Ataxia telangiectasia and Rad3-related (ATR) inhibition by VE-822 potently reversed 5-flourouracil resistance in colorectal cancer cells through targeting DNA damage response.

BACKGROUND: VE-822 is a novel inhibitor of ATR, a key kinase involved in the DNA damage response pathway. The role of ATR inhibition in reversing drug resistance in various cancer types has been investigated. Therefore, this study investigated the effects of ATR inhibition by VE-822 on reversing 5-fluorouracil (5-FU) resistance in colorectal cancer cell line (Caco-2). METHODS: Caco-2 and 5-FU resistance Caco-2 (Caco-2/5-FU) cells were treated with 5-FU and VE-822, alone and in combination. Cell proliferation and viability were assessed by MTT assay and Trypan Blue staining. P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1) activities were measured by Rhodamine123 accumulation and uptake assay. The mRNA levels of P-gp, MRP-1, ataxia telangiectasia and Rad3-related (ATR) and checkpoint kinase 1 (CHK1) were measured by qRT-PCR. Western blot was used to measure the protein levels of P-gp, MRP-1, γ-H2AX, ATR and CHK1 in cells. 8-Oxo-2'-deoxyguanosine (8-oxo-dG) levels were determined via ELISA. Apoptosis was evaluated by ELISA death assay, DAPI staining and lactate dehydrogenase (LDH) assay. RESULTS: The Caco-2/5-FU cells showed lower levels of 5-FU mediated proliferation inhibition in comparison to Caco-2 cells. VE-822 decreased the IC50 value of 5-FU on resistant cells. In addition, the expression levels and activity of P-gp and MRP-1 were significantly decreased in resistant cells treated with VE-822 (P < 0.05). The combination of 5-FU and VE-822 increased apoptosis in Caco-2/5-FU cells by downregulating CHK1 and ATR and upregulating γ-H2AX and 8-oxo-dG. CONCLUSION: The simultaneous treatment of resistant colorectal cancer cells with 5-FU and ATR inhibitor, VE-822, was demonstrated to be effective in reversing drug resistance and potentiating 5-FU mediated anticancer effects via targeting DNA damage.

Immunosenescence and Inflammaging in COVID-19.

Despite knowledge gaps in understanding the full spectrum of the hyperinflammatory phase caused by SARS-CoV-2, according to the World Health Organization (WHO), COVID-19 is still the leading cause of death worldwide. Susceptible people to severe COVID-19 are those with underlying medical conditions or those with dysregulated and senescence-associated immune responses. As the immune system undergoes aging in the elderly, such drastic changes predispose them to various diseases and affect their responsiveness to infections, as seen in COVID-19. At-risk groups experience poor prognosis in terms of disease recovery. Changes in the quantity and quality of immune cell function have been described in numerous literature sites. Impaired immune cell function along with age-related metabolic changes can lead to features such as hyperinflammatory response, immunosenescence, and inflammaging in COVID-19. Inflammaging is related to the increased activity of the most inflammatory factors and is the main cause of age-related diseases and tissue failure in the elderly. Since hyperinflammation is a common feature of most severe cases of COVID-19, this pathway, which is not fully understood, leads to immunosenescence and inflammaging in some individuals, especially in the elderly and those with comorbidities. In this review, we shed some light on the age-related abnormalities of innate and adaptive immune cells and how hyperinflammatory immune responses contribute to the inflammaging process, leading to clinical deterioration. Further, we provide insights into immunomodulation-based therapeutic approaches, which are potentially important considerations in vaccine design for elderly populations.

Pyridoxine for treatment of levetiracetam-induced behavioral adverse events: A randomized double-blind placebo-controlled trial.

BACKGROUND: Levetiracetam is a broad-spectrum antiseizure medication with known behavioral side effects. The possible beneficial effect of pyridoxine on improvement of these psychiatric problems has been suggested in few previous studies. This clinical trial aimed to investigate the effect of pyridoxine on behavioral side effects of levetiracetam in adult patients with epilepsy. METHODS: This study was a randomized double-blind placebo-controlled clinical trial on 53 adult patients with epilepsy with behavioral side effects after treatment by levetiracetam. Patients who met the study criteria were randomized to receive 40 mg/day pyridoxine or placebo. Their psychiatric state was surveyed by SCL-90-R questionnaire before and three weeks after initiation of treatment. RESULTS: There were no statistically significant differences in the behavioral adverse effects between the pyridoxine-treated group and the placebo group. CONCLUSION: Although this study showed no statistically significant beneficial effects of pyridoxine on the behavioral adverse effects of levetiracetam, placebo-controlled trials with a larger size and higher doses are needed to determine whether it is effective or not.

Innate and adaptive immune responses against coronavirus.

Coronaviruses (CoVs) are a member of the Coronaviridae family with positive-sense single- stranded RNA. In recent years, the CoVs have become a global problem to public health. The immune responses (innate and adaptive immunity) are essential for elimination and clearance of CoVs infections, however, uncontrolled immune responses can result in aggravating acute lung injury and significant immunopathology. Gaining profound understanding about the interaction between CoVs and the innate and adaptive immune systems could be a critical step in the field of treatment. In this review, we present an update on the host innate and adaptive immune responses against SARS-CoV, MERS-CoV and newly appeared SARS-CoV-2.

Let-7a Could Serve as A Biomarker for Chemo-Responsiveness to Docetaxel in Gastric Cancer.

