Cytotoxicity Study of Cyclopentapeptide Analogues of Marine Natural Product Galaxamide towards Human Breast Cancer Cells. Oxid Med Cell Longev. 2017;2017:8392035. [PMID: 29410736 PMCID: PMC5749289 DOI: 10.1155/2017/8392035]

Anti-cancer properties of Sansalvamide A, its derivatives, and analogs: an updated review

As peptide-based therapies gain recognition for their potential anti-cancer activity, cyclic peptides like Sansalvamide A, a marine-derived cyclic depsipeptide, have emerged as a potential anti-cancer agent due to their potent activity against various cancer types in preclinical studies. This review offers a comprehensive overview of Sansalvamide A, including its sources, structure-activity relationship, and semi-synthetic derivatives. The review also aims to outline the mechanisms through which Sansalvamide A and its analogs exert their anti-proliferative effects and to discuss the need for enhancements in pharmacokinetic profiles for better clinical utility. An extensive literature search was conducted, focusing on studies that detailed the anti-cancer activity of Sansalvamide A, its pharmacokinetics, and mechanistic pathways. Data from both in vitro and in vivo studies were collated and analyzed. Sansalvamide A and its analogs demonstrated significant anti-cancer activity across various cancer models, mediated through Hsp 90 inhibition, Topoisomerase inhibition, and G0/G1 cell cycle arrest. However, their pharmacokinetic properties were identified as a significant limitation, requiring improvement for effective clinical translation. Despite its notable anti-cancer effects, the utility of Sansalvamide A is currently limited by its pharmacokinetic characteristics. Therefore, while Sansalvamide A exhibits promise as an anti-cancer agent, there is a compelling need for further clinical and toxicological studies and optimization of its pharmacokinetic profile to fully exploit its therapeutic potential alongside modern cancer therapies.

Galaxamide alleviates cisplatin-induced premature ovarian insufficiency via the PI3K signaling pathway in HeLa tumor-bearing mice

BACKGROUND

It is challenging to improve the effects of chemotherapy and reduce its adverse impact on the ovaries. Our previous study suggested that the combination of galaxamide could enhance the antitumor effect of cisplatin (CIS) in HeLa cell xenograft mice. However, their potential effects on ovarian tissues remain unknown.

METHODS

The Hela tumor-bearing female BALB/c mice model was established and randomly divided into three groups: control group (PBS group), CIS group (0.3 mg/kg CIS group) and galaxamide group (0.3 mg/kg CIS + 3 mg/kg galaxamide-treated group). The serum sex hormones levels, ovarian morphology, functional and molecular characterisation were determined and compared with those of the control group.

RESULTS

The hormonal effects indicated premature ovarian insufficiency (POI) associated with CIS-induced tumor-bearing mice. CIS induces the apoptosis in primordial and developing follicles and subsequently increases follicular atresia, eventually leading to follicle loss. After cotreatment, galaxamide significantly increased anti-Mullerian hormone (AMH) and follicle-stimulating hormone receptor (FSHR) expression and prevented the CIS-induced PI3K pathway, which triggers follicle activation, apoptosis or atresia.

CONCLUSION

These findings demonstrate that galaxamide could attenuate CIS-induced follicle loss by acting on the PI3K signaling pathway by stimulating AMH and/or FSHR and thus provides promising therapeutic options for patients with cervical cancer.

Antitumor activity of galaxamide involved in cell apoptosis and stemness by inhibiting Wnt/β-catenin pathway in cervical cancer

Our previous work reported that galaxamide, a cyclopeptide extracted from the seaweed Galaxaura filamentosa, showed antiproliferative activity against HeLa cells by MTT assay. In this study, the growth-inhibitory effects of galaxamide in HeLa cells and xenograft mouse models were investigated. It was found galaxamide significantly inhibited cell growth, colony formation, migration, and invasion and induced cell apoptosis by inhibiting the Wnt signaling pathway in HeLa cells. RNA sequencing revealed that galaxamide regulated stemness by Wnt6 signaling pathway in HeLa cells. By analyzing The Cancer Genome Atlas database, Wnt6 was found to be negatively/positively correlated with stemness- and apoptosis-related genes in human cervical cancer. Cancer stem-like cells (CSCs) isolated and enriched from HeLa cells demonstrated elevated Wnt6 and β-catenin genes compared with nonstem HeLa cells. After galaxamide treatment, CSCs showed abrogation of sphere-forming ability, along with inhibition of stemness-related and Wnt pathway genes. Galaxamide treatment was also accompanied by the induction of apoptosis in HeLa cells, which was consistent with the results in BALB/c nude mice. Our results provide evidence that suppression of stemness by downregulating the Wnt signaling pathway is the molecular mechanism by which galaxamide effectively inhibits cell growth and induces apoptosis in cervical cancer cells.

