Cytotoxic Compounds Derived from Marine Sponges. A Review (2010-2012)

Red Sea Sponge Callyspongia siphonella Extract Induced Growth Inhibition and Apoptosis in Breast MCF-7 and Hepatic HepG-2 Cancer Cell Lines in 2D and 3D Cell Cultures

Introduction

The increasing incidence of cancer diseases necessitates the urgent exploration of new bioactive compounds. One of the trends in drug discovery is marine sponges which is gaining significant support due to the abundant production of natural pharmaceutical compounds obtained from marine ecosystems. This study evaluates the anticancer properties of an organic extract from the Red Sea sponge Callyspongia siphonella (C. siphonella) on HepG-2 and MCF-7 cancer cell lines.

Methods

C. siphonella was collected, freeze-dried, and extracted using a methanol-dichloromethane mixture. The extract was analyzed via Liquid Chromatography-Mass Spectrometry. Cytotoxic effects were assessed through cell viability assays, apoptosis detection, cell cycle analysis, mitochondrial membrane potential assays, scratch-wound healing assays, and 3D cell culture assays.

Results

Fifteen compounds were identified in the C. siphonella extract. The extract showed moderate cytotoxicity against MCF-7 and HepG-2 cells, with IC50 values of 35.6 ± 6.9 μg/mL and 64.4 ± 8 μg/mL, respectively, after 48 hours of treatment. It induced cell cycle arrest at the G2/M phase in MCF-7 cells and the S phase in HepG-2 cells. Apoptosis increased significantly in both cell lines, accompanied by reduced mitochondrial membrane potential. The extract inhibited cell migration, with notable reductions after 24 and 48 hours. In 3D cell cultures, the extract had IC50 values of 5.1 ± 2 μg/mL for MCF-7 and 166.4 ± 27 μg/mL for HepG-2 after 7 days of treatment, showing greater potency in MCF-7 spheres compared to HepG-2 spheres.

Discussion and Conclusion

The anticancer activity is attributed to the bioactive compounds. The C. siphonella extract's ability to induce apoptosis, disrupt mitochondrial membrane potential, and arrest the cell cycle highlights its potential as a novel anticancer agent. Additional research is required to investigate the underlying mechanism by which this extract functions as a highly effective anticancer agent.

Manzamine-A Alters In Vitro Calvarial Osteoclast Function

Manzamine-A is a marine-derived alkaloid that has demonstrated antimalarial and antiproliferative properties and is an emerging drug lead compound as a possible intervention in certain cancers. This compound has been found to modulate SIX1 gene expression, a target that is critical for the proliferation and survival of cells via various developmental pathways. As yet, little research has focused on manzamine-A and how its use may affect tissue systems including bone. Here we hypothesized that manzamine-A, through its interaction with SIX1, would alter precursor cells that give rise to the bone cell responsible for remodeling: the osteoclast. We further hypothesized reduced effects in differentiated osteoclasts, as these cells are generally not mitotic. We interrogated the effects of manzamine-A on preosteoclasts and osteoclasts. qrtPCR, MTS cell viability, Caspase 3/7, and TRAP staining were used as a functional assay. Preosteoclasts show responsiveness to manzamine-A treatment exhibited by decreases in cell viability and an increase in apoptosis. Osteoclasts also proved to be affected by manzamine-A but only at higher concentrations where apoptosis was increased and activation was reduced. In summary, our presented results suggest manzamine-A may have significant effects on bone development and health through multiple cell targets, previously shown in the osteoblast cell lineage, the cell responsible for mineralized tissue formation, and here in the osteoclast, the cell responsible for the removal of mineralized tissue and renewal via precipitation of bone remodeling.

