Sinularin induces DNA damage, G2/M phase arrest, and apoptosis in human hepatocellular carcinoma cells

Construction of lncRNA prognostic model related to disulfidptosis in lung adenocarcinoma

Background

Lung cancer is one of the malignant tumors with the highest rates of morbidity and mortality worldwide. One of the most common histological types of lung cancer is lung adenocarcinoma (LUAD). Despite the fact that development in medicine has significantly improved some patients' prognoses, the overall survival (OS) rate is still very low. In glucose-deficient SLC7A11-overexpressed cancer cells, the accumulation of disulfide molecules leads to abnormal disulfide bonding between actin cytoskeletal proteins, interferes with their tissues, and eventually leads to actin network collapse and cell death. This mode of cell death is called disulfidptosis. Studies have shown that disulfidptosis may be a new target for cancer treatment. However, the role of disulfidptosis in LUAD is still unknown.

Methods

LUAD transcriptome and clinical information from The Cancer Genome Atlas (TCGA) was downloaded. The co-expression analysis, Least Absolute Shrinkage and Selection Operator (LASSO) regression, and Cox regression analysis was performed to screen the disulfidptosis-related lncRNAs (DRLs) and build the prognostic model. Kaplan-Meier curve, Cox regression analysis, and receiver operating characteristic (ROC) curve was used to validate the model. Then a nomogram is made to predict the prognosis of LUAD patients. Finally, fresh-collected clinical samples were used to verify the expression of DRLs in LUAD.

Results

The prognostic model with six DRLs was developed to predict the prognosis of LUAD, with superior prognosis value compared to other clinical variables. The Cox regression analysis revealed that T stage, N stage and the risk score were identified as independent variables that affected LUAD prognosis. ROC curve revealed that the model has a moderate diagnostic value, with an AUC of 1-year 0.684, 3-year 0.664, and 5-year 0.588. Moreover, nine medications connected to LUAD treatment were acquired through drug sensitivity analysis. LUAD tissue validation showed that AC012073.1, AC012615.1, EMSLR, and SNHG12 were highly expressed, while AL606834.1 and AL365181.2 with low expression.

Conclusion

Six DRLs were screened and verified to construct the prognostic model, which can accurately predict the LUAD prognosis. It establishes a basis for further exploration into the molecular mechanisms underlying LUAD and identification of potential biomarkers for diagnosis, prognosis, and therapeutic targets.

A network pharmacology- and transcriptomics-based investigation reveals an inhibitory role of β-sitosterol in glioma via the EGFR/MAPK signaling pathway

Glioma is characterized by rapid cell proliferation, aggressive invasion, altered apoptosis and a poor prognosis. β-Sitosterol, a kind of phytosterol, has been shown to possess anticancer activities. Our current study aims to investigate the effects of β-sitosterol on gliomas and reveal the underlying mechanisms. Our results show that β-sitosterol effectively inhibits the growth of U87 cells by inhibiting proliferation and inducing G2/M phase arrest and apoptosis. In addition, β-sitosterol inhibits migration by downregulating markers of epithelial-mesenchymal transition (EMT). Mechanistically, network pharmacology and transcriptomics approaches illustrate that the EGFR/MAPK signaling pathway may be responsible for the inhibitory effect of β-sitosterol on glioma. Afterward, the results show that β-sitosterol effectively suppresses the EGFR/MAPK signaling pathway. Moreover, β-sitosterol significantly inhibits tumor growth in a U87 xenograft nude mouse model. β-Sitosterol inhibits U87 cell proliferation and migration and induces apoptosis and cell cycle arrest in U87 cells by blocking the EGFR/MAPK signaling pathway. These results suggest that β-sitosterol may be a promising therapeutic agent for the treatment of glioma.

Michelia compressa-Derived Santamarine Inhibits Oral Cancer Cell Proliferation via Oxidative Stress-Mediated Apoptosis and DNA Damage

The anti-oral cancer effects of santamarine (SAMA), a Michelia compressa var. compressa-derived natural product, remain unclear. This study investigates the anticancer effects and acting mechanism of SAMA against oral cancer (OC-2 and HSC-3) in parallel with normal (Smulow-Glickman; S-G) cells. SAMA selectively inhibits oral cancer cell viability more than normal cells, reverted by the oxidative stress remover N-acetylcysteine (NAC). The evidence of oxidative stress generation, such as the induction of reactive oxygen species (ROS) and mitochondrial superoxide and the depletion of mitochondrial membrane potential and glutathione, further supports this ROS-dependent selective antiproliferation. SAMA arrests oral cancer cells at the G2/M phase. SAMA triggers apoptosis (annexin V) in oral cancer cells and activates caspases 3, 8, and 9. SAMA enhances two types of DNA damage in oral cancer cells, such as γH2AX and 8-hydroxy-2-deoxyguanosine. Moreover, all of these anticancer mechanisms of SAMA are more highly expressed in oral cancer cells than in normal cells in concentration and time course experiments. These above changes are attenuated by NAC, suggesting that SAMA exerts mechanisms of selective antiproliferation that depend on oxidative stress while maintaining minimal cytotoxicity to normal cells.

Sinularin stabilizes FOXO3 protein to trigger prostate cancer cell intrinsic apoptosis

Sinularin, a natural product that purified from soft coral, exhibits anti-tumor effects against various human cancers. However, the mechanisms are not well understood. In this study, we demonstrated that Sinularin inhibited the viability of human prostate cancer cells in a dose-dependent manner and displayed significant cytotoxicity only at high concentration against normal prostate epithelial cell RWPE-1. Flow cytometry assay demonstrated that Sinularin induced tumor cell apoptosis. Further investigations revealed that Sinularin exerted anti-tumor activity through intrinsic apoptotic pathway along with up-regulation of pro-apoptotic protein Bax and PUMA, inhibition of anti-apoptotic protein Bcl-2, mitochondrial membrane potential collapses, and release of mitochondrial proteins. Furthermore, we illustrated that Sinularin induced cell apoptosis via up-regulating PUMA through inhibition of FOXO3 degradation by the ubiquitin-proteasome pathway. To explore how Sinularin suppress FOXO3 ubiquitin-proteasome degradation, we tested two important protein kinases AKT and ERK that regulate FOXO3 stabilization. The results revealed that Sinularin stabilized and up-regulated FOXO3 via inhibition of AKT- and ERK1/2-mediated FOXO3 phosphorylation and subsequent ubiquitin-proteasome degradation. Our findings illustrated the potential mechanisms by which Sinularin induced cell apoptosis and Sinularin may be applied as a therapeutic agent for human prostate cancer.

