Correlation Of Expression Of WWOX And JNK With Clinicopathologic Features In Human Breast Carcinoma

BackgroudThe WW domain-containing oxidoreductase(WWOX)gene,which is located at the fragile site FRA16D,encodes a 46 kDa protein containing 2 functional WW domains in the NH2-terminal region and a short-chain dehydrogenase domain(SDR).The WW domains are correlated with the proteins interactions.The SDR domain of the WWOX protein exhibits dehydrogenase activity in the presence of selected steroid substrates.It can be demonstrated that WWOX plays an important role in steroid-related regulated tissues,such as prostate,ovary,and breast tissues.The presence of WWOX as a tumor suppressor gene has been already reported in osteosarcoma,breast cancer,ovarian cancer and other cancers,while the functional mechanisms involved still unclear.c-Jun N-terminal kinase(JNK)is a member of the mitogen-activated protein kinase superfamily.The JNK family,consisting of 3 isoforms(JNK1,JNK2,and JNK3),are encoded by 3 separate genes and alternatively spliced to create at least 10 variants of 46 and 55 kDa.JNK1 and JNK2 are expressed in most tissues,whereas JNK3expression is mainly restricted to express in brain,heart,and testis tissues.The JNK signaling transduction pathway participates in many physiological processes,including inflammatory responses,morphogenesis,cell proliferation,differentiation,survival,and death.JNK is also widely acknowledged to be involved in the cancer's development and progression.JNK is proven to physically interact with WWOX and inhibit apoptosis in human hepatocellular carcinoma(HCC).It is demonstrated that JNK has completely opposite functions in liver cancer and breast cancer.However,the relevance of WWOX and JNK in breast cancer and HCC has remained unclear.MethodsA total of 40 paired breast carcinoma and adjacent normal tissueswere obtained from female patients who were surgically treated in Qilu Hospital ofShandong University(Jinan,China)between February 2016 and January 2017.The age of the patients were 37 to 77 years,the median age was 52 years.Samples were snap frozen in-80? refrigerator until further analysis.Western blot and Immunohistochemical staining were performed to assess the protein expression of WWOX and JNK in breast carcinoma and adjacent tissues.RT-PCR was performed to assess the mRNA expression of WWOX and JNK in breast carcinoma and adjacent tissues.The patients' all clinical pathological factors(ER,PR,HER-2,P53,Ki-67 and so on)were collected.All statistic analyses were performed with SPSS 23.0 statistical software package.The X2 test was carried out to analyze the relationship between WWOX and JNK expression and the clinical and pathological characters of these patients.Results1.The expression of WWOX and JNK mRNA in breast carcinoma samples was significantly lower than that of the corresponding adjacent non-tumorous tissues(P<0.01),a highly significant positive correlation was observed between the mRNA expression levels of WWOX and JNK in the cancer tissues(r=0.47,P=0.002,).2.The expression levels of WWOX and JNK protein detected by Western blotanalysis in breast carcinoma were significantly lower contradistinguished with those in the matched adjacent non-cancerous tissues(P<0.01),the relative expression levels of WWOX and JNK protein detected by Western blot analysis(Spearman test,r=0.603,P<0.01)were compliance with the mRNA expression results.3.The IHC assay made clear that 77.5%(31/40)patients' expression of WWOX in breast carcinoma tissue was reduced compared with that in the normal breast tissue,and 75%(30/40)patients' expression of JNK in breast carcinoma tissue was reduced contradistinguish with that in the para-carcinoma tissue,A highly significant positive correlation was observed between the expression levels of WWOX and JNK in the cancer tissues(r=0.3 8,P=0.029).4.The result of IHC has shown that lack of WWOX expression in breast carcinoma was associated with TNM stage(P= 0.001)and the lymph node metastases(P=0.01).However,no correlation was determined between WWOX expression and other clinicopathologic features,namely,age,ER status,PR status,P53 status,Ki67 status.JNK expression was not associated with other clinicopathological features.ConclusionsThe mRNA expression levels of both JNK and WWOX were downregulated in carcinoma tissues relative to those in the adjacent normal tissues,as determined by Western blot analysis and IHC.JNK expression was positively correlated with WWOX expression.It may suggest that both WWOX and JNK play important roles in breast cancer and involve in the cancer's development and progression.The interaction of them may be a promising therapeutic target for anti-tumor therapy.