BATF2Expression Is Associated With The Prognosis Of Colorectal Cancer

Background:Colorectal cancer(CRC) is one of the malignant tumors that seriously threats human lifeand health. Although medical level is constantly progressing, the morbidity and mortalitycaused by CRC are still rising. Control and reduction of the morbidity and mortality of CRCbecome a tough problem to be solved. Increasingly more researchers have focused onbiomarkers with high sensitivity and specificity for the targeted treatment of CRC.BATF2, also named SARI, belongs to the BATF subfamily basic leucine zipper protein.It is an AP-1inhibitor induced by type I interferon. Recently, it was shown that BATF2washighly expressed in normal tissues, rather than in the relevant tumor tissues. OverexpressedBATF2could significantly inhibit the tumor cells proliferation, but not in the normal cells.The specific tumor-suppressing role of BATF2makes it in conformity with the characteristicsof many tumor suppressor genes. Nevertheless, the exact role of BATF2in CRC needs to beverified with plenty of clinical specimens.In addition, it was reported for the first time in2008that BATF2located in the nucleusand had a tumor-repressing effect via binding to activator protein-1. However, the followingstudies on this gene were concentrated on the expression level, instead of the subcellularlocalization. Immunohistochemical picture shows BATF2located in the cytoplasm of cancercells, which went against the location in the nucleus in the first report. It was not reasonablyexplained in these studies why it appeared in tumor cell cytoplasm, not to mention furtherexploration on clinical significance of its subcellular localization.Objective:To investigate influence of BATF2expression on the prognosis of patients in CRC andpericarcinomatous tissues and cells and to preliminarily explore its various subcellularlocalization. Methods：1. BATF2expression was detected in human CRC and pericarcinomatous tissues and celllines by immunohistochemistry and Western blot. Correlation analysis was conductedbetween BATF2expression and patients’ clinical pathological parameters, including gender,age, organ, location, tumor size, histological grade and clinical stage. Kaplan Meier survivalcurve and multiariable Cox model were used to assess the predictable value of BATF2expression on the survival time and prognosis of CRC patients.2. BATF2expression both in cytoplasm and nucleus in human CRC andpericarcinomatous tissues and cell lines was tested with immunohistochemistry andimmunofluorescence and Western blot methods. Statistical analysis was conducted betweenits different positions and the corresponding clinical pathological parameters. The influence ofits subcellular localization on prognosis was analyzed by Kaplan Meier method andmultiariable Cox model, respectively.3. BATF2was suppressed in CRC cells using lentivirus interference method. Growth ratewas examined by CCK-8and colony forming ability was tested by clone formation test, whilecell cycle was measured by flow cytometry.Results:1. BATF2expression in pericarcinoma was higher than that in CRC (P<0.001). Theexpression of BATF2was significantly correlated with tumor size, lymphatic metastasis,histological grade and TNM clinical stage. The Overall Survival and Disease-Free Survivaltime of CRC patients with high BATF2level was longer than that with low BATF2level（P<0.001）, while the mortality and recurrence risk was lower (P<0.001).2. BATF2expression in nucleus was also higher in pericarcinoma tissues and normal celllines than that of CRC (P<0.001). There was no significant difference in cytoplasm yet(P=0.8759). BATF2expression in nucleus was interrelated with tumor size, histological grade,lymphatic metastasis and clinical pathological stage. Moreover, the prognosis of patients withhigher BATF2expression in the nucleus was much better than that with lower BATF2expression, while the mortality and recurrence risk was lower.3. CRC cells with lower BATF2expression grew significantly faster than that withhigher BATF2expression, possibly through shortening cell cycle.Conclusions:1. BATF2expression was lower in CRC tissues and cell lines, which could be considered as a CRC prognostic indicator.2. BATF2expression in the nucleus of pericarcinomatous tissues was higher that of CRCtissues, which could also be used as a CRC prognostic factor.3. Downregulation of BATF2could promote CRC cells proliferation. BackgroundLymphoma is one of the most common hematological malignancies, which are becomingincreasingly more and threatening the health and quality of our life. Positive and effectivetreatment will reduce the morbidity and mortality of lymphoma patients. Although multidrugtherapy does good to three-quarter of the patients, some are still resistant to the therapy.Therefore, researchers gradually turned their eyes on novel molecular therapies to improve thetreatment programs.AG490is a kind of synthesized Benzylidene malononitrile derivative, making thestructure of which similar to tyrosine. AG490can specifically inhibit Janus kinase2(JAK2)/signal transducer and activator of transcription3(STAT3) signaling pathway, whichleads to tumor inhibition. Research indicates that it has significant effect on suppressingleukemia, prostate cancer, breast cancer and colon cancer. It can not only induce tumor cellsapoptosis, but also have no influence on the growth and maturity of normal precursorhematopoietic stem cells, especially in leukemia research. These characteristics make AG490applicable in clinical use, the mechanism of which becomes a hotspot as well. Consequently,this present study investigated the effect of AG490on lymphoma cells proliferation and thecorresponding mechanism, in order to provide experimental basis for its clinical use.MethodsNamalwa and JeKo-1lymphoma cells, Jurkat T-cell leukemia cells and THP-1monocytic leukemia cells were treated with variant doses of AG490(0μM,2μM,20μM,50μM and200μM) for24hours. The effect of AG490on cell proliferation was measured byCCK-8assay. The mRNA and protein level of BATF2were detected by Real Time PCR andWestern blot. When BATF2expression was silenced by siRNA, the cell viability wasmeasured by CCK-8assay.ResultsNamalwa, Jurkat and JeKo-1cells proliferation were inhibited by AG490dose-dependently(P<0.05), while the relevant BATF2mRNA and protein expression wereupregulated(P<0.05). As to THP-1cells, AG490had no effect on its proliferation and BATF2 expression had no upregulation as well. With BATF2silenced by siRNA in Namalwa cells,the depressing effect ofAG490on cell proliferation evidently decreased(P<0.05).ConcusionsThe efficiency of killing tumor cells by AT490and its induced BATF2expression arepositively correlated. When BATF2expression is down-regulated, the inhibitory effect ofAG490on Namalwa cell proliferation is significantly reduced.