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

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

Biological activity of recombinant human PDX1 protein produced from Escherichia coli

Pancreatic and duodenum homeobox 1 (PDX1) is considered as a pivotal transcription factor that acts as a "master regulator" in pancreatogenesis and maintenance of β-cells. Earlier study has reported that PDX1 also functions as a tumor suppressor in human gastric cancer cells by inhibiting cell growth. Here, we report the bioactivity of the purified human PDX1 fusion protein using various assays like cell migration, proliferation, cell cycle analysis, and gene expression. In cancer cells, recombinant PDX1 protein reduced cell migration and proliferation, and arrested cell growth by inducing apoptosis in gastric cancer cells. In pancreatic ductal cancer cells, the application of the PDX1 protein resulted in the induction of insulin gene expression. The results of these experiments demonstrate the biological activity imparted by recombinant human PDX1 fusion protein on gastric and pancreatic cancer cells and its usefulness as a biological tool to elucidate its function in various cellular processes.

A comparative study of novel ruthenium(III) and iron(III) complexes containing uracil; docking and biological studies

Structural and biological studies were conducted on the novel complexes [Fe(U)2(H2O)2]Cl3 (FeU) and [Ru(U)2(H2O)2]Cl3 (RuU) (U = 5,6-Diamino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione) to develop an anticancer drug candidate. The two complexes have been synthesized and characterized. Based on our findings, these complexes have octahedral geometry. The DNA-binding study proved that both complexes coordinated with CT-DNA. The docking study confirmed the potency of both complexes in downregulating the topoisomerase I protein through their high binding affinity. Biological studies have established that both complexes can act as potent anticancer agents against three cancer cell lines. RuU or FeU complexes induce apoptosis in breast cancer cells by increasing caspase9 protein and inhibiting proliferating cell nuclear antigen (PCNA) activity. In addition, both complexes down-regulate topoisomerase I expression in breast cancer cells. Therefore, the RuU and FeU complexes' anticancer activities were mediated via both apoptosis induction and topoisomerase I down-regulation. In conclusion, both complexes have dual anticancer activity pathways that may be responsible for the selective cytotoxicity of the complexes. This makes them more suitable for the development of novel cancer treatment strategies.

Sinularin Induces Oxidative Stress-Mediated Apoptosis and Mitochondrial Dysfunction, and Inhibits Angiogenesis in Glioblastoma Cells

Glioblastoma multiforme (GBM) is a cancer of largely unknown cause that leads to a 5-year survival rate of approximately 7% in the United States. Current treatment strategies are not effective, indicating a strong need for the development of novel therapies. In this study, the outcomes of sinularin, a marine-derived product, were evaluated against GBM. Our cellular studies using GBM cells revealed that sinularin induces cell death. The measured half maximal inhibitory concentrations (IC50) values ranged from 30 to 6 μM at 24-72 h. Cell death was induced via the generation of ROS leading to mitochondria-mediated apoptosis. This was evidenced by annexin V/propidium iodine staining and an upregulation of cleaved forms of the pro-apoptotic proteins caspase 9, 3, and PARP, and supported by CellROXTM Green, MitoSOXTM Red, and CM-H2DCFDA staining methods. In addition, we observed a downregulation of the antioxidant enzymes SOD1/2 and thioredoxin. Upon treatment with sinularin at the ~IC50 concentration, mitochondrial respiration capacities were significantly reduced, as shown by measuring the oxygen consumption rates and enzymatic complexes of oxidative phosphorylation. Intriguingly, sinularin significantly inhibited indicators of angiogenesis such as vessel tube formation, cell migration, and cell mobility in human umbilical vein endothelial cells or the fusion cell line EA.Hy926. Lastly, in a transgenic zebrafish model, intersegmental vessel formation was also significantly inhibited by sinularin treatment. These findings indicate that sinularin exerts anti-brain cancer properties that include apoptosis induction but also antiangiogenesis.

The Effect of Encapsulated Apigenin Nanoparticles on HePG-2 Cells through Regulation of P53

Apigenin (Ap) is one of the most important natural flavonoids that has potent anticancer activity. This study was designed, for the first time, to load Ap into chitosan to improve its hydrophobicity and then it was coated with albumin-folic acid to increase its stability and bioavailability and to target cancer cells. The newly developed encapsulated Ap (Ap-CH-BSA-FANPs) was characterized and tested in vitro. The zeta potential of −17.0 mV was within the recommended range (−30 mV to +30 mV), indicating that encapsulated apigenin would not quickly settle and would be suspended. The in vitro results proved the great anticancer activity of the encapsulated apigenin on HePG-2 cells compared to pure Ap. The treated HePG-2 cells with Ap-CH-BSA-FANPs demonstrated the induction of apoptosis by increasing p53 gene expression, arresting the cell cycle, increasing caspase-9 levels, and decreasing both the MMP9 gene and Bcl-2 protein expression levels. Moreover, the higher antioxidant activity of the encapsulated apigenin treatment was evident through increasing SOD levels and decreasing the CAT concentration. In conclusion, the Ap-CH-BSA-FANPs were easy to produce with low coast, continued drug release, good loading capacity, high solubility in physiological pH, and were more stable than the formerly Ap-loaded liposomes or PLGA. Moreover, Ap-CH-BSA-FANPs may be a promising chemotherapeutic agent in the treatment of HCC.

