Transcriptome and proteome analysis reveals the anti-cancer properties of Hypnea musciformis marine macroalga extract in liver and intestinal cancer cells.

BACKGROUND: Marine seaweeds are considered as a rich source of health-promoting compounds by the food and pharmaceutical industry. Hypnea musciformis is a marine red macroalga (seaweed) that is widely distributed throughout the world, including the Mediterranean Sea. It is known to contain various bioactive compounds, including sulfated polysaccharides, flavonoids, and phlorotannins. Recent studies have investigated the potential anticancer effects of extracts from H. musciformis demonstrating their cytotoxic effects on various cancer cell lines. The anticancer effects of these extracts are thought to be due to the presence of bioactive compounds, particularly sulfated polysaccharides, which have been shown to have anticancer and immunomodulatory effects. However, further studies are needed to fully understand the molecular mechanisms that underlie their anticancer effects and to determine their potential as therapeutic agents for cancer treatment. METHODS: H. musciformis was collected from the Aegean Sea (Greece) and used for extract preparation. Transcriptome and proteome analysis was performed in liver and colon cancer human cell lines following treatment with H. musciformis seaweed extracts to characterize its anticancer effect in detail at the molecular level and to link transcriptome and proteome responses to the observed phenotypes in cancer cells. RESULTS: We have identified that treatment with the seaweed extract triggers a p53-mediated response at the transcriptional and protein level in liver cancer cells, in contrast to colon cancer cells in which the effects are more associated with metabolic changes. Furthermore, we show that in treated HepG2 liver cancer cells, p53 interacts with the chromatin of several target genes and facilitates their upregulation possibly through the recruitment of the p300 co-activator. CONCLUSIONS: Overall, the available evidence suggests that extracts from H. musciformis have the potential to serve as a source of anticancer agents in liver cancer cells mainly through activation of a p53-mediated anti-tumor response that is linked to inhibition of cellular proliferation and induction of cell death.

Role of melatonin in carcinogenesis and metastasis: From mechanistic insights to intermeshed networks of noncoding RNAs.

In recent years, seminal studies have been devoted to unraveling the puzzling mysteries associated with the cancer preventive/inhibitory role of melatonin. Our current knowledge of the translational mechanisms and the detailed structural insights have highlighted the characteristically exclusive role of melatonin in the inhibition of carcinogenesis and metastatic dissemination. This mini-review outlines recent discoveries related to mechanistic role of melatonin in prevention of carcinogenesis and metastasis. Moreover, another exciting facet of this mini-review is related to phenomenal breakthroughs linked with regulation of noncoding RNAs by melatonin in wide variety of cancers.

Cucurbitacin mediated regulation of deregulated oncogenic signaling cascades and non-coding RNAs in different cancers: Spotlight on JAK/STAT, Wnt/ß-catenin, mTOR, TRAIL-mediated pathways.

Research over decades has enabled us in developing a better understanding of the multifaceted and heterogeneous nature of cancer. High-throughput technologies have helped the researchers in unraveling of the underlying mechanisms which centrally regulate cancer onset, metastasis and drug resistance. Our rapidly expanding knowledge about signal transduction cascade has added another layer of complexity to already complicated nature of cancer. Deregulation of cell signaling pathways played a linchpin role in carcinogenesis and metastasis. Cucurbitacins have gained tremendous attention because of their remarkable pharmacological properties and considerable ability to mechanistically modulate myriad of cell signaling pathways in different cancers. In this review, we have attempted to provide a mechanistic and comprehensive analysis of regulation of oncogenic pathways by cucurbitacins in different cancers. We have partitioned this review into separate sections for exclusive analysis of each signaling pathway and critical assessment of the knowledge gaps. In this review, we will summarize most recent and landmark developments related to regulation of Wnt/ß-catenin, JAK/STAT, mTOR, VEGFR, EGFR and Hippo pathway by cucurbitacins. Moreover, we will also address how cucurbitacins regulate DNA damage repair pathway and TRAIL-driven signaling in various cancers. However, there are still outstanding questions related to regulation of SHH/GLI, TGF/SMAD and Notch-driven pathway by cucurbitacins in different cancers. Future studies must converge on the analysis of full-fledge potential of cucurbitacins by in-depth analysis of these pathways and how these pathways can be therapeutically targeted by cucurbitacins.

