Inhibition of ERK1/2 or AKT Activity Equally Enhances Radiation Sensitization in B16F10 Cells

Quinoline conjugates for enhanced antimalarial activity: a review on synthesis by molecular hybridization and structure-activity relationship (SAR) investigation

Malaria, caused by the various Plasmodium falciparum strains, has been one of the deadliest diseases spread across the world. Over the years, several researchers have been employed to analyse molecular hybridization techniques for the synthesis of combination drugs to overcome the resistance gained by the parasite against the existing drugs. Hence, some of the significant contributions since 2019 till date have been summarised in the present review. Based on structure, the hybrids have been classified into bi-pharmacophores - having two pharmacologically active groups, tri-pharmacophores - having three pharmacologically active groups, metal-based and other miscellaneous hybrids. A thorough study of existing molecules could also reveal new leads for the development of anti-malarial agents with efficacy better than the preceding ones.

Hypoglycemic and hypolipidemic effects of Garcinia cambogia extracts in streptozotocin-nicotinamide induced diabetic rat model

BACKGROUND AND OBJECTIVES

Diabetes mellitus, a global health problem, is associated with metabolic complications such as hyperglycemia, hyperlipidemia, hypertension, cardiovascular diseases, and loss of vision. The present study evaluated the antidiabetic and antihyperlipidemic effects of ethanol extract of Garcinia cambogia (L.) N. Robson (G. cambogia) fruit rind in a streptozotocin-nicotinamide induced diabetic Wistar Rat model.

MATERIALS AND METHODS

Streptozotocin-nicotinamide was injected intraperitoneally to induce diabetes in Wistar rats. Five groups of rats (n=6) - normal control, diabetic, diabetic treated with G. cambogia at 400 mg/kg and 800 mg/kg body weight, and diabetic treated with metformin at 500 mg/kg body weight, were studied. Blood samples were collected after three weeks of treatment. Random blood glucose (RBG), Serum total cholesterol levels (TCL), serum total triglyceride levels (TGL), high-density lipoprotein levels, and body weight were measured.

RESULTS

Although G. cambogia treatment did not have any antidiabetic activity (p>0.05) rind in the streptozotocin-nicotinamide induced diabetic Wistar Rat model, it decreased the serum TCL, and body weight significantly (P<0.05).

CONCLUSIONS

Ethanolic extract of G. cambogia fruit rind possesses anti-obesity activity and significantly reduces total cholesterol but does not have antidiabetic activity.

Acute and chronic toxicity studies on ethanolic leaf extracts of Clerodendrum viscosum and Leucas indica in Swiss albino mice

BACKGROUND AND OBJECTIVES

To evaluate the safe dose range of Clerodendrum viscosum (C. viscosum) and Leucas indica (L. indica) ethanolic leaf extracts of acute and chronic oral toxicity study in Swiss Albino mice.

MATERIALS AND METHODS

The Organization for Economic Co-operation and Development guideline was used for the toxicity studies. C. viscosum and L. indica plant extract were administered orally in a single dose of 2000 mg/kg, and general behavior, adverse effects, and mortality were studied for 72 h. For the chronic toxicity study, both plant extracts were administered orally to a separate set of animals at 300 mg/kg doses for 90 days. Animals body weight was taken out, blood and gastric juice were collected for biochemical parameters, and vital organs were collected for histopathological studies after sacrificing test and control group animals.

RESULTS

Both in acute and chronic toxicity assay, there was no significant alteration in body weight, physical signs, symptoms, hematological, biochemical parameters, and body organ weights compared to the normal group. The liver, kidney, and stomach histology did not show any drug-induced lesion.

CONCLUSIONS

The result indicates that the oral administration of C. viscosum and L. indica ethanolic plant extract did not cause any toxicological effects. Hence it could be regarded as a safe natural product for therapeutic use.

Phytocompounds from the medicinal and dietary plants: Multi-target agents for cancer prevention and therapy

