Fascaplysin inhibit ovarian cancer cell proliferation and metastasis through inhibiting CDK4

A systematic review on understanding the mechanistic pathways and clinical aspects of natural CDK inhibitors on cancer progression.: Unlocking cellular and biochemical mechanisms

Cell division, differentiation, and controlled cell death are all regulated by phosphorylation, a key biological function. This mechanism is controlled by a variety of enzymes, with cyclin-dependent kinases (CDKs) being particularly important in phosphorylating proteins at serine and threonine sites. CDKs, which contain 20 unique components, serve an important role in regulating vital physiological functions such as cell cycle progression and gene transcription. Methodologically, an extensive literature search was performed using reputable databases such as PubMed, Google Scholar, Scopus, and Web of Science. Keywords encompassed "cyclin kinase," "cyclin dependent kinase inhibitors," "CDK inhibitors," "natural products," and "cancer therapy." The inclusion criteria, focused on relevance, publication date, and language, ensured a thorough representation of the most recent research in the field, encompassing articles published from January 2015 to September 2023. Categorization of CDKs into those regulating transcription and those orchestrating cell cycle phases provides a comprehensive understanding of their diverse functions. Ongoing clinical trials featuring CDK inhibitors, notably CDK7 and CDK4/6 inhibitors, illuminate their promising potential in various cancer treatments. This review undertakes a thorough investigation of CDK inhibitors derived from natural (marine, terrestrial, and peptide) sources. The aim of this study is to provide a comprehensive comprehension of the chemical classifications, origins, target CDKs, associated cancer types, and therapeutic applications.

Marine-Derived Bisindoles for Potent Selective Cancer Drug Discovery and Development

Marine-derived bisindoles exhibit structural diversity and exert anti-cancer influence through multiple mechanisms. Comprehensive research has shown that the development success rate of drugs derived from marine natural products is four times higher than that of other natural derivatives. Currently, there are 20 marine-derived drugs used in clinical practice, with 11 of them demonstrating anti-tumor effects. This article provides a thorough review of recent advancements in anti-tumor exploration involving 167 natural marine bisindole products and their derivatives. Not only has enzastaurin entered clinical practice, but there is also a successfully marketed marine-derived bisindole compound called midostaurin that is used for the treatment of acute myeloid leukemia. In summary, investigations into the biological activity and clinical progress of marine-derived bisindoles have revealed their remarkable selectivity, minimal toxicity, and efficacy against various cancer cells. Consequently, they exhibit immense potential in the field of anti-tumor drug development, especially in the field of anti-tumor drug resistance. In the future, these compounds may serve as promising leads in the discovery and development of novel cancer therapeutics.

A New Mild Method for Synthesis of Marine Alkaloid Fascaplysin and Its Therapeutically Promising Derivatives

Fascaplysin is a marine alkaloid which is considered to be a lead drug candidate due to its diverse and potent biological activity. As an anticancer agent, fascaplysin holds a great potential due to the multiple targets affected by this alkaloid in cancer cells, including inhibition of cyclin-dependent kinase 4 (CDK4) and induction of intrinsic apoptosis. At the same time, the studies on structural optimization are hampered by its rather high toxicity, mainly caused by DNA intercalation. In addition, the number of methods for the syntheses of its derivatives is limited. In the current study, we report a new two-step method of synthesis of fascaplysin derivatives based on low temperature UV quaternization for the synthesis of thermolabile 9-benzyloxyfascaplysin and 6-tert-butylfascaplysin. 9-Benzyloxyfascaplysin was used as the starting compound to obtain 9-hydroxyfascaplysin. However, the latter was found to be chemically highly unstable. 6-tert-Butylfascaplysin revealed a significant decrease in DNA intercalation when compared to fascaplysin, while cytotoxicity was only slightly reduced. Therefore, the impact of DNA intercalation for the cytotoxic effects of fascaplysin and its derivatives needs to be questioned.

