Combined paclitaxel, cisplatin and fluorouracil therapy enhances ionizing radiation effects, inhibits migration and induces G0/G1 cell cycle arrest and apoptosis in oral carcinoma cell lines

Synthesis, Anticancer Activity and Molecular Docking Studies of Novel N-Mannich Bases of 1,3,4-Oxadiazole Based on 4,6-Dimethylpyridine Scaffold

Cancer is one of the greatest challenges in modern medicine today. Difficult and long-term treatment, the many side effects of the drugs used and the growing resistance to treatment of neoplastic cells necessitate new approaches to therapy. A very promising targeted therapy is based on direct impact only on cancer cells. As a continuation of our research on new biologically active molecules, we report herein the design, synthesis and anticancer evaluation of a new series of N-Mannich-base-type hybrid compounds containing morfoline or different substituted piperazines moieties, a 1,3,4-oxadiazole ring and a 4,6-dimethylpyridine core. All compounds were tested for their potential cytotoxicity against five human cancer cell lines, A375, C32, SNB-19, MCF-7/WT and MCF-7/DX. Two of the active N-Mannich bases (compounds 5 and 6) were further evaluated for growth inhibition effects in melanoma (A375 and C32), and normal (HaCaT) cell lines using clonogenic assay and a population doubling time test. The apoptosis was determined with the neutral version of comet assay. The confocal microscopy method enabled the visualization of F-actin reorganization. The obtained results demonstrated that compounds 5 and 6 have cytotoxic and proapoptotic effects on melanoma cells and are capable of inducing F-actin depolarization in a dose-dependent manner. Moreover, computational chemistry approaches, molecular docking and electrostatic potential were employed to study non-covalent interactions of the investigated compounds with four receptors. It was found that all the examined molecules exhibit a similar binding affinity with respect to the chosen reference drugs.

Ganoderma lucidum polysaccharides inhibit in vitro tumorigenesis, cancer stem cell properties and epithelial-mesenchymal transition in oral squamous cell carcinoma

ETHNOPHARMACOLOGICAL RELEVANCE

The polysaccharides of the millenary mushroom Ganoderma lucidum (GL) have been shown for decades to present anti-tumor activities, but few studies evaluated its importance on cancer stem cells and EMT process. Cancer stem cells (CSC) drive the development of carcinoma and are also involved in cancer treatment failure, being a good target for treatment success. Also, the process of epithelial-mesenchymal transition (EMT) is involved in metastasis and cancer relapse. Besides that, the increasing incidence worldwide of oral squamous cell carcinoma (OSCC) became a public health issue with a high rate of metastasis and poor quality of life for patients during and after treatment.

AIM OF THE STUDY

to evaluate G. lucidum polysaccharides (GLPS) in vitro effects on OSCC, focusing on hallmarks associated with tumorigenesis using the SCC-9, a squamous cells carcinoma lineage from the tongue.

MATERIALS AND METHODS

SCC-9 cells were treated in vitro for 72h with different GLPS concentrations. The controls cells were maintained with culture media only and cisplatin was used as treatment control. After the treatment period, the cells were evaluated.

RESULTS

GLPS treatment changed cell morphology and granularity, delayed migration, decreased colony, and impaired sphere formation, thereby leading to a non-invasive and less proliferative behavior of tumoral cells. Additionally, GLPS downregulated CSC, EMT, and drug sensitivity (ABC) markers.

CONCLUSIONS

These results show that the natural product GLPS has the potential to be an important ally for tongue squamous cell carcinoma treatment, bringing the millenary compound to modern therapy, providing a basis for future studies and the improvement of life quality for OSCC patients.