Bioactive Steroids Bearing Oxirane Ring

This review explores the biological activity and structural diversity of steroids and related isoprenoid lipids, with a particular focus on compounds containing an oxirane ring. These natural compounds are derived from fungi, fungal endophytes, as well as extracts of plants, algae, and marine invertebrates. To evaluate their biological activity, an extensive examination of refereed literature sources was conducted, including in vivo and in vitro studies and the utilization of the QSAR method. Notable properties observed among these compounds include strong anti-inflammatory, antineoplastic, antiproliferative, anti-hypercholesterolemic, antiparkinsonian, diuretic, anti-eczematic, anti-psoriatic, and various other activities. Throughout this review, 3D graphs illustrating the activity of individual steroids are presented, accompanied by images of selected terrestrial or marine organisms. Furthermore, this review provides explanations for specific types of biological activity associated with these compounds. The data presented in this review are of scientific interest to the academic community and carry practical implications in the fields of pharmacology and medicine. By analyzing the biological activity and structural diversity of steroids and related isoprenoid lipids, this review offers valuable insights that contribute to both theoretical understanding and applied research. This review draws upon data from various authors to compile information on the biological activity of natural steroids containing an oxirane ring.

Novel Insights in the Potential of Halogenated Polyketide–Peptide Molecules as Lead Compounds in Cancer Drug Discovery

In this interdisciplinary study, we selected two compounds, namely, smenamide A, a peptide–polyketide, and smenolactone D, a polyketide, as models because they are representative of two different classes of molecules isolated from the marine sponge Smenospongia aurea. The organic extract of Smenospongia aurea was analyzed using a combination of high-resolution LC-MS/MS and molecular networking, a recently developed method for automated LC-MS data analysis. The analyses were targeted to highlight clusters made by chlorinated compounds present in the extracts. Then, the two model compounds were analyzed for their bioactivity. Data reported here show that smenamide A did not exhibit a cytotoxic effect, while smenolactone D was cytotoxic on different tumor cell lines and was able to induce different types of cell death, including ferroptosis and apoptosis.

Marine Sponge Aaptos suberitoides Extract Improves Antiproliferation and Apoptosis of Breast Cancer Cells without Cytotoxicity to Normal Cells In Vitro

The anticancer effects and mechanisms of marine sponge Aaptos suberitoides were rarely assessed, especially for methanol extract of A. suberitoides (MEAS) to breast cancer cells. This study evaluated the differential suppression effects of proliferation by MEAS between breast cancer and normal cells. MEAS demonstrated more antiproliferation impact on breast cancer cells than normal cells, indicating oxidative stress-dependent preferential antiproliferation effects on breast cancer cells but not for normal cells. Several oxidative stress-associated responses were highly induced by MEAS in breast cancer cells but not normal cells, including the generations of cellular and mitochondrial oxidative stress as well as the depletion of mitochondrial membrane potential. MEAS downregulated cellular antioxidants such as glutathione, partly contributing to the upregulation of oxidative stress in breast cancer cells. This preferential oxidative stress generation is accompanied by more DNA damage (γH2AX and 8-hydroxy-2-deoxyguanosine) in breast cancer cells than in normal cells. N-acetylcysteine reverted these MEAS-triggered responses. In conclusion, MEAS is a potential natural product for treating breast cancer cells with the characteristics of preferential antiproliferation function without cytotoxicity to normal cells in vitro.

Manzamine-A Alters In Vitro Calvarial Osteoblast Function

Manzamine-A is a marine-derived alkaloid which has anti-viral and anti-proliferative properties and is currently being investigated for its efficacy in the treatment of certain viruses (malaria, herpes, HIV-1) and cancers (breast, cervical, colorectal). Manzamine-A has been found to exert effects via modulation of SIX1 gene expression, a gene critical to craniofacial development via the WNT, NOTCH, and PI3K/AKT pathways. To date little work has focused on Manzamine-A and how its use may affect bone. We hypothesize that Manzamine-A, through SIX1, alters bone cell activity. Here, we assessed the effects of Manzamine-A on cells that are responsible for the generation of bone, pre-osteoblasts and osteoblasts. PCR, qrtPCR, MTS cell viability, Caspase 3/7, and functional assays were used to test the effects of Manzamine-A on these cells. Our data suggests Six1 is highly expressed in osteoblasts and their progenitors. Further, osteoblast progenitors and osteoblasts exhibit great sensitivity to Manzamine-A treatment exhibited by a significant decrease in cell viability, increase in cellular apoptosis, and decrease in alkaline phosphatase activity. In silico binding experiment showed that manzamine A potential as an inhibitor of cell proliferation and survival proteins, i.e., Iκb, JAK2, AKT, PKC, FAK, and Bcl-2. Overall, our data suggests Manzamine-A may have great effects on bone health overall and may disrupt skeletal development, homeostasis, and repair.

