Ujjal K. Bhawal

Alveolar Bone Marrow as a Cell Source for Regenerative Medicine: Differences Between Alveolar and Iliac Bone Marrow Stromal Cells

We isolated and expanded BMSCs from human alveolar/jaw bone at a high success rate (70%). These cells had potent osteogenic potential in vitro and in vivo, although their chondrogenic and adipogenic potential was less than that of iliac cells.

Downregulation of miR-126 induces angiogenesis and lymphangiogenesis by activation of VEGF-A in oral cancer

Background:MicroRNA (miRNA)-126 (miR-126) is an endothelial-specific miRNA located within intron 7 of epidermal growth factor-like domain 7 (EGFL7). However, the role of miR-126 in cancer is controversial.Methods:We examined the function of miR-126 in oral squamous cell carcinoma (OSCC) cells. Furthermore, a series of 118 cases with OSCC were evaluated for the expression levels of miR-126.Results:MicroRNA-126 (miR-126) was associated with cell growth and regulation of vascular endothelial growth factor-A activity, and demethylation treatment increased expression levels of miR-126 and EGFL7 in OSCC cells. A significant association was found between miR-126 expression and tumour progression, nodal metastasis, vessel density, or poor prognosis in OSCC cases. In the multivariate analysis, decreased miR-126 expression was strongly correlated with disease-free survival.Conclusion:The present results suggest that miR-126 might be a useful diagnostic and therapeutic target in OSCC.

The expression of receptor for advanced glycation end products is associated with angiogenesis in human oral squamous cell carcinoma

The receptor for advanced glycation end products (RAGE) is associated with cancer progression in several human cancers. In this study, we examined the roles of RAGE in the angiogenesis of oral squamous cell carcinoma (OSCC). RAGE concentration was examined in 20 OSCC tumors by enzyme-linked immunosorbent assay (ELISA). The microvessel density (MVD) and lymph vessel density (LVD) were examined by immunostaining. Concentrations of vascular endothelial growth factor (VEGF) and VEGF-C were examined in tumor tissues by ELISA. Tumoral RAGE concentration was associated with higher tumor MVD (P = 0.0123) and tumor VEGF concentration (P = 0.0344), but not with LVD and VEGF-C concentration. Treatment with RAGE ligand, high-mobility group box (HMGB)-1 increased the secretion of VEGF but not that of VEGF-C in human OSCC cell lines, HSC-3 and HSC-4. The effect of HMGB-1 was abrogated by RAGE down-regulation by antisense S-oligodeoxynucleic acid. These results suggest that RAGE expression is closely associated to angiogenesis in OSCC.

High mobility group box‐1‐inducible melanoma inhibitory activity is associated with nodal metastasis and lymphangiogenesis in oral squamous cell carcinoma

Melanoma inhibitory activity (MIA) is an 11‐kDa secretory protein isolated from malignant melanoma cells that is correlated with invasion and metastasis in various human malignancies. We examined MIA expression in 62 oral squamous cell carcinomas (OSCC) by immunohistochemistry. MIA expression was significantly associated with nodal metastasis (P = 0.00018). MIA expression was also associated with expression of high mobility group box‐1 (HMGB1) (P < 0.0001) and lymph vessel density (P < 0.0001). Expression levels of MIA, HMGB1, nuclear factor kB (NFkB) p65 and HMGB1–NFkB p65 binding were significantly higher in a metastatic human OSCC cell line (HSC3) than those in a non‐metastatic OSCC cell line (HSC4). Treatment with receptor for advanced glycation end products (RAGE) antisense or small interfering RNA and human recombinant HMGB1 (hrHMGB1) did not affect MIA expression, whereas HMGB1 antisense or siRNA treatment decreased MIA expression in HSC3 cells. Then HMGB1 enhanced MIA expression as an NFkB cofactor but not as a RAGE ligand. MIA neutralization by MIA antibodies increased extracellular signal‐related kinase 1/2 phosphorylation, but decreased p38 phosphorylation and the expression of vascular epithelial growth factor (VEGF)‐C and ‐D. Treatment with p38 inihibitor decreased VEGF‐C and ‐D expression in HSC3 cells. These results suggest that MIA expression is enhanced by the interaction of intracellular HMGB1 and NFkBp65 and MIA is closely involved in tumor progression and nodal metastasis by the increments of VEGF‐C and VEGF‐D in OSCC. (Cancer Sci 2008; 99: 1806– 1812)