2-Methoxy-5((3,4,5-trimethosyphenyl) seleninyl) phenol causes G2/M cell cycle arrest and apoptosis in NSCLC cells through mitochondrial apoptotic pathway and MDM2 inhibition

Nonsmall cell lung cancer (NSCLC) is one of the most common malignancies and needs novel and effective chemotherapy. In this study, our purpose is to explore the anticancer effects of 2-methoxy-5((3,4,5-trimethosyphenyl) seleninyl) phenol (SQ) on human NSCLC (A549 and H460) cells. We found that SQ suppressed the proliferation of NSCLC cells in time- and dose-dependent manners, and blocked the cells at G2/M phase, which was relevant to microtubule depolymerization. Additionally, SQ induced A549 and H460 cell apoptosis by activating the mitochondrial apoptotic pathway. Further, we demonstrated that SQ enhanced the generation of reactive oxygen species (ROS), and pretreatment with N-acetyl- L-cysteine (NAC) attenuated SQ-induced cell apoptosis. Meanwhile, SQ mediated-ROS generation caused DNA damage in A549 and H460 cells. Our data also revealed that SQ-induced apoptosis was correlated with the inhibition of mouse double minute 2 (MDM2) in A549 and H460 cells. In summary, our research indicates that the novel compound SQ has great potential for therapeutic treatment of NSCLC in future.

In vitro and in vivo evaluation of antioxidant and neuroprotective properties of antipsychotic D2AAK1

The susceptibility of neurons to free radical toxicity partially underlies the pathomechanism of neurodegenerative diseases. On the other hand, excitotoxicity also contributes to neurodegeneration. Our previous studies demonstrated the unique properties of D2AAK1 as a potent multi-target ligand of aminergic G protein-coupled receptors (GPCRs) which dose-dependently stimulates growth, survival of neurons, and promotes their integrity. The aim of our study was to investigate the potential neuroprotective and antioxidant properties of D2AAK1. Here we show that D2AAK1 activates cellular and molecular neuroprotective mechanisms, prevents cells from excitotoxicity and free radicals. Furthermore, D2AAK1 induced no genotoxic events in neuronal cells in vitro. Most importantly, D2AAK1 protects neurons from the effects of high temperatures by molecular chaperones activation. The D2AAK1 effects on selected organs was further evaluated in mice and no pathological changes were observed after chronic administration. In the light of our experiments, D2AAK1 can be further developed into a potential treatment for neurodegenerative diseases, in particular related to memory impairment. In summary, D2AAK1 has promising properties for potential treatments of neurodegenerative diseases.

Developing natural marine products for treating liver diseases

In recent years, marine-derived bioactive compounds have gained increasing attention because of their higher biodiversity vs land-derived compounds. A number of marine-derived compounds are proven to improve lipid metabolism, modulate the gut microbiota, and possess anti-inflammatory, antioxidant, antibacterial, antiviral, and antitumor activities. With the increasing understanding of the molecular landscape underlying the pathogenesis of chronic liver diseases, interest has spiked in developing new therapeutic drugs and medicine food homology from marine sources for the prevention and treatment of liver diseases.

Cytotoxic Compounds from Alcyoniidae: An Overview of the Last 30 Years

The octocoral family Alcyoniidae represents a rich source of bioactive substances with intriguing and unique structural features. This review aims to provide an updated overview of the compounds isolated from Alcyoniidae and displaying potential cytotoxic activity. In order to allow a better comparison among the bioactive compounds, we focused on molecules evaluated in vitro by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, by far the most widely used method to analyze cell proliferation and viability. Specifically, we surveyed the last thirty years of research, finding 153 papers reporting on 344 compounds with proven cytotoxicity. The data were organized in tables to provide a ranking of the most active compounds, to be exploited for the selection of the most promising candidates for further screening and pre-clinical evaluation as anti-cancer agents. Specifically, we found that (22S,24S)-24-methyl-22,25-epoxyfurost-5-ene-3β,20β-diol (16), 3β,11-dihydroxy-24-methylene-9,11-secocholestan-5-en-9-one (23), (24S)-ergostane-3β,5α,6β,25 tetraol (146), sinulerectadione (227), sinulerectol C (229), and cladieunicellin I (277) exhibited stronger cytotoxicity than their respective positive control and that their mechanism of action has not yet been further investigated.

Carnosic Acid Induces Antiproliferation and Anti-Metastatic Property of Esophageal Cancer Cells via MAPK Signaling Pathways

Background

Carnosic acid (CA) is a polyphenolic diterpene extracted from rosemary. Reports have shown that CA possesses anticancer activity. However, whether CA inhibits esophageal squamous cell carcinoma, an aggressive type of esophageal cancer, remains untested.

Methods

The effects of CA on cell survival, migration, and apoptosis were evaluated by a combination of MTT, colony formation assay, flow cytometry, and Transwell assay. The potential signaling pathways involved were investigated via Western blot assay.

Results

CA dose-dependently inhibited cell proliferation, apoptosis, migration, and colony formation. Mechanistically, CA arrested the cell cycle at G2/M phase, promoted cell apoptosis, induced DNA damage, and inhibited the MAPK signaling pathways.

Conclusion

Our results suggest that CA is a potential anticancer drug for esophageal squamous cell carcinoma.

