Cephalochromin induces G0/G1 cell cycle arrest and apoptosis in A549 human non-small-cell lung cancer cells by inflicting mitochondrial disruption

Potential candidates from marine and terrestrial resources targeting mitochondrial inhibition: Insights from the molecular approach

Mitochondria are the target sites for multiple disease manifestations, for which it is appealing to researchers' attention for advanced pharmacological interventions. Mitochondrial inhibitors from natural sources are of therapeutic interest due to their promising benefits on physiological complications. Mitochondrial complexes I, II, III, IV, and V are the most common sites for the induction of inhibition by drug candidates, henceforth alleviating the manifestations, prevalence, as well as severity of diseases. Though there are few therapeutic options currently available on the market. However, it is crucial to develop new candidates from natural resources, as mitochondria-targeting abnormalities are rising to a greater extent. Marine and terrestrial sources possess plenty of bioactive compounds that are appeared to be effective in this regard. Ample research investigations have been performed to appraise the potentiality of these compounds in terms of mitochondrial disorders. So, this review outlines the role of terrestrial and marine-derived compounds in mitochondrial inhibition as well as their clinical status too. Additionally, mitochondrial regulation and, therefore, the significance of mitochondrial inhibition by terrestrial and marine-derived compounds in drug discovery are also discussed.

N-Propargylic β-enaminones in breast cancer cells: Cytotoxicity, apoptosis, and cell cycle analyses

Breast cancer is one of the most common cancers worldwide and the discovery of new cytotoxic agents is needed. Enaminones are regarded to be a significant structural motif that is found in a variety of pharmacologically active compounds however the number of studies investigating the anticancer activities of N-propargylic β-enaminones (NPEs) is limited. Herein we investigated the potential cytotoxic and apoptotic effects of 23 different NPEs (1-23) on human breast cancer cells. Cytotoxicity was evaluated via MTT assay. Apoptotic cell death and cell cycle distributions were investigated by flow cytometry. CM-H2DCFDA dye was used to evaluate cellular ROS levels. Expression levels of Bcl-2, Bax, p21, and Cyclin D1 were measured by quantitative real-time PCR. ADME properties were calculated using the ADMET 2.0 tool. NPEs 4, 9, 16, and 21 showed selective cytotoxic activity against breast cancer cells with SI values >2. NPEs induced apoptosis and caused significant changes in Bcl-2 and Bax mRNA levels. The cell cycle was arrested at the G0/G1 phase and levels of p21 and Cyclin D1 were upregulated in both breast cancer cells. ROS levels were significantly increased by NPEs, suggesting that the cytotoxic and apoptotic effects of NPEs were mediated by ROS. ADME analysis revealed that NPEs showed favorable distributions in both breast cancer cell lines, meaning good lipophilicity values, low unfractionated values, and high bioavailability. Therefore, these potential anticancer compounds should be further validated by in vivo studies for their appropriate function in human health with a safety profile, and a comprehensive drug interaction study should be performed.

Discovery of the mechanism of n-propylparaben-promoting the proliferation of human breast adenocarcinoma cells by activating human estrogen receptors via metabolomics analysis

BACKGROUND

N-propylparaben (PP), a type of paraben, is commonly used as a preservative or antibacterial agent in daily chemicals, medicine, food, cosmetics, feed, and various industrial preservatives. Although PP promotes the growth of human breast adenocarcinoma (MCF-7) cells by activating the human estrogen receptor (ER), the mechanism responsible for this type of programmed cell proliferation is poorly understood.

OBJECTIVE

To clarify the effect of PP on cell metabolic function and the potential molecular mechanism of PP induced MCF-7 cell proliferation from a new perspective.

METHODS

To use high-resolution mass spectrometry-based metabolomics combined with bioinformatics analysis to analyze the molecular mechanism.

RESULTS

The results illustrated that differential endogenous compounds related to the effects of PP on cell metabolic functions were detected. PP was found to promote glycolysis in MCF-7 cells and enhance the tricarboxylic acid cycle (TCA cycle) in mitochondria, thus improving the energy supply to these tumor cells for metabolic function and promotion of rapid proliferation. Moreover, we found that PP promoted cell proliferation by affecting the mitogen-activated protein kinase (MAPK) signaling pathway of MCF-7 cells.

CONCLUSION

Our results revealed the molecular mechanism of low concentration PP promoting MCF-7 cell proliferation by activating ER.

Use of Early Donated COVID-19 Convalescent Plasma Is Optimal to Preserve the Integrity of Lymphatic Endothelial Cells

Convalescent plasma therapy (CPT) has gained significant attention since the onset of the coronavirus disease 2019 (COVID-19) pandemic. However, clinical trials designed to study the efficacy of CPT based on antibody concentrations were inconclusive. Lymphatic transport is at the interplay between the immune response and the resolution of inflammation from peripheral tissues, including the artery wall. As vascular complications are a key pathogenic mechanism in COVID-19, leading to inflammation and multiple organ failure, we believe that sustaining lymphatic vessel function should be considered to define optimal CPT. We herein sought to determine what specific COVID-19 convalescent plasma (CCP) characteristics should be considered to limit inflammation-driven lymphatic endothelial cells (LEC) dysfunction. CCP donated 16 to 100 days after the last day of symptoms was characterized and incubated on inflammation-elicited adult human dermal LEC (aHDLEC). Plasma analysis revealed that late donation correlates with higher concentration of circulating pro-inflammatory cytokines. Conversely, extracellular vesicles (EVs) derived from LEC are more abundant in early donated plasma (r = −0.413, p = 0.004). Thus, secretion of LEC-EVs by an impaired endothelium could be an alarm signal that instigate the self-defense of peripheral lymphatic vessels against an excessive inflammation. Indeed, in vitro experiments suggest that CCP obtained rapidly following the onset of symptoms does not damage the aHDLEC junctions as much as late-donated plasma. We identified a particular signature of CCP that would counteract the effects of an excessive inflammation on the lymphatic endothelium. Accordingly, an easy and efficient selection of convalescent plasma based on time of donation would be essential to promote the preservation of the lymphatic and immune system of infected patients.

