Cancer is one of the leading causes of death worldwide. Several treatments are available for cancer treatment, but many treatment methods are ineffective against multidrug-resistant cancer. Multidrug resistance (MDR) represents a major obstacle to effective therapeutic interventions against cancer. This review describes the known MDR mechanisms in cancer cells and discusses ongoing laboratory approaches and novel therapeutic strategies that aim to inhibit, circumvent, or reverse MDR development in various cancer types. In this review, we discuss both intrinsic and acquired drug resistance, in addition to highlighting hypoxia- and autophagy-mediated drug resistance mechanisms. Several factors, including individual genetic differences, such as mutations, altered epigenetics, enhanced drug efflux, cell death inhibition, and various other molecular and cellular mechanisms, are responsible for the development of resistance against anticancer agents. Drug resistance can also depend on cellular autophagic and hypoxic status. The expression of drug-resistant genes and the regulatory mechanisms that determine drug resistance are also discussed. Methods to circumvent MDR, including immunoprevention, the use of microparticles and nanomedicine might result in better strategies for fighting cancer.

A major manifestation of autoimmune polyendocrine syndrome type 1 (APS1) is hypoparathyroidism, which is suggested to result from aberrant immune responses against the parathyroid glands. The calcium-sensing receptor (CaSR), which plays a pivotal role in maintaining calcium homeostasis by sensing blood calcium levels and regulating release of parathyroid hormone (PTH), is an autoantibody target in APS1. In this study, the aim was to characterize the binding sites, specificity, functional affinity, IgG subclass, and functional effects of CaSR autoantibodies using phage-display technology, ELISA, and bioassays. The results indicated that CaSR autoantibody binding sites were at aa 41-69, 114-126, 171-195, and 260-340 in the extracellular domain of the receptor. Autoantibodies against CaSR epitopes 41-69, 171-195, and 260-340 were exclusively of the IgG1 subclass. Autoantibody responses against CaSR epitope 114-126 were predominantly of the IgG1 with a minority of the IgG3 subclass. Only autoantibodies recognizing CaSR epitopes 114-126 and 171-195 affected receptor activity; inositol-phosphate accumulation was increased significantly in HEK293-CaSR cells, and PTH secretion from PTH-C1 cells was reduced significantly when either were incubated with purified Ab and Ca 2+ compared with Ca 2+ alone. In conclusion, although the majority of APS1 patients do not have CaSR-stimulating autoantibodies, the hypoparathyroid state in a small minority of patients is the result of functional suppression of the parathyroid glands.

Neither CaSR nor NALP5 antibodies were found to be specific or sensitive markers for HP in APECED. Further investigations are required to determine the exact role of the autoimmune response against the CaSR and NALP5 in the pathogenesis of this autoimmune syndrome.

Drug-resistance-associated mutation in essential proteins of the viral life cycle is a major concern in anti-retroviral therapy. M46I, a non-active site mutation in HIV-1 protease has been clinically associated with saquinavir resistance in HIV patients. A 100 ns molecular dynamics (MD) simulation and MM-PBSA calculations were performed to study the molecular mechanism of M46I-mutation-based saquinavir resistance. In order to acquire deeper insight into the drug-resistance mechanism, the flap curling, closed/semi-open/open conformations, and active site compactness were studied. The M46I mutation significantly affects the energetics and conformational stability of HIV-1 protease in terms of RMSD, RMSF, Rg, SASA, and hydrogen formation potential. This mutation significantly decreased van der Waals interaction and binding free energy (∆G) in the M46I–saquinavir complex and induced inward flap curling and a wider opening of the flaps for most of the MD simulation period. The predominant open conformation was reduced, but inward flap curling/active site compactness was increased in the presence of saquinavir in M46I HIV-1 protease. In conclusion, the M46I mutation induced structural dynamics changes that weaken the protease grip on saquinavir without distorting the active site of the protein. The produced information may be utilized for the discovery of inhibitor(s) against drug-resistant HIV-1 protease.

