[hsa_circ_0001776 targeting miR-1265 regulates the development of lung squamous cell carcinoma and clinical significance].

To further explore the role and mechanism of hsa_circ_0001776 and mir-1265 in lung squamous carcinoma by verifying the expression level of hsa_circ_0001776 in plasma, tissues, and cells of lung squamous carcinoma. Plasma was collected from patients with lung squamous carcinoma treated at Tangshan People's Hospital and healthy individuals from 2020 to 2022. Lung squamous carcinoma tissue microarrays purchased from Shanghai Xinchao Biotechnology Company in 2022. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression of hsa_circ_0001776 in lung squamous carcinoma plasma, tissues, and cells, and fluorescence in situ hybridization was used to verify the expression of hsa_circ_0001776 in lung squamous carcinoma. The localization of hsa_circ_0001776 in NCI-H1703 was verified by fluorescence in situ hybridization. The lung squamous carcinoma cells NCI-H1703 and NCI-H226 were cultured and divided into the circ-negative control (NC) group, hsa_circ_0001776 overexpression group, miR-NC group, miR-1265 mimic group, hsa_circ_0001776+miR-NC group, and hsa_circ_0001776+miR-1265 mimic group.The cell proliferation, motility and apoptosis were detected by the cell counting kit-8 (CCK-8) method, clone formation, Transwell invasion and migration, and scratch assay, and flow cytometry, respectively. The downstream of hsa_circ_0001776 was predicted by circular RNA interactome website, and the interaction between hsa_circ_0001776, miR-1265 was further determined by dual luciferase reporter gene assay, and nude mice subcutaneous tumorigenesis assay detected the growth of transplanted tumors. Fluorescence in situ hybridization results showed that the fluorescence intensity of hsa_circ_0001776 in lung squamous carcinoma tissues was lower than that in paracancerous tissues, and the fluorescence intensity of miR-1265 in lung squamous carcinoma tissues was higher than that in paracancerous tissues (both ＜0.05). The expression level of hsa_circ_0001776 in the plasma of lung squamous carcinoma patients was lower than that in the plasma of healthy people, and the expression level of miR-1265 was higher than that in the plasma of healthy people (both ＜0.05). The expression levels of hsa_circ_0001776 in lung squamous carcinoma cells NCI-H1703, NCI-H226 and SK-MES-1 were lower than that in bronchial epithelial cells BEAS-2B (all ＜0.05), and the relative expression levels of miR-1265 in NCI-H1703 and NCI-H226 were higher than that in human bronchial epithelial cells BEAS -2B (all ＜0.05). The expression of hsa_circ_0001776 was correlated with age, lymph node metastasis, clinical stage, and tumor stage in patients with lung squamous carcinoma (all ＜0.05). Fluorescence in situ hybridization results showed that hsa_circ_0001776 was mainly expressed in the cytoplasm. The results of dual-luciferase reporter assay showed complementary binding of miR-1265 to hsa_circ_0001776. The absorbance values of the hsa_circ_0001776 overexpression group in NCI-H1703 and NCI-H226 cells were lower than that of the circ-NC group (＜0.05). The number of cell clones in the hsa_circ_0001776 overexpressed group was (52±3) and (53±4), the number of migrating cells was (476±17) and (113±7), the number of invading cells was (100±2) and (184±2), and the cell migration rate was (25.00±4.36)% and (36.02±5.55)%, which were lower than those of the circ-NC group [(104±4) and (106±2), (783±29) and (517±16), (657±45) and (473±9), (48.95±8.69)% and (48.70±1.57)%, all ＜0.05]. The apoptosis rates in the overexpression hsa_circ_0001776 group were (24.77±2.303)% and (19.67±1.16)%, respectively, both higher than those in the circ-NC group [(11.83±1.15)% and (9.50±0.66)%, respectively, both ＜0.05]. MiR-1265 mimic group had a higher apoptotic rate in the NCI-H1703 and NCI-H226 than those of the miR-NC groups (＜0.05). miR-1265 mimic group had (56±13) and (51±8) cell clones, (556±13) and (405±6) migrating cells, (486±6) and (359±7) invading cells, cell migration rates of (68.56±5.51)%, (81.74±8.04)%, were higher than those of miR-NC group [(31±4) and (21±8), (154±19) and (186±5), (227±6) and (176±7), (25.83±4.26)% and (53.12±4.14) %, all ＜0.05]. The apoptotic rates in the miR-1265 mimic group were (11.83±2.55)% and (17.50±1.05)%, respectively, which were lower than those in the miR-NC group [(32.67±4.44)% and (39.90±2.88)%, respectively, both <0.05]. The absorbance values of NCI-H1703 and NCI-H226 in the overexpression of hsa_circ_0001776+miR-1265 mimic group were higher than those of the overexpression of hsa_circ_0001776+miR-NC group (<0.05). The overexpression of hsa_circ_0001776+miR-1265 mimic group had (128±15) and (133±8) cell clones, (623±10) and (310±7) migrating cells, (643±16) and (420±7) invading cells, (66.39±4.46)% cell migration rate and (68.60±3.53)%, were higher than those of the hsa_circ_0001776+miR-NC group [(86±7) and (80±16), (380±11) and (115±5), (152±7) and (94±4), respectively, (31.41±5.91)% and (30.94±0.67)%, all ＜0.05]. The apoptotic rates in the overexpression of hsa_circ_0001776+miR-1265 mimic group were (19.27±0.15)% and (11.53±0.75)%, respectively, both lower than those in the overexpression of hsa_circ_0001776+miR-NC group [(27.77±1.29)% and (18.43±0.71)%, both ＜0.05]. The results of the subcutaneous tumorigenesis assay in nude mice showed that the volume of tumors in the overexpression of hsa_circ_0001776 group was lower than that in the circ-NC group (＜0.05). hsa_circ_0001776 is downregulated in lung squamous cell carcinoma, and hsa_circ_0001776 can inhibit the development of lung squamous cell carcinoma by targeting miR-1265.