Induction of Isochromanones by Co-Cultivation of the Marine Fungus Cosmospora sp. and the Phytopathogen Magnaporthe oryzae

Microbial co-cultivation is a promising approach for the activation of biosynthetic gene clusters (BGCs) that remain transcriptionally silent under artificial culture conditions. As part of our project aiming at the discovery of marine-derived fungal agrochemicals, we previously used four phytopathogens as model competitors in the co-cultivation of 21 marine fungal strains. Based on comparative untargeted metabolomics analyses and anti-phytopathogenic activities of the co-cultures, we selected the co-culture of marine Cosmospora sp. with the phytopathogen Magnaporthe oryzae for in-depth chemical studies. UPLC-MS/MS-based molecular networking (MN) of the co-culture extract revealed an enhanced diversity of compounds in several molecular families, including isochromanones, specifically induced in the co-culture. Large scale co-cultivation of Cosmospora sp. and M. oryzae resulted in the isolation of five isochromanones from the whole co-culture extract, namely the known soudanones A, E, D (1-3) and their two new derivatives, soudanones H-I (4-5), the known isochromans, pseudoanguillosporins A and B (6, 7), naphtho-γ-pyrones, cephalochromin and ustilaginoidin G (8, 9), and ergosterol (10). Their structures were established by NMR, HR-ESIMS, FT-IR, electronic circular dichroism (ECD) spectroscopy, polarimetry ([α]D), and Mosher's ester reaction. Bioactivity assays revealed antimicrobial activity of compounds 2 and 3 against the phytopathogens M. oryzae and Phytophthora infestans, while pseudoanguillosporin A (6) showed the broadest and strongest anti-phytopathogenic activity against Pseudomonas syringae, Xanthomonas campestris, M. oryzae and P. infestans. This is the first study assessing the anti-phytopathogenic activities of soudanones.

Shikonin Inhibits Non-Small-Cell Lung Cancer H1299 Cell Growth through Survivin Signaling Pathway

Overexpressed survivin is associated with worse survival of several types of human tumors. In this study, the antitumor activity of shikonin in non-small-cell lung cancer (NSCLC) by regulating survivin pathway was investigated. Results showed that shikonin inhibited the NSCLC H1299 cell proliferation in a dose-dependent manner. Moreover, shikonin fits well with survivin by molecular docking. Shikonin also inhibited the mRNA expression and protein level of survivin in H1299 cells. Shikonin arrested H1299 cell cycle at the G0/G1 phase by regulating CDK/cyclin family members. In addition, shikonin regulated the expression of X-linked inhibitor of apoptosis- (XIAP-) mediated caspases 3 and 9, thus leading to the damage of mitochondrial membrane potential and induction of H1299 cell apoptosis. Overall, shikonin inhibited H1299 cell growth by inducing apoptosis and blocking the cell cycle. The underlying mechanism involves targeting survivin, which subsequently regulates the protein expression of XIAP/caspase 3/9, CDK2/4, and cyclin E/D1. Thus, shikonin, a survivin inhibitor, is a promising therapeutic strategy in NSCLC treatment.

Emerging Importance of Survivin in Stem Cells and Cancer: the Development of New Cancer Therapeutics

Survivin is one of the rare proteins that is differentially expressed in normal and cancer cells and is directly or indirectly involved in numerous pathways required for tumor maintenance. It is expressed in almost all cancers and its expression has been detected at early stages of cancer. These traits make survivin an exceptionally attractive target for cancer therapeutics. Even with these promising features to be an oncotherapeutic target, there has been limited success in the clinical trials targeting survivin. Only recently it has emerged that survivin was not being specifically targeted which could have resulted in the negative clinical outcome. Also, focus of research has now shifted from survivin expression in the overall heterogeneous tumor cell populations to survivin expression in cancer stem cells as these cells have proved to be the major drivers of tumors. Therefore, in this review we have analyzed the expression of survivin in normal and cancer cells with a particular focus on its expression in cancer stem cell compartment. We have discussed the major signaling pathways involved in regulation of survivin. We have explored the current development status of various types of interventions for inhibition of survivin. Furthermore, we have discussed the challenges involving the development of potent and specific survivin inhibitors for cancer therapeutics. Finally we have given insights for some of the promising future anticancer treatments.

Metabolites from Clonostachys Fungi and Their Biological Activities

Clonostachys (teleomorph: Bionectria) fungi are well known to produce a variety of secondary metabolites with various biological activities to show their pharmaceutical and agrochemical applications. Up to now, at least 229 secondary metabolites, mainly including 84 nitrogen-containing metabolites, 85 polyketides, 40 terpenoids, and 20 other metabolites, have been reported. Many of these compounds exhibit biological activities, such as cytotoxic, antimicrobial, antileishmanial, antimalarial activities. This mini-review aims to summarize the diversity of the secondary metabolites as well as their occurrences in Clonostachys fungi and biological activities.

Lewis Acid Mediated Electrophilic Cyanation of 2,2'-Biphenols

A Lewis acid mediated electrophilic cyanation of 2,2'-biphenols with a trifluoromethanesulfonyl (Tf) protecting group is reported. The cyanation reactions with less toxic, commercially available MeSCN as a cyanating reagent afforded a range of 3-cyan-2,2'-biphenols in moderate to high yields. The use of trifluoromethanesulfonyl (Tf) as a protecting group is crucial to the success of this transformation. Moreover, the cyanated products were readily transformed into various synthetically useful molecules. This protocol features high efficiency, excellent regioselectivity, and good functional group compatibility and may provide a practical tool for the synthesis and modification of biologically active compounds, catalysts, and ligands.