Bioactive Compounds from Marine Sponges and Algae: Effects on Cancer Cell Metabolome and Chemical Structures

Metabolomics represent the set of small organic molecules generally called metabolites, which are located within cells, tissues or organisms. This new “omic” technology, together with other similar technologies (genomics, transcriptomics and proteomics) is becoming a widely used tool in cancer research, aiming at the understanding of global biology systems in their physiologic or altered conditions. Cancer is among the most alarming human diseases and it causes a considerable number of deaths each year. Cancer research is one of the most important fields in life sciences. In fact, several scientific advances have been made in recent years, aiming to illuminate the metabolism of cancer cells, which is different from that of healthy cells, as suggested by Otto Warburg in the 1950s. Studies on sponges and algae revealed that these organisms are the main sources of the marine bioactive compounds involved in drug discovery for cancer treatment and prevention. In this review, we analyzed these two promising groups of marine organisms to focus on new metabolomics approaches for the study of metabolic changes in cancer cell lines treated with chemical extracts from sponges and algae, and for the classification of the chemical structures of bioactive compounds that may potentially prove useful for specific biotechnological applications.

Evidence that Indo-Pacific bottlenose dolphins self-medicate with invertebrates in coral reefs

Indo-Pacific bottlenose dolphins (Tursiops aduncus) have been observed queueing up in natural environments to rub particular body parts against selected corals (Rumphella aggregata, Sarcophyton sp.) and sponges (Ircinia sp.) in the Egyptian Northern Red Sea. It was hypothesized that the presence of bioactive metabolites accounts for this selective rubbing behavior. The three invertebrates preferentially accessed by the dolphins, collected and analyzed by hyphenated high-performance thin-layer chromatography contained seventeen active metabolites, providing evidence of potential self-medication. Repeated rubbing allows these active metabolites to come into contact with the skin of the dolphins, which in turn could help them achieve skin homeostasis and be useful for prophylaxis or auxiliary treatment against microbial infections. This interdisciplinary research in behavior, separation science, and effect-directed analysis highlighted the importance of particular invertebrates in coral reefs, the urgent need to protect coral reefs for dolphins and other species, and calls for further vertebrate-invertebrate interaction studies.

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Dolphins rubbed body parts against specifically selected corals and sponges

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Behavioral studies were linked with hyphenated bioanalytical technique

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Vertebrate-invertebrate interaction in coral reefs may serve self-medication

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Molecular formulae were assigned to known and unknown bioactive molecules

Marine Demospongiae: A Challenging Treasure of Bioactive Compounds

In the last decades, it has been demonstrated that marine organisms are a substantial source of bioactive compounds with possible biotechnological applications. Marine sponges, in particular those belonging to the class of Demospongiae, have been considered among the most interesting invertebrates for their biotechnological potential. In this review, particular attention is devoted to natural compounds/extracts isolated from Demospongiae and their associated microorganisms with important biological activities for pharmacological applications such as antiviral, anticancer, antifouling, antimicrobial, antiplasmodial, antifungal and antioxidant. The data here presented show that this class of sponges is an exciting source of compounds, which are worth developing into new drugs, such as avarol, a hydroquinone isolated from the marine sponge Disidea avara, which is used as an antitumor, antimicrobial and antiviral drug.

Anti-inflammatory, anti-infectious and anti-cancer potential of marine algae and sponge: A review

Marine organisms are potentially a pretty good source of highly bioactive secondary metabolites that are best known for their anti-inflammation, anti-infection, and anti-cancer potential. The growing threat of bacterial resistance to synthetic antibiotics, is a potential source to screen terrestrial and marine natural organisms to discover promising anti-inflammatory and antimicrobial agents which can synergistically overcome the inflammatory and infectious disases. Algae and sponge have been studied enormously to evaluate their medicinal potential to fix variety of diseases, especially inflammation, infections, cancers, and diabetes. Cytarabine is the first isolated biomolecule from marine organism which was successfully practiced in clinical setup as chemotherapeutic agent against xylogenous leukemia both in acute and chronic conditions. This discovery opened the horizon for systematic evaluation of broad range of human disorders. This review is designed to look into the literature reported on anti-inflammatory, anti-infectious, and anti-cancerous potential of algae and sponge to refine the isolated compounds for value addition process.