Combined therapy with cisplatin and 5-AZA-2CdR modifies methylation and expression of DNA repair genes in oral squamous cell carcinoma

The methylation and expression of DNA repair system genes has been studied in several tumor types. These genes have been associated with resistance to chemotherapy treatments by epigenetic regulation. Studies have yet to show the effects of combined therapy using an epigenetic drug (5-aza-2CdR) and cisplatin (CDDP) on DNA repair genes in oral squamous cell carcinoma (OSCC). This study proposed to investigate the effects of CDDP in combination with 5-aza-2CdR on the methylation of MGMT and MLH1 genes in oral cancer cells. Oral squamous cell carcinoma cell lineages (SCC-9, SCC-15, and SCC-25) were submitted to 72 hours of treatment: 0.1 μM CDDP (or 4.44 μM SCC-9), 0.1 μM and 0.3 μM 5-aza-2CdR (or 1 μM and 3 μM SCC-9), and the drugs in combination. Cell viability was assessed by MTT, DNA methylation of MGMT and MLH1 genes by Methylation Sensitivity High-Resolution Melting (MS-HRM), and the relative expression of the genes by RT-qPCR. The results show that all treatments reduced cell viability; however, in SCC-15 and SCC-9 (IC₅₀ value), 5-aza-2CdR promotes cell sensitization to cytotoxic effect of cisplatin. The MGMT promoter region was 100% demethylated in the SCC-15 and SCC-25 cells but partially (50%) methylated in SCC-9 before drug treatment. Treatment with IC₅₀ CDDP value kept the methylation status and decreased MGMT expression in SCC-9; MGMT gene in SCC-15 and SCC-25 cells became downregulated after treatment with 5-aza-2CdR. MLH1 was demethylated, but the treatments with low-doses and combined drugs decreased the expression in SCC-9 and SCC-25; however high doses of 5-aza-2CdR and drug combination with IC₅₀ value CDDP increased expression of MLH1 in SCC-9. The data presented suggest that epigenetic drugs associated with chemotherapy have clinical translational potential as a therapy strategy to avoid or reverse cancer resistance, requiring further investigation.

A non-toxic, reversibly released imaging probe for oral cancer that is derived from natural compounds

CD44 is emerging as an important receptor biomarker for various cancers. Amongst these is oral cancer, where surgical resection remains an essential mode of treatment. Unfortunately, surgery is frequently associated with permanent disfigurement, malnutrition, and functional comorbidities due to the difficultly of tumour removal. Optical imaging agents that can guide tumour tissue identification represent an attractive approach to minimising the impact of surgery. Here, we report the synthesis of a water-soluble fluorescent probe, namely HA-FA-HEG-OE (compound 1), that comprises components originating from natural sources: oleic acid, ferulic acid and hyaluronic acid. Compound 1 was found to be non-toxic, displayed aggregation induced emission and accumulated intracellularly in vesicles in SCC-9 oral squamous cells. The uptake of 1 was fully reversible over time. Internalization of compound 1 occurs through receptor mediated endocytosis; uniquely mediated through the CD44 receptor. Uptake is related to tumorigenic potential, with non-tumorigenic, dysplastic DOK cells and poorly tumorigenic MCF-7 cells showing only low intracellular levels and highlighting the critical role of endocytosis in cancer progression and metastasis. Together, the recognised importance of CD44 as a cancer stem cell marker in oral cancer, and the reversible, non-toxic nature of 1, makes it a promising agent for real time intraoperative imaging.

Monte Carlo simulation and dosimetry measurements of an experimental approach for in vitro HDR brachytherapy irradiation

Irradiation of tumor cell lines is a useful way to investigate the effects of ionizing radiation on biological molecules. We designed an easy and reproducible approach for in vitro experimental high dose rate brachytherapy, which was simulated by a Monte Carlo code and dosimetrically characterized by experimental methods to evaluate the correspondence between planned doses and doses absorbed by the cells. This approach is an acrylic platform containing T25 tissue culture flasks and multiwell tissue culture plates. It allows nine parallel needles carrying an ¹⁹²Ir source to irradiate the adherent cells. The whole system composed of the acrylic platform, tissue culture flasks and ¹⁹²Ir source tracking was simulated by the Monte Carlo N-Particle transport code (MCNPX). Dosimetric measurements were taken by well ionization chamber and radiochromic films. There was a slight difference, averaging from 2% to 7%, between the MCNPX results and film dosimetry results regarding uniform radiation created by the source arrangement. The results showed different values for planned and measured doses in each cell culture plate, which was attributed to the non-equivalent water material used and to the lack of full scattering coming from the top of the platform. This last contribution was different for each tissue culture plate and an individual dose correction factor was calculated. The dose correction factor must be applied to match the planned dose and the actual doses absorbed by the cells. The designed approach is an efficient tool for in vitro brachytherapy experiments for most commercial cell culture plates.

