Raf kinase inhibitor protein combined with phosphorylated extracellular signal-regulated kinase offers valuable prognosis in gastrointestinal stromal tumor

BACKGROUND Gastrointestinal stromal tumors(GISTs)are the most common mesenchymal tumors of the gastrointestinal tract.Tyrosine kinase inhibitors,such as imatinib,have been used as first-line therapy for the treatment of GISTs.Although these drugs have achieved considerable efficacy in some patients,reports of resistance and recurrence have emerged.Extracellular signal-regulated kinase 1/2(ERK1/2)protein,as a member of the mitogen-activated protein kinase(MAPK)family,is a core molecule of this signaling pathway.Nowadays,research reports on the important clinical and prognostic value of phosphorylated-ERK(P-ERK)and phosphorylated-MAPK/ERK kinase(P-MEK)proteins closely related to raf kinase inhibitor protein(RKIP)have gradually emerged in digestive tract tumors such as gastric cancer,colon cancer,and pancreatic cancer.However,literature on the expression of these downstream proteins combined with RKIP in GIST is scarce.This study will focus on this aspect and search for answers to the problem.AIM To detect the expression of RKIP,P-ERK,and P-MEK protein in GIST and to analyze their relationship with clinicopathological characteristics and prognosis of this disease.Try to establish a new prognosis evaluation model using RKIP and PERK in combination with analysis and its prognosis evaluation efficacy.METHODS The research object of our experiment was 66 pathologically diagnosed GIST patients with complete clinical and follow-up information.These patients received surgical treatment at China Medical University Affiliated Hospital from January 2015 to January 2020.Immunohistochemical method was used to detect the expression of RKIP,PERK,and P-MEK proteins in GIST tissue samples from these patients.Kaplan-Meier method was used to calculate the survival rate of 63 patients with complete follow-up data.A Nomogram was used to represent the new prognostic evaluation model.The Cox multivariate regression analysis was conducted separately for each set of risk evaluation factors,based on two risk classification systems[the new risk grade model vs the modified National Institutes of Health(NIH)2008 risk classification system].Receiver operating characteristic(ROC)curves were used for evaluating the accuracy and efficiency of the two prognostic evaluation systems.RESULTS In GIST tissues,RKIP protein showed positive expression in the cytoplasm and cell membrane,appearing as brownish-yellow or brown granules.The expression of RKIP was related to GIST tumor size,NIH grade,and mucosal invasion.P-ERK protein exhibited heterogeneous distribution in GIST cells,mainly in the cytoplasm,with occasional presence in the nucleus,and appeared as brownish-yellow granules,and the expression of P-ERK protein was associated with GIST tumor size,mitotic count,mucosal invasion,and NIH grade.Meanwhile,RKIP protein expression was negatively correlated with P-ERK expression.The results in COX multivariate regression analysis showed that RKIP protein expression was not an independent risk factor for tumor prognosis.However,RKIP combined with P-ERK protein expression were identified as independent risk factors for prognosis with statistical significance.Furthermore,we establish a new prognosis evaluation model using RKIP and P-ERK in combination and obtained the nomogram of the new prognosis evaluation model.ROC curve analysis also showed that the new evaluation model had better prognostic performance than the modified NIH 2008 risk classification system.CONCLUSION Our experimental results showed that the expression of RKIP and P-ERK proteins in GIST was associated with tumor size,NIH 2008 staging,and tumor invasion,and P-ERK expression was also related to mitotic count.The expression of the two proteins had a certain negative correlation.The combined expression of RKIP and P-ERK proteins can serve as an independent risk factor for predicting the prognosis of GIST patients.The new risk assessment model incorporating RKIP and P-ERK has superior evaluation efficacy and is worth further practical application to validate.

