title: Caveolin-1 accumulation in the tongue cancer tumor microenvironment is significantly associated with poor prognosis: an in-vivo and in-vitro study.
abstract: BACKGROUND
  Caveolin-1 (CAV1) may be upregulated by hypoxia and acts in a tumor-dependent manner. We investigated CAV1 in tongue squamous cell carcinoma (TSCC) and its association with clinical outcomes, and studied in vitro possible ways for CAV1 accumulation in the tumor microenvironment (TME).
  
  
  METHODS
  TSCC cases (N = 64) were immunohistochemically stained for CAV1. Scores were separately assessed in the tumor and TME and plotted for association with recurrence and survival (univariate analysis with log-rank test). In vitro studies were performed on a 3D myoma organotypic model, a mimicker of TME. Prior to monoculturing HSC-3 tongue cancer cells, the model underwent modifications in oxygenation level (1%O2 hypoxia to upregulate CAV1) and/or in the amount of natural soluble factors [deleted by 14-day rinsing (rinsed myoma, RM), to allow only HSC-3-derived factors to act]. Controls included normoxia (21%O2) and naturally occurring soluble factors (intact myoma, IM). HSC-3 cells were also co-cultured with CaDEC12 cells (fibroblasts exposed to human tongue cancer). CAV1 expression and cellular distribution were examined in different cellular components in hypoxic and rinsed myoma assays. Twist served as a marker for the process of epithelial-mesenchymal transition (EMT). Exosomes isolated from HSC-3 media were investigated for containing CAV1.
  
  
  RESULTS
  Expression of CAV1 in TSCC had a higher score in TME than in the tumor cells and a negative impact on recurrence (p = 0.01) and survival (p = 0.003). Monocultures of HSC-3 revealed expression of CAV1 mainly in the TME-like myoma assay, similar to TSCC. CAV1+, alpha-smooth muscle actin (αSMA) + and Twist + CAF-like cells were observed surrounding the invading HSC-3, possibly reflecting EMT. RM findings were similar to IM, inferring action of HSC-3 derived factors, and no differences were seen when hypoxia was induced. HSC-3-CaDEC12 co-cultures revealed CAV1+, αSMA+ and cytokeratin-negative CAF-like cells, raising the possibility of CaDEC12 cells gaining a CAF phenotype. HSC-3-derived exosomes were loaded with CAV1.
  
  
  CONCLUSIONS
  Accumulation of CAV1-TME in TSCC had a negative prognostic value. In vitro studies showed the presence of CAV1 in cancer cells undergoing EMT and in fibroblasts undergoing trans-differentiation to CAFs. CAV1 delivery to the TME involved cancer cell-derived exosomes.
authors: Department of Oral Pathology and Oral Medicine, School of Dental Medicine, Tel Aviv University, Tel Aviv, 69978, Israel. mvered@post.tau.ac.il.|Institute of Pathology, The Chaim Sheba Medical Center, Tel Hashomer, Israel. mvered@post.tau.ac.il.
authors: Marilena
authors: M
authors: Vered
authors: Department of Diagnostics and Oral Medicine, Institute of Dentistry, University of Oulu, Oulu, Finland. meri.lehtonen@hotmail.fi.
authors: Meri
authors: M
authors: Lehtonen
authors: Department of Diagnostics and Oral Medicine, Institute of Dentistry, University of Oulu, Oulu, Finland. Lari.Hotakainen@student.oulu.fi.
authors: Lari
authors: L
authors: Hotakainen
authors: Department of Diagnostics and Oral Medicine, Institute of Dentistry, University of Oulu, Oulu, Finland. emma.pirila@oulu.fi.
authors: Emma
authors: E
authors: Pirilä
authors: Department of Diagnostics and Oral Medicine, Institute of Dentistry, University of Oulu, Oulu, Finland. susanna.teppo@gmail.com.
authors: Susanna
authors: S
authors: Teppo
authors: Department of Diagnostics and Oral Medicine, Institute of Dentistry, University of Oulu, Oulu, Finland. pia.nyberg@oulu.fi.|Oulu University Hospital, Oulu, Finland. pia.nyberg@oulu.fi.
authors: Pia
authors: P
authors: Nyberg
authors: Biocenter Oulu, University of Oulu, Oulu, Finland. raija.sormunen@oulu.fi.|Medical Research Center, Oulu, Finland. raija.sormunen@oulu.fi.
authors: Raija
authors: R
authors: Sormunen
authors: Department of Oral Pathology and Oral Medicine, School of Dental Medicine, Tel Aviv University, Tel Aviv, 69978, Israel. ayelet.zlotogorski@gmail.com.
authors: Ayelet
authors: A
authors: Zlotogorski-Hurvitz
authors: Department of Diagnostics and Oral Medicine, Institute of Dentistry, University of Oulu, Oulu, Finland. tuula.salo@oulu.fi.|Oulu University Hospital, Oulu, Finland. tuula.salo@oulu.fi.|Biocenter Oulu, University of Oulu, Oulu, Finland. tuula.salo@oulu.fi.|Medical Research Center, Oulu, Finland. tuula.salo@oulu.fi.|Institute of Dentistry, University of Helsinki, Helsinki, Finland. tuula.salo@oulu.fi.
authors: Tuula
authors: T
authors: Salo
authors: Department of Oral Pathology and Oral Medicine, School of Dental Medicine, Tel Aviv University, Tel Aviv, 69978, Israel. ddayan@post.tau.ac.il.
authors: Dan
authors: D
authors: Dayan
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000401:mortality; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D018929:Cell Culture Techniques; D018920:Coculture Techniques; D005260:Female; D005500:Follow-Up Studies; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D014062:Tongue Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology; D014407:Tumor Cells, Cultured; D059016:Tumor Microenvironment / Q000235:genetics
chemical_list: D051242:Caveolin 1
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