Recent advances of bioactive proteins/polypeptides in the treatment of breast cancer

Proteins do not only serve as nutrients to fulfill the demand for food, but also are used as a source of bioactive proteins/polypeptides for regulating physical functions and promoting physical health. Female breast cancer has the highest incidence in the world and is a serious threat to women's health. Bioactive proteins/polypeptides exert strong anti-tumor effects and exhibit inhibition of multiple breast cancer cells. This review discussed the suppressing effects of bioactive proteins/polypeptides on breast cancer in vitro and in vivo, and their mechanisms of migration and invasion inhibition, apoptosis induction, and cell cycle arrest. This may contribute to providing a basis for the development of bioactive proteins/polypeptides for the treatment of breast cancer.

Graphical abstract

Cyclic Peptides for the Treatment of Cancers: A Review

Cyclic peptides have been widely reported to have therapeutic abilities in the treatment of cancer. This has been proven through in vitro and in vivo studies against breast, lung, liver, colon, and prostate cancers, among others. The multitude of data available in the literature supports the potential of cyclic peptides as anticancer agents. This review summarizes the findings from previously reported studies and discusses the different cyclic peptide compounds, the sources, and their modes of action as anticancer agents. The prospects and future of cyclic peptides will also be described to give an overview on the direction of cyclic peptide development for clinical applications.

Photoinduced Synthesis of Methylated Marine Cyclopeptide Galaxamide Analogs with Isoindolinone as Anticancer Agents

The methylation of amino acid residues has played an important role in the biological function of bioactive peptides. In this paper, various methyl-modified and stereostructural-modified marine cyclopeptide galaxamide analogs with isoindolinone were synthesized by a photoinduced single electron transfer cyclization reaction. It was found that the single-methyl substitution was beneficial for the bioactivity of cyclic analogs with isoindolinone fragments, and the influence of methylation on bioactivity is uncertain and is sometimes case-specific. The compound with a single methyl group at Gly5 (compound 8) showed the strongest antiproliferative activity against HepG-2 cells. The tumor cell apoptosis, cell cycle, mitochondrial membrane potential, intracellular Ca2+ concentration and lactate dehydrogenase activity have been studied extensively to evaluate the antitumor potential of compound 8. Western blotting tests showed that compound 8 could decrease the MDM2 level and increase p53 levels efficiently. Careful molecular docking suggested that cyclic peptide 8 could bind firmly with MDM2 oncoprotein, indicating that MDM2 may be a potential drug target of the prepared peptides.

Natural Cyclopeptides as Anticancer Agents in the Last 20 Years

Cyclopeptides or cyclic peptides are polypeptides formed by ring closing of terminal amino acids. A large number of natural cyclopeptides have been reported to be highly effective against different cancer cells, some of which are renowned for their clinical uses. Compared to linear peptides, cyclopeptides have absolute advantages of structural rigidity, biochemical stability, binding affinity as well as membrane permeability, which contribute greatly to their anticancer potency. Therefore, the discovery and development of natural cyclopeptides as anticancer agents remains attractive to academic researchers and pharmaceutical companies. Herein, we provide an overview of anticancer cyclopeptides that were discovered in the past 20 years. The present review mainly focuses on the anticancer efficacies, mechanisms of action and chemical structures of cyclopeptides with natural origins. Additionally, studies of the structure-activity relationship, total synthetic strategies as well as bioactivities of natural cyclopeptides are also included in this article. In conclusion, due to their characteristic structural features, natural cyclopeptides have great potential to be developed as anticancer agents. Indeed, they can also serve as excellent scaffolds for the synthesis of novel derivatives for combating cancerous pathologies.

Understanding the function of the tumor microenvironment, and compounds from marine organisms for breast cancer therapy

The pathology and physiology of breast cancer (BC), including metastasis, and drug resistance, is driven by multiple signaling pathways in the tumor microenvironment (TME), which hamper antitumor immunity. Recently, long non-coding RNAs have been reported to mediate pathophysiological develop-ments such as metastasis as well as immune suppression within the TME. Given the complex biology of BC, novel personalized therapeutic strategies that address its diverse pathophysiologies are needed to improve clinical outcomes. In this review, we describe the advances in the biology of breast neoplasia, including cellular and molecular biology, heterogeneity, and TME. We review the role of novel molecules such as long non-coding RNAs in the pathophysiology of BC. Finally, we provide an up-to-date overview of anticancer compounds extracted from marine microorganisms, crustaceans, and fishes and their synergistic effects in combination with other anticancer drugs. Marine compounds are a new discipline of research in BC and offer a wide range of anti-cancer effects that could be harnessed to target the various pathways involved in BC development, thus assisting current therapeutic regimens.

Novel 3,4-seco-3,19-dinorspongian and 5,17-epoxy-19-norspongian diterpenes from the marine sponge Spongia sp

Twelve new norspongian diterpenes, dinorspongians A-F (1–6) and epoxynorspongians A–F (7–12), were isolated from the marine sponge Spongia sp.