Scutellaria baicalensis Georgi and Their Natural Flavonoid Compounds in the Treatment of Ovarian Cancer: A Review

Ovarian cancer (OC) is one of the most common types of cancer in women with a high mortality rate, and the treatment of OC is prone to high recurrence rates and side effects. Scutellaria baicalensis (SB) is a herbal medicine with good anti-cancer activity, and several studies have shown that SB and its flavonoids have some anti-OC properties. This paper elucidated the common pathogenesis of OC, including cell proliferation and cell cycle regulation, cell invasion and metastasis, apoptosis and autophagy, drug resistance and angiogenesis. The mechanisms of SB and its flavonoids, wogonin, baicalein, baicalin, Oroxylin A, and scutellarein, in the treatment of OC, are revealed, such as wogonin inhibits proliferation, induces apoptosis, inhibits invasion and metastasis, and increases the cytotoxicity of the drug. Baicalein also inhibits vascular endothelial growth factor (VEGF) expression etc. Analyzing their advantages and disadvantages in treating OC provides a new perspective on the role of SB and its flavonoids in OC treatment. It serves as a resource for future OC research and development.

Marine-Derived Lead Fascaplysin: Pharmacological Activity, Total Synthesis, and Structural Modification

Fascaplysin is a planar structure pentacyclic alkaloid isolated from sponges, which can effectively induce the apoptosis of cancer cells. In addition, fascaplysin has diverse biological activities, such as antibacterial, anti-tumor, anti-plasmodium, etc. Unfortunately, the planar structure of fascaplysin can be inserted into DNA and such interaction also limits the further application of fascaplysin, necessitating its structural modification. In this review, the biological activity, total synthesis and structural modification of fascaplysin will be summarized, which will provide useful information for pharmaceutical researchers interested in the exploration of marine alkaloids and for the betterment of fascaplysin in particular.

Fascaplysin Induces Apoptosis and Ferroptosis, and Enhances Anti-PD-1 Immunotherapy in Non-Small Cell Lung Cancer (NSCLC) by Promoting PD-L1 Expression

Fascaplysin is a natural product isolated from sponges with a wide range of anticancer activities. However, the mechanism of fascaplysin against NSCLC has not been clearly studied. In this study, fascaplysin was found to inhibit migration by regulating the wnt/β-catenin signaling pathway and reversing the epithelial-mesenchymal transition phenotype. Further research showed that the anti-NSCLC effect of fascaplysin was mainly through the induction of ferroptosis and apoptosis. Fascaplysin-induced ferroptosis in lung cancer cells, evidenced by increased levels of ROS and Fe²⁺ and downregulation of ferroptosis-associated protein and endoplasmic reticulum stress, was involved in fascaplysin-induced ferroptosis. In addition, ROS was found to mediate fascaplysin-induced apoptosis. Fascaplysin significantly upregulated the expression of PD-L1 in lung cancer cells, and enhanced anti-PD-1 antitumor efficacy in a syngeneic mouse model. Therefore, these results suggest that fascaplysin exerts anticancer effects by inducing apoptosis and ferroptosis in vitro, and improving the sensitivity of anti-PD-1 immunotherapy in vivo. Fascaplysin is a promising compound for the treatment of NSCLC.

Bisindole natural products: A vital source for the development of new anticancer drugs

Currently, the number of new cancer cases and deaths worldwide is increasing year on year. In addition to the requirement for cancer prevention, the top priority is still to seek the effective cure of cancer. In over a half century of constant exploration, increasing attention has been paid to the excellent anticancer activity of natural products, with more and more natural products isolated, identified and detected. For this study, the focus lies the natural products of bisindole, where two indole molecules are indirectly linked or directly polymerized, developing the diversity of structure and mechanism, accompanied with the better anticancer activity than monomers. There has been a long history of applying indirubin and vincristine in cancer treatment, verifying the anticancer effect of bisindoles. Vincribine, midostaurin and other anticancer drugs have also been developed and commercialized. In this paper, a review regarding the potential therapeutic effect of bisindole alkaloids extracted from various natural products was carried out, in which the progress made in research of 242 bisindole alkaloids for cancer treatment was introduced. These compounds may be applicable as medicinal products for clinical research in the future.

