05). Beclin 1 was highly expressed in male than female patients with gastric carcinoma (P < 0.05). The 65-year-elder patients with gastric carcinoma had higher Beclin 1 expression than the younger ones (P < 0.05). The diffuse-type carcinomas showed less Beclin 1 expression than intestinal- and mixed-type ones (P < 0.05). In intestinal-type gastric carcinoma, Beclin 1 expression was inversely associated with venous invasion, lymph node metastasis, and tumor-node-metastasis (TNM) staging (P < 0.05). Kaplan-Meier analysis indicated that Beclin 1 expression was positively linked to favorable prognosis of the patients with overall and intestinal-type carcinoma (P < 0.05). Cox's proportional hazard model indicated that venous invasion, lymph node metastasis, distant metastasis, TNM staging, and Beclin 1 expression were independent prognostic factors for gastric carcinomas (P < 0.05). It was suggested that aberrant Beclin 1 expression is closely linked to pathogenesis, metastasis, and differentiation of gastric carcinoma. Beclin 1 expression might be employed to indicate the favorable prognosis of gastric carcinomas as an independent factor.

BACKGROUND: Autophagy is believed to be important in tumorigenesis and tumor progression. The human beclin-1 gene, a key regulator of autophagy formation, located on chromosome 17q21, has been identified as the mammalian orthologue of Atg6 (autophagy-related gene) and may be a haploinsufficient tumor suppressor gene. Loss of expression or point mutation could serve as a mechanism of loss of beclin-1 tumor suppressor function in cancers. However, our recent study revealed that point mutation of the beclin-1 gene is a rare event in papillary thyroid carcinoma (PTC). METHODS: We investigated the expression of beclin-1 in human PTC. Tissue samples from 86 cases of papillary thyroid carcinoma were used for the present study. 57 cases of papillary thyroid carcinoma were with lymph node metastasis. The expression of beclin-1 in tumor, normal tissue adjacent to tumor, distant normal tissue, metastatic lymph node and normal lymph node was examined with immunohistochemistry. The beclin-1 expression between tumor and normal tissue, metastatic and normal lymph node was also analyzed. RESULTS: The expression of beclin-1 was detected in 88.4% (76/86) of the tumors and 98.2% (56/57) of metastatic lymph nodes. In contrast, normal tissues adjacent to tumor, distant normal tissues and normal lymph nodes showed no or very weak expression of beclin-1. Beclin-1 was significantly correlated with tumorigenesis and lymph node metastasis in human PTC. CONCLUSIONS: High expression of beclin-1 in PTC and metastatic lymph node suggest that neo-expression of beclin-1 may play a role in tumorigenesis and lymph node metastasis in human PTC.