Mini Reviews in Medicinal Chemistry - Volume 22, Issue 12, 2022

In recent years, with the development of nuclear medicine imaging technology, radionuclide- labeled tumor imaging agents have shown unique advantages in the early diagnosis of tumors. Due to the relatively low cost of SPECT in the clinic with the convenient preparation and suitable properties of ^99mTc, ^99mTc-labeled tumor metabolic imaging agents prepared based on principles of tumor metabolism have gained considerable attention. This article briefly introduces the progress in the research of ^99mTc-labeled glucose derivatives, amino acid derivatives, nucleotide derivatives, and other tumor metabolic imaging agents and proposes the prospects for the development of ^99mTclabeled tumor metabolic imaging agents.

Cancer treatments are known for their life-threatening toxicities attributed to their low selectivity; hence, new therapeutic approaches are being developed as alternatives. Among those approaches is the DNA repair mechanism, where its inhibition results selectively in the death of cancerous cells. Poly(ADP-Ribose) Polymerase (PARP) is one of the enzymes involved in the repair of damaged DNA. The inhibition of PARP shows to be a promising approach for effective targeted treatment of cancer, especially in tumours with pre-existing Homologous-Repair (HR) defects (i.e., BRCA). Nicotinamide, which is one of the PARP catalytic products, was the first identified PARP inhibitor (PARPi). The first FDA-approved PARPi was Olaparib in 2014 for the treatment of BRCA mutated advanced ovarian cancer. Several clinical trials have been conducted to further improve PARPi. However, there are some concerns related to drug resistance, PARPi sensitive-tumour identification, and toxic accumulation of PARPi. This report will review the uses of PARPi, drug design and development of PARPi from past to present, current issues, and prospective plans.

Among all the parasitic diseases in humans, malaria is the most significant and malicious one. The widespread species are Plasmodium falciparum and Plasmodium vivax, but the infection caused by the former is the deadliest. According to the November 2018 report of the World Health Organization (WHO), a total of 219 million cases of malaria were reported globally in 2017, which led to an estimated 435,000 deaths. Mortality due to malaria is estimated at 1.5 - 2.7 million deaths each year. Among all the complications associated with Plasmodium falciparum infection, cerebral malaria (CM) is the most fretful, accounting for almost 13% of all malaria-related deaths. CM is a medical emergency that requires immediate clinical testing and treatment. A compromised microcirculation, with sequestration of parasitized erythrocytes, is central in the disease pathology. No effective therapeutic agents are available yet for the treatment of CM, and therefore, potential interventions are needed to be developed urgently. The currently available anti-malarial drugs lack lipophilicity and are thus not able to reach the brain tissues. Therefore, safe, cost-effective agents with improved lipophilicity possessing the potential to target brain tissues are needed to be searched in order to fight CM worldwide. The aim of present review is to systematically revise the published research work available concerning the development and evaluation of some potential drug targets in the management of CM.

Sarcoidosis is a worldwide inflammatory disorder of unknown etiology that is characterized by the formation of non-caseatingimmune granulomas in involved organs,most commonly in the lungs and eyes. Although clinical manifestations of sarcoidosis depend on the organs involved, the most common symptoms include fatigue, fever, weight loss, eye pain, dyspnea, and chest pain. Sarcoidosis usually undergoes spontaneous regression, yet its chronic form progressively threatens the involved organs through the induction of fibrotic damage. Despite decades of medical research, the etiology of sarcoidosis still remains unclear. Nevertheless, a combination of contributors, including genetic factors, environmental exposures, and microbial agents, is believed to trigger the inflammatory state observed in this disease. Furthermore, a highly polarized Th1 and Th17 response with diminished immunomodulatory mechanisms constitute the most significant immunological event associated with this disorder. Indeed, sarcoid granulomas, which consist of highly activated antigen-presenting cells (APCs) and lymphocytes, maintaina robust specialized niche to facilitate antigen presentation and exaggerated immune responses. Both the unknown etiology and multisystem nature of the disease have hampered the development of specific therapeutics and definitive diagnostic assays for sarcoidosis. Consequently, its diagnosis and treatment still represent a challenging task for clinicians. In this article, we aim to summarize contemporary findings of sarcoidosis and its etiology, pathogenesis, and treatment.

Evidence from multiple scientific studies suggests that the Bacillus Calmette–Guérin (BCG) vaccine, widely used worldwide as a preventive measure against tuberculosis, also offers crossprotection against other pathogens. This review aimed to gather data from research that studied the mechanisms involved in the immunological protection induced by the BCG vaccine, which may be important in the control of viral infections, such as COVID-19. Through a literature review, we compiled information about the different BCG strains used worldwide, as well as the responses and protection elicited by them. We commented on the mechanisms of immune response to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and we discussed the possibility of cross-protection of different BCG strains on the control of COVID-19. Due to the immunomodulatory properties of BCG, some BCG strains were able to induce an effective cellular immune response and, through epigenetic modifications, activate cells of the innate immune system, such as monocytes, macrophages and natural killer cells, which are crucial for the control of viral infections. Although several vaccines have already been developed and used in an attempt to control the COVID-19 pandemic, some BCG vaccine strains may help stimulate the basal defences against these pathogens and can be used as additional defences in this and future pandemics.

‘Epigenetic’ regulation of genes via post-translational modulation of proteins is a wellexplored approach for disease therapies, particularly cancer chemotherapeutics. Histone deacetylases (HDACs) are one of the important epigenetic targets and are mainly responsible for balancing the acetylation/deacetylation of lysine amino acids on histone/nonhistone proteins along with histone acetyltransferase (HAT). HDAC inhibitors (HDACIs) have become important biologically active compounds for the treatment of cancers due to cell cycle arrest, differentiation, and apoptosis in tumor cells, thus leading to anticancer activity. Out of the four classes of HDAC, i.e., Class I, II, III, and IV, HDACIs act on Class IV (Zinc dependent HDAC), and various FDA-approved drugs belong to this category. The required canonical pharmacophore model (zinc-binding group, surface recognition cap, and appropriate linker) supported by HDACIs, various heterocyclic moieties containing compounds exhibiting HDAC inhibitory activity, and structure-activity relationship of different synthetic derivatives reported during the last twelve years have been summarized in this review.