Synergistic cytotoxicity of the CDK4 inhibitor Fascaplysin in combination with EGFR inhibitor Afatinib against Non-small Cell Lung Cancer

In the absence of suitable molecular markers, non-small cell lung cancer (NSCLC) patients have to be treated with chemotherapy with poor results at advanced stages. Therefore, the activity of the anticancer marine drug fascaplysin was tested against primary NSCLC cell lines established from pleural effusions. Cytotoxicity of the drug or combinations were determined using MTT assays and changes in intracellular phosphorylation by Western blot arrays. Fascaplysin revealed high cytotoxicity against NSCLC cells and exhibit an activity pattern different of the standard drug cisplatin. Furthermore, fascaplysin synergizes with the EGFR tyrosine kinase inhibitor (TKI) afatinib to yield a twofold increased antitumor effect. Interaction with the Chk1/2 inhibitor AZD7762 confirm the differential effects of fascplysin and cisplatin. Protein phosphorylation assays showed hypophosphorylation of Akt1/2/3 and ERK1/2 as well as hyperphosphorylation of stress response mediators of H1299 NSCLC cells. In conclusion, fascaplysin shows high cytotoxicity against pleural primary NSCLC lines that could be further boosted when combined with the EGFR TKI afatinib.

Molecular modeling studies of [4-(3H-benzoimidazol-5-yl)-pyrimidin-2-yl]-amine-based CDK4 inhibitors

Aim: CDK4 is a promising target for breast cancer therapy. This study aimed to explore the structure-activity relationship of CDK4 inhibitor abemaciclib analogs and design potent CDK4 inhibitors for breast cancer treatment. Methods & results: A faithful 3D quantitative structure-activity relationship model was established by molecular docking, comparative molecular field analysis and comparative molecular similarity index analysis based on 56 abemaciclib analogs. Molecular dynamics simulation studies revealed the key residues of the interaction between CDK4 and inhibitors. Four novel inhibitors with satisfactory predicted binding affinity to CDK4 were designed. Conclusion: The 3D quantitative structure-activity relationship and molecular dynamics simulation studies provide valuable insight into the development of novel CDK4 inhibitors.

Comparison of the Inhibitory Binding Modes Between the Planar Fascaplysin and Its Nonplanar Tetrahydro-β-carboline Analogs in CDK4

Fascaplysin is a natural marine product originating from sponges, attracting widespread attention due to its potential inhibitory activities against CDK4. However, its clinical application has been largely limited because of serious adverse effects caused by planar skeleton. To reduce the serious adverse effects, 18 tetrahydro-β-carboline analogs (compounds 6a-i and 7a-i) were designed and synthesized via breaking the planarity of fascaplysin, and the biological activities of the synthesized compounds were evaluated by MTT assay and CDK4/CycD3 enzyme inhibition assay. The title compounds showed varying degrees of inhibitory activities, especially the cytotoxicity of compound 6c against HeLa cells (IC₅₀ = 1.03 ± 0.19 μM) with quite weak cytotoxicity toward the normal cells WI-38 (IC₅₀ = 311.51 ± 56.06 μM), and the kinase inhibition test indicated that compound 6c was a potential CDK4 inhibitor. In order to further compare the action mechanisms of planar and nonplanar molecules on CDK4, the studied complexes of CDK4 bound with fascaplysin and three representative compounds (compound 6a-c) with bioactivities gradient were constructed by molecular docking and further verified through molecular dynamic simulation, which identified the key residues contributing to the ligands' binding. By comparing the binding modes of the constructed systems, it could be found that the residues contributing significantly to compound 6c's binding were highly consistent with those contributing significantly to fascaplysin's binding. Through the design, synthesis of the nonplanar fascaplysin derivatives, and binding mechanism analysis, some valuable hints for the discovery of antitumor drug candidates could be provided.

