Epithelial to mesenchymal transition in head and neck squamous carcinoma: association of Src activation with E-cadherin down-regulation, vimentin expression, and aggressive tumor features.
BACKGROUND
Epithelial-mesenchymal transformations (EMT) are critical for the invasion, progression, and metastasis of epithelial carcinogenesis. The role of EMT in head and neck squamous carcinoma (HNSC) tumorigenesis remains unexplored. In the current study, the expressions of several factors associated with the induction of EMT in HNSC cell lines and tumor specimens were investigated to define their functional and pathologic role in HNSC.


METHODS
Eleven HNSC cell lines and 50 primary tumor tissue specimens formed the materials of this study. Western blot analysis as well as immunohistochemical, and functional techniques were used to assess the status of activated Src (p-Src), E-cadherin, and vimentin in both cell lines and tumor tissues and the results were correlated with patients' clinicopathologic parameters.


RESULTS
The results demonstrated the inverse expression of p-Src and E-cadherin in the majority of cell lines and in primary tumor tissues compared with normal squamous mucosa. Elevated levels of p-Src were accompanied by down-regulation of E-cadherin and the expression of vimentin in epithelial tumor cells. In vitro inhibition of Src led to E-cadherin reexpression and increased cell contact in squamous carcinoma cell lines. Immunophenotypic analysis of these markers in primary tumor tissues demonstrated a significant correlation between increased p-Src, decreased E-cadherin, and vimentin expression and aggressive tumor features including penetrating invasive fronts, high-grade sarcomatoid transformation, and lymph node metastasis.


CONCLUSIONS
The results of the current study indicate that Src and E-cadherin may play an important role in EMT, invasion, and aggressive clinicopathologic features of HNSC. These proteins may be targeted for the therapeutic intervention of patients with HNSC.
Mandal
Mahitosh
M
Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Myers
Jeffery N
JN
Lippman
Scott M
SM
Johnson
Faye M
FM
Williams
Michelle D
MD
Rayala
Suresh
S
Ohshiro
Kazufumi
K
Rosenthal
David I
DI
Weber
Randal S
RS
Gallick
Gary E
GE
El-Naggar
Adel K
AK
D015820:Cadherins / Q000032:analysis*; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000201:enzymology / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation; D004789:Enzyme Activation; D004848:Epithelium / Q000473:pathology*; D066246:ErbB Receptors / Q000032:analysis; D006258:Head and Neck Neoplasms / Q000737:chemistry / Q000201:enzymology / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008648:Mesoderm / Q000473:pathology*; D011743:Pyrimidines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D019061:src-Family Kinases / Q000378:metabolism*
C412373:AG 1879; D015820:Cadherins; D011743:Pyrimidines; D034741:RNA, Small Interfering; D066246:ErbB Receptors; D019061:src-Family Kinases