title: Investigating the Radioresistant Properties of Lung Cancer Stem Cells in the Context of the Tumor Microenvironment.
abstract: Lung cancer is the most common cause of cancer-related deaths worldwide and non-small cell lung cancer (NSCLC) accounts for ~85% of all lung cancer. While recent research has shown that cancer stem cells (CSC) exhibit radioresistant and chemoresistant properties, current cancer therapy targets the bulk of the tumor burden without accounting for the CSC and the contribution of the tumor microenvironment. CSC interaction with the stroma enhances NSCLC survival, thus limiting the efficacy of treatment. The aim of this study was to elucidate the role of CSC and the microenvironment in conferring radio- or chemoresistance in an in vitro tumor model for NSCLC. The novel in vitro three-dimensional (3D) NSCLC model of color-coded tumor tissue analogs (TTA) that we have developed is comprised of human lung adenocarcinoma cells, fibroblasts, endothelial cells and NSCLC cancer stem cells maintained in low oxygen conditions (5% O2) to recapitulate the physiologic conditions in tumors. Using this model, we demonstrate that a single 5 Gy radiation dose does not inhibit growth of TTA containing CSC and results in elevated expression of cytokines (TGF-α, RANTES, ENA-78) and factors (vimentin, MMP and TIMP), indicative of an invasive and aggressive phenotype. However, combined treatment of single dose or fractionated doses with cisplatin was found to either attenuate or decrease the proliferative effect that radiation exposure alone had on TTA containing CSC maintained in hypoxic conditions. In summary, we utilized a 3D NSCLC model, which had characteristics of the tumor microenvironment and tumor cell heterogeneity, to elucidate the multifactorial nature of radioresistance in tumors.
authors.affiliation: a  Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, 40536-0596; and b Department of Radiation Medicine, University of Kentucky Albert B. Chandler Hospital, Lexington, Kentucky 40536-0293.
authors.forename: Ryan
authors.initials: R
authors.lastname: Chan
authors.affiliation: a  Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, 40536-0596; and b Department of Radiation Medicine, University of Kentucky Albert B. Chandler Hospital, Lexington, Kentucky 40536-0293.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Sethi
authors.affiliation: a  Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, 40536-0596; and b Department of Radiation Medicine, University of Kentucky Albert B. Chandler Hospital, Lexington, Kentucky 40536-0293.
authors.forename: Amar
authors.initials: A
authors.lastname: Jyoti
authors.affiliation: a  Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, 40536-0596; and b Department of Radiation Medicine, University of Kentucky Albert B. Chandler Hospital, Lexington, Kentucky 40536-0293.
authors.forename: Ronald
authors.initials: R
authors.lastname: McGarry
authors.affiliation: a  Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky, 40536-0596; and b Department of Radiation Medicine, University of Kentucky Albert B. Chandler Hospital, Lexington, Kentucky 40536-0293.
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Upreti
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000528:radiation effects; D016207:Cytokines / Q000276:immunology*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy*; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects*; D011836:Radiation Tolerance; D011879:Radiotherapy Dosage; D059016:Tumor Microenvironment / Q000528:radiation effects*
chemical_list: D016207:Cytokines
references.citation: Transl Oncol. 2011 Dec;4(6):365-76
references.pmid: 22191001
references.citation: Oncogene. 1997 Sep 4;15(10):1191-7
references.pmid: 9294612
references.citation: Lung Cancer. 2013 Jul;81(1):117-22
references.pmid: 23562674
references.citation: Differentiation. 1982;23(1):43-59
references.pmid: 6759279
references.citation: Proc Natl Acad Sci U S A. 2009 Sep 22;106(38):16281-6
references.pmid: 19805294
references.citation: Cancer Res. 2012 May 15;72(10):2473-80