Drug resistance in targeted cancer therapies with RAF inhibitors

Hyperactive RAS/RAF/MEK/ERK signaling has a well-defined role in cancer biology.Targeting this pathway results in complete or partial regression of most cancers.In recent years,cancer genomic studies have revealed that genetic alterations that aberrantly activate the RAS/RAF/MEK/ERK signaling mainly occur on RAF or upstream,which motivated the extensive development of RAF inhibitors for cancer therapy.Currently,the first-generation RAF inhibitors have been approved for treating late-stage cancers with BRAF(V600E)mutations.Although these inhibitors have achieved promising outcomes in clinical treatments,their efficacy is abolished by quick-rising drug resistance.Moreover,cancers with hyperactive RAS exhibit intrinsic resistance to these drugs.To resolve these problems,the second-generation RAF inhibitors have been designed and are undergoing clinical evaluations.Here,we summarize the recent findings from mechanistic studies on RAF inhibitor resistance and discuss the critical issues in the development of next-generation RAF inhibitors with better therapeutic index,which may provide insights for improving targeted cancer therapy with RAF inhibitors.

The inhibitor effect of RKIP on inflammasome activation and inflammasome-dependent diseases

Aberrant inflammasome activation contributes to the pathogenesis of various human diseases,including atherosclerosis,gout,and metabolic disorders.Elucidation of the underlying mechanism involved in the negative regulation of the inflammasome is important for developing new therapeutic targets for these diseases.Here,we showed that Raf kinase inhibitor protein(RKIP)negatively regulates the activation of the NLRP1,NLRP3,and NLRC4 inflammasomes.RKIP deficiency enhanced caspase-1 activation and IL-1P secretion via NLRP1,NLRP3,and NLRC4 Inflammasome activation In primary macrophages.The overexpression of RKIP in THP-1 cells inhibited NLRP1,NLRP3,and NLRC4 inflammasome activation.RKIP-deficient mice showed increased sensitivity to Aluminduced peritonitis and Salmonella typhimurium-induced inflammation,indicating that RKIP inhibits NLRP3 and NLRC4 inflammasome activation in vivo.Mechanistically,RKIP directly binds to apoptosis-associated speck-like protein containing a caspase-recruitment domain(ASC)and competes with NLRP1,NLRP3,or NLRC4 to interact with ASC thus interrupting inflammasome assembly and activation.The depletion of RKIP aggravated inflammasome-related diseases such as monosodium urate(MSU)-induced gouty arthritis and high-fat diet(HFD)-induced metabolic disorders.Furthermore,the expression of RKIP was substantially downregulated in patients with gouty arthritis or type 2 diabetes(T2D)compared to healthy controls.Collectively,our findings suggest that RKIP negatively regulates NLRP1,NLRP3,and NLRC4 inflammasome activation and is a potential therapeutic target for the treatment of inflammasome-related diseases.

Urothelial bladder cancer progression: lessons learned from the bench

Urothelial bladder carcinoma(UBC)is an intricate malignancy with a variable natural history and clinical behavior.Despite developments in diagnosis/prognosis refi nement and treatment modalities,the recurrence rate is high,and progression from non-muscle to muscle invasive UBC commonly leads to metastasis.Moreover,patients with muscle-invasive or extra-vesical disease often fail the standard chemotherapy treatment,and overall survival rates are poor.Thus,UBC remains a challenge in the oncology fi eld,representing an ideal candidate for research on biomarkers that could identify patients at increased risk of recurrence,progression,and chemo-refractoriness.However,progress toward personalized medicine has been hampered by the unique genetic complexity of UBC.Recent genome-wide expression and sequencing studies have brought new insights into its molecular features,pathogenesis and clinical diversity,revealing a landscape where classical pathology is intersected by the novel and heterogeneous molecular groups.Hence,it seems plausible to postulate that only an integrated signature of prognostic/predictive biomarkers inherent in different cancer hallmarks will reach clinical validation.In this review,we have summarized ours and others’research into novel putative biomarkers of progression and chemoresistance that encompass several hallmarks of cancer:tumor neovascularization,invasion and metastasis,and energy metabolism reprogramming of the tumor microenvironment.