Characterization of lncRNA-Associated ceRNA Network to Reveal Potential Prognostic Biomarkers in Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is one of the most fatal malignant tumors harmful to human health. The complexity and behavior characteristics of long-non-coding RNA (lncRNA)-associated competing endogenous RNA (ceRNA) network in LUAD patients are still unclear. The purpose of this study was to elucidate the regulatory networks of dysregulated RNAs, view, and identify potential prognosis signatures involved in LUAD. The expression profiles of mRNAs, lncRNAs, and miRNAs were obtained from the TCGA database. In total, 2078 DEmRNAs, 257 DElncRNAs, and 101 DEmiRNAs were sorted out. A PPI network including 45 DEmRNAs was constructed. Ten hub genes in the PPI network associated with cell cycle-related pathways were identified and they played key roles in regulating cell proliferation. A total of three DEmiRNAs, seven DElncRNAs, and six DEmRNAs were enrolled in the ceRNA network. Except for certain genes without any published study reports, all the genes in the ceRNA network played an essential role in controlling tumor cell proliferation and were associated with prognosis in LUAD. Finally, based on step regression and Cox regression survival analysis, we identified four candidate biomarkers, including miR490, miR1293, LINC01740, and IGF2BP1, and established a risk model based on the four genes. Our study provided a global view and systematic dissection of the lncRNA-associated ceRNA network, and the identified four genes might be novel important prognostic factors involved in LUAD pathogenesis.

Knockdown of PLAT enhances the anticancer effect of gefitinib in non-small cell lung cancer

Background

Tyrosine kinase inhibitors (TKIs), such as gefitinib, are widely used as standard treatments for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations. However, the subsequent inevitable drug resistance has become a major challenge in clinical treatment. The aim of this study was to investigate the role of tissue-type plasminogen activator (PLAT) in gefitinib resistance in NSCLC.

Methods

The function of PLAT was determined using gefitinib-resistant cells and a nude mouse model. The gene knockdown was achieved by Lentivirus based RNA silence technique. Expression of relevant genes and proteins, cell viability, proliferation, apoptosis, cell cycle, reactive oxygen species levels, mitochondrial membrane potential and differential gene expression was detected by RT-qPCR, western blot, cell counting kit-8 assay, EdU incorporation, flow cytometry, JC-1 dye assay and complementary DNA arrays. The effects of PLAT knockdown on tumorigenesis was analyzed in vivo.

Results

Gefitinib-resistant cells expressed higher levels of PLAT and that knockdown of PLAT in resistant cells restored gefitinib sensitivity. Tumor proliferation was limited in vivo following PLAT knockdown. Moreover, PLAT knockdown affected mitochondrial function, caused caspase activation and cell cycle arrest, and activated TNF-α signaling, leading to apoptosis of gefitinib-resistant PC9 cells.

Conclusions

Our results suggest that PLAT reduces apoptosis of NSCLC cells and knockdown of PLAT enhances anticancer effect of gefitinib by upregulating TNF-α signaling.

From old to new - Repurposing drugs to target mitochondrial energy metabolism in cancer

Although we have entered the era of personalized medicine and tailored therapies, drugs that target a large variety of cancers regardless of individual patient differences would be a major advance nonetheless. This review article summarizes current concepts and therapeutic opportunities in the area of targeting aerobic mitochondrial energy metabolism in cancer. Old drugs previously used for diseases other than cancer, such as antibiotics and antidiabetics, have the potential to inhibit the growth of various tumor entities. Many drugs are reported to influence mitochondrial metabolism. However, here we consider only those drugs which predominantly inhibit oxidative phosphorylation.

Design of Fungal Co-Cultivation Based on Comparative Metabolomics and Bioactivity for Discovery of Marine Fungal Agrochemicals

Microbial co-cultivation is employed for awakening silent biosynthetic gene clusters (BGCs) to enhance chemical diversity. However, the selection of appropriate partners for co-cultivation remains a challenge. Furthermore, competitive interactions involving the suppression of BGCs or upregulation of known, functional metabolite(s) during co-cultivation efforts is also common. Herein, we performed an alternative approach for targeted selection of the best co-cultivation pair. Eight marine sediment-derived fungi were classified as strong or weak, based on their anti-phytopathogenic potency. The fungi were co-cultured systematically and analyzed for their chemical profiles and anti-phytopathogenic activity. Based on enhanced bioactivity and a significantly different metabolite profile including the appearance of a co-culture specific cluster, the co-culture of Plenodomus influorescens (strong) and Pyrenochaeta nobilis (weak) was prioritized for chemical investigation. Large-scale co-cultivation resulted in isolation of five polyketide type compounds: two 12-membered macrolides, dendrodolide E (1) and its new analog dendrodolide N (2), as well as two rare azaphilones spiciferinone (3) and its new analog 8a-hydroxy-spiciferinone (4). A well-known bis-naphtho-γ-pyrone type mycotoxin, cephalochromin (5), whose production was specifically enhanced in the co-culture, was also isolated. Chemical structures of compounds 1-5 were elucidated by NMR, HRMS and [] analyses. Compound 5 showed the strongest anti-phytopathogenic activity against Xanthomonas campestris and Phytophthora infestans with IC₅₀ values of 0.9 and 1.7 µg/mL, respectively.

Amphiphilic Block Copolymers Bearing Hydrophobic γ-Tocopherol Groups with Labile Acetal Bond

High concentrations of γ-tocopherol (γTCP) tend to show antioxidant, anti-inflammatory, and anticancer effects. In this study, we prepared polymer micelles under acidic conditions with a controlled release of γTCP due to the decomposition of pendant acetal bonds. First, a precursor diblock copolymer composed of poly(ethylene glycol) (PEG) and acrylic acid (AA) was prepared. This was followed by the synthesis of an amphiphilic diblock copolymer (PEG₅₄-P(AA/VE6/γTCP29)₁₄₀), incorporated into hydrophobic γTCP pendant groups attached to the main chain through an acetal bond. The prepared PEG₅₄-P(AA/VE6/γTCP29)₁₄₀ was further dispersed in water to form polymer micelles composed of hydrophobic cores that were generated from a hydrophobic block containing γTCPs and hydrophilic shells on the surface. Under acidic conditions, γTCP was then released from the core of the polymer micelles due to the decomposition of the pendant acetal bonds. In addition, polymer micelles swelled under acidic conditions due to hydration of the core.

