| Background and Objective: Gastric cancer is one of the most common malignant tumors in human being,which is the second cause leads to the cancer death worldwide.The incidence of gastric cancer varies in different regions and populations,the incidence is very high in East Asia,Eastern Europe and southern europe.Advanced gastric cancer(AGC)accounts for one of the highest mortality in East Asia.Even the incidence of AGC declined recently,the mortality rate of AGC remained high,mainly due to its delayed diagnosis and lack of precise prognostic serum markers.Most of the early gastric cancer patients can be cured after the treatment,but most patients is in advanced stage,which means low survival rate.More than two thirds of gastric cancer patients are unresectable,but patients with a resectable tumor still have a high rate of recurrence or metastasis in the near future.Besides lymphatic and hematogenous metastasis,the AGC patients may have detached cancer cells dissemination in the peritoneal cavity,which can lead to peritoneal carcinomatosis(PC),which represents an advanced stage of gastric cancer and is associated with poor survival rates.Peritoneal metastasis of advanced gastric cancer is the latest stage of disease development,which can only be given basic treatment.Nowadays,there are some therapeutic methods of advanced gastric cancer: surgical treatment,perioperative chemotherapy and targeted therapy.Surgical treatment is the basic treatment of advanced gastric cancer advanced gastric cancer should be treated with standard radical gastrectomy.On chemotherapy,the results of ACTS.GC and CLASSIC research confirmed that D2 radical resection combined with postoperative adjuvant chemotherapy in advanced gastric cancer(stage II and stage III)was superior to simple operation.Up to now,there is no effective treatment for PC from AGC,although the original retrospective trial of CRS+HIPEC achieved a mean overall survival time of 8.9 months with little adverse effects.Cytoreductive surgery(CRS)and hyperthermic intraperitoneal chemotherapy(HIPEC)had been widely accepted as an effective method for treating AGC.Several studies demonstrate that hyperthermia enhances the efficacies of antitumor drugs and increases the chemosensitivity of neoplastic cells.So CRS+ HIPEC is the best choice for treating AGC.Nevertheless,the exact mechanism of these treatment remains elusive,and other high-level clinical studies are still under investigation.Studies have shown that long noncoding RNA(lnc RNA)has a conserved secondary structure that interacts with proteins,DNA and RNA,also play an important role in many biological processes.Lnc RNAs are important factors in the control of gene expression in tumors and lnc RNAs have been shown to play an important role in the development and progression of tumors.Studies have shown aberrant expression of lnc RNAs can lead to abnormalities of gene expression and tumorigenesis.Moreover,the dysregulated expression of lnc RNAs has been recognized as a feature of many types of cancers and been shown to promote the development,invasion,and metastasis of tumors by various mechanisms.Although lnc RNAs were confirmed to be involved in the development of AGC,there was little research of their mechanism in AGC.Therefore,the identification of AGC-associated lnc RNAs and the associated mechanism under require further elucidation.In our study,we try to analysis the lnc RNA aberrant expression profiles before and after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy of AGC to find out AGC-associated lnc RNAs.In order to understand their mechanism in AGC,we analyzed potential roles of these lnc RNAs in the regulation of calcium pathway,Gn RH pathway,Toll-like receptor pathway,and p53 pathways.Research methods: 1.The AGC serum samples were prospectively collected from six patients 1 h before and 1 h after CRS+HIPEC.(The diagnosis of adenocarcinoma was confirmed by histopathology.All CRS and HIPEC procedures were performed by the same team of surgical oncologists and anesthesiologists.Abdominal exploration was performed according to previously reported methods.Hyperthermic perfusion was performed with 4 L of 43 °C heated saline supplied with 60 mg of cisplatin and 1000 mg of 5-fluorouracil(5-Fu).)After total RNA was extracted,we used the gene chip to analysed the lnc RNA and m RNA.Using box plot,Scatter plots,Volcano plots,hierarchical clustering and other methods to establish a differential expression profile of lnc RNA and m RNA in gastric cancer.2.The differentially expressed m RNA and lnc RNA were analyzed by bioinformatics.Using the method of biological informatics to analyzed the differentially expresseion of m RNA and lnc RNA,including lnc RNA functional analysis and GO analysis,path analysis and so on.3.According to the result of biological information,we choose eight lnc RNA abnormal expression and has certain research value.The expression of lnc RNA,which has receive the treatment of CRS + HIPEC after 1h,was further confirmed by real-time quantitative PCR.Research result: 1.Using the Microarray Analysis,we analyzed the expression profiles of AGC lnc RNA and m RNA,we found that among 33,045 lnc RNAs,154 lnc RNAs were found to be upregulated more than 2-fold in AGC after CRS+HIPEC while 412 lnc RNAs were downregulated more than 2-fold,suggesting these lnc RNAs might possess important functions during the treatments of AGC.2.We used GENCODE annotation to identified that some lnc RNAs with enhancer-like functions.The expression profiles of eight enhancer-like lnc RNAs showed that they were differentially expressed(fold change>2.0,P<0.05)before and after CRS+HIPEC.3.Through the Pathway Analysis,ten upregulated pathways and downregulated were identified.Such as calcium pathway,Gn RH pathway,Toll-like receptor pathway,p53 pathways and tight junction and steroid hormone metabolism pathways.4.At last,we used the real-time quantitative PCR to verify eight lnc RNAs were screened(include BC031243,RP11356I2.2,CR605611,CEACAMP10,linc RNA-MCTP2-2,linc RNA-AKR1C3-2,RP11-128M1.1,and RP11909N17.3).We found that the microarray results of several of the lnc RNAs were consistent with the results of RT-PCR.Of these,BC031243 and RP11-356I2.2 exhibited the most significant change in our analysis of six pairs of serum samples 1h before and after CRS+HIPEC(P<0.05)Conclusion: In our study,we analyzed the aberrant expression profiles of lnc RNA in the samples before and after treatment with AGS CRS + HIPEC,then screened the differentially expressed lnc RNAs.The GO analysis were used to further analyze the function of these lnc RNAs in Biological Process,Cellular Component and Molecular Function.Using Pathway analysis,we analyzed these lnc RNAs playing a regulatory roles in the calcium pathway,Gn RH pathway,Toll-like receptor pathway and p53 pathway.Finally,we found that two lnc RNA(BC031243 and RP11-356I2.2)were changed most significant after CRS+HIPEC,it is speculated that they may play a key role in the development of AGC.However,we cannot rule out hyperthermia and chemotherapy cause the two lnc RNA aberrebt expression individually or cooperatively. |
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