The marine-derived pachycladin diterpenoids as novel inhibitors of wild-type and mutant EGFR

Anticancer activity of Araguspongine C via inducing apoptosis, and inhibition of oxidative stress, inflammation, and EGFR-TK in human lung cancer cells: An in vitro and in vivo study

The advanced non-small cell lung cancer (NSCLC) that harbors epidermal growth factor receptor (EGFR) mutations has put a selective pressure on the discovery and development of newer EGFR inhibitors. Therefore, the present study intends to explore the pharmacological effect of Araguspongine C (Aragus-C) as anticancer agent against lung cancer. The effect of Aragus-C was evaluated on the viability of the A549 and H1975 cells. Further biochemical assays were performed to elaborate the effect of Aragus-C, on the apoptosis, cell-cycle analysis, and mitochondrial membrane potential in A549 cells. Western blot analysis was also conducted to determine the expression of EGFR in A549 cells. Tumor xenograft mice model from A549 cells was established to further elaborate the pharmacological activity of Aragus-C. Results suggest that Aragus C showed significant inhibitory activity against A549 cells as compared to H1975 cells. It has been found that Aragus-C causes the induction of apoptosis and promotes cell-cycle arrest at the G2/M phase of A549 cells. It also showed a reduction in the overexpression of EGFR in A549 cells. In tumor xenograft mice model, it showed a significant reduction of tumor volume in a dose-dependent manner, with maximum inhibitory activity was reported by the 8 mg/kg treated group. It also showed significant anti-inflammatory and antioxidant activity by reducing the level of TNF-α, IL-1β, IL-6, and MDA, with a simultaneous increase of superoxide dismutase and glutathione peroxidase. We have demonstrated the potent anti-lung cancer activity of Aragus-C, and it may be considered as a potential therapeutic choice for NSCLC treatment.

Targeting epidermal growth factor receptor and its downstream signaling pathways by natural products: A mechanistic insight

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase (RTK) that maintains normal tissues and cell signaling pathways. EGFR is overactivated and overexpressed in many malignancies, including breast, lung, pancreatic, and kidney. Further, the EGFR gene mutations and protein overexpression activate downstream signaling pathways in cancerous cells, stimulating the growth, survival, resistance to apoptosis, and progression of tumors. Anti-EGFR therapy is the potential approach for treating malignancies and has demonstrated clinical success in treating specific cancers. The recent report suggests most of the clinically used EGFR tyrosine kinase inhibitors developed resistance to the cancer cells. This perspective provides a brief overview of EGFR and its implications in cancer. We have summarized natural products-derived anticancer compounds with the mechanistic basis of tumor inhibition via the EGFR pathway. We propose that developing natural lead molecules into new anticancer agents has a bright future after clinical investigation.

The application and sustainable development of coral in traditional medicine and its chemical composition, pharmacology, toxicology, and clinical research

This review discusses the variety, chemical composition, pharmacological effects, toxicology, and clinical research of corals used in traditional medicine in the past two decades. At present, several types of medicinal coral resources are identified, which are used in 56 formulas such as traditional Chinese medicine, Tibetan medicine, Mongolian medicine, and Uyghur medicine. A total of 34 families and 99 genera of corals are involved in medical research, with the Alcyoniidae family and Sarcophyton genus being the main research objects. Based on the structural types of compounds and the families and genera of corals, this review summarizes the compounds primarily reported during the period, including terpenoids, steroids, nitrogen-containing compounds, and other terpenoids dominated by sesquiterpene and diterpenes. The biological activities of coral include cytotoxicity (antitumor and anticancer), anti-inflammatory, analgesic, antibacterial, antiviral, immunosuppressive, antioxidant, and neurological properties, and a detailed summary of the mechanisms underlying these activities or related targets is provided. Coral toxicity mostly occurs in the marine ornamental soft coral Zoanthidae family, with palytoxin as the main toxic compound. In addition, nonpeptide neurotoxins are extracted from aquatic corals. The compatibility of coral-related preparations did not show significant acute toxicity, but if used for a long time, it will still cause toxicity to the liver, kidneys, lungs, and other internal organs in a dose-dependent manner. In clinical applications, individual application of coral is often used as a substitute for orthopedic materials to treat diseases such as bone defects and bone hyperplasia. Second, coral is primarily available in the form of compound preparations, such as Ershiwuwei Shanhu pills and Shanhu Qishiwei pills, which are widely used in the treatment of neurological diseases such as migraine, primary headache, epilepsy, cerebral infarction, hypertension, and other cardiovascular and cerebrovascular diseases. It is undeniable that the effectiveness of coral research has exacerbated the endangered status of corals. Therefore, there should be no distinction between the advantages and disadvantages of listed endangered species, and it is imperative to completely prohibit their use and provide equal protection to help them recover to their normal numbers. This article can provide some reference for research on coral chemical composition, biological activity, chemical ecology, and the discovery of marine drug lead compounds. At the same time, it calls for people to protect endangered corals from the perspectives of prohibition, substitution, and synthesis.

