Background/Aim: The aim of the study was to evaluate the antitumor potential and combination effects of chemotherapeutic drugs. Materials and Methods: The cytotoxicity of 20 drip-type classical and molecular-targeted anticancer drugs was examined against 4 human oral squamous cell carcinoma cell lines and 5 human oral normal mesenchymal and epithelial cells. Cell cycle progression was monitored by a cell sorter. Combination effect was evaluated by combination index. Results: Most of the classical anticancer drugs showed much higher antitumor activity than moleculartargeted drugs, except bortezomib. Among 12 classical anticancer drugs, taxanes and gemsitabine showed the highest tumor-specificity (TS) and potency-selectivity expression (PSE) values, whereas platinum analogs showed the least TS value. Combination of two classical or a classical and a moleculartargeted drug showed mostly additive or antagonistic effect. 5-FU and cisplatin did not produce a subG 1 population, but induced G 2 /M or G 1 /S arrest, regardless of the addition of cetuximab. Cetuximab, nibolumab and bortezomib showed potent keratinocyte toxicity. Conclusion: The present TS monitoring system may provide useful information for building up the treatment regimens of anticancer drugs.

Since many anticancer drugs show severe adverse effects such as mucositis, peripheral neurotoxicity, and extravasation, it was crucial to explore new compounds with much reduced adverse effects. Comprehensive investigation with human malignant and nonmalignant cells demonstrated that derivatives of chromone, back-bone structure of flavonoid, showed much higher tumor specificity as compared with three major polyphenols in the natural kingdom, such as lignin-carbohydrate complex, tannin, and flavonoid. A total 291 newly synthesized compounds of 17 groups (consisting of 12 chromones, 2 esters, and 3 amides) gave a wide range of the intensity of tumor specificity, possibly reflecting the fitness for the optimal 3D structure and electric state. Among them, 7-methoxy-3-[(1E)-2-phenylethenyl]-4H-1-benzopyran-4-one (compound 22), which belongs to 3-styrylchromones, showed the highest tumor specificity. 22 induced subG1 and G2 + M cell population in human oral squamous cell carcinoma cell line, with much less keratinocyte toxicity as compared with doxorubicin and 5-FU. However, 12 active compounds selected did not necessarily induce apoptosis and mitotic arrest. This compound can be used as a lead compound to manufacture more active compound.

Background/Aim: Although chemotherapy agents, such as oxaliplatin, cisplatin, paclitaxel and bortezomib frequently cause severe peripheral neuropathy, very few studies have reported the effective strategy to prevent this side effect. In this study, we first investigated whether these drugs show higher neuropathy compared to a set of 15 other anticancer drugs, and then whether antioxidants, such as sodium ascorbate, N-acetyl-L-cysteine, and vitamin B12 have any protective effect against them. Materials and Methods: Rat PC12 cells were induced to differentiate into neuronal cells by repeated overlay of serum-free medium supplemented with nerve growth factor. The cytotoxic levels of anticancer drugs against four human oral squamous cell carcinoma cell lines, three normal oral cells, and undifferentiated and differentiated PC12 cells were determined by the 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Cells were sorted for apoptotic cells (distributed into subG 1 phase) and cells at different stages of cell cycle (G 1 , S and G 2 /M). Results: All 19 anticancer drugs showed higher cytotoxicity against PC12 compared to oral normal cells. Among them, bortezomib showed the highest cytotoxicity against both undifferentiated and differentiated PC12 cell and, committed them to undergo apoptosis. Sodium ascorbate and N-acetyl-L-cysteine, but not vitamin B12, completely reversed the cytotoxicity of bortezomib. Conclusion: Bortezomibinduced neuropathy might be ameliorated by antioxidants.