Numb suppression promoted the pathogenesis of SiHa cells by stimulating Notch and Hedgehog signaling pathways

Background: Cervical cancer is a life -threatening disease prevalent in the female population. Although many important advances have taken place in the diagnosis and treatment of cervical cancer, its mechanisms have not been fully elucidated to date. The aim of this study was to clarify the functional role of Numb in human cervical squamous carcinomas. Methods: The expression and location of Numb in SiHa cell lines was detected by Western blotting and immunofluorescence. Numb gene knockdown using shRNA plasmid and a Numb transfection system were used to assess its function in vivo and in vitro. Twenty-five normal cervical epithelium, 60 CIN, 203 squamous carcinoma and 21 lymph node tissue specimens of the cervix tissue were collected from clinical specimens. The expression of Numb protein was detected by Western blotting and immunofluorescence, and data on clinical variables were collected by retrospective chart review. The mechanistic studies of the Numb regulation progression were identified by Western blotting. Results: Ectopic expression of Numb confers cervical squamous carcinomas with malignant features including malignant proliferation, migration and invasion. Meanwhile, Numb repression in tumor cells dramatically accelerated the progression of cervical squamous carcinomas in xenograft mouse model. Furthermore, our data revealed that Numb inhibition promotes malignant transformation of cervical squamous carcinoma through stimulation of Notch and Hedgehog -dependent pathways. Clinical evidence also showed that in squamous cervical cancer with different lymph node metastases, Numb expression was significantly lower in the lymphatic metastasis group than in the no lymph node metastasis group. Conclusions: Collectively, our findings indicated that ectopic expression of Numb was an important factor in the progression of cervical cancer and that low Numb expression levels can be used as an indicator of the prognosis of squamous cervical cancer.