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Objective:To investigate the effect and mechanism of long non-coding RNA (lncRNA) TTN-AS1 on the radiosensitivity of breast cancer cells. Methods:The expression of TTN-AS1 in breast cancer cells was detected by real-time reverse transcription PCR (qRT-PCR). MDA-MB-231 cells were divided into the 0 Gy group, 4 Gy group, negative control (NC) +4 Gy group, si- TTN-AS1+4 Gy group, si- TTN-AS1+ miR-107 inhibitor+4 Gy group, and si- TTN-AS1+ miR-107 inhibitor+si- HMGA1+4 Gy group. CCK-8 assay and flow cytometry were used to detect the proliferation and apoptosis rates in each group. Results:Compared with breast epithelial cells, TTN-AS1 was significantly highly expressed in breast cancer cell lines ( P<0.001). Compared with the NC+4 Gy group, the cell proliferation ability was significantly decreased ( P<0.05) and cell apoptosis was significantly increased ( P<0.001) in the si- TTN-AS1+4 Gy group. Compared with the 0 Gy group, the expression levels of TTN-AS1 and HMGA1 from 8 h to 24 h after radiotherapy were significantly up-regulated (both P<0.01), whereas the expression of miR-107 was significantly down-regulated from 8 h to 24 h after radiotherapy in the 4 Gy group ( P<0.001). The cell proliferation ability in the si- TTN-AS1+ miR-107 inhibitor+4 Gy group was significantly higher than that in the si- TTN-AS1+4 Gy group ( P<0.001), and cell apoptosis was significantly lower than that in the si- TTN-AS1+4 Gy group ( P<0.001). Compared with the si- TTN-AS1+ miR-107 inhibitor+4 Gy group, cell proliferation ability was significantly decreased ( P<0.001), whereas cell apoptosis was significantly increased in the si- TTN-AS1+ miR-107 inhibitor+si- HMGA1+4 Gy group ( P<0.001). Conclusion:TTN-AS1 can promote the radiosensitivity of breast cancer cells by regulating the miR-107/ HMGA1 signaling axis.
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@#[Abstract] Objective：To study the expression of long non-coding RNA(lncRNA) titin antisense RNA1 (TTN-AS1) in lung adenocarcinoma (LUAD) tissues, and explore its relationship with clinicopathologic characteristics and prognosis of LUAD patients. Methods: The TTN-AS1 expression in LUAD data set was analyzed using TCGAdatabase. 52 pairs of tumor tissues and matched para-carcinoma tissues from LUAD patients, who underwent surgical resection and were later pathologically conformed in Fourth Hospital of Hebei Medical University between Jan. 2014 and Jan. 2015, were used in this study. qPCR was performed to detect TTN-AS1 expression in the specimens. Then, the correlations between TTN-AS1 expression and clinicopathologic characteristics were analyzed. Survival analysis was used to determine the significance of TTN-AS1 expression for predicting the prognosis of LUAD patients. Results: TCGAdatabase analysis and qPCR results showed that TTN-AS1 expression in LUAD tissues was significantly higher than that in normal lung and para-carcinoma tissues (both P<0.01). TTN-AS1 expression in LUAD tissues was significantly correlated with the TNM stage and lymph node metastasis (P<0.05), but not correlated with gender, age, tumor invasion range (P>0.05). Kaplan-Meier univariate analysis result demonstrated that the patients with high TTN-AS1 expression had shorter post-operative disease-free survival (DFS) and overall survival (OS) than those patients with low TTN-AS1 expression (all P<0.01). Cox proportional hazard regression model result demonstrated that wider tumor invasion range, positive lymph node metastasis and high TTN-AS1 expression were significantly correlated with shorter postoperative DFS and OS (P<0.05). Conclusion: TTN-AS1 was highly expressed in LUAD tissues, and closely correlated with TNM stage and lymph node metastasis of LUAD patients (all P<0.05). High expression of TTN-AS1 is significantly correlated with shorter DFS and OS, indicating that TTN-AS1 may be a biomarker for predicting poor prognosis of LUAD patients.