Neoantimycin F, a Streptomyces-Derived Natural Product Induces Mitochondria-Related Apoptotic Death in Human Non-Small Cell Lung Cancer Cells

Streptomyces-derived natural products have been become a major focus of anti-tumor drug discovery studies. Neoantimycin F (NAT-F), was isolated from Streptomyces conglobatus by our group. Here, we examined the anti-cancer activities and its underlying molecular mechanisms implicated in NAT-F-induced apoptosis of non-small cell lung cancer (NSCLC) cells. Our results showed that NAT-F exerted excellent growth-inhibitory activity against PC9 and H1299 cells in a concentration-dependent manner. NAT-F-induced cell cycle arrest at S and G₀/G₁ phase in PC9 and H1299 cells, respectively. Further investigation revealed that the key proteins (including cyclinD1, cyclinE1, cyclinB1, CDK2, and CDK4) were involved in the cell regulation by NAT-F. Additionally, NAT-F significantly increased the production of reactive oxygen species (ROS), induced DNA damage, nuclear condensation, and cell apoptosis in both cell lines. Moreover, loss of the mitochondrial membrane potential (MMP) was markedly induced by NAT-F. Additional results revealed that NAT-F could up-regulate pro-apoptotic protein Bax and down-regulate anti-apoptotic protein Bcl-2, Mcl-1, and Bcl-x_L, resulting in cytochrome c release from mitochondria and sequential activation of caspase-9 and -3, as well as the cleavage of poly (ADP-ribose) polymerase. Meanwhile, c-Jun N-terminal kinase (JNK), p38 MAPK (p38), and extracellular signal-regulated kinase (ERK) signaling pathway were also involved in anti-cancer activity of NAT-F in NSCLC cells. Taken together, these findings indicated that NAT-F possessed anti-proliferative effect and induced apoptosis in NSCLC cells in vitro and may be conducive to promote the development of novel anti-NSCLC agents.

Ethanolic Extract of Lagerstroemia Speciosa (L.) Pers., Induces Apoptosis and Cell Cycle Arrest in HepG2 Cells

Lagerstroemia speciosa (L.) Pers., (Lythraceae) also called Banaba is a native plant of southeast Asia and is widely used in traditional medicinal system. Herbal tea from banaba leaves are used to reduce weight and diabetes. We investigated the cytotoxic potentials of ethanolic banaba leaves extract (EBLE) against human hepatocellular carcinoma (HepG2) cell line. Lagerstroemia speciosa leaves were extracted and obtained from M/s. Quimico Herbal Extract Manufacturer, Bengaluru, India, and it contains 20% corosolic acid. Cells were treated with 50, 100, and 150 µg/ml of EBLE for 24 h, and cytotoxicity was evaluated by MTT assay. Apoptosis-related morphology was investigated by DAPI nuclear staining. Protein and gene expressions of p-Akt, FOXO1, p53, MDM2, p21, p27, CDK4, cyclin D1, and E1 were evaluated through Western blotting and qPCR. EBLE treatments caused significant, concentration-dependent cytotoxicity. DAPI staining and flow cytometry studies showed chromatin condensation, increased apoptotic cell population and cell cycle arrest at subG0/G1 phase upon EBLE treatments respectively. Furthermore, EBLE treatments significantly increased the expressions of p53, p21, p27, FOXO1, while p-Akt, MDM2, CDK4, cyclin D1, and E1 expressions were downregulated. These findings suggested that EBLE induces G1-phase of cell cycle arrest and apoptosis in HepG2 cells. EBLE may serve as a therapeutic agent against hepatocellular carcinoma.

HADC8 Inhibitor WK2-16 Therapeutically Targets Lipopolysaccharide-Induced Mouse Model of Neuroinflammation and Microglial Activation

Glial activation and neuroinflammatory processes play important roles in the pathogenesis of brain abscess and neurodegenerative diseases. Activated glial cells can secrete various proinflammatory cytokines and neurotoxic mediators, which contribute to the exacerbation of neuronal cell death. The inhibition of glial activation has been shown to alleviate neurodegenerative conditions. The present study was to investigate the specific HDAC8 inhibitor WK2-16, especially its effects on the neuroinflammatory responses through glial inactivation. WK2-16 significantly reduced the gelatinolytic activity of MMP-9, and expression of COX-2/iNOS proteins in striatal lipopolysaccharide (LPS)-induced neuroinflammation in C57BL/6 mice. The treatment of WK2-16 markedly improved neurobehavioral deficits. Immunofluorescent staining revealed that WK2-16 reduced LPS-stimulated astrogliosis and microglial activation in situ. Consistently, cellular studies revealed that WK2-16 significantly suppressed LPS-induced mouse microglia BV-2 cell proliferation. WK2-16 was proven to concentration-dependently induce the levels of acetylated SMC3 in microglial BV-2 cells. It also reduced the expression of COX-2/iNOS proteins and TNF-α production in LPS-activated microglial BV-2 cells. The signaling studies demonstrated that WK2-16 markedly inhibited LPS-activated STAT-1/-3 and Akt activation, but not NF-κB or MAPK signaling. In summary, the HDAC8 inhibitor WK2-16 exhibited neuroprotective effects through its anti-neuroinflammation and glial inactivation properties, especially in microglia in vitro and in vivo.