Targeting NQO1/GPX4-mediated ferroptosis by plumbagin suppresses in vitro and in vivo glioma growth.

BACKGROUND: Ferroptosis has attracted increasing interest in cancer therapy. Emerging evidences suggest that naturally occurring naphthoquinones exhibit potent anti-glioma effects via various mechanisms. METHODS: The anti-glioma effects of plumbagin were evaluated by in vitro and in vivo experiments. Anti-glioma mechanism of plumbagin was studied by proteomics, flow cytometry, MDA assay, western blot, and RT-PCR. Gene knockdown/overexpression, molecular docking, PharmMappper database, and coimmunoprecipitation were used to study the targets of plumbagin. RESULTS: Plumbagin showed higher blood-brain barrier penetration ability than that of lapachol and shikonin and elicited significant growth inhibitory effects in vitro and in vivo. Ferroptosis was the main mechanism of plumbagin-induced cell death. Mechanistically, plumbagin significantly downregulated the protein and mRNA levels of xCT and decreased GPX4 protein levels. NAD(P)H quinone dehydrogenase 1 (NQO1) was revealed as a plumbagin predictive target using PharmMappper database and molecular docking. Plumbagin enhanced NQO1 activity and decreased xCT expression, resulting in NQO1-dependent cell death. It also induced GPX4 degradation via the lysosome pathway and caused GPX4-dependent cell death. CONCLUSIONS: Plumbagin inhibited in vitro and in vivo glioma growth via targeting NQO1/GPX4-mediated ferroptosis, which might be developed as a novel ferroptosis inducer or anti-glioma candidate.

Alnustone inhibits the growth of hepatocellular carcinoma via ROS- mediated PI3K/Akt/mTOR/p70S6K axis.

Alnustone, a diarylheptane compound, exhibits potent growth inhibition against hepatocellular carcinoma (HCC) BEL-7402 cells. However, the underlying mechanisms associated with its anticancer activity remain unknown. In the present study, we evaluated the anticancer effect of alnustone against several human cancers focused on HCC and the possible associated mechanisms. The results showed that alnustone significantly inhibited the growth of several cancer cells by CCK-8 assay. Alnustone markedly induced apoptosis and decreased mitochondrial membrane potential in BEL-7402 and HepG2 cells. Alnustone inhibited the expression of proteins related to apoptosis and PI3K/Akt/mTOR/p70S6K pathways and generated ROS production in BEL-7402 and HepG2 cells. Moreover, N-acetyl-L-cysteine (NAC, a ROS inhibitor) could significantly reverse the effects of alnustone on the growth inhibition of BEL-7402 and HepG2 cells and the expression of proteins related to apoptosis and PI3K/Akt/mTOR signaling pathway in HepG2 cells. Furthermore, alnustone significantly inhibited tumor growth of HepG2 xenografts, obviously induced apoptosis in the tumor tissues and improved the pathological condition of liver tissues of mice in vivo. The study provides evidence that alnustone is effective against HCC via ROS-mediated PI3K/Akt/mTOR/p70S6K pathway and the compound has the potential to be developed as a novel anticancer agent for the treatment of HCC clinically.

Regulation of cell signaling pathways by Schisandrin in different cancers: Opting for "Swiss Army Knife" instead of "Blunderbuss".

There has been an exponential growth in the field of molecular oncology and cutting-edge research has enabled us to develop a better understanding of therapeutically challenging nature of cancer. Based on the mechanistic insights garnered from decades of research, puzzling mysteries of multifaceted nature of cancer have been solved to a greater extent. Our rapidly evolving knowledge about deregulated oncogenic cell signaling pathways has allowed us to dissect different oncogenic transduction cascades which play critical role in cancer onset, progression and metastasis. Pharmacological targeting of deregulated pathways has attracted greater than ever attention in the recent years. Henceforth, discovery and identification of high-quality biologically active chemicals and products is gaining considerable momentum. There has been an explosion in the dimension of natural product research because of tremendous potential of chemopreventive and pharmaceutical significance of natural products. Schisandrin is mainly obtained from Schisandra chinensis. Schisandrin has been shown to be effective against different cancers because of its ability to inhibit/prevent cancer via modulation of different cell signaling pathways. Importantly, regulation of non-coding RNAs by schisandrin is an exciting area of research that still needs detailed and comprehensive research.   However, we still have unresolved questions about pharmacological properties of schisandrin mainly in context of its regulatory role in TGF/SMAD, SHH/GLI, NOTCH and Hippo pathways.