The antiproliferative effects of ataxia-telangiectasia mutated and ATM- and Rad3-related inhibitions and their enhancements with the cytotoxicity of DNA damaging agents in cholangiocarcinoma cells

OBJECTIVE

To investigate whether the inhibitions of ataxia-telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR) kinases by their specific inhibitors, KU-55933 and VE-821, respectively, are able to promote the cytotoxic activity of genotoxic agents including gemcitabine, 5-Fluorouracil, cisplatin and doxorubicin, in cholangiocarcinoma (CCA) and immortalized cholangiocyte cell lines.

METHODS

Cell viability of cells treated with DNA damaging agents, alone and in combination with KU-55933 and VE-821, was determined by MTT assay. The changes of cell cycle distribution were evaluated by flow cytometry analysis. Colony formation was conducted to assess the effects of KU-55933 and VE-821 on cell proliferation. The levels of protein expression and phosphorylation were examined by western blot analysis.

KEY FINDINGS

The cytotoxic effects of DNA damaging agents varied among CCA cell lines. Each DNA damaging drug induced different phases of the cell cycle in CCA cells. The combinations of both KU-55933 and VE-821 with DNA damaging agents promoted more cytotoxic activity than single inhibition in some CCA cell lines. ATM and ATR inhibitors decreased the effects of DNA damaging agent-induced ATM-Chk2 and ATR-Chk1 activations in CCA cells.

CONCLUSIONS

Inhibitions of ATM and ATR potentiated the cytotoxic effects of DNA damaging agents in CCA cells, especially p53 defective HuCCA1 and RMCC1 cell lines.

Cytotoxic Effects of Pistacia Atlantica (Baneh) Fruit Extract on Human KB Cancer Cell Line

Plants with anticancer properties are considered as cancer preventive and treatment sources, due to their some biological effects. Apoptosis induction and anti-proliferative effects of Baneh extract on various cancer cell lines have been reported. Hence, this study was designed to evaluate the cytotoxic effects of this fruit on KB and human gingival fibroblast cell lines (HGF). KB and HGF cells were treated with various concentrations of ethanolic Baneh extract and cisplatin as positive control. Cytotoxic activity and apoptosis induction were investigated using WST-1 and Annexin V assays. Data were analyzed using ANOVA and student's t-tests. IC50 after 24 and 48 hours treatment were respectively 2.6 and 1 mg/mL for KB cell line, and 1.5 and 1.6 mg/mL for HGF cell. During 48 hours Baneh extract induced apoptosis without significant necrosis, in a time- and dose-dependent manner. The induction of apoptosis in KB cells was significantly higher than HGF. It seems that ethanolic extract of Baneh contains compounds that can suppress KB cell growth through the induction of apoptosis. Within 48 hours, less cytotoxic effects were observed on normal fibroblast cells; therefore, it might be a potential anticancer agent.

Molecular Markers of Anticancer Drug Resistance in Head and Neck Squamous Cell Carcinoma: A Literature Review

This manuscript provides an update to the literature on molecules with roles in tumor resistance therapy in head and neck squamous cell carcinoma (HNSCC). Although significant improvements have been made in the treatment for head and neck squamous cell carcinoma, physicians face yet another challenge-that of preserving oral functions, which involves the use of multidisciplinary therapies, such as multiple chemotherapies (CT) and radiotherapy (RT). Designing personalized therapeutic options requires the study of genes involved in drug resistance. This review provides an overview of the molecules that have been linked to resistance to chemotherapy in HNSCC, including the family of ATP-binding cassette transporters (ABCs), nucleotide excision repair/base excision repair (NER/BER) enzymatic complexes (which act on nonspecific DNA lesions generated by gamma and ultraviolet radiation by cross-linking and forming intra/interchain chemical adducts), cisplatin (a chemotherapeutic agent that causes DNA damage and induces apoptosis, which is a paradox because its effectiveness is based on the integrity of the genes involved in apoptotic signaling pathways), and cetuximab, including a discussion of the genes involved in the cell cycle and the proliferation of possible markers that confer resistance to cetuximab.