Soft Coral-Derived Dihydrosinularin Exhibits Antiproliferative Effects Associated with Apoptosis and DNA Damage in Oral Cancer Cells

Dihydrosinularin (DHS) is an analog of soft coral-derived sinularin; however, the anticancer effects and mechanisms of DHS have seldom been reported. This investigation examined the antiproliferation ability and mechanisms of DHS on oral cancer cells. In a cell viability assay, DHS showed growth inhibition against several types of oral cancer cell lines (Ca9-22, SCC-9, OECM-1, CAL 27, OC-2, and HSC-3) with no cytotoxic side effects on non-malignant oral cells (HGF-1). Ca9-22 and SCC-9 cell lines showing high susceptibility to DHS were selected to explore the antiproliferation mechanisms of DHS. DHS also causes apoptosis as detected by annexin V, pancaspase, and caspase 3 activation. DHS induces oxidative stress, leading to the generation of reactive oxygen species (ROS)/mitochondrial superoxide (MitoSOX) and mitochondrial membrane potential (MitoMP) depletion. DHS also induced DNA damage by probing γH2AX phosphorylation. Pretreatment with the ROS scavenger N-acetylcysteine (NAC) can partly counter these DHS-induced changes. We report that the marine natural product DHS can inhibit the cell growth of oral cancer cells. Exploring the mechanisms of this cancer cell growth inhibition, we demonstrate the prominent role DHS plays in oxidative stress.

Comparison of Antioxidant and Anticancer Properties of Soft Coral-Derived Sinularin and Dihydrosinularin

Marine natural products are abundant resources for antioxidants, but the antioxidant property of the soft corals-derived sinularin and dihydrosinularin were unknown. This study aimed to assess antioxidant potential and antiproliferation effects of above compounds on cancer cells, and to investigate the possible relationships between them. Results show that sinularin and dihydrosinularin promptly reacted with 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS), and hydroxyl (^•OH), demonstrating a general radical scavenger activity. Sinularin and dihydrosinularin also show an induction for Fe⁺³-reduction and Fe⁺²-chelating capacity which both strengthen their antioxidant activities. Importantly, sinularin shows higher antioxidant properties than dihydrosinularin. Moreover, 24 h ATP assays show that sinularin leads to higher antiproliferation of breast, lung, and liver cancer cells than dihydrosinularin. Therefore, the differential antioxidant properties of sinularin and dihydrosinularin may contribute to their differential anti-proliferation of different cancer cells.

Oxidative Stress-Dependent Synergistic Antiproliferation, Apoptosis, and DNA Damage of Ultraviolet-C and Coral-Derived Sinularin Combined Treatment for Oral Cancer Cells

Combined treatment is increasingly used to improve cancer therapy. Non-ionizing radiation ultraviolet-C (UVC) and sinularin, a coral Sinularia flexibilis-derived cembranolide, were separately reported to provide an antiproliferation function to some kinds of cancer cells. However, an antiproliferation function using the combined treatment of UVC/sinularin has not been investigated as yet. This study aimed to examine the combined antiproliferation function and explore the combination of UVC/sinularin in oral cancer cells compared to normal oral cells. Regarding cell viability, UVC/sinularin displays the synergistic and selective killing of two oral cancer cell lines, but remains non-effective for normal oral cell lines compared to treatments in terms of MTS and ATP assays. In tests using the flow cytometry, luminescence, and Western blotting methods, UVC/sinularin-treated oral cancer cells exhibited higher reactive oxygen species production, mitochondrial superoxide generation, mitochondrial membrane potential destruction, annexin V, pan-caspase, caspase 3/7, and cleaved-poly (ADP-ribose) polymerase expressions than that in normal oral cells. Accordingly, oxidative stress and apoptosis are highly induced in a combined UVC/sinularin treatment. Moreover, UVC/sinularin treatment provides higher G2/M arrest and γH2AX/8-hydroxyl-2'deoxyguanosine-detected DNA damages in oral cancer cells than in the separate treatments. A pretreatment can revert all of these changes of UVC/sinularin treatment with the antioxidant N-acetylcysteine. Taken together, UVC/sinularin acting upon oral cancer cells exhibits a synergistic and selective antiproliferation ability involving oxidative stress-dependent apoptosis and cellular DNA damage with low toxic side effects on normal oral cells.

Sinularin, an Anti-Cancer Agent Causing Mitochondria-Modulated Apoptosis and Cytoskeleton Disruption in Human Hepatocellular Carcinoma

Liver cancer remains a leading cause of death, despite advances in anti-cancer therapies. To develop novel drugs, natural products are being considered as a good source for exploration. In this study, a natural product isolated from a soft coral was applied to evaluate its anti-cancer activities in hepatocellular carcinoma SK-HEP-1 cells. Sinularin was determined to have half-maximal inhibitory concentration (IC₅₀) values of ~10 μM after 24, 48, and 72 h. The TUNEL assay and annexin V/PI staining results showed that sinularin induced DNA fragmentation and apoptosis, respectively. An investigation at the molecular level demonstrated that the expression levels of cleaved caspases 3/9 were significantly elevated at 10 μM sinularin. Mitochondrial and intracellular reactive oxygen species (ROS) levels were significantly increased following sinularin treatment, which also affected the mitochondrial membrane potential. In addition, it significantly lowered the mitochondrial respiration parameters and extracellular acidification rates at 10 μM. Further investigation showed that sinularin significantly attenuated wound healing, cell migration, and potential colony formation at 10 μM. Fluorescence microscopic observations showed that the distribution of F-actin filaments was significantly altered at 10 μM sinularin. Supported by Western blot analyses, the expression levels of AKT, p-ERK (extracellular-signal-related kinase), vimentin and VEGF were significantly down-regulated, whereas p-p38, pJNK and E-cadherin were significantly increased. Overall, at the IC₅₀ concentration, sinularin was able to significantly affect SK-HEP-1 cells.

Tiliacora racemosa leaves induce oxidative stress mediated DNA damage leading to G2/M phase arrest and apoptosis in cervical cancer cells SiHa

ETHNOPHARMACOLOGICAL RELEVANCE

The Menispermaceae plant Tiliacora racemosa is immensely popular in Indian traditional Ayurvedic medicine as "Krishnavetra" for its remarkable anti-cancerous property, and is commonly used by tribal population for the treatment of skin infections, snake bites and filariasis.

