Current Medicinal Chemistry - Volume 25, Issue 5, 2018

Background: Lung cancer accounts for one in five cancer deaths worldwide and mutations in the gene encoding for the Kirsten rat sarcoma (KRAS) oncoprotein define the largest molecular subset of non-small cell lung cancer (NSCLC). These tumors are characterized by activated MAPK signaling, however, no targeted inhibitors of mutant KRAS or of downstream signaling molecules have yet been approved for routine clinical use. Objective: The primary objective of this review is to critically summarize the current developmental state of MEK and ERK inhibitors in pre-clinical models and in human clinical trials for KRAS mutant lung cancer particularly in light of the newly emerging concept of immune checkpoint blockade. Method: We performed a Pubmed-based literature search and considered publications from the fields of basic and translational biomedicinal and biochemistry research, as well as from past and ongoing human clinical trials (www.clinicaltrials.gov). Results and Conclusions: MAPK pathway targeting agents are efficacious in pre-clinical models but their benefit is limited for patients with KRAS mutant NSCLC due to the lack of predictive factors, toxicity and the adaptive dynamic kinome reprogramming within the tumor. Overall, MEK inhibitors have advanced further in clinical development compared to ERK inhibitors. New treatment strategies as e.g. immune checkpoint blockade are currently revolutionizing the treatment paradigms and future clinical trials need to show if they replace MAPK targeting strategies or are used as add-on.

Background: Testicular germ cell tumor (TGCT) is the most common solid malignancy occurring in young men between 20 and 34 years of age, and its incidence has increased significantly over the last decades. TGCTs can be subdivided into seminoma and nonseminoma germ cell tumors (NSGCTs), which includes yolk sac tumor, choriocarcinoma, embryonal cell carcinoma, and teratoma. Seminomas and NSGCTs present significant differences in therapy, prognosis, and both show characteristics of the Primordial Germ Cells (PGCs). Methods: I undertook a search of bibliographic data from peer-reviewed research literature. Results: Seventy papers were included in the mini-review showing that a large number of new biomarkers have given further advantages to discriminate the different histotypes and could represent useful novel molecular targets for anticancer strategies. Conclusion: A deeper understanding of the pathogenesis of TGCTs is likely to significantly improve not only our knowledge on stem cells and oncogenesis but also the disease management with more selective tumor treatment.

Background: Neuroblastoma is the most common extracranial solid tumor in infancy. The majority of children have a disseminated disease at diagnosis with bone marrow as the most common site of metastasis. Although several prognostic factors have been defined (i.e. age, stage, histology, recurrent genetic anomalies), the identification of non-invasive biomarkers for disease follow-up and therapy monitoring is indeed still a clinical need. Aberrant regulation of microRNAs (miRNAs) expression has been implicated in several malignancies. Objectives: In this mini-review, we describe the recent findings about miRNAs in neuroblastoma, both in the tumor and circulation, with particular focus on those involved in tumor progression and drug resistance. Furthermore, we will discuss the use of specific miRNAs as potential therapeutic tools in this tumor. Results: Several miRNAs have been identified to be down- or up-regulated in primary tumors and have been associated with MYCN amplification, differentiation, dissemination and chemoresistance. Little evidence is available in the literature about circulating miRNAs which are of particular interest as potential biomarkers for liquid biopsy. Conclusion: Identification of body-fluid markers for non-invasive diagnosis, risk stratification, treatment monitoring and tumor follow-up, is gaining growing interest, especially in the pediatric field. miRNAs are suitable candidates as biomarkers in neuroblastoma but further investigations are needed to expand knowledge regarding their role in this malignancy to design specific approaches of miRNAs-mediated therapies.

Background: Macrophage migration inhibitory factor (MIF) was firstly described in the 1960s as a pleiotropic cytokine affecting a variety of immune cells. Different physiological functions mainly involving inflammatory reactions such as chemokine-like function and regulating systemic stress responses have been reported. Objective: In several clinical studies the use of MIF as a biomarker has been investigated promising support for diseases with an inflammatory aspect such as sepsis, systemic infections and autoimmune diseases. This article in detail reviews clinical data and evaluates the function as biomarker focusing on inflammatory and autoimmune diseases. Conclusion: Recent studies suggest MIF to be a marker for different inflammatory diseases and might serve as therapeutic target in the future.

The cutaneous route is attractive for the delivery of drugs in the treatment of a wide variety of diseases. However the stratum corneum (SC) is an effective barrier that hampers skin penetration. Within this context, liposomes emerge as a potential carrier for improving topical delivery of therapeutic agents. In this review, we aimed to discuss key aspects for the topical delivery by drug-loaded liposomes. Phospholipid type and phase transition temperature have been shown to affect liposomal topical delivery. The effect of surface charge is subject to considerable variation depending on drug and composition. In addition, modified vesicles with the presence of components for permeation enhancement, such as surfactants and solvents, have been shown to have a considerable effect. These liposomes include: Transfersomes, Niosomes, Ethosomes, Transethosomes, Invasomes, coated liposomes, penetration enhancer containing vesicles (PEVs), fatty acids vesicles, Archaeosomes and Marinosomes. Furthermore, adding polymeric coating onto liposome surface could influence cutaneous delivery. Mechanisms of delivery include intact vesicular skin penetration, free drug diffusion, permeation enhancement, vesicle adsorption to and/or fusion with the SC, trans-appendageal penetration, among others. Finally, several skin conditions, including acne, melasma, skin aging, fungal infections and skin cancer, have benefited from liposomal topical delivery of drugs, with promising in vitro and in vivo results. However, despite the existence of some clinical trials, more studies are needed to be conducted in order to explore the potential of liposomes in the dermatological field.

Triterpenoids are natural compounds with a large variety of biological activities such as anticancer, antiviral, antibacterial, antifungal, antiparazitic, antiinflammatory and others. Despite their low toxicity and simple availability from the natural resources, their clinical use is still severely limited by their higher IC50 and worse pharmacological properties than in the currently used therapeutics. This fact encouraged a number of researchers to develop new terpenic derivatives more suitable for the potential clinical use. This review summarizes a new approach to improve both, the activity and ADME-Tox properties by connecting active terpenes to another modifying molecules using click reactions. Within the past few years, this synthetic approach was well explored yielding a lot of great improvements of the parent compounds along with some less successful attempts. A large quantity of the new compounds presented here are superior in both activity and ADME-Tox properties to their parents. This review should serve the researchers who need to promote their hit triterpenic structures towards their clinical use and it is intended as a guide for the chemical synthesis of better drug candidates.