Current Pharmaceutical Design - Volume 29, Issue 22, 2023

Cancer has remained to be one of the major challenges in medicine and regarded as the second leading cause of death worldwide. Different types of cancer may resist anti-cancer drugs following certain mutations such as those in tumor suppressor genes, exhaustion of the immune system, and overexpression of drug resistance mediators, which increase the required concentration of anticancer drugs so as to overcome drug resistance. Moreover, treatment with a high dose of such drugs is highly associated with severe normal tissue toxicity. Administration of low-toxic agents has long been an intriguing idea to enhance tumor suppression. Naturally occurring agents e.g., herb-derived molecules have shown a dual effect on normal and malignant cells. On the one hand, these agents may induce cell death in malignant cells, while on the other hand reduce normal cell toxicity. Nobiletin, one of the well-known polymethoxyflavones (PMFs), has reportedly shown various beneficial effects on the suppression of cancer and the protection of normal cells against different toxic agents. Our review aims to explain the main mechanisms underlying nobiletin as an inhibitor of cancer. We have reviewed the mechanisms of cancer cell death caused by nobiletin, such as stimulation of reactive oxygen species (ROS), modulation of immune evasion mechanisms, targeting tumor suppressor genes, and modulation of epigenetic modulators, among others; the inhibitory mechanisms of nobiletin affecting tumor resistance properties such as modulation of hypoxia, multidrug resistance, angiogenesis, epithelial-mesenchymal transition (EMT) have been fully investigated. Also, the inhibition of anti-apoptotic and invasive mechanisms induced by nobiletin will later be discussed. In the end, protective mechanisms of nobiletin on normal cells/tissue, clinical trial results, and future perspectives are reviewed.

Cancer is a collection of diseases in which aberrant cells grow uncontrolled and invade surrounding tissues. Cancer can be classified as carcinoma, sarcoma, leukemia, or lymphoma. The deadliest cancers are lung, breast, colorectal, pancreatic, and prostate. Chemotherapy, surgery, and radiotherapy are the usual cancer treatments. However, drug resistance poses a significant barrier to cancer treatment. Macroalgae are wellknown producers of bioactive compounds with antimicrobial, antioxidant, anti-inflammatory, and anti-cancer properties. Red algae, in particular, are a prominent source of bioactive substances, such as polysaccharides, phenolic compounds, lipids, sterols, alkaloids, and terpenoids. Therefore, molecules from marine resources could be an appealing way to identify new cancer treatment alternatives. This study aimed to provide a brief overview of what is currently known regarding the potential of red macroalgae in cancer treatment by discussing the primary therapeutic targets of the disease and identifying compounds or extracts with bioactive characteristics against them.

The most frequent mutated oncogene KRAS in lung cancer is targeted by KRAS G12C-directed drugs, such as Sotorasib and Adagrasib. Still, other alleles frequently expressed in pancreatic and colon cancer may be attacked indirectly by hitting the guanine nucleotide exchange factor (GEF) SOS1 that loads and activates KRAS. The first modulators of SOS1 were found to act as agonists and defined a hydrophobic pocket at the catalytic site. High throughput screenings resulted in the detection of SOS1 inhibitors Bay-293 and BI-3406 comprising amino quinazoline scaffolds optimized for binding to the pocket by various substituents. The first inhibitor, BI-1701963, is in clinical studies alone or in combination with a KRAS inhibitor, a MAPK inhibitor or chemotherapeutics. An optimized agonist, VUBI-1, shows activity against tumor cells by destructive overactivation of cellular signaling. This agonist was used to formulate a proteolysis targeting chimera (PROTAC), that labels SOS1 for degradation by proteasomal degradation through a linked VHL E3 ligase ligand. This PROTAC exhibited the highest SOS1-directed activity due to target destruction, recycling and removal of SOS1 as a scaffolding protein. Although other first PROTACs have entered clinical trials, each conjugate must be meticulously adapted as an efficient clinical drug.