Chemical Diversity and Bioactivity of Marine Sponges of the Genus Oceanapia: A Review

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The marine sponges of the genus Oceanapia sp. is comprised of more than 50 species and are distributed in the seas around the tropical and subtropical regions. They are mainly found in the northern Indian oceans, Japan, and the south pacific coast. They are highly colored and known to be a rich source of various secondary metabolites, particularly, alkaloids. Several other secondary metabolites were also reported from this genus which include terpenes, sphingolipids, ceramides, cerebrosides, acetylenic acids, and thiocyanatins, etc. Many of these compounds isolated from this genus exhibited various biological properties including anticancer, antimicrobial, anti-HIV, ichthyotoxicity and nematocidal activities. Although several secondary metabolites have been reported from this genus, a dedicated review of the chemicals and biological activities of this genus is so far lacking. Keeping this in mind this review describes the various chemical entities isolated from the sponges of the genus Oceanapia detailing their chemical structures along with their reported biological properties.

In Silico Prediction of Steroids and Triterpenoids as Potential Regulators of Lipid Metabolism

This review focuses on a rare group of steroids and triterpenoids that share common properties as regulators of lipid metabolism. This group of compounds is divided by the type of chemical structure, and they represent: aromatic steroids, steroid phosphate esters, highly oxygenated steroids such as steroid endoperoxides and hydroperoxides, α,β-epoxy steroids, and secosteroids. In addition, subgroups of carbon-bridged steroids, neo steroids, miscellaneous steroids, as well as synthetic steroids containing heteroatoms S (epithio steroids), Se (selena steroids), Te (tellura steroids), and At (astatosteroids) were presented. Natural steroids and triterpenoids have been found and identified from various sources such as marine sponges, soft corals, starfish, and other marine invertebrates. In addition, this group of rare lipids is found in fungi, fungal endophytes, and plants. The pharmacological profile of the presented steroids and triterpenoids was determined using the well-known computer program PASS, which is currently available online for all interested scientists and pharmacologists and is currently used by research teams from more than 130 countries of the world. Our attention has been focused on the biological activities of steroids and triterpenoids associated with the regulation of cholesterol metabolism and related processes such as anti-hyperlipoproteinemic activity, as well as the treatment of atherosclerosis, lipoprotein disorders, or inhibitors of cholesterol synthesis. In addition, individual steroids and triterpenoids were identified that demonstrated rare or unique biological activities such as treating neurodegenerative diseases, Alzheimer's, and Parkinson's diseases with a high degree of certainty over 95 percent. For individual steroids or triterpenoids or a group of compounds, 3D drawings of their predicted biological activities are presented.

Cytotoxic Potential, Metabolic Profiling, and Liposomes of Coscinoderma sp. Crude Extract Supported by in silico Analysis

Introduction

Sponge-Coscinoderma sp. (Family: Spongiidae) is a coastal sponge that possesses a broad variety of natural-products. However, the exact chemical constituents and cytotoxic activity of the extract are still undefinable.

Methodology

In the present study, the metabolomic profiling of Coscinoderma sp. dereplicated 20 compounds, utilizing liquid chromatography coupled with high-resolution mass spectrometry (LC-HRESIMS). Coscinoderma-derived crude extract, before and after encapsulation within nanosized liposomes, was in vitro screened against hepatic, breast, and colorectal carcinoma human cell lines (HepG2, MCF-7, and Caco-2, respectively).

Results

The identified metabolites were fit to diverse chemical classes, covering diterpenes, an indole alkaloid, sesterterpenoid, sterol, and methylherbipoline salt. Comprehensive in silico experiments predicted several compounds in the sponge-derived extract (eg, compounds 1-15) to have an anticancer potential via targeting multiple targets. The crude extract showed moderate antiproliferative activities towards studied cell lines with IC₅₀ values range from 10.7 to 12.4 µg/mL. The formulated extract-containing liposomes (size 141±12.3nm, PDI 0.222, zeta potential 20.8 ± 2.3), significantly enhanced the in vitro anticancer activity of the entrapped extract (IC₅₀ values ranged from 1.7 to 4.1 µg/mL).

