title: Pentoxifylline sensitizes human cervical tumor cells to cisplatin-induced apoptosis by suppressing NF-kappa B and decreased cell senescence.
abstract: BACKGROUND
  Worldwide, cervical cancer is the second most common causes of cancer in women and represents an important mortality rate. Cisplatin (CIS) is a very important antitumoral agent and can lead tumor cells toward two important cellular states: apoptosis and senescence. In some types of cancers pentoxifylline (PTX) sensitizes these cells to the toxic action of chemotherapeutics drugs such as adriamycin, inducing apoptosis. In the present work, we studied in vitro whether PTX alone or in combination with CIS induces apoptosis and/or senescence in cervix cancer HeLa and SiHa cell lines infected with HPV types 16 and 18, respectively, as well as in immortalized keratinocytyes HaCaT cells.
  
  
  METHODS
  HeLa (HPV 18+), SiHa (HPV 16+) cervix cancer cells and non-tumorigenic immortalized HaCaT cells (control) were treated with PTX, CIS or both. The cellular toxicity and survival fraction of PTX and CIS were determinate by WST-1 and clonogenic assays respectively. Apoptosis, caspase activation and phosphorylation of ERK1/2, p38, p65 (NF-κB), Bcl-2 and Bcl-XL anti-apoptotic proteins were determinated by flow cytometry. Senescence by microscopy. Phosphorylation of IκBα and IκB total were measured by ELISA. Pro-apoptotic, anti-apoptotic and senescence genes, as well as HPV-E6/7 mRNA expression, were detected by RT-PCR.
  
  
  RESULTS
  Our results show that after 24 hours of incubation PTX per se is toxic for cancer cells affecting cell viability and inducing apoptosis. The toxicity in HaCaT cells was minimal. CIS induces apoptosis in HeLa and SiHa cells and its effect was significantly increases when the cells were treated with PTX + CIS. In all studies there was a direct correlation with levels of caspases (-3, -6, -7, -9 and -8) activity and apoptosis. CIS induces important levels of senescence and phosphorylation of ERK1/2, p38, p65/RELA, and IκBα, and decreased the expression of anti-apoptotic protein Bcl-XL. Surprisingly these levels were significantly reduced by PTX in tumor cells, and at the same time, increases the expression of pro-apoptotic genes.
  