AIM OF THE STUDY

This present study intends to identify the modus operandi behind the cytotoxic activity of Tiliacora racemosa leaves in cervical cancer cells SiHa. Focus has been instilled in the ability of the plant extract to target multiple signaling pathways leading to cell cycle arrest and cell death in SiHa cells, followed by a pharmacological characterization to identify the bioactive principle.

MATERIALS AND METHODS

T. racemosa leaves extracted in methanol, ethyl acetate, hexane and aqueous solvent were screened for cytotoxicity in HeLa, SiHa, C33A (cervical cancer cells) and HEK cells by MTT assay. SiHa cells were treated with the most potent extract (TRM). Cellular morphology, clonogenic and wound healing potential, presence of intracellular ROS and NO, lipid peroxidation, activity of cellular antioxidants (SOD, CAT, GSH), DNA damage detection by comet assay and localisation of γ-H2AX foci, intracellular expression of PARP-1, Bax/Bcl2 and caspase-3, loss in mitochondrial membrane potential by JC1 (flow cytometry) and Rh123 (microscopy), cell cycle analysis, Annexin-FITC assay, AO/EtBr microscopy and apoptotic proteome profiling were undertaken in the treated cells. All the related proteins were studied by immunoblots. Effect of NAC (ROS-scavenger) on cell viability, DNA damage and apoptosis were studied. Phytochemical characterization of all TR extracts was followed by LC-MS analysis of TRM and isolated alkaloid of TR was assessed for cytotoxicity.

RESULTS

The methanol extract of T. racemosa (TRM) rich in bisbenzylisoquinoline and other alkaloids impeded the proliferation of cervical cancer cells SiHa in vitro through disruption of cellular redox homeostasis caused by increase in cellular ROS and NO with concomitant decrease in the cellular antioxidants. Double-stranded DNA damage was noted from γH2AX foci accumulation and Parp-1 activation leading to ATM-Chk2-p53 pathway arresting the cells at G2/M-phase through cyclin B1 inhibition. The mitochondrial membrane potential was also disturbed leading to caspase-3 dependent apoptotic induction by both extrinsic and intrinsic pathway. Immunoblots show TRM also inhibited PI3K/Akt and NFκB pathway. NAC pre-treatment rescued the cell viability proving DNA damage and apoptosis to be direct consequences of ROS overproduction. Lastly, the therapeutic potential of T. racemosa is was hypothesized to be possibly derived from its alkaloid content.

CONCLUSION

This study proves the age old ethnnopharmacological anticancer role of T. racemosa. The leaf extracts inhibited the anomalous proliferation of SiHa cells by virtue of G2/M-phase cell cycle arrest and apoptotic cell death. Oxidative stress mediated double stranded DNA damage paved the way towards apoptotic cell death through multiple routes, including PI3K/Akt/NFκB pathway. The abundant alkaloid content of T. racemosa was denoted as the probable responsible cytotoxic principle.

Anticancer Molecular Mechanism of Protocatechuic Acid Loaded on Folate Coated Functionalized Graphene Oxide Nanocomposite Delivery System in Human Hepatocellular Carcinoma

Liver cancer is listed as the fifth-ranked cancer, responsible for 9.1% of all cancer deaths globally due to its assertive nature and poor survival rate. To overcome this obstacle, efforts have been made to ensure effective cancer therapy via nanotechnology utilization. Recent studies have shown that functionalized graphene oxide (GO)-loaded protocatechuic acid has shown some anticancer activities in both passive and active targeting. The nanocomposites’ physicochemical characterizations were conducted. A lactate dehydrogenase experiment was conducted to estimate the severity of cell damage. Subsequently, a clonogenic assay was carried out to examine the colony-forming ability during long-term exposure of the nanocomposites. The Annexin V/ propidium iodide analysis showed that nanocomposites induced late apoptosis in HepG2 cells. Following the intervention of nanocomposites, cell cycle arrest was ascertained at G2/M phase. There was depolarization of mitochondrial membrane potential and an upregulation of reactive oxygen species when HepG2 cells were induced by nanocomposites. Finally, the proteomic profiling array and quantitative reverse transcription polymerase chain reaction revealed the expression of pro-apoptotic and anti-apoptotic proteins induced by graphene oxide conjugated PEG loaded with protocatechuic acid drug folic acid coated nanocomposite (GOP–PCA–FA) in HepG2 cells. In conclusion, GOP–PCA–FA nanocomposites treated HepG2 cells exhibited significant anticancer activities with less toxicity compared to pristine protocatechuic acid and GOP–PCA nanocomposites, due to the utilization of a folic acid-targeting nanodrug delivery system.

A specific inhibitor of polo-like kinase 1, GSK461364A, suppresses proliferation of Raji Burkitt's lymphoma cells through mediating cell cycle arrest, DNA damage, and apoptosis