Discussion

Encapsulation of both the hydrophilic and the lipophilic components of the extract within the lipid-based nanovesicles enhanced the cellular uptake and accessibility of the entrapped cargo. This study introduces liposomal nano-vesicles as a promising approach to improve the therapeutic potential of sponge-derived extracts.

Caspase Cascade Activation During Apoptotic Cell Death of Human Lung Carcinoma Cells A549 Induced by Marine Sponge Callyspongia aerizusa

Introduction

In this study, Callyspongia aerizusa (CA), one of the most popular marine sponges for cancer therapy research, was investigated for its phytochemical compounds and evaluated for its anticancer activity in various cell lines. Since lung cancer is the most frequently diagnosed cancer, a solution from this marine source is a good choice to address the resistance to anticancer agents. Elucidation of the underlying mechanism of cell death elicited by a CA extract in human lung carcinoma cells A549 was undertaken.

Methods

The presence of secondary metabolites in CA methanol extract was revealed by gas chromatography-mass spectrometry (GC-MS) and evaluated on four cancerous cell lines and a non-cancerous cell line using Cell Counting Kit-8. Since the activity of CA extract in A549 cells was then evaluated through clonogenic assay, morphological detection of apoptosis, polymerase chain reaction (PCR) and Western blot assay, were also presented in this study.

Results

GC-MS analysis revealed the presence of two ergosteroids, ergost-22-en-3-one, (5β,22E), and ergost-7-en-3-ol, (35β) in the sponge extract that was suggested to suppress A549 cells (IC₅₀ 9.38 μg/mL), and another cancerous cell’s viability (IC₅₀ 3.12–10.72 μg/mL) in 24 h, but not in the non-cancerous cells. Moreover, CA extract was also able to reduce the colony-forming ability of A549 cells, and through A549 cells morphology seems that apoptosis is the underlying mechanism of cell death. Further, the treatment with CA extract induced the up-regulation of caspase-9, caspase-3, and PARP-1, and the down-regulation of BCL-2, in both mRNA and proteins expression level, promoting apoptotic cell death via caspase cascade.

Conclusion

These findings suggest that the compounds in CA extract possess the ability to induce apoptotic cell death in A549 cells and could become a promising candidate for future anticancer therapy.

Cytotoxic Alkaloids Derived from Marine Sponges: A Comprehensive Review

Marine sponges (porifera) have proved to be a prolific source of unique bioactive secondary metabolites, among which the alkaloids occupy a special place in terms of unprecedented structures and outstanding biological activities. Identification of active cytotoxic alkaloids extracted from marine animals, particularly sponges, is an important strive, due to lack of knowledge on traditional experiential and ethnopharmacology investigations. In this report, a comprehensive survey of demospongian bioactive alkaloids in the range 1987-2020 had been performed with a special emphasis on the potent cytotoxic activity. Different resources and databases had been investigated, including Scifinder (database for the chemical literature) CAS (Chemical Abstract Service) search, web of science, Marin Lit (marine natural products research) database. More than 230 representatives of different classes of alkaloids had been reviewed and classified, different genera belonging to the phylum porifera had been shown to be a prolific source of alkaloidal molecules, including Agelas sp., Suberea sp., Mycale sp., Haliclona sp., Epipolasis sp., Monanchora sp., Crambe sp., Reniera sp., and Xestospongia sp., among others. The sufficient production of alkaloids derived from sponges is a prosperous approach that requires more attention in future studies to consider the constraints regarding the supply of drugs, attained from marine organisms.

