title: Chronic exposure to cigarette smoke leads to activation of p21 (RAC1)-activated kinase 6 (PAK6) in non-small cell lung cancer cells.
abstract: Epidemiological data clearly establishes cigarette smoking as one of the major cause for lung cancer worldwide. Recently, targeted therapy has become one of the most preferred modes of treatment for cancer. Though certain targeted therapies such as anti-EGFR are in clinical practice, they have shown limited success in lung cancer patients who are smokers. This demands discovery of alternative drug targets through systematic investigation of cigarette smoke-induced signaling mechanisms. To study the signaling events activated in response to cigarette smoke, we carried out SILAC-based phosphoproteomic analysis of H358 lung cancer cells chronically exposed to cigarette smoke. We identified 1,812 phosphosites, of which 278 phosphosites were hyperphosphorylated (≥ 3-fold) in H358 cells chronically exposed to cigarette smoke. Our data revealed hyperphosphorylation of S560 within the conserved kinase domain of PAK6. Activation of PAK6 is associated with various processes in cancer including metastasis. Mechanistic studies revealed that inhibition of PAK6 led to reduction in cell proliferation, migration and invasion of the cigarette smoke treated cells. Further, siRNA mediated silencing of PAK6 resulted in decreased invasive abilities in a panel of non-small cell lung cancer (NSCLC) cells. Consistently, mice bearing tumor xenograft showed reduced tumor growth upon treatment with PF-3758309 (group II PAK inhibitor). Immunohistochemical analysis revealed overexpression of PAK6 in 66.6% (52/78) of NSCLC cases in tissue microarrays. Taken together, our study indicates that PAK6 is a promising novel therapeutic target for NSCLC, especially in smokers.
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.
authors.forename: Remya
authors.initials: R
authors.lastname: Raja
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.
authors.forename: Nandini A
authors.initials: NA
authors.lastname: Sahasrabuddhe
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|Department of Biochemistry and Molecular Biology, Pondicherry University, Puducherry, 605014, India.
authors.forename: Aneesha
authors.initials: A
authors.lastname: Radhakrishnan
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|Department of Biochemistry and Molecular Biology, Pondicherry University, Puducherry, 605014, India.
authors.forename: Nazia
authors.initials: N
authors.lastname: Syed
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India.
authors.forename: Hitendra S
authors.initials: HS
authors.lastname: Solanki
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|Amrita School of Biotechnology, Amrita University, Kollam, 690 525, India.
authors.forename: Vinuth N
authors.initials: VN
authors.lastname: Puttamallesh
authors.affiliation: Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India.
authors.forename: Sai A
authors.initials: SA
authors.lastname: Balaji
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|Amrita School of Biotechnology, Amrita University, Kollam, 690 525, India.
authors.forename: Vishalakshi
authors.initials: V
authors.lastname: Nanjappa
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India.
authors.forename: Keshava K
authors.initials: KK
authors.lastname: Datta
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.
authors.forename: Niraj
authors.initials: N
authors.lastname: Babu
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|Amrita School of Biotechnology, Amrita University, Kollam, 690 525, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Renuse
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India.
authors.forename: Arun H
authors.initials: AH
authors.lastname: Patil
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21231, USA.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Izumchenko
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|Amrita School of Biotechnology, Amrita University, Kollam, 690 525, India.|YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University, Mangalore, 575018, India.|NIMHANS-IOB Proteomics and Bioinformatics Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bangalore, 560029, India.
authors.forename: T S Keshava
authors.initials: TS
authors.lastname: Prasad
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21231, USA.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Chang
authors.affiliation: Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India.
authors.forename: Annapoorni
authors.initials: A
authors.lastname: Rangarajan
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21231, USA.
authors.forename: David
authors.initials: D
authors.lastname: Sidransky
authors.affiliation: McKusick-Nathans Institute of Genetic Medicine, Baltimore, Maryland, 21205, USA.|Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.|Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.|Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.
authors.forename: Akhilesh
authors.initials: A
authors.lastname: Pandey
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University, Mangalore, 575018, India.
authors.forename: Harsha
authors.initials: H
authors.lastname: Gowda
authors.affiliation: Institute of Bioinformatics, International Tech Park, Bangalore, 560 066, India.|YU-IOB Center for Systems Biology and Molecular Medicine, Yenepoya University, Mangalore, 575018, India.
authors.forename: Aditi
authors.initials: A
authors.lastname: Chatterjee
mesh_terms: D000818:Animals; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D066246:ErbB Receptors / Q000378:metabolism; D020868:Gene Silencing; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D010766:Phosphorylation; D020543:Proteome; D011720:Pyrazoles / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D012906:Smoke / Q000009:adverse effects*; D062789:Tobacco Products; D054462:p21-Activated Kinases / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: C550923:PF 3758309; D020543:Proteome; D011720:Pyrazoles; D011758:Pyrroles; C107953:RAC1 protein, human; D034741:RNA, Small Interfering; D012906:Smoke; C512478:EGFR protein, human; D066246:ErbB Receptors; C429007:PAK6 protein, human; D054462:p21-Activated Kinases; D020830:rac1 GTP-Binding Protein
keywords: NSCLC; mass spectrometry; p21 (RAC1)-activated kinase 6; smoking