Polo-like kinase 1 (PLK1) is a prominent mediatory player during the cell cycle, mitosis, and cytokinesis in eukaryotic cells. Besides its physiological roles, PLK1 expression is upregulated in a wide range of human malignant tumors and its overexpression worsens prognosis, therefore, specific inhibition of PLK1 in tumor cells is a fascinating approach for the development of novel chemotherapeutics. The present study elucidated the potential cytotoxic effects of a PLK1 inhibitor, GSK461364A, in five cancer cell lines including Raji, K562, PC3, MCF-7, MDA-MB-231, along with noncancerous L929 cells by XTT assay. The cells were treated for 24 h with GSK461364A at different concentrations ranged between 0.5 and 40 μM and significant cytotoxicity was observed in all treated groups with the IC50 values between 2.36 and 4.08 μM. GSK461364A was also found to be safer with lower cytotoxicity against L929 cells and the IC50 value was found to be greater than 40 μM. Raji cells were identified as the most sensitive cell line against GSK461364A with the lowest IC50 values, hence it was selected for further studies to evaluate the underlying mechanism of cytotoxic activity. The treatment of Raji cells with GSK461364A caused a cell cycle arrest at the G2/M phase, also altered TOS, which is an indicator of oxidative stress, and DNA damage response, significantly. The Annexin V binding assay revealed that GSK461364A treatment significantly increased in the percentage of early and late apoptotic cells. Fluorescence imaging also showed that GSK461364A treatment significantly induced apoptosis of Raji cells. The apoptotic effect of the compound has also been confirmed by increased expressions of Bax and cleaved caspase 3 and along with the decreased expression of BCL-2. The results demonstrated that GSK461364A induced anticancer effects which was mainly promoted by cell cycle arrest, oxidative stress, DNA damage, and finally apoptosis in Burkitt's lymphoma cells. Taken together, the present results emphasized that GSK461364A could be a useful therapeutic agent in patients with Burkitt's lymphoma. However, further studies are required to consolidate the anticancer activity of this promising compound.

Cyclobutane pyrimidine dimers from UVB exposure induce a hypermetabolic state in keratinocytes via mitochondrial oxidative stress

Ultraviolet B radiation (UVB) is an environmental complete carcinogen, which induces and promotes keratinocyte carcinomas, the most common human malignancies. UVB induces the formation of cyclobutane pyrimidine dimers (CPDs). Repairing CPDs through nucleotide excision repair is slow and error-prone in placental mammals. In addition to the mutagenic and malignancy-inducing effects, UVB also elicits poorly understood complex metabolic changes in keratinocytes, possibly through CPDs. To determine the effects of CPDs, CPD-photolyase was overexpressed in keratinocytes using an N1-methyl pseudouridine-containing in vitro-transcribed mRNA. CPD-photolyase, which is normally not present in placental mammals, can efficiently and rapidly repair CPDs to block signaling pathways elicited by CPDs. Keratinocytes surviving UVB irradiation turn hypermetabolic. We show that CPD-evoked mitochondrial reactive oxygen species production, followed by the activation of several energy sensor enzymes, including sirtuins, AMPK, mTORC1, mTORC2, p53, and ATM, is responsible for the compensatory metabolic adaptations in keratinocytes surviving UVB irradiation. Compensatory metabolic changes consist of enhanced glycolytic flux, Szent-Györgyi-Krebs cycle, and terminal oxidation. Furthermore, mitochondrial fusion, mitochondrial biogenesis, and lipophagy characterize compensatory hypermetabolism in UVB-exposed keratinocytes. These properties not only support the survival of keratinocytes, but also contribute to UVB-induced differentiation of keratinocytes. Our results indicate that CPD-dependent signaling acutely maintains skin integrity by supporting cellular energy metabolism.

Synergistic Effect of α-Solanine and Cisplatin Induces Apoptosis and Enhances Cell Cycle Arrest in Human Hepatocellular Carcinoma Cells

AIM

The clinical application of cisplatin is limited by severe side effects associated with high applied doses. The synergistic effect of a combination treatment of a low dose of cisplatin with the natural alkaloid α-solanine on human hepatocellular carcinoma cells was evaluated.

METHODS

HepG2 cells were exposed to low doses of α-solanine and cisplatin, either independently or in combination. The efficiency of this treatment modality was evaluated by investigating cell growth inhibition, cell cycle arrest, and apoptosis enhancement.

RESULTS

α-solanine synergistically potentiated the effect of cisplatin on cell growth inhibition and significantly induced apoptosis. This synergistic effect was mediated by inducing cell cycle arrest at the G2/M phase, enhancing DNA fragmentation and increasing apoptosis through the activation of caspase 3/7 and/or elevating the expression of the death receptors DR4 and DR5. The induced apoptosis from this combination treatment was also mediated by reducing the expression of the anti-apoptotic mediators Bcl-2 and survivin, as well as by modulating the miR-21 expression.

CONCLUSION

Our study provides strong evidence that a combination treatment of low doses of α-solanine and cisplatin exerts a synergistic anticancer effect and provides an effective treatment strategy against hepatocellular carcinoma.

Apigetrin induces extrinsic apoptosis, autophagy and G2/M phase cell cycle arrest through PI3K/AKT/mTOR pathway in AGS human gastric cancer cell

Apigetrin is a flavonoid glycoside phytonutrient derived from fruits and vegetables that is well known for a variety of biological activities such as antioxidant and anti-inflammatory activities. In the current study, we determined the effect of apigetrin on AGS gastric cancer cell. Apigetrin reduced cancer cell proliferation and induced G2/M phase cell cycle arrest by regulating cyclin B1, cdc25c and cdk1 protein expression in AGS cell. Apigetrin treatment caused apoptotic cell death in AGS cells, characterized by the accumulation of apoptosis portion, cleavage of caspase-3 and poly ADP-ribose polymerase (PARP). Apigetrin-treated cells increased the expression of extrinsic apoptosis pathway proteins and mRNA. However, intrinsic apoptosis pathway related proteins were not altered. In addition, AGS cells treated with apigetrin increased autophagic cell death, featured by the formation of autophagic vacuole and acidic vesicular organelles. Autophagy marker proteins, such as LC3B-II and beclin-1, were increased, and p62, an autophagy flux marker protein, was also increased by endoplasmic reticulum stress. Also, the phosphorylation of PI3K/AKT/mTOR pathway proteins and its downstream targets in apigetrin-treated AGS cells was identified to be decreased. Taken together, these data suggest that apigetrin-treated AGS cells induced G2/M phase cell cycle arrest, extrinsic apoptosis and autophagic cell death through PI3K/AKT/mTOR pathway, which can lead to the inhibition of gastric cancer development. Thus, our findings strongly indicate that apigetrin is a basic natural derived compound that could be used as a nutrient source with potential anticancer activities against gastric cancer.