Four New Pregnane-10,2-carbolactones from an Epipolasis sp. Marine Sponge

Four new pregnane steroids, 3β,4β,16β-trihydroxypregna-5,17-diene-10,2-carbolactone (1), 16β-acetoxy-3β,4β-dihydroxypregna-5,17-diene-10,2-carbolactone (2), 12β-acetoxy-3β,4β,16β-trihydroxypregna-5,17-diene-10,2-carbolactone (3), and 12β,16β-diacetoxy-3β,4β-dihydroxypregna-5,17-diene-10,2-carbolactone (4) were isolated from an extract of an Epipolasis sp. marine sponge. The structures of the new compounds were determined by extensive NMR spectroscopic analysis and comparison with data from previously reported compounds.

Isolation and characterization of antiplasmodial constituents from the marine sponge Coscinoderma sp

Six known compounds, namely two halisulfates 1 and 2 and four epidioxy sterols 3-6, were isolated from the marine sponge Coscinoderma sp. The structures of these compounds were confirmed by nuclear magnetic resonance (1H and 13C NMR) spectroscopy, and their antiplasmodial activities were determined against the chloroquine-resistant Dd2 strain of Plasmodium falciparum. The epidioxy steroids 3-6 all showed moderate to weak antiplasmodial activity, with IC50 values of 2.7 μM for (24S)-5α,8α-epidioxy-24-methylcholesta-6-en-3β-ol (3), 11.6 μM for 5α,8α-epidioxycholesta-6,24(28)-dien-3β-o1 (4), 2.33 μM for 5α,8α-epidioxy-24-methylcholesta-6,9(11)-24(28)-trien-3β-ol (5), and between 12 and 24 μM for 5α,8α-epidioxycholesta-6-en-3β-ol (6). In contrast, halisulfate 2 (1) was inactive, and halisulfate 1 (2) had an of IC50 value of about 24 μM.

The Marine Natural Product Manzamine A Inhibits Cervical Cancer by Targeting the SIX1 Protein

Natural products remain an important source of drug leads covering unique chemical space and providing significant therapeutic value for the control of cancer and infectious diseases resistant to current drugs. Here, we determined the antiproliferative activity of a natural product manzamine A (1) from an Indo-Pacific sponge following various in vitro cellular assays targeting cervical cancer (C33A, HeLa, SiHa, and CaSki). Our data demonstrated the antiproliferative effects of 1 at relatively low and non-cytotoxic concentrations (up to 4 μM). Mechanistic investigations confirmed that 1 blocked cell cycle progression in SiHa and CaSki cells at G1/S phase and regulated cell cycle-related genes, including restoration of p21 and p53 expression. In apoptotic assays, HeLa cells showed the highest sensitivity to 1 as compared to other cell types (C33A, SiHa, and CaSki). Interestingly, 1 decreased the levels of the oncoprotein SIX1, which is associated with oncogenesis in cervical cancer. To further investigate the structure-activity relationship among manzamine A (1) class with potential antiproliferative activity, molecular networking facilitated the efficient identification, dereplication, and assignment of structures from the manzamine class and revealed the significant potential in the design of optimized molecules for the treatment of cervical cancer. These data suggest that this sponge-derived natural product class warrants further attention regarding the design and development of novel manzamine analogues, which may be efficacious for preventive and therapeutic treatment of cancer. Additionally, this study reveals the significance of protecting fragile marine ecosystems from climate change-induced loss of species diversity.

Marine Invertebrate Extracts Induce Colon Cancer Cell Death via ROS-Mediated DNA Oxidative Damage and Mitochondrial Impairment

Marine compounds are a potential source of new anticancer drugs. In this study, the antiproliferative effects of 20 invertebrate marine extracts on three colon cancer cell models (HGUE-C-1, HT-29, and SW-480) were evaluated. Extracts from two nudibranchs (Phyllidia varicosa, NA and Dolabella auricularia, NB), a holothurian (Pseudocol ochirus violaceus, PS), and a soft coral (Carotalcyon sp., CR) were selected due to their potent cytotoxic capacities. The four marine extracts exhibited strong antiproliferative effects and induced cell cycle arrest at the G2/M transition, which evolved into early apoptosis in the case of the CR, NA, and NB extracts and necrotic cell death in the case of the PS extract. All the extracts induced, to some extent, intracellular ROS accumulation, mitochondrial depolarization, caspase activation, and DNA damage. The compositions of the four extracts were fully characterized via HPLC-ESI-TOF-MS analysis, which identified up to 98 compounds. We propose that, among the most abundant compounds identified in each extract, diterpenes, steroids, and sesqui- and seterterpenes (CR); cembranolides (PS); diterpenes, polyketides, and indole terpenes (NA); and porphyrin, drimenyl cyclohexanone, and polar steroids (NB) might be candidates for the observed activity. We postulate that reactive oxygen species (ROS) accumulation is responsible for the subsequent DNA damage, mitochondrial depolarization, and cell cycle arrest, ultimately inducing cell death by either apoptosis or necrosis.

