Exploiting Sequential Therapy For The Targeted Elimination Of Cucurbitacin E-Mediated Senescent Colon Cancer Cells

Colon cancer(CRC)is one of the most common digestive tract cancers in the world.The incidence and mortality of CRC in my country are increasing year by year.In recent years,although the methods of anticancer treatment such as surgery and chemotherapy have been continuously improved,the total survival rate and prognosis of CRC patients are not ideal.In view of the drug resistance of tumor cells on chemotherapy drugs and the toxic and side effects of chemotherapy drugs,the clinical treatment effect of CRC is seriously limited.Therefore,finding a safe and efficient new CRC treatment strategy is extremely urgent.Finding effective active ingredients with anticancer activity and low toxic side effects from natural products is currently a hot topic of research.Cucurbitacin E,as an important active ingredient in the clinical drug "Cucurbitacin Tablets",is a natural product with a wide range of pharmacological activities,mainly including liver protection,anti-inflammatory,antibacterial,anti-tumor,treatment of cardiovascular diseases,and improvement of body immunity.Our research team has previously found that cucurbitacin E has great potential in inducing tumor cell senescence.Cell senescence is a process that leads to irreversible cell cycle arrest and is considered an important strategy for tumor suppression.Various internal and external factors can trigger cell senescence,including oncogene activation,DNA damage,telomere dysfunction,and cell stress.In addition,cell senescence is closely related to biological processes such as tumor suppression,tissue repair,and embryogenesis.Recent research has shown that genetic models that specifically eliminate senescent cells have proven the therapeutic benefits of targeting senescence.Senescence inducing drugs cause senescent cells to acquire unique new weaknesses that can be selectively targeted by senolytics.Senolytics is a class of drugs that can selectively kill senescent cells.Senolytics is based on the principle of sequential therapy,which first induces tumor cells to senescence and then selectively kills senescent tumor cells.This strategy is actively being explored for use in anticancer therapy.However,the molecular mechanism of CE-induced senescence in CRC cells is still unclear.In this topic,we clarified the specific mechanism of CE-induced CRC cell senescence,and utilized the fatal weakness of CE-induced CRC cell senescence,and further explored the mechanism of targeted clearance of CE-induced senescent CRC cells based on sequential therapy.The research content of this topic mainly includes:1.By constructing an AOM/DSS mouse colon cancer model,it was observed that the tumor diameter and average number of tumors in the CE treated group were significantly smaller than those in the AOM/DSS induced group;HE staining and immunohistochemical analysis showed that CE treatment could inhibit the proliferation of colon cancer cells and enhance DNA damage response and aging indicators;β-Galactosidase(SA-β-Gal)staining results showed that CE-induced CRC cell senescence could be reversed by overexpression of TFAP4,and knocking down TFAP4 significantly promoted CE-induced CRC cell senescence;using mi Rwalk-2 database analysis,it was found that CE treatment of CRC cells significantly promoted the expression of mi R-371b-5p;the results of the luciferase reporter system show that mi R-371b-5p significantly reduced the luciferase activity of wild-type TFAP4 3’-UTR.These results indicate that CE treatment directly targets and degrades TFAP4 by inducing the expression of mi R-371b-5p.The downregulation of TFAP4 is a key factor in CE-induced CRC cell senescence.2.The changes of senescence related markers in CRC cells were detected at the transcription level through cell transfection and q PCR experiments.The results showed that mi R-371b-5p inhibitors could upregulate the expression of p53,p21,and p16.We suggest the specific mechanism of CE-induced CRC cell senescence,that is,CE mainly induces CRC cell senescence by regulating the mi R-371b-5p/ TFAP4 signal axis.3.The results of SA-β-Gal staining experiment show that knocking down FBXW7 can trigger CRC cell senescence,and resveratrol can clear senescent CRC cells;through the construction of FBXW7 overexpression plasmid and SA-β-Gal staining experiments,it was found that overexpression of FBXW7 can also eliminate CE-induced senescent CRC cells.The above results suggest that sequential therapy based on resveratrol treatment or activation of FBXW7 can target the elimination of senescent CRC cells.In summary,CE treatment directly targets the degradation of TFAP4 through the high expression of mi R-371b-5p,thereby inducing CRC cell senescence;sequential therapy based on resveratrol treatment or activation of FBXW7 can target the elimination of senescent CRC cells induced by CE.The research results of this topic not only reveal the specific mechanism of CE-induced CRC cell senescence,but also propose a new efficacy of sequential therapy based on resveratrol or overexpression of FBXW7 in selectively eliminating senescent CRC cells.The research results not only provide new ideas and scientific basis for the "drug repurposing" of cucurbitacin E in CRC,but also provide new strategies for targeted clinical treatment of CRC.