{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:36:58Z","timestamp":1787027818634,"version":"build-2736575974"},"reference-count":56,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2024,10,31]],"date-time":"2024-10-31T00:00:00Z","timestamp":1730332800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000057","name":"National Institute of General Medical Sciences, NIH","doi-asserted-by":"publisher","award":["P20 GM103442"],"award-info":[{"award-number":["P20 GM103442"]}],"id":[{"id":"10.13039\/100000057","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cells"],"abstract":"<jats:p>Urothelial carcinoma (UC) is prevalent, especially in elderly males. The high rate of recurrence, treatment regime, and follow-up monitoring make UC a global health and economic burden. Arsenic is a ubiquitous toxicant that can be found in drinking water, and it is known that exposure to arsenic is associated with UC development. Around 25% of diagnosed UC cases are muscle-invasive (MIUC) which have poor prognosis and develop chemoresistance, especially if tumors are associated with squamous differentiation (SD). The immortalized UROtsa cell line is derived from normal human urothelium and our lab has malignantly transformed these cells using arsenite (As3+). These cells represent a basal subtype model of MIUC and the tumors derived from the As3+-transformed cells histologically and molecularly resemble clinical cases of the basal subtype of MIUC that have focal areas SD and expression of the basal keratins (KRT1, 5, 6, 14, and 16). Our previous data demonstrate that KRT6 protein expression correlates to areas of SD within the tumors. For this study, we performed a lentiviral knockdown of KRT6 in As3+-transformed UROtsa cells to evaluate the effects on morphology, gene\/protein expression, growth, colony formation, and cisplatin sensitivity. The knockdown of KRT6 resulted in decreased expression of the basal keratins, decreased growth, decreased colony formation, and increased sensitivity to cisplatin, the standard treatment for MIUC. The results of this study suggest that KRT6 plays a role in UC cell growth and is an exploitable target to increase cisplatin sensitivity for MIUC tumors that may have developed resistance to cisplatin treatment.<\/jats:p>","DOI":"10.3390\/cells13211803","type":"journal-article","created":{"date-parts":[[2024,10,31]],"date-time":"2024-10-31T06:55:37Z","timestamp":1730357737000},"page":"1803","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Knockdown of Keratin 6 Within Arsenite-Transformed Human Urothelial Cells Decreases Basal\/Squamous Expression, Inhibits Growth, and Increases Cisplatin Sensitivity"],"prefix":"10.3390","volume":"13","author":[{"given":"Nelofar","family":"Nargis","sequence":"first","affiliation":[{"name":"Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Donald A.","family":"Sens","sequence":"additional","affiliation":[{"name":"Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aaron A.","family":"Mehus","sequence":"additional","affiliation":[{"name":"Department of Pathology, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58202, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,10,31]]},"reference":[{"key":"ref_1","first-page":"307","article-title":"Multidisciplinary Management of Muscle-Invasive Bladder Cancer: Current Challenges and Future Directions","volume":"38","author":"Werntz","year":"2018","journal-title":"Am. Soc. Clin. Oncol. Educ. Book."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"540","DOI":"10.1016\/j.cell.2017.09.007","article-title":"Comprehensive Molecular Characterization of Muscle-Invasive Bladder Cancer","volume":"171","author":"Robertson","year":"2017","journal-title":"Cell"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1980","DOI":"10.1001\/jama.2020.17598","article-title":"Bladder Cancer: A Review","volume":"324","author":"Lenis","year":"2020","journal-title":"JAMA"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"5678","DOI":"10.1158\/1078-0432.CCR-04-2421","article-title":"Breast cancer molecular subtypes respond differently