Mere15, a novel polypeptide from Meretrix meretrix, inhibits proliferation and metastasis of human non-small cell lung cancer cells through regulating the PI3K/Akt/mTOR signaling pathway.

Mere15, an anticancer polypeptide with a molecular weight of 15 kDa, is extracted from the marine species Meretrix meretrix. A previous study in our laboratory has confirmed that Mere15 displays a potent antitumor activity. However, the underlying mechanism of Mere15 still remains unclear. The effect of Mere15 on the growth of a variety of tumor cells was measured by the CCK-8 assay. Hoechst33342/PI double staining and flow cytometry assays were used to detect the apoptosis status of cancer cells. Western blotting was used to detect the expression of apoptosis-related proteins, migration and invasion-related protein, and the changes in the PI3K/Akt/mTOR signaling pathway-related proteins. Treatment with Mere15 inhibited cancer cell growth significantly. Scratch wound-healing assay, as well as Transwell experiments, revealed that the polypeptide was able to inhibit the invasion and migration of NSCLC cells significantly. Western blotting analysis confirmed that treatment with Mere15 inhibited the phosphorylation of PI3K, Akt, and mTOR significantly. The effects of Mere15 were also evaluated in the presence of an activator or inhibitor of the PI3K/Akt/mTOR pathway. Downregulated expression of MMP-2, MMP-9, and Snail, and increased expression of E-cadherin were also found in cells treated with Mere15. In vivo study revealed that Mere15 inhibited tumor growth significantly in xenograft nude mice bearing NCI-H460 cancer cells. The study provides evidence that Mere15 has the potential to be developed as a novel antimetastatic agent for the treatment of NSCLC patients. The work also provides further evidence that targeting PI3K/Akt/mTOR pathway is an important strategy for overcoming cancer metastasis.

Marine Bromophenol Bis(2,3,6-Tribromo-4,5-Dihydroxybenzyl)ether Inhibits Angiogenesis in Human Umbilical Vein Endothelial Cells and Reduces Vasculogenic Mimicry in Human Lung Cancer A549 Cells.

Angiogenesis, including the growth of new capillary blood vessels from existing ones and the malignant tumors cells formed vasculogenic mimicry, is quite important for the tumor metastasis. Anti-angiogenesis is one of the significant therapies in tumor treatment, while the clinical angiogenesis inhibitors usually exhibit endothelial cells dysfunction and drug resistance. Bis(2,3,6-tribromo-4,5-dihydroxybenzyl)ether (BTDE), a marine algae-derived bromophenol compound, has shown various biological activities, however, its anti-angiogenesis function remains unknown. The present study illustrated that BTDE had anti-angiogenesis effect in vitro through inhibiting human umbilical vein endothelial cells migration, invasion, tube formation, and the activity of matrix metalloproteinases 9 (MMP9), and in vivo BTDE also blocked intersegmental vessel formation in zebrafish embryos. Moreover, BTDE inhibited the migration, invasion, and vasculogenic mimicry formation of lung cancer cell A549. All these results indicated that BTDE could be used as a potential candidate in anti-angiogenesis for the treatment of cancer.

Progress of Bromophenols in Marine Algae from 2011 to 2020: Structure, Bioactivities, and Applications.

Marine algae contain various bromophenols that have been shown to possess a variety of biological activities, including antiradical, antimicrobial, anticancer, antidiabetic, anti-inflammatory effects, and so on. Here, we briefly review the recent progress of these marine algae biomaterials and their derivatives from 2011 to 2020, with respect to structure, bioactivities, and their potential application as pharmaceuticals.

Regulation of signaling pathways by ß-elemene in cancer progression and metastasis.