Cardamonin enhances the anti-proliferative effect of cisplatin on ovarian cancer

The mammalian target of rapamycin (mTOR) is well-known as a promising therapeutic target in various cancer cells. mTOR activation decreases the sensitivity of ovarian cancer to cisplatin. Cardamonin inhibits the proliferation of various cancer cells by mTOR suppression. The present study examined whether cardamonin combined with cisplatin is efficacious for the anti-proliferation of ovarian cancer cells. The anti-proliferative effect was determined by MTT and cell cycle assays. Activation of the mTOR signal pathway and the expression of anti-apoptotic proteins were evaluated by western blot analysis. Cardamonin significantly enhanced the effects of cisplatin on cell proliferation and cell cycle progression. The expression of B cell lymphoma-2, X-linked inhibitor of apoptosis protein and Survivin was significantly decreased following combination treatment. Furthermore, the activation of mTOR and its downstream 70 kDa ribosomal protein S6 kinase was inhibited by cardamonin. These results demonstrated that the combinatorial effects of cardamonin and cisplatin on anti-proliferation were enhanced by suppressing the expression of anti-apoptotic proteins and activation of mTOR in ovarian cancer cells.

Curcumin analog EF24 induces apoptosis and downregulates the mitogen activated protein kinase/extracellular signal-regulated signaling pathway in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies worldwide. Diphenyldifluoroketone (EF24) is a curcumin analog that has been demonstrated to improve anticancer activity; however, its therapeutic potential and mechanisms in oral cancer remain unknown. In the present study, the effect of EF24 on apoptosis induction and its potential underlying mechanism in the CAL‑27 human OSCC cell line was investigated. To achieve this, various concentrations of cisplatin or EF24 were administrated to CAL‑27 cells for 24 h, and cell viability, apoptotic DNA fragmentation, and cleaved caspase 3 and 9 levels were evaluated. To investigate the potential underlying mechanism, the levels of mitogen‑activated protein kinase kinase 1 (MEK1) and extracellular signal‑regulated kinase (ERK), two key proteins in the mitogen‑activated protein kinase/ERK signaling pathway, were additionally examined. The results indicated that EF24 and cisplatin treatment decreased cell viability. EF24 treatment increased the levels of activated caspase 3 and 9, and decreased the phosphorylated forms of MEK1 and ERK. Sequential treatments of EF24 and 12‑phorbol‑13‑myristate acetate, a MAPK/ERK activator, resulted in a significant increase of activated MEK1 and ERK, and reversed cell viability. These results suggested that EF24 has potent anti‑tumor activity in OSCC via deactivation of the MAPK/ERK signaling pathway. Further analyses using animal models are required to confirm these findings in vivo.

The Exploitation of Low-Energy Electrons in Cancer Treatment

Given the distinct characteristics of low-energy electrons (LEEs), particularly at energies less than 30 eV, they can be applied to a wide range of therapeutic modalities to improve cancer treatment. LEEs have been shown to efficiently produce complex molecular damage resulting in substantial cellular toxicities. Since LEEs are produced in copious amounts from high-energy radiation beam, including photons, protons and ions; the control of LEE distribution can potentially enhance the therapeutic radio of such beams. LEEs can play a substantial role in the synergistic effect between radiation and chemotherapy, particularly halogenated and platinum-based anticancer drugs. Radiosensitizing entities containing atoms of high atomic number such as gold nanoparticles can be a source of LEE production if high-energy radiation interacts with them. This can provide a high local density of LEEs in a cell and produce cellular toxicity. Auger-electron-emitting radionuclides also create a high number of LEEs in each decay, which can induce lethal damage in a cell. Exploitation of LEEs in cancer treatment, however, faces a few challenges, such as dosimetry of LEEs and selective delivery of radiosensitizing and chemotherapeutic molecules close to cellular targets. This review first discusses the rationale for utilizing LEEs in cancer treatment by explaining their mechanism of action, describes theoretical and experimental studies at the molecular and cellular levels, then discusses strategies for achieving modification of the distribution and effectiveness of LEEs in cancerous tissue and their associated clinical benefit.