Deep-Sea Sponges and Corals off the Western Coast of Florida-Intracellular Mechanisms of Action of Bioactive Compounds and Technological Advances Supporting the Drug Discovery Pipeline

The majority of natural products utilized to treat a diverse array of human conditions and diseases are derived from terrestrial sources. In recent years, marine ecosystems have proven to be a valuable resource of diverse natural products that are generated to defend and support their growth. Such marine sources offer a large opportunity for the identification of novel compounds that may guide the future development of new drugs and therapies. Using the National Oceanic and Atmospheric Administration (NOAA) portal, we explore deep-sea coral and sponge species inhabiting a segment of the U.S. Exclusive Economic Zone, specifically off the western coast of Florida. This area spans ~100,000 km2, containing coral and sponge species at sea depths up to 3000 m. Utilizing PubMed, we uncovered current knowledge on and gaps across a subset of these sessile organisms with regards to their natural products and mechanisms of altering cytoskeleton, protein trafficking, and signaling pathways. Since the exploitation of such marine organisms could disrupt the marine ecosystem leading to supply issues that would limit the quantities of bioactive compounds, we surveyed methods and technological advances that are necessary for sustaining the drug discovery pipeline including in vitro aquaculture systems and preserving our natural ecological community in the future. Collectively, our efforts establish the foundation for supporting future research on the identification of marine-based natural products and their mechanism of action to develop novel drugs and therapies for improving treatment regimens of human conditions and diseases.

Enzyme Inhibitors from Gorgonians and Soft Corals

For decades, gorgonians and soft corals have been considered promising sources of bioactive compounds, attracting the interest of scientists from different fields. As the most abundant bioactive compounds within these organisms, terpenoids, steroids, and alkaloids have received the highest coverage in the scientific literature. However, enzyme inhibitors, a functional class of bioactive compounds with high potential for industry and biomedicine, have received much less notoriety. Thus, we revised scientific literature (1974-2022) on the field of marine natural products searching for enzyme inhibitors isolated from these taxonomic groups. In this review, we present representative enzyme inhibitors from an enzymological perspective, highlighting, when available, data on specific targets, structures, potencies, mechanisms of inhibition, and physiological roles for these molecules. As most of the characterization studies for the new inhibitors remain incomplete, we also included a methodological section presenting a general strategy to face this goal by accomplishing STRENDA (Standards for Reporting Enzymology Data) project guidelines.

New Cladiellin-Type Diterpenoids from the South China Sea Soft Coral Cladiella krempfi: Structures and Molecular Docking Analysis in EGFRs

Two new cladiellin-type diterpenoids (1 and 2) and four known related compounds 3–6, were isolated from the South China Sea soft coral Cladiella krempfi. Compound 2 is the third example of cladiellins of an unusual peroxy group in the C-6 position in C. krempfi. The structures and absolute configurations of the new compounds were established by extensive spectroscopic analysis, X-ray diffraction, and/or chemical correlation. In bioassay, all the compounds were evaluated for cytotoxicity and epidermal growth factor receptor (EGFR) inhibitory activity. A molecular docking experiment was conducted to study the structure–activity relationship of cladiellin-type diterpenoids on EGFR inhibitory activity.

