The Role of CALML3 in Oral Squamous Cell Carcinoma

Objectives: The aims of the project were to determine the expression of CALML3 in a cohort of normal, dysplastic and oral squamous cell carcinoma cell lines and ex vivo, in normal oral mucosa, oral potentially malignant lesions (OPML) and oral squamous cell carcinoma (OSCC). We also aimed to determine the phenotypic changes resulting from overexpression of CALML3 in OSCC cells.
Methods: The mRNA and protein expression of CALML3 were measured by qPCR and western blot in cell lines and in normal oral mucosa, OPML and OSCC by immunohistochemistry. The relationship of CALML3 expression to that of markers of differentiation and expression of myosin-X (a protein related to CALML3 activity) was also determined by qPCR and western blot respectively. The effects of re-expressing CALML3 in OPML and OSCC cell lines were investigated by means of transient transfection of CALML3. The effects of expression of CALM3 on migration and proliferation of the cells were assessed as well as on expression of differentiation markers and myosin-X.
Results: CALML3 was down-regulated in OSCC with a pattern of localisation in tissues similar to previous studies. It was found that CALML3 expression changes are unlikely to merely be a consequence of immortalisation. The expression of CALML3 mRNA correlates with involucrin mRNA expression. CALML3 re-expression has no effect on the migration of OSCC cells and this may be due to the increased expression of myosin-X in OSCC. Finally, ectopic expression of CALML3 had no effect on proliferation or expression of involucrin.
Conclusions: This study has supported previous findings regarding loss of CALML3 expression in OSCC. However, it has shown that CALML3 is not important in the migration of OSCC as it is in other cancers. The phenotypic changes resulting from this down-regulation in OSCC remain unclear.