Evaluation of the Cytotoxicity and Apoptotic Induction in Human Liver Cell Lines Exposed to Three Food Additives

BACKGROUND

Rapid lifestyle, especially among people living in urban areas, has led to increasing reliance on the processed food market. Unfortunately, harmful effects caused by the excessive use of food additives in such type of industry are often neglected.

OBJECTIVE

This proposal investigates in vitro cytotoxic and apoptotic effects of three food preservatives commonly consumed in daily meals; sodium sulphite, boric acid, and benzoic acid.

METHODS

The effect of the three preservatives on cell viability was tested on two different cell lines; normal liver cell line THLE2 and human hepatocellular carcinoma cancer cell line HepG2 using MTT assay. Cell cycle arrest was measured using flow cytometry by propidium iodide. Measurement of expression levels of two central genes, p53 and bcl-2 that play key roles in cell cycle and apoptosis was carried out in HepG2 cells using real time-PCR.

RESULTS

Although the effect was more significantly realized in the HepG2 cell line, the viability of both cell lines was decreased by all of the three tested compounds. Flow cytometric analysis of HepG2 cells treated with sodium sulphite, boric acid, and benzoic acid has revealed an increase in G2/M phase cell cycle arrest. In Sodium sulphite and boric acid-treated cells, expression levels of p53 were up-regulated, while that of the Bcl2 was significantly down-regulated. On the other hand, Benzoic acid has shown an anti-apoptotic feature based on the increased expression levels of Bcl-2 in treated cells.

CONCLUSION

In conclusion, all of the tested compounds have decreased the cell line viability and induced both cell cycle arrest and apoptotic events indicating their high potential of being cytotoxic and genotoxic materials.

Lanatoside C Induces G2/M Cell Cycle Arrest and Suppresses Cancer Cell Growth by Attenuating MAPK, Wnt, JAK-STAT, and PI3K/AKT/mTOR Signaling Pathways

Cardiac glycosides (CGs) are a diverse family of naturally derived compounds having a steroid and glycone moiety in their structures. CG molecules inhibit the α-subunit of ubiquitous transmembrane protein Na⁺/K⁺-ATPase and are clinically approved for the treatment of cardiovascular diseases. Recently, the CGs were found to exhibit selective cytotoxic effects against cancer cells, raising interest in their use as anti-cancer molecules. In this current study, we explored the underlying mechanism responsible for the anti-cancer activity of Lanatoside C against breast (MCF-7), lung (A549), and liver (HepG2) cancer cell lines. Using Real-time PCR, western blot, and immunofluorescence studies, we observed that (i) Lanatoside C inhibited cell proliferation and induced apoptosis in cell-specific and dose-dependent manner only in cancer cell lines; (ii) Lanatoside C exerts its anti-cancer activity by arresting the G2/M phase of cell cycle by blocking MAPK/Wnt/PAM signaling pathways; (iii) it induces apoptosis by inducing DNA damage and inhibiting PI3K/AKT/mTOR signaling pathways; and finally, (iv) molecular docking analysis shows significant evidence on the binding sites of Lanatoside C with various key signaling proteins ranging from cell survival to cell death. Our studies provide a novel molecular insight of anti-cancer activities of Lanatoside C in human cancer cells.

Molecular Mechanisms Underlying Yatein-Induced Cell-Cycle Arrest and Microtubule Destabilization in Human Lung Adenocarcinoma Cells

Yatein is an antitumor agent isolated from Calocedrus formosana Florin leaves extract. In our previous study, we found that yatein inhibited the growth of human lung adenocarcinoma A549 and CL1-5 cells by inducing intrinsic and extrinsic apoptotic pathways. To further uncover the effects and mechanisms of yatein-induced inhibition on A549 and CL1-5 cell growth, we evaluated yatein-mediated antitumor activity in vivo and the regulatory effects of yatein on cell-cycle progression and microtubule dynamics. Flow cytometry and western blotting revealed that yatein induces G₂/M arrest in A549 and CL1-5 cells. Yatein also destabilized microtubules and interfered with microtubule dynamics in the two cell lines. Furthermore, we evaluated the antitumor activity of yatein in vivo using a xenograft mouse model and found that yatein treatment altered cyclin B/Cdc2 complex expression and significantly inhibited tumor growth. Taken together, our results suggested that yatein effectively inhibited the growth of A549 and CL1-5 cells possibly by disrupting cell-cycle progression and microtubule dynamics.

Sinularin exerts anti-tumor effects against human renal cancer cells relies on the generation of ROS

Sinularin, a soft corals-derived natural product, exerts anti-tumorigenic activity in various types of human cancer cells. However, the action of Sinularin and its mechanism in renal carcinoma is not well understood. In the current study, we demonstrated that Sinularin inhibited the viability of human renal cancer cells 786-O and ACHN in a dose- and time-dependent manner, but did not show significant toxicity against non-malignant HRCEpic cells. Cell cycle analysis revealed that Sinularin induced G2/M arrest significantly. In addition, Sinularin could induce apoptosis in cells along with caspase-3/-9 activation, release of mitochondrial proteins, up-regulation of pro-apoptotic Bcl-2 family proteins and inhibition of anti-apoptotic Bcl-2 family proteins. Sinularin could also repress the activation of PI3K/Akt/mTOR signaling pathway. Moreover, Sinularin triggered the activation of MAPKs and p38 activation was essential for the anti-tumor effect of Sinularin. The generation of ROS (reactive oxygen species) was critical for Sinularin-induced apoptosis since ROS scavenger NAC (N-acetyl cysteine) could block the Sinularin-triggered apoptosis. In conclusion, all the results indicated that Sinularin may be applied as a therapeutic natural agent for human renal cancer.

Raltitrexed increases radiation sensitivity of esophageal squamous carcinoma cells

Background

Radiation therapy remains an important therapeutic modality, especially for those patients who are not candidates for radical resection. Many strategies have been developed to increase the radiosensitivity of esophageal cancer, with some success.

