Research On Antitumor Mechanism Of Microtubule Destabilizing Agents And Molecular Marker GPC1

Esophageal cancer is one of the most common cancers in the world,which has a low five-year survival rate and poor prognosis.It is easy to produce drug resistance after chemotherapy,and there is a lack of effective treatment.Therefore,it is urgent for looking for effective small molecule drugs for esophageal cancer or screening for effective bimarkers.Pancreatic ductal carcinoma(PDAC)is one of the most serious malignancies in the world.Due to the lack of obvious early symptoms,most patients have advanced or metastasis at the initial diagnosis.So,it is imperative to screen bimarkers for early diagnosis of pancreatic cancer to achieve early diagnosis and treatment.The first part of this thesis reveals the antitumor mechanism of novel microtubule destabilizing agents(MDAs)for esophageal squamous cell carcinoma.Three novel MDAs,SL-3-19,SL-1-73 and IG-105,were used to inhibit the proliferation of five esophageal cancer cell lines.Cell proliferation assay found that all three drugs have significant inhibition effects on esophageal cancer cells,especially SL-3-19.Immunofluorescence and Western blotting revealed that all three drugs disrupted the mature microtubule network and blocked the expression of the mature microtubule marker AC-a-Tubulin in esophageal cancer cells.Based on the observation of the above results,SL-3-19 has an outstanding anti-tumor activity.Therefore,SL-3-19 was selected as a key drug for follow-up mechanism exploration.To further understand the mechanism of SL-3-19,flow cytometry was used to find that SL-3-19 could induce cell cycle arrest in G2/M phase,leading to an increase of apoptosis.Western blotting also showed SL-3-19 could increase activation of Caspases family molecules;while Mcl-1,Bcl-2,and p-ERK levels were significantly down-regulated,suggesting that SL-3-19 can promote apoptosis in esophageal cancer and down-regulate the expression of anti-apoptotic protein.Meanwhile,it can inhibit the activation of MEK/ERK proliferation pathway.In vivo and in vitro angiogenesis experiments showed all three drugs destroyed tumor micro vasculature,and SL-3-19 showed prominent effects.In vivo experiments showed that both SL-3-19 and SL-1-73 could inhibit the growth of xenograft tumor model.SL-3-19 is exceptional,and did not cause significant body weight changes and no influence for various organs of nude mice.Overall,SL-3-19 has a low IC50 value,significant anti-proliferative activity in vivo and in vitro,and excellent anti-angiogenic effects,suggesting that SL-3-19 may be an effective candidate for the treatment of esophageal cancer in the future.In the second part,we demonstrated that GPC1 is an very promising tumor marker for pancreatic ductal carcinoma.This study firstly analyzed the RNA-sequencing dataset from the cancer genome atlas(TCGA)which includes 178 PD AC samples.The results showed that GPC1 mRNA was silenced in normal pancreata;however,it was re-expressed in PDAC tissues probably because of the promoter hypomethylation.The subsequent immunohistochemistry staining assay based on 186 PD AC samples revealed that GPC1 was barely expressed in normal pancreas tissues and adjacent noncancerous pancreata.In tumor tissues,59.7%(111/186)of samples showed positive expression.Notably,GPC1 was elevated in 63.6%(34/55)of early stage cases.The correlation analysis showed that high levels of GPC1 were associated with poorer differentiation and larger tumor diameters.Kaplan-Meier analysis showed a significant difference in overall survival between the groups categorized by GPC1 expression(P =0.0028).Multivariate analyses indicated that GPC1 was a significant risk factor for poor overall survival with a 1.82-fold increase in the hazard ratio(P = 0.0022).In summary,GPC1 was ectopically expressed and served as an independent poor prognostic factor in PDAC.Our findings highlighted the alluring prospect of GPC1 as an early diagnostic and prognostic marker as well as a therapeutic target for PD AC.