to preoperative chemotherapy","volume":"11","author":"Rouzier","year":"2005","journal-title":"Clin. Cancer Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"681","DOI":"10.1016\/j.ajpath.2013.05.013","article-title":"Toward a molecular pathologic classification of urothelial carcinoma","volume":"183","author":"Lauss","year":"2013","journal-title":"Am. J. Pathol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"152","DOI":"10.1016\/j.ccr.2014.01.009","article-title":"Identification of distinct basal and luminal subtypes of muscle-invasive bladder cancer with different sensitivities to frontline chemotherapy","volume":"25","author":"Choi","year":"2014","journal-title":"Cancer Cell"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Lindgren, D., Sj\u00f6dahl, G., Lauss, M., Staaf, J., Chebil, G., L\u00f6vgren, K., Gudjonsson, S., Liedberg, F., Patschan, O., and M\u00e5nsson, W. (2012). Integrated genomic and gene expression profiling identifies two major genomic circuits in urothelial carcinoma. PLoS ONE, 7.","DOI":"10.1371\/journal.pone.0038863"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1002\/path.4886","article-title":"Molecular classification of urothelial carcinoma: Global mRNA classification versus tumour-cell phenotype classification","volume":"242","author":"Eriksson","year":"2017","journal-title":"J. Pathol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3110","DOI":"10.1073\/pnas.1318376111","article-title":"Intrinsic subtypes of high-grade bladder cancer reflect the hallmarks of breast cancer biology","volume":"111","author":"Damrauer","year":"2014","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1038\/nrurol.2014.129","article-title":"Intrinsic basal and luminal subtypes of muscle-invasive bladder cancer","volume":"11","author":"Choi","year":"2014","journal-title":"Nat. Rev. Urol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1177\/107327481702400113","article-title":"Urothelial Carcinoma With Squamous Differentiation Is Associated With High Tumor Stage and Pelvic Lymph-Node Metastasis","volume":"24","author":"Liu","year":"2017","journal-title":"Cancer Control"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"e1063","DOI":"10.1016\/j.clgc.2017.07.008","article-title":"Squamous Differentiation Predicts Poor Response to Cisplatin-Based Chemotherapy and Unfavorable Prognosis in Urothelial Carcinoma of the Urinary Bladder","volume":"15","author":"Minato","year":"2017","journal-title":"Clin. Genitourin. Cancer"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1073274818800269","DOI":"10.1177\/1073274818800269","article-title":"Clinical Significance of Squamous Differentiation in Urothelial Carcinoma of the Bladder","volume":"25","author":"Minato","year":"2018","journal-title":"Cancer Control"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1759","DOI":"10.1007\/s00345-018-2544-8","article-title":"Forty years of cisplatin-based chemotherapy in muscle-invasive bladder cancer: Are we understanding how, who and when?","volume":"37","author":"Schardt","year":"2019","journal-title":"World J. Urol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1778","DOI":"10.1056\/NEJMoa2309863","article-title":"Nivolumab plus Gemcitabine-Cisplatin in Advanced Urothelial Carcinoma","volume":"389","author":"Sonpavde","year":"2023","journal-title":"N. Engl. J. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"875","DOI":"10.1056\/NEJMoa2312117","article-title":"Enfortumab Vedotin and Pembrolizumab in Untreated Advanced Urothelial Cancer","volume":"390","author":"Powles","year":"2024","journal-title":"N. Engl. J. Med."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"434","DOI":"10.1289\/ehp.10279","article-title":"Transformation of human urothelial cells (UROtsa) by as and cd induces the expression of keratin 6a","volume":"116","author":"Somji","year":"2008","journal-title":"Environ. Health Perspect."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1225","DOI":"10.1289\/ehp.021101225","article-title":"Expression of hsp 27, hsp 60, hsc 70, and hsp 70 stress response genes in cultured human urothelial cells (UROtsa) exposed to lethal and sublethal concentrations of sodium arsenite","volume":"110","author":"Rossi","year":"2002","journal-title":"Environ. Health Perspect."