Identification of differentially expressed genes and enriched pathways in lung cancer using bioinformatics analysis

Lung cancer is the leading cause of cancer‑associated mortality worldwide. The aim of the present study was to identify the differentially expressed genes (DEGs) and enriched pathways in lung cancer by bioinformatics analysis, and to provide potential targets for diagnosis and treatment. Valid microarray data of 31 pairs of lung cancer tissues and matched normal samples (GSE19804) were obtained from the Gene Expression Omnibus database. Significance analysis of the gene expression profile was used to identify DEGs between cancer tissues and normal tissues, and a total of 1,970 DEGs, which were significantly enriched in biological processes, were screened. Through the Gene Ontology function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, 77 KEGG pathways associated with lung cancer were identified, among which the Toll‑like receptor pathway was observed to be important. Protein‑protein interaction network analysis extracted 1,770 nodes and 10,667 edges, and identified 10 genes with key roles in lung cancer with highest degrees, hub centrality and betweenness. Additionally, the module analysis of protein‑protein interactions revealed that 'chemokine signaling pathway', 'cell cycle' and 'pathways in cancer' had a close association with lung cancer. In conclusion, the identified DEGs, particularly the hub genes, strengthen the understanding of the development and progression of lung cancer, and certain genes (including advanced glycosylation end‑product specific receptor and epidermal growth factor receptor) may be used as candidate target molecules to diagnose, monitor and treat lung cancer.

Therapeutic strategies involving survivin inhibition in cancer

Survivin is a small protein that belongs to the inhibitor of apoptosis protein family. It is abundantly expressed in tumors compared with adult differentiated tissues, being associated with poor prognosis in many human neoplasms. This apoptotic inhibitor has a relevant role in both the promotion of cancer cell survival and in the inhibition of cell death. Consequently, aberrant survivin expression stimulates tumor progression and confers resistance to several therapeutic strategies in a variety of tumors. In fact, efficient survivin downregulation or inhibition results in spontaneous apoptosis or sensitization to chemotherapy and radiotherapy. Therefore, all these features make survivin an attractive therapeutic target to treat cancer. Currently, there are several survivin inhibitors under clinical evaluation, although more specific and efficient survivin inhibitors are being developed. Moreover, novel combination regimens targeting survivin together with other therapeutic approaches are currently being designed and assessed. In this review, recent progress in the therapeutic options targeting survivin for cancer treatment is analyzed. Direct survivin inhibitors and their current development status are explored. Besides, the major signaling pathways implicated in survivin regulation are described and different therapeutic approaches involving survivin indirect inhibition are evaluated. Finally, promising novel inhibitors under preclinical or clinical evaluation as well as challenges of developing survivin inhibitors as a new therapy for cancer treatment are discussed.

Hexavalent chromium induces oxidative stress and mitochondria-mediated apoptosis in isolated skin fibroblasts of Indo-Pacific humpback dolphin

The increasing gas emissions and industrial wastewater discharge of anthropogenic hexavalent chromium (Cr(VI)) have been growing health concerns to the high trophic level marine mammals. Our previous studies showed that Indo-Pacific humpback dolphin (Sousa chinensis), stranded on the Pearl River Estuary region, contained exceedingly high levels of Cr in their skin-tissues. Unfortunately, the molecular toxic mechanisms on this mammal are absent, limiting our understanding of the eco-physiological impacts of Cr(VI) on dolphins. Thus, the cytotoxicity effects of Cr(VI) were analyzed on fibroblasts we isolated from the skin of S. chinensis (ScSF). This study showed that Cr(VI) markedly inhibited the viability of ScSF cells via induction of apoptosis accompanied by an increase in the production of reactive oxygen species and the population of G2/M arrest or apoptotic sub-G1 phase cells, up-regulation of p53, and activation of caspase-3. Further investigation on intracellular mechanisms indicated that Cr(VI) induced depletion of mitochondrial membrane potential in cells through regulating the expression of anti-apoptotic (Bcl-2) and pro-apoptotic (Bax) proteins, resulting in decrease of the ATP level, cytochrome c release from mitochondria into cytosol, and the activation of caspase-9. Furthermore, antioxidants N-acetylcysteine and vitamin C displayed chemoprotective activity against Cr(VI) via suppression of p53 expression, indicating that the Cr(VI)-induced cell death may be mediated by oxidative stress. Overall, these results provide insights into the potential mechanisms underlying the cytotoxicity of Cr(VI) in Indo-Pacific humpback dolphin skin cells, offer experimental support for the proposed protective role of antioxidants in Cr(VI)-induced toxicity, and suggest that Cr(VI) contamination is one of key health concern issues for the protection of Indo-Pacific humpback dolphin.

The organic ester O,O'-diethyl-(S,S)-ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoate dihydrochloride attenuates murine breast cancer growth and metastasis

Pharmacological treatment of cancer is mostly limited by drug-toxicity and resistance. It has been noticed that new organic ester ligand, O,O’-diethyl-(S,S)-ethylenediamine-N,N’-di-2-(3-cyclohexyl)propanoate dihydrochloride (named DE-EDCP) showed effective cytotoxic capacities against several human and mouse cancer cell lines. However, its effects on tumor growth and metastasis are unexplored. The aim of present study was to examine the ability of DE-EDCP to inhibit 4T1 murine breast cancer growth and progression and to explore possible molecular mechanisms. DE-EDCP exhibited significant tumoricidal activity on human and murine breast cancer cell lines. Further, marked reduction of murine breast cancer growth and progression by DE-EDCP was shown. DE-EDCP exhibits fewer side-effects compared to cisplatin as a conventional chemotherapeutic. Results obtained from in vivo and in vitro experiments indicate that DE-EDCP induces apoptosis and inhibits proliferation of 4T1 cells. DE-EDCP increases percentage of 4T1 cells in late apoptosis, expression of pro-apoptotic Bax and caspase-3, while decreases expression of anti-apoptotic Bcl-2. DE-EDCP treatment increased the percentage of TUNEL-positive nuclei and reduced Ki-67 expression in breast cancer tissue. DE-EDCP decreased expression of cyclin D3 and Ki-67, increased expression of cyclin-dependent kinase inhibitors p16, p21 and p27 and arrested 4T1 cells in G0/G1 cell cycle phase. Expression of STAT3 and downstream regulated molecules, NANOG and SOX2, was reduced in 4T1 cells after DE-EDCP treatment.