Entry of ß-elemene into various phases of clinical trials advocates its significance as a premium candidate likely to gain access to mainstream medicine. Based on the insights gleaned from decades of research, it seems increasingly transparent that ß-elemene has shown significant ability to modulate multiple cell signaling pathways in different cancers. We partition this multicomponent review into how ß-elemene strategically modulates various signal transduction cascades. We have individually summarized regulation of tumor necrosis factor related apoptosis-inducing ligand, signal transducers and activators of transcription, transforming growth factor/SMAD, NOTCH, and mammalian target of rapamycin pathways by ß-elemene. Last, we will discuss the results of clinical trials of ß-elemene and how effectively we can use these findings to stratify patients who can benefit most from ß-elemene.

Aqueous extract of clove inhibits tumor growth by inducing autophagy through AMPK/ULK pathway.

Cloves (Syzygium aromaticum), a traditional Chinese medicinal herb, displays broad biological activity. In the present study, the aqueous extract of clove (AEC) was prepared, and its anticancer affects were studied. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetra-zolium (MTS) analysis revealed that AEC was able to inhibit cancer cell growth in vitro on several cancer cell lines; the IC50 is around 150 µg/ml for human pancreatic ASPC-1 and human colon HT-29 cancer cells. Treatment of the cancer cells with AEC also diminished the colony formation significantly in both human pancreatic ASPC-1 cancer cells and human colon HT-29 cancer cells. In vivo study revealed that AEC inhibited the tumor growth significantly in HT-29 xenograft mice model. Transmission electron microscope, flow cytometry assay, and fluorescence microscope analysis confirmed that AEC is capable of inducing cell autophagy. Further study showed that AMPK/ULK pathway plays an important role in AEC-induced autophagy in cancer cells. Analysis of AEC components was performed by liquid chromatograph mass spectrometer approach, and more than nine constitutes were identified in AEC fraction. The study provides evidence that AEC has potential to be developed as a novel anticancer agent or as an adjuvant in cancer chemotherapy.

Piperlongumine as anticancer agent: The story so far about killing many birds with one stone.

Piperlongumine is a biologically and pharmacologically active constituent of the plant Piper longum. This compound is gradually gaining attention because of its ability to inhibit/prevent different cancers. Modern era of molecular oncology is incomplete without ground-breaking discoveries made in the field of cell signaling pathways. High-throughput technologies have considerably improved our understanding about wide ranging signal transduction cascades which play crucial role in cancer development and progression. It is exciting to note that piperlongumine has been shown to pleiotropically modulate different oncogenic signaling pathways. We partition this multi-component review into discrete sections and categorically summarize key findings related to excellent ability of piperlongumine to therapeutically target JAK-STAT, NF-kB and PI3K/AKT/mTOR pathways. We also set spotlight on regulation of TRAIL pathway and autophagy by piperlongumine in different cancers. On the basis of the current understanding of piperlongumine, molecular biologists and pharmacologists will develop the next generation of translational studies, which will prove to be helpful in improving the clinical outcome and getting a step closer to personalized medicine.

Maslinic acid as an effective anticancer agent.

Maslinic acid (2α,3ß-dihydroxyolean-12-en-28-oic acid) is a naturally occurring pentacyclic triterpenic compound. Maslinic acid is gradually gaining attention as an excellent pharmacologically active product because of its premium biological properties. In this review we will focus on chemopreventive properties of Maslinic acid against different cancers. Seemingly, available data is limited and we have yet to unravel how Maslinic acid therapeutically targeted oncogenic cell signal transduction cascades in different cancers. Moreover, there are visible knowledge gaps about the ability of Maslinic acid to modulate oncogenic and tumor suppressor microRNAs in various cancers.

Maslinic acid induces autophagy by down-regulating HSPA8 in pancreatic cancer cells.

