DLC1 as a regulator of proliferation, invasion, cell cycle, and apoptosis in cutaneous squamous cell carcinoma

Tumour Biol. 2013 Oct;34(5):2633-43. doi: 10.1007/s13277-013-0813-0. Epub 2013 Apr 28.

Abstract

Increasing evidence has demonstrated that the tumor suppressor gene deleted in liver cancer-1 (DLC1) is tightly implicated in the development and progression of tumors and is verified to be downregulated in a variety of tumors. However, the roles and precise molecular mechanisms of DLC1 in cutaneous squamous cell carcinoma (cutaneous SCC) remain to be elucidated. In the present study, we confirmed the reduced level in cutaneous SCC tissues and cells, and DLC1 mRNA relative level in cutaneous SCC tissues with lymph node metastasis (0.801 ± 0.079) was markedly lower than those without lymph node metastasis (1.245 ± 0.071) (P < 0.0001). Importantly, the survival rates of patients with low DLC1 level were lower than those with high DLC1 level (P = 0.0051). Further investigation revealed that DLC1 overexpression inhibited proliferation and arrested cell cycle at G0/G1 phase in A431 cells, which may be tightly associated with upregulation of p21 protein and downregulation of cyclin D1 and cdk2 proteins. Moreover, the decreases of FAK and p-FAK as well as the increase of E-cadherin level mediated by elevated DLC1 level suppressed invasion in A431 cells. Additionally, DLC1 overexpression induced apoptosis coupled with elevations of Bax level and caspase-3 activity and decrease of Bcl-2 level in A431 cells. Taken altogether, our data presented herein suggest that DLC1 plays a pivotal role in the development and progression of cutaneous SCC, which may be in part achieved by regulating the signaling pathway related to proliferation, invasion, cell cycle, and apoptosis in cutaneous SCC cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis*
  • Carcinoma, Squamous Cell / metabolism*
  • Carcinoma, Squamous Cell / mortality
  • Carcinoma, Squamous Cell / pathology
  • Cell Cycle
  • Cell Line, Tumor
  • Cell Proliferation*
  • Cyclin D1 / metabolism
  • Cyclin-Dependent Kinase 2 / metabolism
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism
  • GTPase-Activating Proteins / genetics
  • GTPase-Activating Proteins / metabolism*
  • Humans
  • Kaplan-Meier Estimate
  • Neoplasm Invasiveness*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Skin Neoplasms / metabolism*
  • Skin Neoplasms / mortality
  • Skin Neoplasms / pathology
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*
  • bcl-2-Associated X Protein / metabolism

Substances

  • BAX protein, human
  • CCND1 protein, human
  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • DLC1 protein, human
  • GTPase-Activating Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Messenger
  • Tumor Suppressor Proteins
  • bcl-2-Associated X Protein
  • Cyclin D1
  • CDK2 protein, human
  • Cyclin-Dependent Kinase 2