In conclusion, DE-EDCP impairs breast cancer growth and progression by triggering cancer cell death and inhibition of cancer cell proliferation. DE-EDCP might be of interest in the development of the new anticancer agent.

Meroterpenoids from a Medicinal Fungus Antrodia cinnamomea

Antrodia cinnamomea, a medicinal fungus indigenous to Taiwan, has been shown to exhibit a broad spectrum of bioactivities for the treatments of alcoholic intoxication, diarrhea, abdominal pain, and fatigue, and a number of active principles have been identified. Among the bioactive entities, clinical trials of antroquinonol and 4-acetyl antroquinonol B are being carried out for curing cancer, hypercholesterolemia, and hyperlipidemia. The total synthesis of antroquinonol has been achieved; however, investigating the structure-activity relationship of this class of compounds remained difficult due to the lack of available analogues. Twenty antroquinonols isolated from A. cinnamomea IFS006 are reported herein. Their structures were elucidated using spectral analysis and by comparison with literature values. Of these, 11 antroquinonol analogues, namely, antroquinonols N-X (1-11), were previously unreported. The growth inhibitory activity of all the antroquinonol analogues was evaluated against human A549 and PC-3 cancer cell lines, and antroquinonol A exhibited the most potent activity, with GI₅₀ values of 5.7 ± 0.2 and 13.5 ± 0.2 μM, respectively. Antroquinonols V (9) and W (10) also showed growth inhibitory activity against A549 cells with GI₅₀ values of 8.2 ± 0.8 and 7.1 ± 2.1 μM, respectively, compared to 5-fluorouracil (GI₅₀ = 4.2 ± 0.2 μM).

Synthesis, characterization, and evaluation of Cd[L-proline]2, a novel histone deacetylase inhibitor that induces epigenetic modification of histone deacetylase isoforms in A549 cells

Histone deacetylases (HDACs) play an important role in the epigenetic regulation of gene expression through their effects on the compact chromatin structure. In clinical studies, several classes of histone deacetylase inhibitors (HDACi) have demonstrated potent anticancer activities with metal complexes. Hence, we synthesized cadmium-proline complexes using both the D- and L-isomers of proline and evaluated their biological activities by observing the efficiency of their inhibition of HDAC activity, ability to reduce the expression of HDAC isoforms in A549 cells and effect on apoptosis. The synthesized compounds were characterized by UV, IR, NMR spectroscopy and elemental analysis. In-vitro cell toxicity was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, and the 50% inhibitory concentration (IC₅₀; 2 μM) was obtained at 12 h. The morphological study at nuclear levels was performed by acridine orange/ethidium bromide (AO/EB) and Hoechst staining, and the results showed an association with cell cycle arrest at the G2/M phase. Both cadmium-proline complexes intensely inhibited HDAC activity at 2 μM concentration. Interestingly, Cd[L-proline]₂ was found to be a potent inhibitor for all HDAC isoforms, whereas Cd[D-proline]₂ inhibited only HDAC1 and 2. HDACi are novel chemotherapeutic drugs that induce hyperacetylation of histones H3 and H4, counteracting the aberrant repression of genes, such as insulin-like growth factor-binding protein 3 (IGFBP-3), p53, and p21. ERK/MAPK signaling pathway resulted in the downregulation of the expression of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9), contributing to the inhibition of metastasis in A549 cells. Apoptosis induction was accompanied by the activation of death receptors and their ligands which recruit initiator caspase 8, decrease in mitochondrial membrane potential (ΔΨm), as well as increased Bax/Bcl₂ ratio, followed by activation of caspases 9 and 3. Our finding suggests that Cd[L-proline]₂ complex accelerates epigenetic rearrangement by HDAC inhibition, which may be the key mechanism for its anticancer activity.

Cancer Cell Specific Delivery of Photosystem I Through Integrin Targeted Liposome Shows Significant Anticancer Activity

Many anticancer drugs are developed for the treatment of cancer from natural sources. Photosystem I (PSI), a protein complex present in the chloroplast, is involved in photosynthesis and generates reactive oxygen species (ROS) in plant. Here, we used the ROS generation property of PSI for cancer therapy. We show that PSI can enter into different kinds of cancer cell like human lung carcinoma (A549) and mouse melanoma (B16F10) cell lines and generate ROS inside the cells. It inhibits the proliferation of cancer cell and causes apoptotic death of cancer cells. We also show that PSI induces apoptosis through mitochondria-dependent internal pathway, induces caspase3, causes DNA fragmentation, and arrests cell cycle at SubG0 phase. We also prepared, using C₁₆-LDV lipopeptide [C16 long chain attached on the N-terminal of the tripeptide containing amino acids leucine (L), aspartic acid (D), and valine (V) abbreviated as NH₂-LDV-COOH], α₄β₁ integrin targeted liposomal formulation of PSI, which specifically kills the cancer cell without affecting normal cells, and it is found to be more potent compared to clinically used drug doxorubicin. Finally, we found that LDV liposomal formulation of PSI inhibits the growth of tumor in C57BL/6J mice model.

Anti-Proliferative Effects of Dendrophthoe pentandra Methanol Extract on BCR/ABL-Positive and Imatinib-Resistant Leukemia Cell Lines

Background:

Imatinib mesylate, a tyrosine kinase inhibitor specifically targeting the BCR/ABL fusion protein, induces hematological remission in patients with chronic myeloid leukemia (CML). However, the majority of CML patients treated with imatinib develop resistance with prolonged therapy. Dendrophthoe pentandra (L.) Miq. is a Malaysian mistletoe species that has been used as a traditional treatment for several ailments such as smallpox, ulcers, and cancers.

Methods:

We developed a resistant cell line (designated as K562R) by long-term co-culture of a BCR/ABL positive CML cell line, K562, with imatinib mesylate. We then investigated the anti-proliferative effects of D. pentandra methanol extract on parental K562 and resistant K562R cells. Trypan blue exclusion assays were performed to determine the IC50 concentration; apoptosis and cell cycle analysis were conducted by flow cytometry.