Maslinic acid (MA), a natural pentacyclictriterpene, displays cytotoxic activity on various types of cancer cells. However, its underlying mechanism is unclear. In this study, we assessed the effect of MA on autophagy of human pancreatic cancer cells, and the potential autophagic pathway was presented. MA inhibited the proliferation and induced autophagy of Panc-28 cells by altering the expressions of autophagy related proteins. SDS-PAGE analysis revealed that one protein band was significantly down-regulated in cells treated with MA, and the band was identified as heat shock protein HSPA8 as analyzed using Western blot and MS, MS/MS approaches. HSPA8 knockdown could significantly inhibit cell viability and enhance the cytotoxic effects of MA, whereas HSPA8 overexpression was able to enhance cell viability, diminishing the effects of MA. Western blot analysis indicated that the effect of MA on the expression of autophagy related genes was increased significantly in cells treated with HSPA8 inhibitor VER-155008, whereas HSPA8 inducer geranylgeranylacetone antagonized the effects of MA. Our study provides evidence that MA is able to induce of autophagy via down-regulation of HSPA8 in Panc-28 cells.

Granulin A Synergizes with Cisplatin to Inhibit the Growth of Human Hepatocellular Carcinoma.

Cisplatin is one of the most potent chemotherapy drugs widely used for cancer treatment. However, due to resistance and toxicity, the application of cisplatin for the treatment of hepatocellular carcinoma (HCC) is limited. Our previous study has shown that granulin A (GRN A), an anticancer peptide, is able to interact with enolase1 (ENO1) and inhibit the growth of HCC in vitro. In the present study, we studied the synergistic effect of the combination of cisplatin and GRN A for the inhibitory effect on HCC. An 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and Chou-Talalay approaches revealed that the combination of GRN A and cisplatin displayed potent synergistic effect. The colony formation and cell viability of HCC cells were inhibited significantly in cells treated with the combination of cisplatin and GRN A, compared with cells treated with cisplatin or GRN A alone. Overexpression of ENO1 diminished the synergistic effect of GRN A and cisplatin in HCC cells. The combination of the two drugs exhibited a more obvious inhibitory effect on cancer cell apoptosis, as analyzed by the cytometry flow, mitochondrial membrane potential (MMP) and western blot analysis. An in vivo study confirmed that the combined use of the two drugs displayed more potent antitumor activity compared to mice treated with cisplatin and GRN A alone; the inhibitory rate of tumor growth was 65.46% and 68.94%, respectively, in mice treated with GRN A and cisplatin. However, the inhibitory rate increased to 86.63% in mice treated with the combination of the two drugs. This study provides evidence that the combination of GRN A and cisplatin is able to sensitize the liver cancer to cisplatin, and that targeting ENO1 is a promising approach for enhancing the antitumor activity of cisplatin.

Preparation and Antitumor Activity of CS5931, A Novel Polypeptide from Sea Squirt Ciona Savignyi.

CS5931 is a novel anticancer agent isolated from the sea squirt Ciona savignyi. However, its content in the species is very low, and developing a novel approach for production of the polypeptide is promising. In the present study, we expressed and purified the polypeptide from E. coli, and the fermentation conditions were studied using response surface methodology. The yield of CS5931 was increased from 2.0 to 7.5 mg/L. The denaturing and renaturation conditions were also studied. Using the optimized renaturation condition, the anticancer activity of refolding CS5931 was increased significantly; the value of IC50 was decreased from 23.2 to 11.6 µM. In vivo study using xenograft nude mice bearing HCT116 cancer cells revealed that CS5931 was able to inhibit the growth of tumor significantly. The study provides a useful approach for obtaining enough amount of CS5931 for further study. This study is also important for developing the polypeptide as a novel anticancer agent.

[Progress of marine anticancer agents targeting cellular proapoptotic molecules].

Apoptosis, a form of programmed cell death, is a critical defense mechanism against the formation and progression of cancer. In vivo, apoptosis functions to eliminate potentially deleterious cells without causing such adverse effects as inflammatory response, and to ensue scar formation. Therefore, activation of the apoptotic pathways becomes an intriguing strategy in the development of chemotherapeutic agents. Marine natural products have become an important source in the discovery of antitumor drugs now since it is more and more feasible to collect organisms from seas. Hundreds of marine compounds have been found to induce apoptosis in tumor cells in recent years and many of them have good antitumor activity. This review summarizes several such compounds, based on their effects on the apoptotic signaling pathways, and highlights the problems in the development of anti-cancer drugs from the natural products.

Cardamonin induces apoptosis by suppressing STAT3 signaling pathway in glioblastoma stem cells.