Exploring the five different genes associated with PKCα in bladder cancer based on gene expression microarray

Much progress has been made in understanding the mechanism of bladder cancer (BC) progression. Protein kinase C‐α (PKCα) is overexpressed in many kinds of cancers. Additionally, PKCα is considered an oncogene that regulates proliferation, invasion, migration, apoptosis and cell cycle in multiple cancers. However, the mechanism underlying how these cellular processes are regulated by PKCα remains unknown. In the present study, we used PKCα siRNA to knock down PKCα gene expression and found that down‐regulation of PKCα could significantly inhibit cell proliferation, migration and invasion and induce apoptosis and G1/S cell cycle arrest in vitro. Overexpression of PKCα promotes tumour growth in vivo. We applied cDNA microarray technology to detect the differential gene expression in J82 cells with PKCα knockdown and found that five key genes (BIRC2, BIRC3, CDK4, TRAF1 and BMP4) were involved in proliferation and apoptosis according to GO analysis and pathway analyses. Correlation analysis revealed a moderate positive correlation between PKCα expression and the expression of five downstream genes. BIRC2 and BIRC3 inhibit apoptosis, whereas CDK4, TRAF1 and BMP4 promote proliferation. Essentially, all five of these target genes participated in proliferation, and apoptosis was regulated by PKCα via the NF‐kB signalling pathway.

Alkaloids of fascaplysin are promising chemotherapeutic agents for the treatment of glioblastoma: Review

Glioblastoma is one of the most aggressive human brain tumors. Even following all the modern protocols of complex treatment, the median patient survival typically does not exceed 15 months. This review analyzes the main reasons for glioblastoma resistance to therapy, as well as attempts at categorizing the main approaches to increasing chemotherapy efficiency. Special emphasis is placed on the specific group of compounds, known as marine alkaloids and their synthetic derivatives exerting a general antitumor effect on glioblastoma cells. The unique mechanisms of marine alkaloid influence on the tumor cells prompt considering them as a promising basis for creating new chemotherapeutic agents for glioblastoma treatment.

Fascaplysin Derivatives Are Potent Multitarget Agents against Alzheimer's Disease: in Vitro and in Vivo Evidence

Alzheimer's disease (AD) is characterized by progressive neurodegeneration and impaired cognitive functions. Fascaplysin is a β-carboline alkaloid isolated from marine sponge Fascaplysinopsis bergquist in 1988. Previous studies have shown that fascaplysin might act on acetylcholinesterase and β-amyloid (Aβ) to produce anti-AD properties. In this study, a series of fascaplysin derivatives were synthesized. The cholinesterase inhibition activities, the neuronal protective effects, and the toxicities of these compounds were evaluated in vitro. Compounds 2a and 2b, the two most powerful compounds in vitro, were further selected to evaluate their cognitive-enhancing effects in animals. Both 2a and 2b could ameliorate cognitive dysfunction induced by scopolamine or Aβ oligomers without affecting locomotor functions in mice. We also found that 2a and 2b could prevent cholinergic dysfunctions, decrease pro-inflammatory cytokine expression, and inhibit Aβ-induced tau hyperphosphorylation in vivo. Most importantly, pharmacodynamics studies suggested that 2b could penetrate the blood-brain barrier and be retained in the central nervous system. All these results suggested that fascaplysin derivatives are potent multitarget agents against AD and might be clinical useful for AD treatment.

Patient-derived bladder cancer xenograft models reveal VEGF and CDK4 enhancing tumor metastasis behavior

New strategies to treat advanced bladder cancer are urgently required. A patient-derived xenograft (PDX) model has become a useful tool to evaluate chemotherapeutics and investigate personalized cancer treatment options. In this study, fresh human bladder cancer specimens (C09303 and C21391) were transplanted subcutaneously into nude mice to establish PDX models. These models well retained pathological characteristics and molecular markers of the original tumor. Primary cells derived from C09303 were cultured and perfused into the bladders of nude mice to establish orthotopic xenograft models. Evident signals of lung and kidney metastases were detected by whole-body optical imaging. Gemcitabine displayed a significant therapeutic effect on the subcutaneous or orthotopic xenograft tumors of C09303. In vitro, matrigel invasion assays showed that C09303 primary culture cells are remarkably invasive. To study the metastatic properties of C09303, we sequenced the genomes of C09303 and C21391, and found that the expression of VEGF and CDK4 was significantly upregulated, and VEGF-knockdown or CDK4-knockdown C09303 cells showed attenuated invasiveness and migration. This PDX model revealed that VEGF and CDK4 enhanced tumor metastasis behavior, suggesting them as novel molecular therapeutic targets. This framework provides a tool for research on metastasis mechanism and individualized treatment for bladder cancer.

