The Clinical Significance Of LGR5Expression In Cervical Cancer And Its Effect On The Biological Behavior Of Cervical Cancer Cells

Cervical cancer is one of the major health problems for women. The global yearlyincidence of cervical cancer was about530,000and the annual death rate was about27,5000. It is the3rdmost common cancer in women worldwide and the second mostfrequent cause of cancer death in women. The incidence of cervical cancer still remainshigh in the developing countries. In China about137,000new cases are diagnosed, about1/5of the world new incidence. Persistent human papillomavirus (HPV) infection is themost important factor in the development of cervical cancer.In recent decades, thanks to the effective screening and comprehensive treatmentcombining surgery, radiation and chemotherapy, the incidence and mortality of cervicalcancer, especial of cancer of early stage is decreasing. But the5-year survival of the latestage and relapsed patients is only3.2%-13%. Recent studies have demonstrated theexistence of a small subpopulation of cancer stem cells (CSC) that are highly tumorigenicand chemo-radio resistant and therefore may provide explanations for the failure totraditional anti-tumor therapies which act only on differentiated tumor cells but not CSCs.Therefore, how to target cancer stem cells should be highlighted in anti-tumor therapy.Leucine-rich repeat containing G-protein-coupled receptor5(LGR5) is regarded as anewly discovered stem cell marker in intestinal mucosa, stomach and hair follicle in theskin. The expression of LGR5is positively regulated by the Wnt signaling pathway whichis involved in the tumorigenesis of various cancers. Patients with LGR5+colorectal cancer and gastric cancer showed better prognosis than patients with LGR5-.Despite the eminent role of LGR5/Wnt signaling in tumorigenesis, the functional roleof LGR5in cervical cancer has not yet been examined. In this study, we studied theexpression pattern of LGR5in clinical samples of cervical squamous cancer of differentpathological grades and investigated its biological function by cervical squamous cancercell line SiHa in vitro and in vivo.Part I The expression and clinical significance of LGR5in cervicalsquamous cancerObjective: To investigate the expression patterns of LGR5in cervical squamouscancer samples and tumor adjacent tissues and analysis the correlation to pathologicalparameters to explore the significance of LGR5expression in the tumorogensis of cervicalcancer.Methods: Cervical squamous cancer samples and adjacent tissues with particularpathological data from31patients were collected. LGR5expression was detected by IHCand the correlation was analyzed by corresponding statistic methods.Results: The IHC staining showed that LGR5expressions in tumor and adjacenttissues were quite different. LGR5molecules were highly and widely expressed in all the31cancer tissues and the expression in adjacent tissues was relatively lower. The LGR5expression was correlated to the pathological grades of the cancer, while uncorrelated tothe lymphatic metastasis by present data.Conclusions: LGR5molecule was abnormally expressed in cervical squamous tissues,correlating to pathological grades. Part II The role of R-spondin1/LGR5signaling in the biologicalfunctions of cervical squamous cell line SiHaObjective: To investigate the role of R-spondin1/LGR5signaling in the biologicalfunctions of cervical cancer cell line SiHa, to explore the underlying mechanisms of LGR5on the tumorogensis of cervical cancer.Methods: The LGR5expression was detected by FCM. Cell counting together withFCM were performed to study cell proliferation and change of cell cycle after R-spondin1stimulation. Intracellular IL-6and TGF-β expression were checked by ICC and FCM.Tumorigenicity in vivo was investigated by transplanting SiHa with or without R-spondin1stimulation to nude mice.Results:①Relatively high expression of LGR5molecule was found on SiHa.②R-spondin1stimulation could promote SiHa proliferation.③R-spondin1stimulation couldincrease the percentage of S period and decrease G1/G0period.④ICC showed that R-spondin1stimulation could promote intracellular IL-6production in dose dependantmanner.⑤In vivo study showed that SiHa cells pretreated with R-spondin1couldevidently promote tumor formation and growth.Conclusions: R-spondin1/LGR5signaling plays an important role in the biologicalfunctions of SiHa cells by promoting cell proliferation and IL-6production in vitro andtumorogensis in vivo, providing new target molecule and strategie for immunotherapy ofcervical cancer.