Results:

D. pentandra extract had greater anti-proliferative effects towards K562R (IC50= 192 μg/mL) compared to K562 (500 μg/mL) cells. Upon treatment with D. pentandra extract at the IC50 concentration: K562 but not K562R demonstrated increase in apoptosis and cell cycle arrest in the G2/M phase.

Conclusion:

D. pentandra methanol extract exerts potent anti-proliferative effect on BCR/ABL positive K562 cells.

Calotropin from Asclepias curasavica induces cell cycle arrest and apoptosis in cisplatin-resistant lung cancer cells

Calotropin (M11), an active compound isolated from Asclepias curasavica L., was found to exert strong inhibitory and pro-apoptotic activity specifically against cisplatin-induced resistant non-small cell lung cancer (NSCLC) cells (A549/CDDP). Molecular mechanism study revealed that M11 induced cell cycle arrest at the G2/M phase through down-regulating cyclins, CDK1, CDK2 and up-regulating p53 and p21. Furthermore, M11 accelerated apoptosis through the mitochondrial apoptotic pathway which was accompanied by increase Bax/Bcl-2 ratio, decrease in mitochondrial membrane potential, increase in reactive oxygen species production, activations of caspases 3 and 9 as well as cleavage of poly ADP-ribose polymerase (PARP). The activation and phosphorylation of JNK was also found to be involved in M11-induced apoptosis, and SP610025 (specific JNK inhibitor) partially prevented apoptosis induced by M11. In contrast, all of the effects that M11 induce cell cycle arrest and apoptosis in A549/CDDP cells were not significant in A549 cells. Drugs with higher sensitivity against resistant tumor cells than the parent cells are rather rare. Results of this study supported the potential application of M11 on the non-small lung cancer (NSCLC) with cisplatin resistance.

Boehmenan, a lignan from the Chinese medicinal plant Clematis armandii, induces apoptosis in lung cancer cells through modulation of EGF-dependent pathways

BACKGROUND

Epidermal growth factor receptor (EGFR) is an effective molecular target for cancer treatment. Boehmenan, a lignan from the dried stems of Clematis armandii, exhibited the potent cytotoxic effects against many cancer cell lines in previous studies. However, the effects and underlying mechanism of boehmenan on non-small cell lung cancer (NSCLC) remains unclear.

PURPOSE

The present study was designed to determine the in vitro anti-cancer properties and underlying molecular mechanisms of boehmenan on A549 NSCLC cells.

STUDY DESIGN/METHODS

Cellular viability and chemoattractive properties of macrophages were investigated by using MTT and transwell migration assay, respectively. Mitochondrial membrane potential (ΔΨm), apoptotic ratio, and cell cycle were measured by flow cytometry. Protein expression was visualized by Western blot using specific antibodies.

RESULTS

Boehmenan concentration-dependently suppressed proliferation and induced G1 phase arrest in A549 NSCLC cells, which were accompanied by reduction of migration, colony formation and increase of apoptosis in A549 cells. In addition, boehmenan treatment markedly modulated apoptosis-related protein (p53, p21, cleaved caspase 3, and cleaved PARP) and cyclin D1 expression and induced ΔΨm collapse in a concentration dependent manner. Furthermore, boehmenan concentration-dependently inhibited EGF-induced activation of EGFR and its downstream signaling molecules, including MEK, Akt, ERK1/2, and STAT3.

CONCLUSION

Taken together, our results suggested that boehmenan-mediated anti-tumor property was mediated by modulation of mitochondria and EGFR signaling pathway in A549 NSCLC cells.

Platinum-zoledronate complex blocks gastric cancer cell proliferation by inducing cell cycle arrest and apoptosis

A series of novel dinuclear platinum complexes based on the bisphosphonate ligands have been synthesized and characterized in our recent study. For the purpose of discovering the pharmacology and action mechanisms of this kind of compounds, the most potent compound [Pt(en)]2ZL was selected for systematic investigation. In the present study, the inhibition effect on the human gastric cancer cell lines SGC7901 and action mechanism of [Pt(en)]2ZL were investigated. The traditional 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2-tetrazolium bromide (MTT) assay and colony formation assay were carried out to study the effect of [Pt(en)]2ZL on the cell viability and proliferation capacity, respectively. The senescence-associated β-galactosidase staining and immunofluorescence staining were also performed to assess the cell senescence and microtubule polymerization. Fluorescence staining and flow cytometry (FCM) were used to monitor the cell cycle distribution and apoptosis, and Western blot analysis was applied to examine the expression of several apoptosis-related proteins. The results demonstrated that [Pt(en)]2ZL exhibited remarkable cytotoxicity and anti-proliferative effects on the SGC7901 cells in a dose- and time-dependent manner, and it also induced cell senescence and abnormal microtubule assembly. The cell apoptosis and cell cycle arrest induced by [Pt(en)]2ZL were also observed with the fluorescence staining and FCM. The expressions of cell cycle regulators (p53, p21, cyclin D1, cyclin E, and cyclin-dependent kinase (CDK)2) and apoptosis-related proteins (Bcl-2, Bax, caspase-3, poly ADP ribose polymerase (PARP), and survivin) were regulated by the treatment of [Pt(en)]2ZL, resulting in the cell cycle arrest and apoptosis. Therefore, [Pt(en)]2ZL exerted anti-tumor effect on the gastric cancer via inducing cell cycle arrest at G1/S phase and apoptosis.

NIR-driven graphitic-phase carbon nitride nanosheets for efficient bioimaging and photodynamic therapy

Photodynamic therapy (PDT) is a noninvasive and promising anticancer therapy modality that utilizes the photochemical reactions of photosensitizers, upon irradiation at a specific wavelength, to yield reactive oxygen species (ROS) to impair malignant cancer cells.