BACKGROUND: MicroRNAs are noncoding RNAs which play critical roles in response to anti-cancer agents. Let-7a and miR-21 are well-known tumor-suppressor and oncomiR miRNAs, respectively. They are involved in tumorigenesis of gastric cancer and have potential to be used as markers in response to the therapy. OBJECTIVE: We aimed to study alterations in the expression of Let-7a and miR-21, and their targets in gastric cancer cell lines after treatment with docetaxel. METHODS: In order to determine the IC50 of docetaxel, MTT assay was performed in AGS, MKN45 and KATO III gastric cancer cell lines. The expression levels of Let-7a and miR-21 and their target genes, HMGA2 and PDCD4, were determined by reverse-transcription quantitative real-time PCR for both treated and untreated cell lines. RESULTS: MTT assay showed higher IC50 concentration of docetaxel in KATO III in comparison with AGS and MKN45, indicating KATO III`s higher resistance to docetaxel. Following the treatment, the expression level of Let-7a was significantly increased in AGS and MKN45, while decreased in KATO III. Expression level of miR- 21 in the three treated cell lines was increased significantly. Not only Let-7a, but also expression level of HMGA2 and PDCD4 genes showed different patterns in KATO III in comparison with AGS and MKN45. CONCLUSION: Down-regulation and up-regulation of Let-7a in docetaxel-resistant and sensitive cell lines, respectively indicates its potential usefulness as biomarker for responsiveness of gastric cancer to the therapy with docetaxel and also for predicting patient`s outcome.

Differential altered expression of let-7a and miR-205 tumor-suppressor miRNAs in different subtypes of breast cancer under treatment with Taxol.

BACKGROUND: MicroRNAs (miRNAs) are small non-coding RNAs which have been considered as major players in the process of carcinogenesis and drug responsiveness of breast cancer. OBJECTIVES: In this study, we aimed to investigate the expression pattern of let-7a and miR-205 tumorsuppressor miRNAs in breast cancer cell lines under treatment with paclitaxel. MATERIAL AND METHODS: The half maximal inhibitory concentration (IC50) of paclitaxel was determined for 4 breast cancer cell lines, including MCF-7, MDA-MB-231, SKBR-3, and BT-474 by an MTT assay. The expression level of let-7a and miR-205, and their targets, K-RAS and HER3, was determined before and after treatment with paclitaxel, using quantitative reverse transcriptase real-time polymerase chain reaction (qRT-PCR). RESULTS: After treatment, the expression level of both let-7a and miR-205 was significantly increased in HER2- overexpressing cell line BT-474 (26.4- and 7.2-fold, respectively). In contrast, the HER2-negative cell lines MCF-7 and MDA-MB-231 showed a significantly decreased expression of both let-7a (30.3- and 13.5-fold, respectively) and miR-205 (20- and 18.1-fold, respectively). Controversially, SKBR-3 revealed a significantly decreased expression of both let-7a (1.3-fold) and miR-205 (1.3-fold). The expression level of K-RAS as a target of let-7a decreased in all cell lines significantly, but the pattern of alteration in the expression level of HER3 as a target of miR-205 in all cell lines was the reverse of the pattern of alteration in the expression level of miR-205. CONCLUSIONS: Our results confirmed a better response of HER2-overexpressing breast cancer to paclitaxel at the miRNA level. One putative reason could be the upregulation of tumor-suppressor miRNAs after treatment with paclitaxel. On the other hand, HER2-negative breast cancer cell lines showed a significantly decreased expression of tumor-suppressor miRNAs, a putative mechanism of resisting the therapy.

HER2 positivity may confer resistance to therapy with paclitaxel in breast cancer cell lines.

INTRODUCTION: MicroRNAs (miRNAs) are short non-coding single-stranded RNAs. Involving in post-transcriptional gene silencing, miRNAs are thought to play important roles in many cancers such as breast cancer. Paclitaxel is used widely in the treatment of breast cancer. In this study, we investigated the effect of paclitaxel treatment on the expression levels of two oncomirs (oncomiRs), miR-21 and miR-203, in breast cancer cell lines. MATERIALS AND METHODS: MTT assay was performed to determine IC50 of paclitaxel for human breast cancer cell lines including MCF-7, MDA-MB-231, SKBR3 and BT-474. After RNA extraction and cDNA synthesis, the expression levels of miRNAs were then quantitatively evaluated using real-time PCR. RESULTS: Our results showed that after treatment, the expression levels of both miR-21 and miR-203 were significantly increased in HER2-positive cell lines, BT-474 and SKBR3. HER2-negative cell lines, MCF-7 and MDA-MB-231, in contrast had significantly decreased expression of both assessed oncomiRs. CONCLUSION: Our results showed that the expression levels of oncomiRs were increased in HER-2 positive breast cancer cells and this finding is in line with previous studies. Our findings present a probable mechanism of resistance against paclitaxel chemotherapy in HER2-positive breast cancers.

The role of oncomirs in the pathogenesis and treatment of breast cancer.

Breast cancer, the most common cancer among women, is a heterogeneous and complex disease, which detail of its precise progression mechanisms is less understood. So, an improved comprehension of the precise molecular mechanisms leading to disease progression and design of effective targeted therapies are required for patients with breast cancer. MicroRNAs demonstrate an uncovered class of small and endogenous non-coding RNAs and play an important role in the normal biological processes, including cell differentiation, proliferation and apoptosis. Some miRNAs, known as oncomiR, show different expression levels in cancer and are capable to effect on cellular transformation, carcinogenesis and metastasis and are characterized by high expression levels in tumors compared to normal tissues. Therefore, oncomiRs can be considered as prognostic biomarkers and therapeutic targets in different types of cancers. Moreover, the utilization of oncomiRs as therapeutic targets for cancer is promising. Accordingly, there is evidence which implies an important role of various oncogenic microRNAs in immunopathogenesis of breast cancer. In this review we will discuss about the role of various oncomiRs such as miR-21, miR-155, miR-10b, and miR-221/222 in the pathogenesis and treatment of breast cancer.