title: AURKA regulates JAK2-STAT3 activity in human gastric and esophageal cancers.
abstract: Aurora kinase A is a frequently amplified and overexpressed gene in upper gastrointestinal adenocarcinomas (UGCs). Using in vitro cell models of UGCs, we investigated whether AURKA can regulate Signal Transducer and Activator of Transcription 3 (STAT3). Our data indicate that overexpression of AURKA in FLO-1 and AGS cells increase STAT3 phosphorylation at the Tyr705 site, whereas AURKA genetic depletion by siRNA results in decreased phosphorylation levels of STAT3 in FLO-1 and MKN45 cells. Immunofluorescence analysis showed that AURKA overexpression enhanced STAT3 nuclear translocation while AURKA genetic knockdown reduced the nuclear translocation of STAT3 in AGS and FLO-1 cells, respectively. Using a luciferase reporter assay, we demonstrated that AURKA expression induces transcriptional activity of STAT3. Pharmacological inhibition of AURKA by MLN8237 reduced STAT3 phosphorylation along with down-regulation of STAT3 pro-survival targets, BCL2 and MCL1. Moreover, by using clonogenic cells survival assay, we showed that MLN8237 single dose treatment reduced the ability of FLO-1 and AGS cells to form colonies. Additional experiments utilizing cell models of overexpression and knockdown of AURKA indicated that STAT3 upstream non-receptor tyrosine kinase Janus kinase 2 (JAK2) is mediating the effect of AURKA on STAT3. The inhibition of JAK2 using JAK2-specific inhibitor AZD1480 or siRNA knockdown, in presence of AURKA overexpression, abrogated the AURKA-mediated STAT3 activation. These results confirm that the AURKA-JAK2 axis is the main mechanism by which AURKA regulates STAT3 activity. In conclusion, we report, for the first time, that AURKA promotes STAT3 activity through regulating the expression and phosphorylation levels of JAK2. This highlights the importance of targeting AURKA as a therapeutic approach to treat gastric and esophageal cancers.
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, United States.
authors: Ahmed
authors: A
authors: Katsha
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, United States.
authors: Janet
authors: J
authors: Arras
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, United States.
authors: Mohammed
authors: M
authors: Soutto
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, United States.
authors: Abbes
authors: A
authors: Belkhiri
authors: Department of Surgery, Vanderbilt University Medical Center, Nashville, TN, United States; Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN, United States; Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, United States. Electronic address: wael.el-rifai@vanderbilt.edu.
authors: Wael
authors: W
authors: El-Rifai
mesh_terms: D064096:Aurora Kinase A / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D004938:Esophageal Neoplasms / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism*
chemical_list: D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D064096:Aurora Kinase A
keywords: AZD1480; Adenocarcinoma; Alisertib; BCL2; Barrett's; Esophageal; Gene regulation; MCL1; MLN8237; Stomach