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1093\/toxsci\/kfh086","article-title":"Inorganic cadmium- and arsenite-induced malignant transformation of human bladder urothelial cells","volume":"79","author":"Sens","year":"2004","journal-title":"Toxicol. Sci. Off. J. Soc. Toxicol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"416","DOI":"10.1002\/jat.1513","article-title":"Keratin 6 expression correlates to areas of squamous differentiation in multiple independent isolates of As+3-induced bladder cancer","volume":"30","author":"Cao","year":"2010","journal-title":"J. Appl. Toxicol. JAT"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Hoggarth, Z.E., Osowski, D.B., Freeberg, B.A., Garrett, S.H., Sens, D.A., Sens, M.A., Zhou, X.D., Zhang, K.K., and Somji, S. (2018). The urothelial cell line UROtsa transformed by arsenite and cadmium display basal characteristics associated with muscle invasive urothelial cancers. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0207877"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.taap.2019.04.021","article-title":"Enrichment of genes associated with squamous differentiation in cancer initiating cells isolated from urothelial cells transformed by the environmental toxicant arsenite","volume":"374","author":"Hoggarth","year":"2019","journal-title":"Toxicol. Appl. Pharmacol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"705","DOI":"10.1007\/s00418-008-0435-6","article-title":"The human keratins: Biology and pathology","volume":"129","author":"Moll","year":"2008","journal-title":"Histochem. Cell Biol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1397","DOI":"10.1083\/jcb.98.4.1397","article-title":"Monoclonal antibody analysis of keratin expression in epidermal diseases: A 48- and 56-kdalton keratin as molecular markers for hyperproliferative keratinocytes","volume":"98","author":"Weiss","year":"1984","journal-title":"J. Cell Biol."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Zhang, X., Yin, M., and Zhang, L.J. (2019). Keratin 6, 16 and 17-Critical Barrier Alarmin Molecules in Skin Wounds and Psoriasis. Cells, 8.","DOI":"10.3390\/cells8080807"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1083\/jcb.132.3.381","article-title":"Onset of re-epithelialization after skin injury correlates with a reorganization of keratin filaments in wound edge keratinocytes: Defining a potential role for keratin 16","volume":"132","author":"Paladini","year":"1996","journal-title":"J. Cell Biol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"5248","DOI":"10.1128\/MCB.20.14.5248-5255.2000","article-title":"Delayed wound healing in keratin 6a knockout mice","volume":"20","author":"Wojcik","year":"2000","journal-title":"Mol. Cell Biol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"921","DOI":"10.1083\/jcb.150.4.921","article-title":"Introducing a null mutation in the mouse K6alpha and K6beta genes reveals their essential structural role in the oral mucosa","volume":"150","author":"Wong","year":"2000","journal-title":"J. Cell Biol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1007\/s12015-010-9208-4","article-title":"The Role of Human Aldehyde Dehydrogenase in Normal and Cancer Stem Cells","volume":"7","author":"Ma","year":"2011","journal-title":"Stem Cell Rev. Rep."},{"key":"ref_30","unstructured":"Kumar, R., and Fisher, P.B. (2020). Chapter Four\u2014EGFR: An essential receptor tyrosine kinase-regulator of cancer stem cells. Advances in Cancer Research, Academic Press."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Slusser-Nore, A., Larson-Casey, J.L., Zhang, R., Zhou, X.D., Somji, S., Garrett, S.H., Sens, D.A., and Dunlevy, J.R. (2016). SPARC Expression Is Selectively Suppressed in Tumor Initiating Urospheres Isolated from As+3- and Cd+2-Transformed Human Urothelial Cells (UROtsa) Stably Transfected with SPARC. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0147362"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1007\/s10565-010-9169-z","article-title":"Comparison of expression patterns of keratin 6, 7, 16, 17, and 19 within multiple independent isolates of As+3- and Cd+2-induced bladder cancer: Keratin 6, 7, 16, 17, and 19 in bladder cancer","volume":"27","author":"Somji","year":"2011","journal-title":"Cell Biol. Toxicol."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Sandquist, E.J., Somji, S., Dunlevy, J.R., Garrett, S.H., Zhou, X.D., Slusser-Nore, A., and Sens, D.A. (2016). Loss of N-Cadherin Expression in Tumor Transplants Produced From As+3- and Cd+2-Transformed Human Urothelial (UROtsa) Cell Lines. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0156310"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"W98","DOI":"10.1093\/nar\/gkx247","article-title":"GEPIA: A web server for cancer and normal gene expression profiling and interactive analyses","volume":"45","author":"Tang","year":"2017","journal-title":"Nucleic Acids Res."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Mehus, A.A., Jones, M., Trahan, M., Kinnunen, K., Berwald, K., Lindner, B., Al-Marsoummi, S., Zhou, X.D., Garrett, S.H., and Sens, D.A. (2023). Pevonedistat Inhibits SOX2 Expression and Sphere Formation but Also Drives the Induction of Terminal Differentiation Markers and Apoptosis within Arsenite-Transformed Urothelial Cells. Int. J. Mol. Sci., 24.","DOI":"10.3390\/ijms24119149"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Sundaram, S., \u017d\u00e1\u010dek, P., Bukowski, M.R., Mehus, A.A., Yan, L., and Picklo, M.J. (2018). Lipidomic Impacts of an Obesogenic Diet Upon Lewis Lung Carcinoma in Mice. Front. Oncol., 8.","DOI":"10.3389\/fonc.2018.00134"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1016\/j.jnutbio.2018.10.005","article-title":"Dietary saturated fatty acid type impacts obesity-induced metabolic dysfunction and plasma lipidomic signatures in mice","volume":"64","author":"Bukowski","year":"2019","journal-title":"J. Nutr. Biochem."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1739","DOI":"10.21873\/anticanres.13280","article-title":"Time-restricted Feeding Attenuates High-fat Diet-enhanced Spontaneous Metastasis of Lewis Lung Carcinoma in Mice","volume":"39","author":"Yan","year":"2019","journal-title":"Anticancer. Res."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Mehus, A.A., Rust, B., Idso, J.P., Hanson, B., Zeng, H., Yan, L., Bukowski, M.R., and Picklo, M.J. (2021). Time-restricted feeding mice a high-fat diet induces a unique lipidomic profile. J. Nutr. Biochem., 88.","DOI":"10.1016\/j.jnutbio.2020.108531"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"710","DOI":"10.1111\/j.1365-2559.2011.03988.x","article-title":"Desmocollin 2 is a new immunohistochemical marker indicative of squamous differentiation in urothelial carcinoma","volume":"59","author":"Hayashi","year":"2011","journal-title":"Histopathology"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"6575","DOI":"10.1038\/s41467-022-34251-3","article-title":"FOXA1 repression drives lineage plasticity and immune heterogeneity in bladder cancers with squamous differentiation","volume":"13","author":"Warrick","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_42","first-page":"2573","article-title":"Clonogenic assay: Adherent cells","volume":"49","author":"Rafehi","year":"2011","journal-title":"J. Vis. Exp."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2315","DOI":"10.1038\/nprot.2006.339","article-title":"Clonogenic assay of cells in vitro","volume":"1","author":"Franken","year":"2006","journal-title":"Nat. Protoc."