Synthetic and Naturally Occurring Heterocyclic Anticancer Compounds with Multiple Biological Targets

Cancer is a complex group of diseases initiated by abnormal cell division with the potential of spreading to other parts of the body. The advancement in the discoveries of omics and bio- and cheminformatics has led to the identification of drugs inhibiting putative targets including vascular endothelial growth factor (VEGF) family receptors, fibroblast growth factors (FGF), platelet derived growth factors (PDGF), epidermal growth factor (EGF), thymidine phosphorylase (TP), and neuropeptide Y4 (NY4), amongst others. Drug resistance, systemic toxicity, and drug ineffectiveness for various cancer chemo-treatments are widespread. Due to this, efficient therapeutic agents targeting two or more of the putative targets in different cancer cells are proposed as cutting edge treatments. Heterocyclic compounds, both synthetic and natural products, have, however, contributed immensely to chemotherapeutics for treatments of various diseases, but little is known about such compounds and their multimodal anticancer properties. A compendium of heterocyclic synthetic and natural product multitarget anticancer compounds, their IC50, and biological targets of inhibition are therefore presented in this review.

Trabectedin (Yondelis®) as a Therapeutic Option in Gynecological Cancers: A Focus on its Mechanisms of Action, Clinical Activity and Genomic Predictors of Drug Response

The use of predictive biomarkers provides potential individualized cancer therapeutic options to prevent therapy failure as well as serious toxicities. Several recent studies showed that predictive and prognostic biomarkers are a notable personalized strategy to improve patients' care in several cancers. Trabectedin (Yondelis®) is a cytotoxic agent, derived from a marine organism, harbouring a significant antitumor activity against several cancers such as soft tissue sarcoma, ovarian, and breast cancers. Recently and with the advent of molecular genetic testing, BRCA mutational status was found as an important predictor of response to this anticancer drug, especially in gynecological cancers. The aim of this updated review is to discuss the mechanisms of action of trabectedin against the wellknown cancer hallmarks described until today. The current advances were also examined related to genomic biomarkers that can be used in the future to predict the efficacy of this potent anticancer natural molecule in various gynecological cancers.

Protein kinases as targets for developing anticancer agents from marine organisms

Protein kinases play a fundamental role in the intracellular transduction because of their ability to phosphorylate plethora of proteins. Over the past three decades, numerous protein kinase inhibitors have been identified and are being used clinically successfully. The biodiversity of marine organisms provides a rich source for the discovery and development of novel anticancer agents in the treatment of human malignancies and a lot of bioactive ingredients from marine organisms display anticancer effects by affecting the protein kinases-mediated pathways. In the present mini-review, anticancer compounds from marine source were reviewed and discussed in context of their targeted pathways associated with protein kinases and the progress of these compounds as anticancer agents in recent five years were emphasized. The molecular entities and their modes of actions were presented. We focused on protein kinases-mediated signaling pathways including PI3K/Akt/mTOR, p38 MAPK, and EGFR. The marine compounds targeting special pathways of protein kinases were highlighted. We have also discussed the existing challenges and prospects related to design and development of novel protein kinase inhibitors from marine sources.

Marine natural compound cyclo(L-leucyl-L-prolyl) peptide inhibits migration of triple negative breast cancer cells by disrupting interaction of CD151 and EGFR signaling

Cyclo (L-Leucyl-L-Prolyl) peptide/CLP is a marine natural metabolite and well recognized as an antimicrobial and antioxidant agent with limited studies on anticancer activity. The current study aims to determine the effect of CLP on migration and growth of triple negative breast cancer cell lines. The anti-growth potential was evaluated by MTT, BrdU and TUNEL assays; DNA damage by γH2AX and Dead green assays; antimigration activity by Boyden chamber invasion and wound healing assays. Interaction of CLP with CD151 was resolved by PatchDock. Effect of CLP on the expression of transmembrane CD151 was evaluated by cell-based ELISA assay. The interaction between CD151 and EGFR was predicted by using FireDoc Web server. Impact of CLP on the interaction of CD151 with EGFR was evaluated by co-immunoprecipitation assay. The effect of CLP on the cell cycle and its controlling proteins was determined by Western blotting. CLP reduced the viability of MDA-MB-231 and MDA-MB-468 TNBC cell lines but not human breast healthy epithelial cell line (MCF-12A) similar to eribulin, standard. CLP also inhibited proliferation; cell cycle and migration. It induced DNA strand breaks, DNA damage, and cell death. It showed the most favorable interactions with CD151 in in silico docking and significantly reduced the expression of membrane-bound CD151 proteins. FireDoc Web study predicted the association between CD151 and EGFR with -29.13 kcal/mol of binding energy. CLP reduced the interaction of CD151 with EGFR along with the expression of cyclin D, CDK4, PAK, RAC1, and P27kiP1. This study concludes that CLP suppresses growth and migration by attenuating cell cycle of TNBC cell lines via EGFR and CD151 signaling. Thus, exploring the EGFR and CD151 signaling pathway targeted by CLP may provide a new approach in the treatment of TNBC.