BackgroundBreast cancer is one of the leading causes of death worldwide, it affects both men and women. In Saudi Arabia, breast cancer has been the most prevalent type of cancer in women, for the past few years. Dietary habits and cultural beliefs vary according to region, and further studies are required to demonstrate the relationship between these dietary habits and cultural beliefs and the risk of developing breast cancer. This study is aimed to discover the relationship between preventive dietary factors of the Mediterranean diet and rates of breast cancer among postmenopausal women in the Makkah region of Saudi Arabia.MethodsA case-control study was conducted in King Abdulla Medical City Hospital, Makkah, Saudi Arabia and included 432 Saudi female participants: 218 in the control group and 214 breast cancer patients. All participants were postmenopausal, around the same age, and all were ethnically Arab Saudis. Data were obtained using a self-administered validated questionnaire.ResultsStudy results showed that a diet that includes 1–2 servings of legumes weekly, 1–5 servings of fish weekly, 1–5 servings of dairy products daily, 3–5 servings of fruits and vegetables daily, and more than one cup of black tea and coffee per day significantly (p < 0.05) reduces the risk of breast cancer.ConclusionThis study demonstrates that consuming a Mediterranean diet, which includes legumes, fish, fruits and vegetables, black tea, coffee, and low intake of dairy products, works as a preventive factor against breast cancer in postmenopausal females from the Makkah region.

Purpose Knowledge of the prevalence of blood group antigens in a given population is important for the prevention of hemolytic reactions. The MNS blood group system (002) has four polymorphic antigens—M, N, S, and s. Anti-S and anti-s antibodies may result in immediate and delayed hemolytic transfusion reactions, and hemolytic disease of the fetus and newborn may occur. The present study investigated the frequencies of the main antigens and phenotypes of the MNS blood group system. Subjects and Methods We randomly obtained 149 samples from anonymous Saudi blood donors living in Jazan Province. Serotyping was conducted using a gel card to investigate (M, N, S, and s) antigens and phenotypes. Results The frequencies of MNS antigens were as follows: M = 89.26%, N = 51.67%, S = 61.07%, and s = 82.55%. Regarding the MNS phenotypes, nine phenotypes were observed in the study population. The most common phenotype was M+N–S+s+ (n = 36, 24.16%), in contrast to the least common phenotype M+N–S–s– (n = 1, 0.67%). The prevalence of the MNS phenotypes in the current study population was highly and significantly different from that in Europeans ( P = 0.044) and African Americans ( P = 0.000). Conclusion In summary, this study reports the frequencies of the MNS antigens and phenotypes in Jazan Province, Saudi Arabia. The most common phenotype was M+N–S+s+, whereas the least observed phenotype was M+N–S–s–. The outcomes of this study may assist the blood banks in Jazan Province to establish an extended phenotyping protocol including the MNS antigens, in particular S and s antigens, to preclude any alloimmunization events.

Albendazolum (ABZ) is a BCS class II drug. It has challenging biopharmaceutical properties, which include poor solubility and dissolution rate. These properties have laid the ground for developing a supersaturated self-nanoemulsifying drug delivery system (S-SNEDDS) to form oil-in-water nanoemulsion in situ to improve the oral bioavailability of ABZ. Based on the ABZ solubility, emulsifying ability, and stability after dispersion in an aqueous phase, an optimal self-nanoemulsifying drug delivery system (SNEDDS) consisting of oleic acid, Tween ® 20, and PEG 600 (X:Y:Z, w/w) was identified, having 10% (w/w) hydroxypropyl methylcellulose (HPMC) E15 lv as its precipitation inhibitor. The optimized system possessed a small mean globule size value (89.2 nm), good dispersion properties (polydispersity index (PDI): 0.278), and preserved the supersaturated state of ABZ. S-SNEDDS was transformed into solid supersaturated self-nanoemulsifying drug delivery systems (SS-SNEDDS) using microcrystalline cellulose as a solid material. The developed S-SNEDDS were characterized for globule size, pH, turbidity, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and flow properties. The data obtained from the results suggest that this S-SNEDDS formulation can enhance the solubility and oral bioavailability of ABZ for appropriate clinical application.

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