Background: Cisplatin, a platinum complex discovered by Rosenberg in 1969, has long been known as the first metal-based anticancer agent. Since then, various similar derivatives of cisplatin have been investigated for pharmacological activity, and the approved complexes have been applied as drugs. Objectives: The aims of the current study are: 1) to summarize the advantages and dose-limiting effects of the approved and unapproved chemotherapy platinum cytostatics, 2) to develop new strategies for the development of platinum anticancer drugs, and 3) to clarify the important factors for the mechanism of action of platinum complexes. Methods: A search was conducted in the literature databases, and the obtained information was summarized and analyzed. Results: Myelosuppression is the main dose-limiting effect and the reason for the disapproval of platinum complexes, such as picoplatin, enloplatin, miboplatin, sebriplatin, zeniplatin, spiroplatin, iproplatin, and ormaplatin. From the basic point of view of inorganic coordination chemistry, such as theoretical calculations, crystal structures of model complexes, docking structures with nucleic acid molecules, spectroscopy, and biological aspects, the importance of physicochemical properties of inorganic platinum complexes for their mechanism of action has been indicated. Spectroscopic methods, such as FTIR, NMR, X-ray crystal structure analysis, and fluorescence microscopy, are important for the investigation of the conformational changes in the binding of platinum complexes and DNA. Conclusion: In the development of platinum complexes, strong anti-cancer drug activity, low toxicity, and resistance can be obtained by the application of polynuclear platinum agents, complexes with targeted activity, and nanoparticle formulations. Electronic structure, stereochemical, and thermodynamic properties are essential for understanding the reaction mechanism of platinum complexes.

Due to ineffective diagnosis and analysis, glioblastoma multiforme (GBM), is still the most aggressive form of all cancers. Standard therapy for GBM comprises resection surgery following chemo and radiotherapy, which offers less efficacious treatment to the malignant nature of glioma. Several treatment strategies involving gene therapy, immunotherapy, and angiogenesis inhibition have been employed recently as alternative therapeutics. The main drawback of chemotherapy is resistance, which is mainly due to the enzymes involved in the therapeutic pathways. Our objective is to provide a clear insight into various nano-architectures used in the sensitization of GBM and their importance in drug delivery and bioavailability. This review includes the overview and summary of articles from Pubmed and Scopus search engines. The present era’s synthetic and natural drugs used in the treatment of GBM are facing poor Blood Brain Barrier (BBB) permeability issues due to greater particle size. This problem can be resolved by using the nanostructures that showcase high specificity to cross the BBB with their nano-scale size and broader surface area. Nano-architectures act as promising tools for effective brain-targeted drug delivery at a concentration well below the final dose of free drug, thus resulting in safe therapeutic effects and reversal of chemoresistance. The present review focuses on the mechanisms involved in the resistance of glioma cells to chemotherapeutic agents, nano-pharmacokinetics, diverse types of nano-architectures used for potent delivery of the medicine and sensitization in GBM, their recent clinical advances, potential challenges, and future perspective.

Aims: The fight against cancer is an active research topic that combines several disciplines to find suitable agents to treat various tumours. Background: Following cisplatin, organometallic compounds, including titanocene derivatives, have been tested as antitumoral agents. However, key issues still need to be addressed in metallodrug chemotherapy relating to solubility, stability, and dosage. Mesoporous silica nanoparticles, being low toxic biocompatible materials with high loading capacity, are ideal candidates to overcome these problems. Objective: This study aimed to prepare and structurally characterize titanocene functionalized mesoporous silica nanoparticles and evaluate their cytotoxic activity against cancer cells. Methods: The preparation of titanocene functionalized mesoporous silica nanoparticles was achieved by synthetic protocols, involving either grafting or tethering. Characterization was carried out using standard techniques, FT-IR, XRD, XRF, TEM, and BET. The titanocene functionalized materials were studied as antitumoral agents in the breast cancer lines MCF-7 and MDA-MB-231. Results: The functionalized MSN showed promising antitumoral activity against cells lines MCF-7 and MDAMB- 231 up to 9 times more than titanocene alone. Conclusion: This study reported the potential of titanocene-functionalized mesoporous silica nanoparticles in future chemotherapeutic actions.