Rebamipide suppresses 5-fluorouracil-induced cell death via the activation of Akt/mTOR pathway and regulates the expression of Bcl-2 family proteins

Oxidative Stress and Chemoradiation-Induced Oral Mucositis: A Scoping Review of In Vitro, In Vivo and Clinical Studies

Chemoradiation-induced mucositis is a debilitating condition of the gastrointestinal tract eventuating from antineoplastic treatment. It is believed to occur primarily due to oxidative stress mechanisms, which generate Reactive Oxygen Species (ROS). The aim of this scoping review was to assess the role of oxidative stress in the development of Oral Mucositis (OM). Studies from the literature, published in MEDLINE and SCOPUS, that evaluated the oxidative stress pathways or antioxidant interventions for OM, were retrieved to elucidate the current understanding of their relationship. Studies failing inclusion criteria were excluded, and those suitable underwent data extraction, using a predefined data extraction table. Eighty-nine articles fulfilled criteria, and these were sub-stratified into models of study (in vitro, in vivo, or clinical) for evaluation. Thirty-five clinical studies evaluated antioxidant interventions on OM's severity, duration, and pain, amongst other attributes. A number of clinical studies sought to elucidate the protective or therapeutic effects of compounds that had been pre-determined to have antioxidant properties, without directly assessing oxidative stress parameters (these were deemed "indirect evidence"). Forty-seven in vivo studies assessed the capacity of various compounds to prevent OM. Findings were mostly consistent, reporting reduced OM severity associated with a reduction in ROS, malondialdehyde (MDA), myeloperoxidase (MPO), but higher glutathione (GSH) and superoxide dismutase (SOD) activity or expression. Twenty-one in vitro studies assessed potential OM therapeutic interventions. The majority demonstrated successful a reduction in ROS, and in select studies, secondary molecules were assessed to identify the mechanism. In summary, this review highlighted numerous oxidative stress pathways involved in OM pathogenesis, which may inform the development of novel therapeutic targets.

Synergistic Cytotoxicity Effect of 5-fluorouracil and SHP2 Inhibitor Demethylincisterol A3 on Cervical Cancer Cell

BACKGROUND

Demethylincisterol A3 (DTA3) has been identified as an SHP2 inhibitor and suppresses the growth of many cancer cells. 5-Fluorouracil (5-FU) is widely used for the clinical treatment of various cancers. However, the combined effects of 5-FU and DTA3 on cervical cancer cells remain unknown.

OBJECTIVE

This study evaluates the mechanism of the combined effects of 5-FU and DTA3 in cervical cancer cells.

METHODS

The synergistic cytotoxic effects of 5-FU and DTA3 in cervical cancer cells were calculated. Apoptosis was analysed by flow cytometry. Western blot analyses were used to examine the related signalling pathways.

RESULTS

DTA3 and 5-FU synergized to induce apoptosis and repress proliferation of cervical cancer cells by downregulating the activation of PI3K/AKT and NF-κB signalling pathway. We provided evidence that the upregulation of SHP2 expression by transfection significantly inhibited the cytotoxicity of 5-FU and DTA3. SHP2 knockdown enhanced the antiproliferation activity of 5-FU, indicating targeting SHP2 sensitized cervical cancer cells to 5-FU.

CONCLUSION

Our study demonstrates that SHP2 inhibitor DTA3 and 5-FU have a synergistic cytotoxic effect on cervical cancer cells. The synergistic combination of SHP2 inhibitor and 5-FU may present a promising strategy for the treatment of cervical cancer.

Effects of Sambucus Ebulus Extract on Cell Proliferation and Viability of Triple-Negative Breast Cancer: An In Vitro and In Vivo Study

BACKGROUND

Triple-negative breast cancer (TNBC) accounts for 15% of all breast cancer (BC) cases and is a severe type of BC. Since medicinal herbs containing biocompatible substances that are accepted by patient more than chemical therapeutics, they can be considered a safe option for treating BC.

OBJECTIVE

This study evaluated the effect of Sambucus Ebulus (S. ebulus) extract on a model of TNBC.

METHODS

S. ebulus extract was prepared using petroleum ether, ethyl acetate, and methanol. The petroleum ether extract was fractionated and analyzed using vacuum liquid chromatography and GC-MS, respectively. MDA-MB-231 and MCF-10A were used as TNBC and normal breast cells, respectively. Flowcytometry and MTT assays were performed to evaluate cell cycle, apoptosis, and viability of the cells. Gene expression analysis was performed using RT-qPCR. Nude mouse allograft tumor models were used, and pathological sections were evaluated.

RESULTS

The findings indicated that S. ebulus extract remarkably decreased cell proliferation and viability. The extract had no toxicity to the normal breast cells but efficiently killed the cancer cells. Cell cycle- and apoptosis-related gene expression showed that fraction 4 of S. ebulus extract significantly increased the expression of Bax, Bak, P53, and c-MYC.

CONCLUSION

This study showed satisfactory results of the effect of S. ebulus extract on clearing BC cells both in vitro and in vivo. Thus, S. ebulus extract may be a safe herbal compound for eliminating BC cells without toxicity to host cells.