Apiosporamide, A 4-hydroxy-2-pyridone Alkaloid, Induces Apoptosis Via PI3K/Akt Signaling Pathway In Osteosarcoma Cells

BACKGROUND

Osteosarcoma (OS) is a common primary malignant bone tumour in children and young adults. Apiosporamide, a 4-hydroxy-2-pyridone alkaloid from a deep-sea-derived fungus, Arthrinium sp. UJNMF0008, showed anti-proliferative effects toward a panel of human cancer cell lines, and the molecular mechanism in MG63 cells was then investigated in the current work.

METHODS

Cell viability was determined with MTT method. Cell proliferation was detected using colony-formation assay. Screening electron microscope was used for morphology observation. Cell cycle and apoptosis was analysed via flow cytometry. Real-time PCR was conducted to evaluate the mRNA expression related with cell apoptosis. The expression levels of proteins related to capase-mediated apoptotic pathway and PI3K/Akt signalling pathway were detected by Western blotting.

RESULTS

Apiosporamide significantly decreased cell viability in cancer cells, and also exhibited excellent anti-proliferative effect. Apiosporamide caused cell cycle arrests at G0/G1 phase in MG63 cells. Moreover, apiosporamide induced apoptosis, activated caspase-3, caspase-8 and caspase-9, and regulated expression of Bax and Bcl-2 in MG63 cells. In addition, apiosporamide also attenuated PI3K/Akt signaling pathway.

CONCLUSION

Apiosporamide effectively suppressed MG63 cells proliferation by inducing apoptosis through PI3K/Akt and caspase-associated apoptotic pathway.

Naturally Drug-Loaded Chitin: Isolation and Applications

Naturally occurring three-dimensional (3D) biopolymer-based matrices that can be used in different biomedical applications are sustainable alternatives to various artificial 3D materials. For this purpose, chitin-based structures from marine sponges are very promising substitutes. Marine sponges from the order Verongiida (class Demospongiae) are typical examples of demosponges with well-developed chitinous skeletons. In particular, species belonging to the family Ianthellidae possess chitinous, flat, fan-like fibrous skeletons with a unique, microporous 3D architecture that makes them particularly interesting for applications. In this work, we focus our attention on the demosponge Ianthella flabelliformis (Linnaeus, 1759) for simultaneous extraction of both naturally occurring ("ready-to-use") chitin scaffolds, and biologically active bromotyrosines which are recognized as potential antibiotic, antitumor, and marine antifouling substances. We show that selected bromotyrosines are located within pigmental cells which, however, are localized within chitinous skeletal fibers of I. flabelliformis. A two-step reaction provides two products: treatment with methanol extracts the bromotyrosine compounds bastadin 25 and araplysillin-I N20 sulfamate, and a subsequent treatment with acetic acid and sodium hydroxide exposes the 3D chitinous scaffold. This scaffold is a mesh-like structure, which retains its capillary network, and its use as a potential drug delivery biomaterial was examined for the first time. The results demonstrate that sponge-derived chitin scaffolds, impregnated with decamethoxine, effectively inhibit growth of the human pathogen Staphylococcus aureus in an agar diffusion assay.

Marine sponges of the genus Stelletta as promising drug sources: chemical and biological aspects

Marine sponges of the genus Stelletta are well known as rich sources of diverse and complex biologically relevant natural products, including alkaloids, terpenoids, peptides, lipids, and steroids. Some of these metabolites, with novel structures and promising biological activities, have attracted a lot of attention from chemists seeking to perform their total synthesis in parallel to intensive biological studies towards new drug leads. In this review, we summarized the distribution of the chemically investigated Stelletta sponges, the isolation, synthesis and biological activities of their secondary metabolites, covering the literature from 1982 to early 2018.

