Although salivary gland adenocarcinoma NOS accounts for third prevalence rate of all salivary gland tumors, it is one of the most aggressive solid tumors. Current therapy does not significantly improve survival rates. Thus, investigating new therapeutic modalities against salivary gland adenocarcinoma NOS is necessary. It is well known that docetaxel(TXT) as an antimicrotubulin agent induces mitotic block in proliferating cells. TXT has significant antitumor effects, and it is currently being tested in patients with malignant tumors, but TXT has not yet been tested in malignant salivary gland tumors. The purpose of this study were to examine the effects of TXT and to evaluate the biological mechanisms of TXT on salivary gland adenocarcinoma NOS. Proliferation, cell cycle regulation, connexin43 expression, apoptosis, and Fas receptor(FasR) expression were measured in cultured SGT cell line. Proliferation was little changed after 10ng/ml TXT exposure, but cellular proliferation was inhibited according to increasing concentration of TXT and time. Especially it was prominently inhibited after 96 hrs at 20ng/ml. G2-M arrest stage showed about up to 5 fold increase after exposure of TXT by flow cytometry. Apoptosis index showed about up to 8 fold increase after exposure of TXT by flow cytometry. Fas expression showed about up to 3 fold increase after exposure of TXT by flow cytometry. Apoptosis showed about up to 3 fold increase at 20ng/ml after exposure of TXT and anti-Fas agonist by flow cytometry. In Immunoslot blotting, Cx 43 protein expression was increased after TXT treatment. It suggested that TXT might induce apoptosis in SGT cells and could be used as a potent and specific chemotherapeutic tool for the treatment of salivary gland adenocarcinoma NOS in future.

Oral squamous cell carcinoma (SCC) is one of the leading causes of cancer mortality worldwide. It is generally thought that adjuvant chemotherapy provides modest prolongation of survival in various carcinoma. Docetaxel (Taxotere, TXT) play a significant role in the treatment of various solid tumors of epithelial origin. CsA (immunosuppressive drug) was widely used as adjunct for the treatment of cancer. Thus, it is important to pursue the apoptosis of IHOK and oral SCC induced by TXT combined with CsA related to the pathogenesis of oral SCC. But TXT combined CsA effect on IHOK and oral SCC remains unclear. After cultured IHOK and HN 22 oral squamous cell carcinoma cell line treated by 10 nM TXT and 1 μM, and caspase inhobitor, respectively, apoptosis index, cytochrome c and caspase-3 -8, -9 mRNA expression by RT-PCR, and procaspase-3 protein amount by immunoslot blotting was prepared. The purpose of this study were to examine the TXT-induced apoptosis pathway via caspase activation by CsA enhancement, and to apply these results to an effective therapeutic treatment plan for oral SCC by TXT combined CsA . 10 nM TXT showed about 60%, 55% celluar apoptosis of IHOK and HN 22, cell line, respectively, while CsA alone did not induce apoptosis in IHOK and HN 22 cell line. 1 μM CsA combined with 10 nM TXT increased apoptosis in IHOK and HN 22 cell line through caspase-3 and cytochrome c mRNA expression, while could not effect on caspase-8 and -9. Caspase inhibitor suppressed apoptosis of IHOK and HN 22 cell line induced by a combination of 1 μM CsA and 10 nM TXT. Immnoslot blotting showed procaspase-3 activation by a combination 1 μM CsA and 10 nM TXT, while caspase inhibitor inhibited activation. It suggested that a combination of CsA and TXT might induce increased apoptosis of IHOK and HN 22 oral squamous cell carcinoma cell line through caspase-3 activation. This treatment with a combination of TXT and CsA may be an effective therapeutic strategy for oral squamous cell carcinoma