Basic-helix-loop-helix (bHLH) transcription factor DEC2 negatively regulates vascular endothelial growth factor expression

DEC1 (BHLHB2/Sharp2/Stra13) and DEC2 (BHLHB3/Sharp1) are basic‐helix‐loop‐helix (bHLH) transcription factors, involved in cellular differentiation, responses to hypoxia and circadian rhythms. We recently showed that the expression of DEC1 and DEC2 was up‐regulated by hypoxia; however, the functions of these two factors under hypoxic conditions have not been elucidated in detail. It is well established that the expression of vascular endothelial growth factor (VEGF) is up‐regulated by hypoxia, and the expression of VEGF in response to hypoxia depends on transcriptional activation by a heterodimer comprising hypoxia‐inducible factor 1α (HIF‐1α) and arylhydrocarbon receptor nuclear translocator 1 (ARNT1). In the present study, we showed that DEC2, but not DEC1, suppressed VEGF gene expression under hypoxic conditions. DEC2 protein was co‐immunoprecipitated with HIF‐1α but not with ARNT1. The binding of HIF‐1α to the hypoxia response element (HRE) in the VEGF promoter was decreased by DEC2 over‐expression, and increased by DEC2 knockdown. We also showed that the circadian expression of VEGF showed a reciprocal pattern to that of DEC2 in cartilage. DEC2 had a circadian oscillation in implanted Sarcoma 180 cells. We conclude that DEC2 negatively regulates VEGF expression and plays an important role in the pathological conditions in which VEGF is involved.

Association of Expression of Receptor for Advanced Glycation End Products and Invasive Activity of Oral Squamous Cell Carcinoma

Objectives: The receptor for advanced glycation end products (RAGE) is a newly recognized factor regulating cancer cell invasion and metastasis. Nevertheless, the involvement of RAGE in the development and progression of oral squamous cell carcinomas has not been elucidated. This study investigated the expression of RAGE in ten oral squamous cell carcinoma cell lines including primary and metastatic cell lines and its association with invasion and metastasis. Methods: Reverse transcriptase-polymerase chain reaction, antisense phosphorothioate (S)-oligodeoxynucleotide assay, preparation of antibody, immunohistochemical staining, immunoblot analysis, migration assay, in vitro invasion assay, and wound-healing assay were used. Results: RAGE protein expression of metastatic cancer cells treated with RAGE antisense S-oligodeoxynucleotide was significantly reduced compared to that of sense S-oligodeoxynucleotide-treated cells. The migration assay showed that invasive activity was significantly reduced in metastatic cancer cells treated with RAGE antisense S-oligodeoxynucleotide. Similarly, during invasion assays, numbers of invading cells were also reduced with the addition of RAGE antisense S-oligodeoxynucleotide-treated cells. A wound-healing assay showed that only a few RAGE antisense S-oligodeoxynucleotide-treated cancer cells migrated into the scraped area, whereas sense S-oligodeoxynucleotide-treated cells showed many budding nests in the scraped area of the metastatic cell lines. Immunohistochemically, oral squamous cell carcinoma cells in the tumour mesenchymal border were often immunopositive, whereas basal cells in the normal mucosa were scarcely positive. Conclusions: These results suggest that RAGE expression appears to be closely associated with the invasiveness of oral squamous cell carcinoma and represents a promising candidate for assessing the future therapeutic potential in treating patients with oral carcinoma.

Receptor for advanced glycation end products (RAGE) is important in the prediction of recurrence in human oral squamous cell carcinoma.

Aims:  Receptor for advanced glycation end products (RAGE) has recently been recognized as a cancer‐associated protein responsible for cancer progression and metastasis in gastrointestinal cancers. The aim was to examine the role of RAGE in oral squamous cell carcinoma (OSCC).

Basic helix-loop-helix transcription factor DEC1 negatively regulates cyclin D1.