Cervical cancer is the fourth leading cause of cancer death among women worldwide. Due to cervical cancer's high incidence and mortality, there is an unmet demand for effective diagnostic, therapeutic, and preventive agents. At present, the preferred treatment strategies for advanced metastatic cervical cancer include surgery, radiotherapy, and chemotherapy. However, cervical cancer is gradually developing resistance to chemotherapy, thereby reducing its efficacy. Over the last several decades, phytochemicals, a general term for compounds produced from plants, have gained attention for their role in preventing cervical cancer. This role in cervical cancer prevention has garnered attention on the medicinal properties of fruits and vegetables. Phytochemicals are currently being evaluated for their ability to block proteins involved in carcinogenesis and chemoresistance against cervical cancer. Chemoresistance to cancer drugs like cisplatin, doxorubicin, and 5-fluorouracil has become a significant limitation of drug-based chemotherapy. However, the combination of cisplatin with other phytochemicals has been identified as a promising alternative to subjugate cisplatin resistance. Phytochemicals are promising chemo-preventive and chemotherapeutic agents as they possess antioxidant, anti-inflammatory, and anti-proliferative potential against many cancers, including cervical cancer. Furthermore, the ability of the phytochemicals to modulate cellular signaling pathways through up and down regulation of various proteins has been claimed for their therapeutic potential. Phytochemicals also display a wide range of biological functions, including cell cycle arrest, apoptosis induction, inhibition of invasion, and migration in cervical cancer cells. Numerous studies have revealed the critical role of different signaling proteins and their signaling pathways in the pathogenesis of cervical cancer. Here, we review the ability of several dietary phytochemicals to alter carcinogenesis by modulating various molecular targets.

Cilostazol eliminates radiation-resistant glioblastoma by re-evoking big conductance calcium-activated potassium channel activity

In spite of radio- and chemotherapy, glioblastoma (GBM) develops therapeutic resistance leading to recurrence and poor prognosis. Therefore, understanding the underlying mechanisms of resistance is important to improve the treatment of GBM. To this end, we developed a radiation-resistant cell model by exposure to consecutive periods of irradiation. Simultaneously, single high-dose irradiation was introduced to determine "when" GBM developed consecutive irradiation-induced resistance (CIIR). We found that CIIR promoted TGF-β secretion, activated pro-survival Akt, and downregulated p21 in a p53-independent manner. Furthermore, CIIR upregulated multidrug-resistant proteins, resulting in temozolomide resistance. CIIR GBM also enhanced cell mobility and accelerated cell proliferation. The big-conductance calcium-activated potassium channel (BK channel) is highly expressed and activated in GBM. However, CIIR diminishes BK channel activity in an expression-independent manner. Cilostazol is a phosphodiesterase-3 inhibitor for the treatment of intermittent claudication and was able to reverse CIIR-induced BK channel inactivation. Paxilline, a BK channel blocker, promoted cell migration and proliferation in parental GBM cells. In contrast, Cilostazol inhibited CIIR-induced cell motility, proliferation, and the ability to form tumor spheres. Moreover, we established a radiation-resistant GBM in vivo model by intracranially injecting CIIR GBM cells into the brains of NOD/SCID mice. We found that Cilostazol delayed tumor in vivo growth and prolonged survival. As such, inactivation of the BK channel assists GBM in developing radiation resistance. Accordingly, restoring BK channel activity may be an effective strategy to improve therapeutic efficacy, and cilostazol could be repurposed to treat GBM.

Serum Ischemia-Modified Albumin, Fibrinogen, High Sensitivity C- Reactive Proteins in Type-2 Diabetes Mellitus without Hypertension and Diabetes Mellitus with Hypertension: A Case-Control Study

Background

The objective of this study was to determine the levels of serum ischemia-modified albumin (IMA), fibrinogen (FIB) and high sensitivity C-reactive protein (hs-CRP) in type 2 diabetes mellitus (T2DM) patients with hypertension (HT) (DMT2HTN) and without HT (DMT2). Also, their association with certain biochemical and physical factors were studied to identify possible risk factors that lead to cardiovascular complications.

Methods

Fasting blood samples were collected from 35 DMT2 or DMT2HTN patients each to analyze differences in serum and plasma levels of IMA, hs-CRP, FIB, total cholesterol (TC), high and low density lipoproteins (HDL and LDL), triglyceride (TG), hemoglobin A1c (HbA1C), glycated hemoglobin and creatinine.

Results

In DMT2 and DMT2HTN patients, IMA, hs-CRP, FIB, TC, TG, HDL, LDL, glycated hemoglobin and creatinine levels, including body mass index (BMI) and waist-to-hip ratio (WHR), were significantly higher relative to healthy controls. In addition, the levels of IMA, hs-CRP and FIB levels showed a strong link to BMI, WHR, TC, TG, LDL and glycated hemoglobin. Lastly, both DMT2 and DMT2HTN patients demonstrated a significant reduction in HDL.