9-Methylfascaplysin Is a More Potent Aβ Aggregation Inhibitor than the Marine-Derived Alkaloid, Fascaplysin, and Produces Nanomolar Neuroprotective Effects in SH-SY5Y Cells

β-Amyloid (Aβ) is regarded as an important pathogenic target for Alzheimer’s disease (AD), the most prevalent neurodegenerative disease. Aβ can assemble into oligomers and fibrils, and produce neurotoxicity. Therefore, Aβ aggregation inhibitors may have anti-AD therapeutic efficacies. It was found, here, that the marine-derived alkaloid, fascaplysin, inhibits Aβ fibrillization in vitro. Moreover, the new analogue, 9-methylfascaplysin, was designed and synthesized from 5-methyltryptamine. Interestingly, 9-methylfascaplysin is a more potent inhibitor of Aβ fibril formation than fascaplysin. Incubation of 9-methylfascaplysin with Aβ directly reduced Aβ oligomer formation. Molecular dynamics simulations revealed that 9-methylfascaplysin might interact with negatively charged residues of Aβ₄₂ with polar binding energy. Hydrogen bonds and π–π interactions between the key amino acid residues of Aβ₄₂ and 9-methylfascaplysin were also suggested. Most importantly, compared with the typical Aβ oligomer, Aβ modified by nanomolar 9-methylfascaplysin produced less neuronal toxicity in SH-SY5Y cells. 9-Methylfascaplysin appears to be one of the most potent marine-derived compounds that produces anti-Aβ neuroprotective effects. Given previous reports that fascaplysin inhibits acetylcholinesterase and induces P-glycoprotein, the current study results suggest that fascaplysin derivatives can be developed as novel anti-AD drugs that possibly act via inhibition of Aβ aggregation along with other target mechanisms.

Protein arginine methylation: an emerging regulator of the cell cycle

Protein arginine methylation is a common post-translational modification where a methyl group is added onto arginine residues of a protein to alter detection by its binding partners or regulate its activity. It is known to be involved in many biological processes, such as regulation of signal transduction, transcription, facilitation of protein–protein interactions, RNA splicing and transport. The enzymes responsible for arginine methylation, protein arginine methyltransferases (PRMTs), have been shown to methylate or associate with important regulatory proteins of the cell cycle and DNA damage repair pathways, such as cyclin D1, p53, p21 and the retinoblastoma protein. Overexpression of PRMTs resulting in aberrant methylation patterns in cancers often correlates with poor recovery prognosis. This indicates that protein arginine methylation is also an important regulator of the cell cycle, and consequently a target for cancer regulation. The effect of protein arginine methylation on the cell cycle and how this emerging key player of cell cycle regulation may be used in therapeutic strategies for cancer are the focus of this review.

Fascaplysin Sensitizes Anti-Cancer Effects of Drugs Targeting AKT and AMPK

Fascaplysin, a natural product isolated from marine sponges, is a potential candidate for the development of anti-cancer drugs. However, the mechanism underlying its therapeutic effect of strengthening anti-cancer efficacy of other drugs is poorly understood. Here, we found that fascaplysin increases phosphorylation of protein kinase B (PKB), also known as AKT, and adenosine monophosphate-activated protein kinase (AMPK), which are considered therapeutic targets for cancer treatment due to their anti-apoptotic or pro-survival functions in cancer. A cell viability assay revealed that pharmacological suppression of AKT using LY294002 enhanced the anti-cancer effect of fascaplysin in various cancer cells. Similarly, fascaplysin was observed to have improved anti-cancer effects in combination with compound C, a selective AMPK inhibitor. Another challenge showed that fascaplysin increased the efficacy of methotrexate (MTX)-mediated cancer therapy by suppressing genes related to folate and purine metabolism. Overall, these results suggest that fascaplysin may be useful for improving the anti-cancer efficacy of targeted anti-cancer drugs, such as inhibitors of phosphoinositide 3-kinase AKT signaling, and chemotherapeutic agents, such as MTX.