Perifosine enhances the potential antitumor effect of 5-fluorourasil and oxaliplatin in colon cancer cells harboring the PIK3CA mutation

Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutation in colon cancer contributes to the poor prognosis of the disease and chemoresistance of tumors. New therapies are needed; however, the lack of knowledge of the mechanism of chemoresistance has hindered progress. In this study, we investigated the mechanism of the reduced sensitivity of colon cancer cells to 5-fluorouracil (5-FU) and oxaliplatin (L-OHP), and the effects of perifosine, an Akt inhibitor that enhances the cytotoxicity of 5-FU and L-OHP in colon cancer cells harboring the PIK3CA mutation. The use of 5-FU or L-OHP alone or in combination induced significant death of Caco-2 cells (PIK3CA wild type), but only weakly decreased the viability of DLD-1 and SW948 cells harboring the PIK3CA mutation. The use of 5-FU and L-OHP, either alone or in combination, strongly suppressed Akt activation, Survivin, Bcl-2, and Bcl-xL expression, and enhanced Puma, phospho-p53, and p53 expression in Caco-2 cells than in DLD-1 cells. In addition, perifosine enhanced the cytotoxicity of the 5-FU and L-OHP combination, inhibited Akt activation and the expression of Survivin, Bcl-2, and Bcl-xL, and increased the expression of Puma, phospho-p53, and p53 in DLD-1 cells. These results indicate that PIK3CA mutation contributes to reduced sensitivity to 5-FU and L-OHP via Akt activation in colon cancer cells. Perifosine increases the efficacy of 5-FU and L-OHP by suppressing Akt activation. Thus, the use of an Akt inhibitor in combination with 5-FU and L-OHP may be beneficial in colon cancer with cells harboring the PIK3CA mutation.

Preparation and Evaluation of Rebamipide Colloidal Nanoparticles Obtained by Cogrinding in Ternary Ground Mixtures

Aphthous stomatitis is one of the side effects of chemotherapy and radiotherapy in cancer treatment. Rebamipide (RB) mouthwash for stomatitis acts as a radical scavenger. However, RB is poorly soluble in water, which leads to aggregation and precipitation of the dispersoid. The particle size of the drug needs to be less than 100 nm for the particles to reach the mucus layer in the oral cavity. In this study, we attempted to prepare nanoparticles of RB by cogrinding with polyvinylpyrrolidone (PVP) or hydroxypropyl cellulose (HPC) and sodium dodecyl sulfate (SDS) using a mixer ball mill, and evaluated the physicochemical properties of RB nanoparticles, the stability of dispersion in water, and permeation of the mucus layer in vitro. By cogrinding, the particle size decreased to around 110 nm, and powder X-ray diffraction (PXRD) of the particles showed totally broad halo patterns, which suggested a decreased crystalline region. Furthermore, the solubility of RB nanoparticles increased by approximately fourfold compared with RB crystals, and the water dispersibility and permeation of the mucus layer were improved. The results suggest that in a ternary ground mixture of RB, PVP or HPC, and SDS, the RB nanoparticles obtained can be applied as a formulation for stomatitis.

Pharmacological and clinical feature of rebamipide: new therapeutic targets

Rebamipide is a cytoprotector developed in Japan where it has been successfully used for the treatment of stomach diseases for 30 years. Initially discovered effects of the drug included the induction of prostaglandins and the elimination of free oxygen radicals. Recent studies discovered new therapeutic targets of the drug, its new forms that made possible using rebamipid for the treatment of such diseases as NSAID enteropathy, ulcerative colitis, radiation colitis, pouchitis, enteropathy with impaired membrane digestion. It is used in endoscopy, ophthalmology, chemotherapy, rheumatology. The aim of this review is to present current information about the pharmacological and clinical feature of rebamipide and to study its therapeutic potential.

Overactivation of Akt Contributes to MEK Inhibitor Primary and Acquired Resistance in Colorectal Cancer Cells

RAS and BRAF-mutated colorectal cancers are associated with resistance to chemotherapy and poor prognosis, highlighting the need for new therapeutic strategies. Although these cancers sometimes respond to mitogen activated protein kinase kinase (MEK) inhibitor treatment, they often acquire resistance via mechanisms, which are poorly understood. Here, we investigated the mechanism of MEK inhibitor resistance in primary- and acquired-resistant cells. Cell viability was examined using the trypan blue dye exclusion assay. Protein expression was analyzed by western blotting. Somatic mutations in colorectal cancer cells were investigated using the polymerase chain reaction array. PD0325901 and trametinib induced cell death in LoVo and Colo-205 cells but not in DLD-1 and HT-29 cells, which have a PIK3CA mutation constitutively activating Akt and NF-κB. Treatment with PD0325901 and trametinib suppressed ERK1/2 activation in all four cell lines but only induced Akt and NF-κB activation in DLD-1 and HT-29 cells. Inhibition of Akt but not NF-κB, overcame MEK inhibitor resistance in DLD-1 and HT-29 cells. Acquired-resistant LoVo/PR, Colo-205/PR and LoVo/TR cells have constitutively active Akt due to a M1043V mutation in the kinase activation loop of PIK3CA and Akt inhibitor resensitized these cells to MEK inhibitor. These results demonstrate that the overactivation of Akt plays a critical role in MEK inhibitor primary and acquired resistance and implicate combined Akt/MEK inhibition as a potentially useful treatment for RAS/BRAF-mutated colorectal cancer.