1.Lobe-Specific Lymph Node Dissection In Solid-Dominant Clinical Stage IA Non-Small Cell Lung Cancer 2.Function And Mechanism Of MARCKSL1 In The Tumorigenesis And Development Of Esophageal Squamous Cell Carcinoma

Background:Lobectomy with systematic lymph node dissection(SND)remains the standard procedure for resectable NSCLC,while recently lobe-specific lymph node dissection(LSND)was reported to be more and more widely applied for it can reduce perioperative complications and promote postoperative recovery in treating early-stage NSCLC patients.However,it is still controversial that LSND can achieve similar effects as SND do in terms of metastasis control and survival outcomes.This study conducted a prospective cohort to investigate whether there are differences in perioperative recovery,recurrence,metastasis and long-term survival between clinical stage IA NSCLC patients who underwent curative lobectomy with SND or LSND.Methods:From 2014 to 2017,data of 546 patients with clinical stage IA solid-dominant NSCLC and underwent curative lobectomies with SND or LSND at our institution were collected.Propensity score matching(PSM)was conducted to eliminate the biases.5-year disease-free survival(DFS)and overall survival(OS)were compared between the groups.Perioperative parameters and postoperative complications were also analyzed.Results:Curative lobectomies with LSND or SND were performed in 100 patients and 446 patients,respectively.After matching,there were 100 patients in each group.No significant differences in 5-year OS(p=0.473)and DFS(p=0.789)were found between the groups.Recurrence patterns were also similar(p=0.733).Perioperative parameters were similar while the incidence of postoperative complications in LSND group was found to be significantly lower than that in SND group(p=0.003).Conclusions:Our study demonstrated that LSND has similar efficiency to SND in terms of survival,recurrence,lymph node dissection and perioperative recovery of clinical stage IA solid-dominant NSCLC patients,besides,significant advantages in reducing postoperative complications.Therefore,curative lobectomies with LSND may be more suitable and practical for clinical stage IA solid-dominant NSCLC patients.Esophageal cancer is one of the most common malignancies worldwide,among which esophageal squamous cell carcinoma(ESC C)is the predominant type,which accounts for about 90%in East Asia.Despite the great advances in early detection and treatment,surgical techniques,chemoradiotherapy and other comprehensive treatment methods,the prognosis of patients with ESCC are still poor.The tumorigenesis and progression of ESCC is a complicated,multi-step process,involving a variety of complex pathways and mechanisms,that has not been clearly illuminated.Therefore,it is imperative to discover applicable biomarkers and novel therapeutic targets in clinical management to improve patients' quality of life and survival outcomes.Myristoylated alanine-rich C kinase substrate like 1(MARCKSL1)is a member of MARCKS family and a key cellular substrate for protein kinase C(PKC).The myristoylation site is on the N-terminal and the effector domain binds to F-actin,Ca2+/calmodulin and acidic phospholipids.Functionally,MARCKSL1 bundles and stabilizes F-actin upon phosphorylation,increasing filopodium dynamics.MARCKSL1 was reported to play a key role in cytoskeletal organization at cell-cell and cell-substrate contacts in epithelial cells and might be relevant to cell motility.Under physiological conditions,MARCKSL1 regulates actin homeostasis,cell adhesion and neuronal migration,promote formation of filopodium and lamellipodium,and is critically functional in early development of the nervous system.In addition,recent studies suggested that high expression of MARCKSL1 could significantly promote the progression of a variety of malignant tumors,and acts as a strong prognosticator to the poor prognosis of patients.However,MARCKSL1 has not been found to be involved in the carcinogenesis of ESCC,besides,the function of MARCKSL1 and the underlying mechanism are still not fully elucidated.In this study,we analyzed the RNA-seq data of the TCGA database and found that the expression level of MARCKSL1 in esophageal cancer was significantly higher than that in normal tissues(p<0.0001).Then,we performed immunohistochemical(IHC)analysis on ESCC in tissue microarray and surgical samples.We found consistent results with those in the TCGA database,that the expression level of MARCKSL1 in tumor tissues was significantly higher than that in normal tissues,suggesting that MARCKSL1 may play an important role in the progression of esophageal cancer.In addition,through analyzing patients' clinicopathological characteristics,we found that the lymph node metastasis rate(p=0.020)of high expression group(HE:IHC score?6)was significantly higher than that of low expression group(LE:IHC score<6).Meanwhile,high expression of MARCKSL1 has also been shown to be related to poor tumor differentiation.Survival analysis showed that the prognosis of patients without lymph node metastasis in LE group was significantly better than that of the same type of patients in HE group(p=0.013).To further explore the function of MARCKSL1 in ESCC,we transiently overexpressed and knocked down the expression of MARCKSL1 in ESCC cells,and explored the effect of MARCKSL1 on the proliferation,invasion and metastasis of ESCC cells in vitro.The results showed that overexpression of MARCKSL1 significantly promoted the migration and invasion of ESCC cells,while knocking down MARCKSL1 significantly attenuated these functions.To preliminarily clarify the mechanism of MARCKSL1 regulating the progression of ESCC,we performed RNA-seq on KYSE 140 cells that were transiently knocked down.The results showed that after knocking down,the expression of 800 genes changed significantly(Fold change?1.2 or ?0.83,and p<0.05),of which 351 genes were significantly up-regulated,while 449 genes were significantly down-regulated.KEGG signaling pathway analysis of the 800 differentially expressed genes found that the genes significantly affected by MARCKSL1 are mainly enriched in signaling pathways such as MAPK,NF-?B and oxidative phosphorylation.Subsequently,we detected the activation of the MAPK pathway through Western Blot.The results showed that the phosphorylation level of MEK,JNK and ERK proteins was significantly reduced,while the expression levels of MEK,JNK and ERK proteins stayed similar,suggesting that MARCKSL1 regulates migration and invasion of ESCC cells by mediating the activation of MAPK.In summary,we found that MARCKSL1 plays as an oncogene in the progression of ESCC,and preliminarily confirmed that MARCKSL1 can promote the migration and invasion of ESCC cells by activating MAPK pathway.Therefore,MARCKSL1 can be used as a novel candidate marker and potential therapeutic target for esophageal squamous cell carcinoma,which may be helpful in the diagnosis and treatment of esophageal cancer and improve the prognosis of patients.