references.pmid: 22414581
references.citation: Pharmacol Ther. 1993 Sep;59(3):329-41
references.pmid: 8309995
references.citation: CA Cancer J Clin. 2010 Sep-Oct;60(5):277-300
references.pmid: 20610543
references.citation: Stem Cells. 2004;22(5):716-24
references.pmid: 15342936
references.citation: Chest. 2007 Sep;132(3 Suppl):243S-265S
references.pmid: 17873172
references.citation: Cancer Res. 2005 Aug 15;65(16):7241-8
references.pmid: 16103075
references.citation: Curr Gene Ther. 2002 May;2(2):255-71
references.pmid: 12109221
references.citation: Curr Opin Biotechnol. 2007 Oct;18(5):460-6
references.pmid: 18023337
references.citation: Nat Protoc. 2006;1(5):2315-9
references.pmid: 17406473
references.citation: Anticancer Res. 2008 May-Jun;28(3A):1459-65
references.pmid: 18630499
references.citation: J Mol Med (Berl). 2013 Apr;91(4):497-506
references.pmid: 23090010
references.citation: Ann N Y Acad Sci. 2004 Dec;1028:351-60
references.pmid: 15650260
references.citation: Am J Physiol. 1996 Oct;271(4 Pt 1):C1172-80
references.pmid: 8897823
references.citation: Int J Oncol. 2013 Jun;42(6):2028-36
references.pmid: 23588995
references.citation: Lung Cancer. 2015 Feb;87(2):98-106
references.pmid: 25512094
references.citation: Exp Physiol. 2006 Sep;91(5):807-19
references.pmid: 16857720
references.citation: Radiother Oncol. 2014 Mar;110(3):538-45
references.pmid: 24440048
references.citation: J Natl Cancer Inst. 1973 Nov;51(5):1417-23
references.pmid: 4357758
references.citation: Oncogene. 2002 Mar 28;21(14):2245-52
references.pmid: 11948407
references.citation: Mediators Inflamm. 2014;2014:292376
references.pmid: 24523569
references.citation: Cell Struct Funct. 2009;34(2):89-96
references.pmid: 19724156
references.citation: Proc Natl Acad Sci U S A. 2001 Dec 18;98(26):14748-50
references.pmid: 11752416
references.citation: Cancers (Basel). 2011 Mar;3(1):1232-52
references.pmid: 21603589
references.citation: Cancer Res. 2000 Oct 15;60(20):5723-30
references.pmid: 11059766
references.citation: Nat Rev Cancer. 2008 Jul;8(7):545-54
references.pmid: 18511937
references.citation: Oncogene. 2015 Apr 9;34(15):1979-90
references.pmid: 24858039
references.citation: J Neuropathol Exp Neurol. 2015 Apr;74(4):293-304
references.pmid: 25756591
references.citation: Tumour Biol. 2014 May;35(5):3945-51
references.pmid: 24420150
references.citation: J Clin Oncol. 2010 May 1;28(13):2181-90
references.pmid: 20351327
references.citation: Mol Cancer. 2013;12(1):94
references.pmid: 23947765
references.citation: J Clin Oncol. 2004 Aug 15;22(16):3218-29
references.pmid: 15249585
references.citation: Clin Cancer Res. 2010 Jun 15;16(12):3113-20
references.pmid: 20530701
references.citation: J Natl Cancer Inst. 2006 Dec 20;98(24):1755-7
references.pmid: 17179471
references.citation: Curr Opin Oncol. 2015 Jan;27(1):64-70
references.pmid: 25415136
references.citation: Cancer Sci. 2009 Jun;100(6):1040-6
references.pmid: 19385971
references.citation: Chest. 2007 Sep;132(3 Suppl):266S-276S
references.pmid: 17873173
references.citation: J Clin Invest. 1998 Aug 1;102(3):465-72
references.pmid: 9691082
references.citation: Biochim Biophys Acta. 2014 Apr;1845(2):182-201
references.pmid: 24440852
references.citation: Cell Mol Life Sci. 2011 Sep;68(18):3033-46
references.pmid: 21637948
references.citation: PLoS One. 2013;8(10):e77366
references.pmid: 24143225
references.citation: J Clin Invest. 2003 Jul;112(1):126-35
references.pmid: 12840067
references.citation: J Cell Physiol. 2009 May;219(2):271-5
references.pmid: 19160417
references.citation: Int J Stem Cells. 2009 May;2(2):109-14
references.pmid: 24855529
references.citation: Transl Cancer Res. 2013 Aug 1;2(4):309-319
references.pmid: 24634853
references.citation: Nat Rev Clin Oncol. 2012 Oct;9(10):591-8
references.pmid: 22926022
references.citation: J Gene Med. 2004 Nov;6(11):1228-37
references.pmid: 15390257
references.citation: Cancer Res. 1987 Jun 1;47(11):2903-10
references.pmid: 3032416
references.citation: Oncol Lett. 2014 Jun;7(6):1903-1910
references.pmid: 24932256