Methods

This study was conducted to determine whether raltitrexed can enhance radiosensitivity of esophageal squamous cell carcinoma (ESCC). ESCC cell lines 24 h were incubated with raltitrexed or DMSO with or without subsequent irradiation. Cell Counting Kit assay-8 assay and clonogenic survival assay were used to measure the cell proliferation and radiosensitization, respectively. Flow cytometry was utilized to examine cell apoptosis and cell cycle distribution in different groups. Immunofluorescence analysis was performed to detect deoxyribonucleic acid (DNA) double-strand breaks. In addition, the expression levels of proteins that are involved in radiation induced signal transduction including Bax, Cyclin B1, Cdc2/pCdc2, and Cdc25C/pCdc25C were examined by western blot analysis.

Results

The results indicated that raltitrexed enhanced radiosensitivity of ESCC cells with increased DNA double-strand breaks, the G2/M arrest, and the apoptosis of ESCC cells induced by radiation. The sensitization enhancement ratio of 1.23–2.10 was detected for ESCC cells with raltitrexed treatment in TE-13 cell line. In vitro, raltitrexed also increased the therapeutic effect of radiation in nude mice.

Conclusion

Raltitrexed increases the radiosensitivity of ESCC. This antimetabolite drug is promising for future clinical trials with concurrent radiation in esophageal cancer.

Marine natural products

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

Sandensolide Induces Oxidative Stress-Mediated Apoptosis in Oral Cancer Cells and in Zebrafish Xenograft Model

Presently, natural sources and herbs are being sought for the treatment of human oral squamous cell carcinoma (OSCC) in order to alleviate the side effects of chemotherapy. This study investigates the effect of sandensolide, a cembrane isolated from Sinularia flexibilis, to inhibit human OSCC cell growth with the aim of developing a new drug for the treatment of oral cancer. In vitro cultured human OSCC models (Ca9.22, SCC9 and HSC-3 cell lines) and oral normal cells (HGF-1), as well as a zebrafish xenograft model, were used to test the cytotoxicity of sandensolide (MTT assay), as well as to perform cell cycle analysis and Western blotting. Both the in vitro bioassay and the zebrafish xenograft model demonstrated the anti-oral cancer effect of sandensolide. Moreover, sandensolide was able to significantly suppress colony formation and induce apoptosis, as well as cell cycle arrest, in OSCC by regulating multiple key proteins. Induction of reactive oxygen species (ROS) was observed in sandensolide-treated oral cancer cells. However, these apoptotic changes were rescued by NAC pretreatment. These findings contribute to the knowledge of the model of action of sandensolide, which may induce oxidative stress-mediated cell death pathways as a potential agent in oral cancer therapeutics.

Sinularin Selectively Kills Breast Cancer Cells Showing G2/M Arrest, Apoptosis, and Oxidative DNA Damage

The natural compound sinularin, isolated from marine soft corals, is antiproliferative against several cancers, but its possible selective killing effect has rarely been investigated. This study investigates the selective killing potential and mechanisms of sinularin-treated breast cancer cells. In 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H- tetrazolium, inner salt (MTS) assay, sinularin dose-responsively decreased the cell viability of two breast cancer (SKBR3 and MDA-MB-231) cells, but showed less effect on breast normal (M10) cells after a 24 h treatment. According to 7-aminoactinomycin D (7AAD) flow cytometry, sinularin dose-responsively induced the G2/M cycle arrest of SKBR3 cells. Sinularin dose-responsively induced apoptosis on SKBR3 cells in terms of a flow cytometry-based annexin V/7AAD assay and pancaspase activity, as well as Western blotting for cleaved forms of poly(ADP-ribose) polymerase (PARP), caspases 3, 8, and 9. These caspases and PARP activations were suppressed by N-acetylcysteine (NAC) pretreatment. Moreover, sinularin dose-responsively induced oxidative stress and DNA damage according to flow cytometry analyses of reactive oxygen species (ROS), mitochondrial membrane potential (MitoMP), mitochondrial superoxide, and 8-oxo-2'-deoxyguanosine (8-oxodG)). In conclusion, sinularin induces selective killing, G2/M arrest, apoptosis, and oxidative DNA damage of breast cancer cells.

2,4,6-Trinitrotoluene Induces Apoptosis via ROS-Regulated Mitochondrial Dysfunction and Endoplasmic Reticulum Stress in HepG2 and Hep3B Cells

2,4,6-trinitrotoluene (TNT) has been reported to cause numerous adverse effects. However, the detailed molecular mechanisms underlying TNT-induced liver toxicity need to be elucidated. In this study, we used HepG2 (p53wt) and Hep3B (p53null) cell lines to investigate the cytotoxic effects of TNT. At first, we found that TNT significantly decreased cell viability and induced DNA damage. Thereafter, through transcriptomic analysis, we observed that the diverse biological functions affected included mitochondrial dysfunction and endoplasmic reticulum (ER) stress. Mitochondrial dysfunction was evidenced by the loss of mitochondrial membrane potential, increased expression of cleaved-caspase-9&-3 and increased caspase-3/7 activity, indicating that apoptosis had occurred. In addition, the expressions of some ER stress-related proteins had increased. Next, we investigated the role of reactive oxygen species (ROS) in TNT-induced cellular toxicity. The levels of DNA damage, mitochondrial dysfunction, ER stress and apoptosis were alleviated when the cells were pretreated with N-acetyl-cysteine (NAC). These results indicated that TNT caused the ROS dependent apoptosis via ER stress and mitochondrial dysfunction. Finally, the cells transfected with CHOP siRNA significantly reversed the TNT-induced apoptosis, which indicated that ER stress led to apoptosis. Overall, we examined TNT-induced apoptosis via ROS dependent mitochondrial dysfunction and ER stress in HepG2 and Hep3B cells.