  
  CONCLUSIONS
  PTX sensitizes cervical cancer cells to CIS-induced apoptosis and decreases the CIS-induced senescence in these cells via inhibition of NF-κB signaling pathway; diminishes expression of antiapoptotic proteins and the activation of caspases.
authors.affiliation: División de Inmunología, Centro de Investigación Biomédica de Occidente, Instituto Mexicano del Seguro Social, Guadalajara, Jalisco, México.
authors.forename: Georgina
authors.initials: G
authors.lastname: Hernandez-Flores
authors.forename: Pablo C
authors.initials: PC
authors.lastname: Ortiz-Lazareno
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Lerma-Diaz
authors.forename: Jorge R
authors.initials: JR
authors.lastname: Dominguez-Rodriguez
authors.forename: Luis F
authors.initials: LF
authors.lastname: Jave-Suarez
authors.forename: Adriana del C
authors.initials: Adel C
authors.lastname: Aguilar-Lemarroy
authors.forename: Ruth
authors.initials: R
authors.lastname: de Celis-Carrillo
authors.forename: Susana
authors.initials: S
authors.lastname: del Toro-Arreola
authors.forename: Yessica C
authors.initials: YC
authors.lastname: Castellanos-Esparza
authors.forename: Alejandro
authors.initials: A
authors.lastname: Bravo-Cuellar
mesh_terms: D000328:Adult; D017304:Annexin A5 / Q000378:metabolism; D000970:Antineoplastic Agents / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D016922:Cellular Senescence / Q000187:drug effects* / Q000502:physiology; D002945:Cisplatin / Q000627:therapeutic use*; D005260:Female; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D010431:Pentoxifylline / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D051020:bcl-X Protein / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D017304:Annexin A5; D000970:Antineoplastic Agents; C494811:BCL2L1 protein, human; D016328:NF-kappa B; D010726:Phosphodiesterase Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases; D002945:Cisplatin; D010431:Pentoxifylline
references.citation: J Cell Mol Med. 2010 Aug;14(8):2073-7
references.pmid: 20597995
references.citation: Chemotherapy. 2006;52(6):308-15
references.pmid: 17008791
references.citation: Oncogene. 2003 Jun 26;22(26):3998-4006
references.pmid: 12821934
references.citation: Mol Pharmacol. 2001 Apr;59(4):657-63
references.pmid: 11259608
references.citation: Presse Med. 2010 Dec;39(12):1330-1
references.pmid: 20888731
references.citation: J Natl Cancer Inst. 1994 Oct 19;86(20):1517-24
references.pmid: 7932806
references.citation: Apoptosis. 2007 Sep;12(9):1733-42
references.pmid: 17505786
references.citation: Curr Protoc Mol Biol. 2001 May;Chapter 14:Unit 14.13
references.pmid: 18265108
references.citation: Neoplasia. 2004 Jan-Feb;6(1):29-40
references.pmid: 15068669
references.citation: Mol Cancer. 2010 May 19;9:114
references.pmid: 20482878
references.citation: J Cell Biol. 2011 Feb 21;192(4):547-56
references.pmid: 21321098
references.citation: Curr Opin Genet Dev. 2011 Feb;21(1):107-12
references.pmid: 21093253
references.citation: Exp Biol Med (Maywood). 2008 Jan;233(1):21-31
references.pmid: 18156302
references.citation: Carcinogenesis. 2000 Mar;21(3):477-84
references.pmid: 10688868
references.citation: Lung Cancer. 2001 Aug-Sep;33(2-3):221-8
references.pmid: 11551417
references.citation: Blood. 2006 Jan 1;107(1):257-64
references.pmid: 16166592
references.citation: Toxicol Pathol. 2007 Jun;35(4):495-516
references.pmid: 17562483
references.citation: Exp Gerontol. 2001 Nov;36(10):1619-37
references.pmid: 11672984
references.citation: Cell Tissue Res. 1998 Jun;292(3):435-45
references.pmid: 9582400
references.citation: Biochem Pharmacol. 2009 Jan 1;77(1):30-45
references.pmid: 18851957
references.citation: CMAJ. 2001 Apr 3;164(7):1017-25
references.pmid: 11314432
references.citation: Cancer Res. 2003 Jun 1;63(11):2705-15
references.pmid: 12782571
references.citation: Clin Hemorheol Microcirc. 2008;40(2):165-6
references.pmid: 19029641
references.citation: J Biol Chem. 2009 Apr 24;284(17):11237-46
references.pmid: 19251701
references.citation: J Biol Chem. 2004 Jan 9;279(2):1050-9
references.pmid: 14593117
references.citation: Blood. 2001 Nov 1;98(9):2603-14
references.pmid: 11675328
references.citation: CA Cancer J Clin. 2011 Mar-Apr;61(2):69-90
references.pmid: 21296855
references.citation: Urol Res. 2001 Jun;29(3):221-7
references.pmid: 11482451
references.citation: Cell Death Differ. 2001 Feb;8(2):182-91
references.pmid: 11313720
references.citation: Methods Mol Med. 2005;110:173-83
references.pmid: 15901935
references.citation: Cancer Epidemiol Biomarkers Prev. 2008 Apr;17(4):810-7
references.pmid: 18398022
references.citation: Nat Protoc. 2006;1(5):2315-9
references.pmid: 17406473
references.citation: Cancer Res. 1999 Jul 1;59(13):3077-83
references.pmid: 10397248
references.citation: Biochim Biophys Acta. 2007 Jan;1775(1):5-20
references.pmid: 17027159
references.citation: Genes Dev. 2008 Jun 15;22(12):1577-90
references.pmid: 18559474
references.citation: Anticancer Drugs. 2009 Mar;20(3):208-14
references.pmid: 19396019
references.citation: J Natl Cancer Inst. 2010 Oct 20;102(20):1536-46
references.pmid: 20858887
references.citation: Blood. 1997 Mar 15;89(6):1845-53
references.pmid: 9058703
references.citation: J Biol Chem. 2004 Jun 18;279(25):26143-8
references.pmid: 15073167
references.citation: Cancer Res. 2010 Jan 15;70(2):440-6
references.pmid: 20068163
references.citation: Cell Prolif. 2000 Feb;33(1):39-50
references.pmid: 10741643
references.citation: J Exp Med. 1999 Jul 19;190(2):253-65
references.pmid: 10432288
references.citation: Cancer Res. 2007 Nov 1;67(21):10466-74
references.pmid: 17974990
references.citation: Biochim Biophys Acta. 2005 Apr 15;1743(3):269-79
references.pmid: 15843040
references.citation: Mol Cancer Ther. 2004 Aug;3(8):895-902
references.pmid: 15299072
references.citation: BMC Cancer. 2006 Aug 23;6:213
references.pmid: 16928273
references.citation: J Neurochem. 2010 Aug;114(3):772-83
references.pmid: 20477944
references.citation: Cancer Biol Ther. 2007 Feb;6(2):178-84
references.pmid: 17218783
references.citation: Tsitologiia. 2007;49(2):115-24
references.pmid: 17432596
references.citation: Science. 1995 Jan 6;267(5194):17
references.pmid: 7848496
references.citation: Pharmacol Rev. 2006 Sep;58(3):621-81
references.pmid: 16968952
references.citation: Clin Cancer Res. 2001 Aug;7(8):2168-81
references.pmid: 11489790
references.citation: Immunol Lett. 2006 Mar 15;103(2):149-58
references.pmid: 16388856
references.citation: Int J Radiat Biol. 2000 Sep;76(9):1197-208
references.pmid: 10993631
references.citation: Toxicology. 2003 Nov 15;193(1-2):153-60
references.pmid: 14599774