Marine natural products for multi-targeted cancer treatment: A future insight

Cancer is world's second largest alarming disease, which involves abnormal cell growth and have potential to spread to other parts of the body. Most of the available anticancer drugs are designed to act on specific targets by altering the activity of involved transporters and genes. As cancer cells exhibit complex cellular machinery, the regeneration of cancer tissues and chemo resistance towards the therapy has been the main obstacle in cancer treatment. This fact encourages the researchers to explore the multitargeted use of existing medicines to overcome the shortcomings of chemotherapy for alternative and safer treatment strategies. Recent developments in genomics-proteomics and an understanding of the molecular pharmacology of cancer have also challenged researchers to come up with target-based drugs. The literature supports the evidence of natural compounds exhibiting antioxidant, antimitotic, anti-inflammatory, antibiotic as well as anticancer activity. In this review, we have selected marine sponges as a prolific source of bioactive compounds which can be explored for their possible use in cancer and have tried to link their role in cancer pathway. To prove this, we revisited the literature for the selection of cancer genes for the multitargeted use of existing drugs and natural products. We used Cytoscape network analysis and Search tool for retrieval of interacting genes/ proteins (STRING) to study the possible interactions to show the links between the antioxidants, antibiotics, anti-inflammatory and antimitotic agents and their targets for their possible use in cancer. We included total 78 pathways, their genes and natural compounds from the above four pharmacological classes used in cancer treatment for multitargeted approach. Based on the Cytoscape network analysis results, we shortlist 22 genes based on their average shortest path length connecting one node to all other nodes in a network. These selected genes are CDKN2A, FH, VHL, STK11, SUFU, RB1, MEN1, HRPT2, EXT1, 2, CDK4, p14, p16, TSC1, 2, AXIN2, SDBH C, D, NF1, 2, BHD, PTCH, GPC3, CYLD and WT1. The selected genes were analysed using STRING for their protein-protein interactions. Based on the above findings, we propose the selected genes to be considered as major targets and are suggested to be studied for discovering marine natural products as drug lead in cancer treatment.

Isoaaptamine Induces T-47D Cells Apoptosis and Autophagy via Oxidative Stress

Aaptos is a genus of marine sponge which belongs to Suberitidae and is distributed in tropical and subtropical oceans. Bioactivity-guided fractionation of Aaptos sp. methanolic extract resulted in the isolation of aaptamine, demethyloxyaaptamine, and isoaaptamine. The cytotoxic activity of the isolated compounds was evaluated revealing that isoaaptamine exhibited potent cytotoxic activity against breast cancer T-47D cells. In a concentration-dependent manner, isoaaptamine inhibited the growth of T-47D cells as indicated by short-(MTT) and long-term (colony formation) anti-proliferative assays. The cytotoxic effect of isoaaptamine was mediated through apoptosis as indicated by DNA ladder formation, caspase-7 activation, XIAP inhibition and PARP cleavage. Transmission electron microscopy and flow cytometric analysis using acridine orange dye indicated that isoaaptamine treatment could induce T-47D cells autophagy. Immunoblot assays demonstrated that isoaaptamine treatment significantly activated autophagy marker proteins such as type II LC-3. In addition, isoaaptamine treatment enhanced the activation of DNA damage (γH2AX) and ER stress-related proteins (IRE1 α and BiP). Moreover, the use of isoaaptamine resulted in a significant increase in the generation of reactive oxygen species (ROS) as well as in the disruption of mitochondrial membrane potential (MMP). The pretreatment of T-47D cells with an ROS scavenger, N-acetyl-l-cysteine (NAC), attenuated the apoptosis and MMP disruption induced by isoaaptamine up to 90%, and these effects were mediated by the disruption of nuclear factor erythroid 2-related factor 2 (Nrf 2)/p62 pathway. Taken together, these findings suggested that the cytotoxic effect of isoaaptamine is associated with the induction of apoptosis and autophagy through oxidative stress. Our data indicated that isoaaptamine represents an interesting drug lead in the war against breast cancer.