Human Skin Cells Are More Sensitive than Human Lung Cells to the Cytotoxic and Cell Cycle Arresting Impacts of Particulate and Soluble Hexavalent Chromium

Hexavalent chromium Cr(VI) is a known human lung carcinogen, with solubility playing an important role in its carcinogenic potency. Dermal exposure to Cr(VI) is common and has been associated with skin damage; however, no link between chromate exposure and skin cancer has been found. In this study, we compared the cytotoxic and clastogenic effects of Cr(VI) and its impacts on cell cycle progression in human lung and skin fibroblasts. We found human skin cells arrested earlier in their cell cycle and exhibit more cytotoxicity than human lung cells, despite taking up similar amounts of Cr. These outcomes are consistent with a hypothesis that different cellular and molecular responses underlie the differences in carcinogenic outcome in these two tissues.

Recent progress in fungus-derived bioactive agents for targeting of signaling machinery in cancer cells

It is becoming increasingly understood that tumor cells may have different mutations and dependencies on diverse intracellular signaling cascades for survival or metastatic potential. Overexpression of oncogenes, inactivation of tumor suppressor genes, genetic/epigenetic mutations, genomic instability, and loss of apoptotic cell death are some of the mechanisms that have been widely investigated in molecular oncology. We partition this multicomponent review into the most recent evidence on the anticancer activity of fungal substances obtained from in vitro and xenografted models, and these fungal substances modulate expression of oncogenic and tumor suppressor miRNAs. There are some outstanding questions regarding fungus-derived chemical-induced modulation of intracellular signaling networks in different cancer cell lines and preclinical models. Certain hints have emerged, emphasizing mechanisms via which apoptosis can be restored in TRAIL-resistant cancer cells. Reconceptualization of the knowledge obtained from these emerging areas of research will enable us to potentially identify natural agents with notable anticancer activity and minimal off-target effects. Integration of experimentally verified evidence obtained from cancer cell line gene expression with large-scale functional screening results and pharmacological sensitivity data will be helpful in identification of therapeutics with substantial efficacy. New tools and technologies will further deepen our understanding of the signaling networks that underlie the development of cancer, metastasis, and resistance to different therapeutics at both a personal and systems-wide level.

UV-emitting upconversion-based TiO2 photosensitizing nanoplatform: near-infrared light mediated in vivo photodynamic therapy via mitochondria-involved apoptosis pathway

Photodynamic therapy (PDT) is a promising antitumor treatment that is based on the photosensitizers that inhibit cancer cells by yielding reactive oxygen species (ROS) after irradiation of light with specific wavelengths. As a potential photosensitizer, titanium dioxide (TiO2) exhibits minimal dark cytotoxicity and excellent ultraviolet (UV) light triggered cytotoxicity, but is challenged by the limited tissue penetration of UV light. Herein, a novel near-infrared (NIR) light activated photosensitizer for PDT based on TiO2-coated upconversion nanoparticle (UCNP) core/shell nanocomposites (UCNPs@TiO2 NCs) is designed. NaYF4:Yb(3+),Tm(3+)@NaGdF4:Yb(3+) core/shell UCNPs can efficiently convert NIR light to UV emission that matches well with the absorption of TiO2 shells. The UCNPs@TiO2 NCs endocytosed by cancer cells are able to generate intracellular ROS under NIR irradiation, decreasing the mitochondrial membrane potential to release cytochrome c into the cytosol and then activating caspase 3 to induce cancer cell apoptosis. NIR light triggered PDT of tumor-bearing mice with UCNPs@TiO2 as photosensitizers can suppress tumor growth efficiently due to the better tissue penetration than UV irradiation. On the basis of the evidence of in vitro and in vivo results, UCNPs@TiO2 NCs could serve as an effective photosensitizer for NIR light mediated PDT in antitumor therapy.

Recent Advances on Small-Molecule Survivin Inhibitors

Survivin, a member of the inhibitor of apoptosisproteins family, is highly expressed in most human neoplasms, but its expression is very low or undetectable in terminally differentiated normal tissues. Survivin has been shown to inhibit cancer cell apoptosis and promote cell proliferation. The overexpression of survivin closely correlates with tumor progression and drug resistance. Because of its key role in tumor formation and maintenance, survivin is considered as an ideal target for anticancer treatment. However, the development of small-molecule survivin inhibitors has been challenging due to the requirement to disrupt the protein-protein interactions. Currently only a limited number of survivin inhibitors have been developed in recent years, and most of these inhibitors reduce survivin levels by interacting with other biomolecules instead of directly interacting with survivin protein. Despite these challenges, developing potent and selective small-molecule survivin inhibitors will be important in both basic science to better understand survivin biology and in translational research to develop potentially more effective, broad-spectrum anticancer agents. In this review, the functions of survivin and its role in cancer are summarized. Recent developments, challenges, and future direction of small-molecule survivin inhibitors are also discussed in detail.

Bis-naphtho-γ-pyrones from fungi and their bioactivities

Bis-naphtho-γ-pyrones are an important group of aromatic polyketides derived from fungi. They have a variety of biological activities including cytotoxic, antitumor, antimicrobial, tyrosine kinase and HIV-1 integrase inhibition properties, demonstrating their potential applications in medicine and agriculture. At least 59 bis-naphtho-γ-pyrones from fungi have been reported in the past few decades. This mini-review aims to briefly summarize their occurrence, biosynthesis, and structure, as well as their biological activities. Some considerations regarding to synthesis, production, and medicinal and agricultural applications of bis-naphtho-γ-pyrones are also discussed.

Simple access to 5-carboalkoxy-2,3-dihydro-4H-pyran-4-ones via domino acylative electrocyclization: the first three step total synthesis of the dihydronaphthopyran-4-one class of natural products

5-Carboalkoxy-2,3-dihydropyran-4-ones synthesised via domino C-acylation/6π-oxaelectrocyclization protocol was employed as a starting material for the first three step total synthesis of dihydronaphthopyran-4-one class of natural products.