Conclusion

DMT2 and DMT2HTN patients have a greater risk of developing cardiovascular related complications. This study suggests that quantifying hs-CRP, IMA and FIB levels can help diagnose the risk of developing complications during the early stages of metabolic and cardiovascular disease. Overall, the specific risk factors may be used for early identification of cardiovascular complications to decrease mortality and morbidity in T2DM patients.

Integrin αvβ3-Akt signalling plays a role in radioresistance of melanoma

Melanoma is a deadly type of skin cancer that is particularly difficult to treat owing to its resistance to radiation therapy. Here, we attempted to determine the key proteins responsible for melanoma radioresistance, with the aim of improving disease response to radiation therapy. Two melanoma cell lines, SK-Mel5 and SK-Mel28, with different radiosensitivities were analysed via RNA-Seq (Quant-Seq) and target proteins with higher abundance in the more radioresistant cell line, SK-Mel28, identified. Among these proteins, integrin αvβ3, a well-known molecule in cell adhesion, was selected for analysis. Treatment of SK-Mel28 cells with cilengitide, an integrin αvβ3 inhibitor, as well as γ-irradiation resulted in more significant cell death than γ-irradiation alone. In addition, Akt, a downstream signal transducer of integrin αvβ3, showed high basic activation in SK-Mel28 and was significantly decreased upon co-treatment with cilengitide and γ-irradiation. MK-2206, an Akt inhibitor, exerted similar effects on the SK-Mel28 cell line following γ-irradiation. Our results collectively demonstrate that the integrin αvβ3-Akt signalling pathway contributes to radioresistance in SK-Mel28 cells, which may be manipulated to improve therapeutic options for melanoma.

Oxidative stress in cervical cancer and its response to chemoradiation

Objectives:

Cervical cancer (CaCx) is one of the leading causes of cancer-related death among women worldwide, with the great social and economic burden. Diagnoses in early stages can decrease mortality and morbidity rates. This study was conducted to evaluate the status of serum total antioxidant capacity (TAC), and malondialdehyde (MDA) and copper concentrations among patients with CaCx to determine the level of oxidative stress and effect on which of chemoradiation.

Materials and Methods:

Fifty patients with histopathologically proven CaCx who visited the department of oncology & gynaecology and 50 age-matched healthy females were selected for the study. Serum TAC, MDA, and copper were estimated in both study groups. The effect of chemoradiation on these was estimated in patients with CaCx.

Results:

The mean ± standard deviation age of the patients was 43.98±6.38 years, whereas that of the controls was 31.56±6.84 years. The mean serum copper and MDA concentrations in the patients was significantly higher as compared with the controls, whereas the mean TAC in the patients was reduced when compared with the controls. After chemoradiation, there was a significant increase and decrease in TAC and MDA, respectively, after chemoradiotherapy, whereas the changes in the copper concentrations were insignificant.

Conclusion:

These results suggest that patients with CaCx were in oxidative stress because the oxidative parameters in serum (copper, MDA) were increased and the defensive TAC was decreased in patients with CaCx and chemoradiotherapy improved their anti-oxidant capacity. Further studies are needed to evaluate the concurrent use of antioxidants with chemoradiotherapy for improving the disease prognosis.

HDAC2 Inhibitor Valproic Acid Increases Radiation Sensitivity of Drug-Resistant Melanoma Cells

Resistance to anticancer drugs limits the effectiveness of chemotherapy in cancers. Melanoma cell lines B16F10C and A375C (parental) and B16F10R and A375R (drug-resistant sublines) were used to test radiation sensitization potential of valproic acid (VPA), an inhibitor of Histone deacetylase2 (HDAC2) and LDN193189 (BMP inhibitor). Inhibitors of other signaling pathways were tested for cross-resistance with the resistant cell lines. Cells were pretreated with low concentrations of VPA/ LDN193189 and exposed to 2 Gy radiation for radiation sensitization experiments. Assays-3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT), live/dead, clonogenic, and melanin estimation were performed to test the effects of radiation sensitization. Interactions of VPA and HDAC2 were studied in silico. Dose-dependent growth inhibition was observed with all tested drugs. Radiation sensitization of melanoma cells with low dose of VPA induced synergistic cell death, decreased clonogenicity, and decreased melanin content. In silico docking showed two stable interactions between Arg39 of HDAC2 and VPA. In conclusion, pretreatment with low doses of VPA has a potential for sensitizing melanoma cells to low doses of radiation. The binding of VPA to HDAC2 reverses the drug resistance in melanoma and induces the cell death. Sensitization effects of VPA can be used for targeting drug-resistant cancers.