DEC1 (also known as Stra13/Bhlhb2/Sharp2) and DEC2 (also known as Bhlhb3/Sharp1) are two paralogous basic helix‐loop‐helix (bHLH) transcriptional regulators which exhibit a robust circadian gene expression pattern in the suprachiasmatic nucleus (SCN) and in peripheral organs. DEC1 has been suggested to play key roles in mammalian cell differentiation, the cell cycle and circadian regulation, hypoxia response, and carcinogenesis. Here we show that DEC1 overexpression exhibits delayed wound healing and reduces cell proliferation, migration, and invasion. DEC1 strongly repressed the promoter activity of cyclin D1. We further identify a possible DEC‐response element in the cyclin D1 promoter region, and confirmed the direct binding of DEC1 to that element. Forced expression of DEC1 efficiently repressed the cyclin D1 promoter and expression. Our clinical data provide the first evidence that there is a strong inverse correlation between DEC1 and cyclin D1 expression in oral cancer, and DEC1 expression significantly correlated with clinicopathological parameters. We suggest that radiation‐induced DEC1 overexpression and Akt phosphorylation in cancer cells are mediated via PI‐3K signalling. Overexpression of DEC1 activates the PI‐3K/Akt signalling pathway through reactive oxygen species (ROS). Copyright

The BHLH transcription factor DEC1 plays an important role in the epithelial-mesenchymal transition of pancreatic cancer

DEC1 (BHLHE40/Stra13/Sharp2) is a basic helix-loop-helix (bHLH) transcription factor that is involved in the regulation of apoptosis and cell proliferation and the response to hypoxia. Epithelial-mesenchymal transition (EMT) is an important step leading to invasion and migration of various tumor cells, and TGF-β treatment has been shown to induce cancer cells to undergo EMT. However, the significance of DEC1 in TGF-β-induced EMT remains unknown. We examined the role of DEC1 in EMT of PANC-1 cells, a human pancreatic cancer cell line. As a result, we found that DEC1 was upregulated by TGF-β in PANC-1 cells, and regulated the expression and the levels of nuclear, cytoplasmic or membrane localization of EMT-related factors, including phosphorylated Smad3 (pSmad3), snail, claudin-4 and N-cadherin. In the presence of TGF-β, DEC1 knockdown by siRNA inhibited morphological changes during EMT processes, while TGF-β induced PANC-1 cells to taken on a spindle-shaped morphology. Furthermore, a combination treatment of DEC1 expression with TGF-β was closely linked to the migration and invasion of PANC-1 cells. Immunohistochemically, DEC1 and pSmad3 were detected within pancreatic cancer tissues, whereas claudin-4 expression was weaker in the cancer tissues compared with the adjacent non-cancer pancreatic tissues. These findings suggest that DEC1 plays an important role in the regulation of these EMT-related factors in pancreatic cancer.

MIA-dependent angiogenesis and lymphangiogenesis are closely associated with progression, nodal metastasis and poor prognosis in tongue squamous cell carcinoma.

We examined the role of angiogenesis/lymphangiogenesis and the relationship between melanoma inhibitory activity (MIA) and angiogenesis or lymphangiogenesis in oral squamous cell carcinoma (OSCC). One hundred and one formalin-fixed, paraffin-embedded specimens of primary OSCC were evaluated for microvessel density (MVD), lymphovessel density (LVD), expression of vascular endothelial growth factor (VEGF), VEGF-C, VEGF-D and MIA. Fresh frozen 18 samples of primary OSCC were further examined for the expression of VEGF, VEGF-C, VEGF-D and MIA protein by enzyme-linked immunosorbent assay (ELISA). In in vitro analysis, we studied the change of VEGF, VEGF-C and VEGF-D expression after MIA siRNA treatment. Higher MVD, LVD and VEGF expression levels were closely associated with tumour progression, nodal metastasis and poor prognosis. Expression levels of VEGF-C and VEGF-D were only related with nodal metastasis. MIA expression was significantly associated with MVD, LVD, VEGF, VEGF-C and VEGF-D expression by immunohistochemistry and ELISA assay. VEGF, VEGF-C, VEGF-D and MIA expression levels of metastatic tongue cancer HSC-3 cells were higher than those with no metastatic HSC-4 cells, and VEGF, VEGF-C and VEGF-D expression levels were decreased by MIA siRNA treatment in both cells. MIA-dependent angiogenesis/lymphangiogenesis might be a useful therapeutic target in progressive and metastatic OSCC.