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Esteban-Villarrubia, J., Torres-Jim\u00e9nez, J., Bueno-Bravo, C., Garc\u00eda-Mondaray, R., Subiela, J.D., and Gajate, P. (2023). Current and Future Landscape of Perioperative Treatment for Muscle-Invasive Bladder Cancer. Cancers, 15.","DOI":"10.3390\/cancers15030566"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Guo, C.C., Bondaruk, J., Yao, H., Wang, Z., Zhang, L., Lee, S., Lee, J.G., Cogdell, D., Zhang, M., and Yang, G. (2020). Assessment of Luminal and Basal Phenotypes in Bladder Cancer. Sci. Rep., 10.","DOI":"10.1038\/s41598-020-66747-7"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Mehus, A.A., Bergum, N., Knutson, P., Shrestha, S., Zhou, X.D., Garrett, S.H., Sens, D.A., Sens, M.A., and Somji, S. (2020). Activation of PPAR\u03b3 and inhibition of cell proliferation reduces key proteins associated with the basal subtype of bladder cancer in As3+-transformed UROtsa cells. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0237976"},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Al-Marsoummi, S., Mehus, A.A., Garrett, S.H., Sens, D.A., and Somji, S. (2024). The Effect of Retinoic Acid on Arsenite-Transformed Malignant UROtsa Bladder Cancer Cells: In Vitro Model of Basal Muscle-Invasive Bladder Cancer. Cancers, 16.","DOI":"10.3390\/cancers16061178"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1789","DOI":"10.1016\/S0002-9440(10)63737-6","article-title":"Activation of peroxisome proliferator-activated receptor-gamma reverses squamous metaplasia and induces transitional differentiation in normal human urothelial cells","volume":"164","author":"Varley","year":"2004","journal-title":"Am. J. Pathol."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Che, D., Wang, M., Sun, J., Li, B., Xu, T., Lu, Y., Pan, H., Lu, Z., and Gu, X. (2021). KRT6A Promotes Lung Cancer Cell Growth and Invasion Through MYC-Regulated Pentose Phosphate Pathway. Front. Cell Dev. Biol., 9.","DOI":"10.3389\/fcell.2021.694071"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1533033820921248","DOI":"10.1177\/1533033820921248","article-title":"KRT6A Promotes EMT and Cancer Stem Cell Transformation in Lung Adenocarcinoma","volume":"19","author":"Yang","year":"2020","journal-title":"Technol. Cancer Res. Treat."},{"key":"ref_51","first-page":"3477","article-title":"Keratin 6A gene silencing suppresses cell invasion and metastasis of nasopharyngeal carcinoma via the \u03b2-catenin cascade","volume":"19","author":"Chen","year":"2019","journal-title":"Mol. Med. Rep."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1590\/S1677-55382007000300006","article-title":"The role of squamous differentiation in patients with transitional cell carcinoma of the bladder treated with radical cystectomy","volume":"33","author":"Antunes","year":"2007","journal-title":"Int. Braz. J. Urol."},{"key":"ref_53","first-page":"7203","article-title":"Squamous differentiation and prognosis in upper urinary tract urothelial carcinoma","volume":"8","author":"Makise","year":"2015","journal-title":"Int. J. Clin. Exp. Pathol."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Li, G., Yu, J., Song, H., Zhu, S., Sun, L., Shang, Z., and Niu, Y. (2017). Squamous differentiation in patients with superficial bladder urothelial carcinoma is associated with high risk of recurrence and poor survival. BMC Cancer, 17.","DOI":"10.1186\/s12885-017-3520-1"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"102075","DOI":"10.1016\/j.labinv.2024.102075","article-title":"Keratin 6A Is Expressed at the Invasive Front and Enhances the Progression of Colorectal Cancer","volume":"104","author":"Kouchi","year":"2024","journal-title":"Lab. Investig."},{"key":"ref_56","first-page":"797","article-title":"Keratin 6, induced by chronic cisplatin exposure, confers chemoresistance in human gastric carcinoma cells","volume":"42","author":"Lim","year":"2019","journal-title":"Oncol. Rep."}],"container-title":["Cells"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4409\/13\/21\/1803\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:25:21Z","timestamp":1760113521000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4409\/13\/21\/1803"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,10,31]]},"references-count":56,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2024,11]]}},"alternative-id":["cells13211803"],"URL":"https:\/\/doi.org\/10.3390\/cells13211803","relation":{},"ISSN":["2073-4409"],"issn-type":[{"value":"2073-4409","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,10,31]]}}}