Objective: Laryngeal squamous cell carcinoma is one of the most common malignant tumors in the head and neck region. Due to the poor response to chemotherapeutics in patients and low survival rate, successful treatment of larynx cancer still remains a challenge. Therefore, the identification of novel treatment options is needed. We investigated the anticancer effects of suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, on two different laryngeal cancer cell lines RK33 and RK45. We also studied the antiproliferative action of SAHA in combination with cisplatin and defined the type of pharmacological interaction between these drugs. Materials and Methods: Viability and proliferation of larynx cancer cell lines were studied by methylthiazolyldiphenyl-tetrazolium bromide method and 5-bromo-2-deoxyuridine incorporation assay, respectively. The type of interaction between SAHA and cisplatin was determined by an isobolographic analysis. Western blotting, flow cytometry and quantitative polymerase chain reaction method were used to determine acetylation of histone H3, cell cycle progression and genes expression, respectively. Apoptosis was assessed by means of nucleosomes released to cytosol. Results: SAHA alone or in combination with cisplatin inhibited larynx cancer cells proliferation, whereas displayed relatively low toxicity against normal cells -primary cultures of human skin fibroblasts. The mixture of SAHA with cisplatin exerted additive and synergistic interaction in RK33 and RK45 cells, respectively. We showed that SAHA induced hyperacetylation of histone H3 K9, K14 and K23 and triggered apoptosis. SAHA also caused cell cycle arrest by upregulation of CDKN1A and downregulation of CCND1 encoding p21WAF1/CIP1 and cyclin D1 proteins, respectively. Conclusion: Our studies demonstrated that SAHA may be considered as a potential therapeutic agent against larynx tumors.

Three curcuminoids: bisdemethoxycurcumin, demethoxycurcumin, and curcumin from turmeric were successfully separated by a high capacity solvent system composed of heptane: chloroform: methanol: water mixture (5: 6: 3: 2 v/v/v/v) tailored for centrifugal partition chromatographs at K-values of 0.504, 1.057, 1.644, respectively. These three ferulic acid derivatives obtained at a purity rate exceeding 95% were analysed by an HPLC-MS spectrometer. Turmeric extract inhibited the proliferation/viability of A549 human lung cancer, HT29 colon cancer, and T98G glioblastoma cell lines in (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay (MTT). Single curcuminoids significantly decreased the viability/proliferation of lung cancer cells in a dose-dependent manner. However, total extract displayed the superior anticancer activity in the investigated cell lines. Crude extract in combination with cisplatin augmented the decrease in the viability of cancer cells compared with single compound treatment in A549 lung cancer cells. Total extract of Curcuma longa could be regarded as being more effective against lung cancer cells in vitro than its separated compounds.

Histone deacetylases (HDACs) play an important role in the epigenetic regulation of gene expression implicated in cancer pathogenesis. Inhibitors of HDACs (HDI) are under investigation as novel anti-cancer drugs, which induce histone hyperacetylation. These agents modulate chromatin structure leading to transcriptional changes of a very large number of genes, which affect signaling pathways, inhibit cell cycle progression and angiogenesis, and induce apoptosis in cancer cells. Currently, several HDI are in clinical trials used in monotherapy or in combination with other cytostatics, showing promising anticancer effects. To date, more than 15 HDIs have been found as potential drugs. This paper reviews the molecular mechanisms of HDI action on cancer cells and summarizes clinical trials of the most promising HDIs in the treatment of patients with hematologic malignancies and solid tumors.

Naturally occurring coumarins are bioactive compounds widely used in Asian traditional medicine. They have been shown to inhibit proliferation, induce apoptosis, and/or enhance the cytotoxicity of currently used drugs against a variety of cancer cell types. The aim of our study was to examine the antiproliferative activity of different linear furanocoumarins on human rhabdomyosarcoma, lung, and larynx cancer cell lines, and dissolve their cellular mechanism of action. The coumarins were isolated from fruits of Angelica archangelica L. or Pastinaca sativa L., and separated using high-performance counter-current chromatography (HPCCC). The identity and purity of isolated compounds were confirmed by HPLC-DAD and NMR analyses. Cell viability and toxicity assessments were performed by means of methylthiazolyldiphenyl-tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays, respectively. Induction of apoptosis and cell cycle progression were measured using flow cytometry analysis. qPCR method was applied to detect changes in gene expression. Linear furanocoumarins in a dose-dependent manner inhibited proliferation of cancer cells with diverse activity regarding compounds and cancer cell type specificity. Imperatorin (IMP) exhibited the most potent growth inhibitory effects against human rhabdomyosarcoma and larynx cancer cell lines owing to inhibition of the cell cycle progression connected with specific changes in gene expression, including CDKN1A. As there are no specific chemotherapy treatments dedicated to laryngeal squamous cell carcinoma and rhabdomyosarcoma, and IMP seems to be non-toxic for normal cells, our results could open a new direction in the search for effective anti-cancer agents.