Verruculosins A-B, New Oligophenalenone Dimers from the Soft Coral-Derived Fungus Talaromyces verruculosus

In an effort to discover new bioactive anti-tumor lead compounds, a specific tyrosine phosphatase CDC25B and an Erb family receptor EGFR were selected as drug screening targets. This work led to the investigation of the soft coral-derived fungus Talaromyces verruculosus and identification of two new oligophenalenone dimers, verruculosins A–B (1–2), along with three known analogues, bacillisporin F (3), duclauxin (4), and xenoclauxin (5). Compound 1 was the first structure of the oligophenalenone dimer possessing a unique octacyclic skeleton. The detailed structures and absolute configurations of the new compounds were elucidated on the basis of spectroscopic data, X-ray crystallography, optical rotation, Electronic Circular Dichroism (ECD) analysis, and nuclear magnetic resonance (NMR) calculations. Among which, compounds 1, 3, and 5 exhibited modest inhibitory activity against CDC25B with IC₅₀ values of 0.38 ± 0.03, 0.40 ± 0.02, and 0.26 ± 0.06 µM, respectively.

A Systematic Review of Recently Reported Marine Derived Natural Product Kinase Inhibitors

Protein kinases are validated drug targets for a number of therapeutic areas, as kinase deregulation is known to play an essential role in many disease states. Many investigated protein kinase inhibitors are natural product small molecules or their derivatives. Many marine-derived natural products from various marine sources, such as bacteria and cyanobacteria, fungi, animals, algae, soft corals, sponges, etc. have been found to have potent kinase inhibitory activity, or desirable pharmacophores for further development. This review covers the new compounds reported from the beginning of 2014 through the middle of 2019 as having been isolated from marine organisms and having potential therapeutic applications due to kinase inhibitory and associated bioactivities. Moreover, some existing clinical drugs based on marine-derived natural product scaffolds are also discussed.

Marine natural products

Covering: January to December 2017This review covers the literature published in 2017 for marine natural products (MNPs), with 740 citations (723 for the period January to December 2017) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1490 in 477 papers for 2017), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. Geographic distributions of MNPs at a phylogenetic level are reported.

Computational Methodologies in the Exploration of Marine Natural Product Leads

Computational methodologies are assisting the exploration of marine natural products (MNPs) to make the discovery of new leads more efficient, to repurpose known MNPs, to target new metabolites on the basis of genome analysis, to reveal mechanisms of action, and to optimize leads. In silico efforts in drug discovery of NPs have mainly focused on two tasks: dereplication and prediction of bioactivities. The exploration of new chemical spaces and the application of predicted spectral data must be included in new approaches to select species, extracts, and growth conditions with maximum probabilities of medicinal chemistry novelty. In this review, the most relevant current computational dereplication methodologies are highlighted. Structure-based (SB) and ligand-based (LB) chemoinformatics approaches have become essential tools for the virtual screening of NPs either in small datasets of isolated compounds or in large-scale databases. The most common LB techniques include Quantitative Structure–Activity Relationships (QSAR), estimation of drug likeness, prediction of adsorption, distribution, metabolism, excretion, and toxicity (ADMET) properties, similarity searching, and pharmacophore identification. Analogously, molecular dynamics, docking and binding cavity analysis have been used in SB approaches. Their significance and achievements are the main focus of this review.

Molecular Targets of Active Anticancer Compounds Derived from Marine Sources

Over the past decades, a number of novel compounds, which are produced in the marine environment, have been found to exhibit the anticancer effects. This review focuses on molecular targets of marine-derived anticancer candidates in clinical and preclinical studies. They are kinases, transcription factors, histone deacetylase, the ubiquitin-proteasome system, and so on. Specific emphasis of this review paper is to provide information on the optimization of new target compounds for future research and development of anticancer drugs, based on the identification of structures of these target molecules and parallel compounds.