Glutamate, a nonessential amino acid, is a major bioenergetic substrate for proliferating normal and neoplastic cells on one hand and an excitatory neurotransmitter that is actively involved in biosynthetic, bioenergetic, metabolic, and oncogenic signaling pathways on the other. It exerts its action through a family of receptors consisting of metabotropic glutamate receptors (mGluRs) and ionotropic glutamate receptors (iGluRs), both of which have been implicated previously in a broad spectrum of acute and chronic neurodegenerative diseases. In this review, we discuss existing data on the role of glutamate as a growth factor for neoplastic cells, the expression of glutamate receptors in various types of benign and malignant neoplasms, and the potential roles that GluRs play in cancer development and progression along with their clinical significance. We conclude that glutamate-related receptors and their signaling pathways may provide novel therapeutic opportunities for a variety of malignant human diseases.

Histone deacetylase inhibitors (HDIs) are promising anticancer drugs, which inhibit proliferation of a wide variety of cancer cells including breast carcinoma cells. In the present study, we investigated the influence of valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA, vorinostat), alone or in combination with cisplatin (CDDP) on proliferation, induction of apoptosis and cell cycle progression in MCF7, T47D and MDA-MB-231 human breast carcinoma cell lines. The type of interaction between HDIs and CDDP was determined by an isobolographic analysis. The isobolographic analysis is a very precise and rigorous pharmacodynamic method, to determine the presence of synergism, addition or antagonism between different drugs with using variety of fixed dose ratios. Our experiments show that the combinations of CDDP with SAHA or VPA at a fixed-ratio of 1:1 exerted additive interaction in the viability of MCF7 cells, while in T47D cells there was a tendency to synergy. In contrast, sub-additive (antagonistic) interaction was observed for the combination of CDDP with VPA in MDA-MB-231 “triple-negative” (i.e. estrogen receptor negative, progesterone receptor negative, and HER-2 negative) human breast cancer cells, whereas combination of CDDP with SAHA in the same MDA-MB-231 cell line yielded additive interaction. Additionally, combined HDIs/CDDP treatment resulted in increase in apoptosis and cell cycle arrest in all tested breast cancer cell lines in comparison with a single therapy. In conclusion, the additive interaction of CDDP with SAHA or VPA suggests that HDIs could be combined with CDDP in order to optimize treatment regimen in some human breast cancers.

Regulation of gene expression is essential for normal physiological functions; thus deregulation of gene expression is common in disease conditions. One level of regulation of gene expression is performed by noncoding RNAs, among which microRNAs (miRNA) are the best studied. Abnormal expression of these molecular players can lead to pathogenic processes such as heart disease, immune system abnormalities, and carcinogenesis, to name but a few. Of a length of 18–25 nucleotides miRNAs are involved in binding partial complementary sequences within the 3′-UTR (3′-untranslated region) of the target mRNAs. Depending on the type of neoplastic transformation, miRNAs can act both as oncogenes (oncomirs) or as tumor suppressors. Because of the great importance of miRNAs, most researches focus on either their role as biomarkers or their potential as therapeutic targets. Herein, we present the review of microRNA biology, function, and tumorigenic potential with emphasis on their role in lung cancer.

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.

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.