Glioblastoma stem cells (GSCs) are the initiating cells in glioblastoma multiforme (GBM) and contribute to the resistance of GBM to chemotherapy and radiation. In the present study, we investigated the effects of cardamonin (3,4,2,4-tetrahydroxychalcone) on the self-renewal and apoptosis of GSCs, and if its action is associated with signal transducer and activator of transcription 3 (STAT3) pathway. CD133(+) GSCs, a kind of GSCs line, was established from human glioblastoma tissues. Cardamonin inhibited the proliferation and induced apoptosis in CD133+ GSCs. The proapoptotic effects of temozolomide (TMZ) were further enhanced by cardamonin in CD133+ GSCs and U87 cells in vitro. For in vivo study, injection of 5 × 10(5) cells of CD133+ GSCs subcutaneously (s.c.) into nude mice, 100 % of large tumors were developed within 8 weeks in all mice; in contrast, only one out of five mice developed a small tumor when 5 × 10(5) cells of CD133(-) GMBs cells were injected. Cardamonin also inhibited STAT3 activation by luciferase assay and suppressed the expression of the downstream genes of STAT3, such as Bcl-XL, Bcl-2, Mcl-1, survivin, and VEGF. Furthermore, cardamonin locked nuclear translocation and dimerization of STAT3 in CD133(+) GSCs. Docking analysis confirmed that cardamonin molecule was successfully docked into the active sites of STAT3 with a highly favorable binding energy of -10.78 kcal/mol. The study provides evidence that cardamonin is a novel inhibitor of STAT3 and has the potential to be developed as a new anticancer agent targeting GSCs. This study also reveals that targeting STAT3 signal pathway is an important strategy for the treatment of human GBM.

Cytotoxicity of the compounds isolated from Pulsatilla chinensis saponins and apoptosis induced by 23-hydroxybetulinic acid.

CONTEXT: The rizoma of Pulsatilla chinensis (Bunge) Regel has been used as a traditional Chinese medicinal herb for thousands of years. Total saponins from P. chinensis can induce the apoptosis of solid cancer cells; however, their activity on chronic myeloid leukemia and the mechanisms remains unknown. OBJECTIVE: To study the activity of total saponins and the main active fractions from P. chinensis saponins on chronic myeloid leukemia, and to illustrate the mechanisms underlying the anticancer activities. MATERIALS AND METHODS: The cytotoxic activity were assayed by MTT; cell cycle arrest and apoptosis were tested by flow cytometry system; changes in the mitochondrial membrane potential were determined using JC-1; and the apoptosis signaling pathway was determined by western blotting. RESULTS: We demonstrated that total P. chinensis saponin displayed cytotoxic activity against K562 cell line. In addition, we identified 23-hydroxybetulinic acid (HBA), pulchinenoside A (PA), and anemoside B4 (AB4) from the total saponins, with the most cytotoxic compound HBA. Glycosylation at C3 and C28 of HBA significantly reduces its cytotoxicity. HBA could promote cell cycle arrest at S phase and induce apoptosis via intrinsic pathway. HBA disrupts mitochondrial membrane potential significantly (p < 0.01) and selectively downregulates the levels of Bcl-2, survivin and upregulates Bax, cytochrome C, cleaved caspase-9 and -3. DISCUSSION AND CONCLUSION: Total saponins from P. chinensis may be effective natural products against human chronic myelogenous leukemia; HBA is one of the bioactive components responsible for its anticancer activity, and could be further investigated as an alternative therapeutic drug for leukemia.

Targeting cellular apoptotic pathway with peptides from marine organisms.

Apoptosis is a critical defense mechanism against the formation and progression of cancer and exhibits distinct morphological and biochemical traits. Targeting apoptotic pathways becomes an intriguing strategy for the development of chemotherapeutic agents. Peptides from marine organisms have become important sources in the discovery of antitumor drugs, especially when modern technology makes it more and more feasible to collect organisms from seas. This primer summarizes several marine peptides, based on their effects on apoptotic signaling pathways, although most of these peptides have not yet been studied in depth for their mechanisms of action. Novel peptides that induce an apoptosis signal pathway are presented in association with their pharmacological properties.