The Inhibitory Effect Of Prunella Vulgaris Extracts On Thyroid Tumors

Background and ObjectiveCancer of the thyroid gland is the most common endocrine malignancy,comprising 90% of endocrine cancers.Well differentiated thyroid carcinoma(WDTC),as the most prevalent pathological type,makes up about 93% of all thyroid cancers.Currently,surgical resection,iodine-131 radiotherapy,and chronic thyroid stimulating hormone(TSH)suppression are still the three major treatments on it.However,surgery might result in various complications,such as hypocalcemia,hoarseness,or postoperative bleeding,while Iodine-131 treatment and TSH inhibitory therapy have limited efficacy and a series of adverse reaction,such as gastrointestinal reactions or osteoporosis.Therefore,comprehensive treatment,mainly including surgical treatment,radioiodide therapy and drug treatment,has been highly developed and widely accepted internationally,but there is still no specific medicine or adjuvant treatment for some refractory WDTC patients.Therefore,our study of the inhibitory effect of Chinese herbs on thyroid tumors is of great significance.As an aromatic plant,Prunella vulgaris(PV)was widely used in traditional medicine for anti-inflammatory,anti-allergy,anti-oxidation,anti-virus and other treatments.Prunella vulgaris extracts(PVE),due to its low toxicity and low incidence of adverse reactions,is currently used for auxiliary support treatment on some benign tumors in clinical practice.However,further studies in recent years have found that some triterpenoids and saponins contained in PVE had significant anti-tumor activities,and were proven to inhibit breast cancer,ovarian cancer,gastric cancer and liver cancer significantly.Thyroid cancer is the most common malignant tumor in the head and neck,so the research on anticancer drugs or mechanisms about it has always been the focus of clinicians and researchers.This experiment aims to demonstrate the inhibitory effect of PVE on WDTC systematically by a series of functional experiments in vitro,animal experiment in vivo and the subsequent analysis of animal tissue samples by IHC and Western Blot,to preliminarily explored the possible anticancer mechanism of PVE and to provide a new idea and direction for the development of anti-tumor drugs on thyroid cancers.Material and Method1.Thyroid cancer cell lines B-CPAP,TPC-1 and SW579 were selected for experiments in vitro.And in B-CPAP cells,the pro-apoptotic effect of PVE was verified by transmission electron microscopy,flow cytometry,TUNEL assay.While in TPC-1 and SW579 cells,the anti-proliferation and anti-migration effects of PVE were tested by MTT assay,cell growth curve,colony formation assay,cell cycle analysis,wound healing assay,cell migration assay.2.A subcutaneous xenograft tumor model of nude mice was established using thyroid cancer cell line TPC-1,and PVE of different concentrations were given by intragastric administration as an intervention.Finally,the inhibitory effect of PVE on thyroid cancer in vivo was evaluated according to the weight,volume of tumors and the tumor inhibition rates in different dose groups.3.Immunohistochemical staining and Western Blot analysis were performed on the tumors obtained from animal experiments to detect the expressions of tumor proliferation-related proteins PCNA,Ki-67 and tumor metastasis-related proteins E-cadherin and ?-catenin qualitatively and quantitatively,so as to preliminarily explore the inhibitory mechanism of PVE on thyroid cancer.4.SPSS 21.0 software was used to analyze the statistical data above,and the data obtained in these experiments were expressed by mean and standard deviation(Mean � SD).One-way ANOVA and t-test were used to analyze the significance.P < 0.05 was considered statistically significant.Result1.After the treatment of PVE in different concentrations on B-CPAP,it was observed that the overall cells were poorly adhered to the wall,the volume of cells was reduced,organelles were swollen and degenerated,and the number of autophagosomes was significantly increased under the transmission electron microscope.The apoptosis rate and apoptosis index detected by flow cytometry and TUNEL assay were also significantly higher than those in negative control group,and there was a dose-dependent manner to some extent.2.In thyroid cancer cell lines TPC-1 and SW579,with the increase of PVE concentration,the proliferation activity of cells detected by MTT assay showed decrease,the number of cell colonies also decreased in the colony formation assay,and cell cycle distribution analysis detected a significant increase in the proportion of cells in the G1 phase of the cell cycle,and a significant decrease in the proportion of cells in the S phase.3.The papillary thyroid carcinoma cell line TPC-1 had the ability to form tumors subcutaneously in Balb/c nude mice.4.Based on the subcutaneous graft model of thyroid carcinoma,the study showed that after the intervention of PVE,the tumor volume and weight decreased significantly.Tumor growth was significantly inhibited,and the inhibition effect was obviously dose-dependent.5.With the increase of administration dose,the expressions of tumor proliferation related proteins PCNA and Ki-67 in tumor samples showed gradual decrease,and the expressions of tumor metastasis related proteins E-cadherin and ?-catenin increased gradually.Conclusion1.In thyroid cancer cell line B-CPAP,PVE has been proved to have a significant pro-apoptotic effect.In thyroid cancer cell lines TPC-1 and SW579,PVE significantly inhibited the proliferation and migration of tumors.Moreover,the pro-apoptosis,anti-proliferation and anti-migration effects of PVE have a significant dose-dependence manner.2.PVE also has an inhibitory effect on thyroid cancer cells in vivo,and this inhibitory effect is positively correlated with the dose.3.The inhibition effect of PVE on tumor growth in mice may be achieved by inhibiting the expression of tumor proliferation related proteins PCNA,Ki-67 and promoting the expression of tumor metastasis related proteins E-cadherin,?-catenin.