Wentilactone A as a novel potential antitumor agent induces apoptosis and G2/M arrest of human lung carcinoma cells, and is mediated by HRas-GTP accumulation to excessively activate the Ras/Raf/ERK/p53-p21 pathway

Exploring the potential of Aspergillus wentii: secondary metabolites and biological properties

Fungi are of considerable importance due to their capacity to biosynthesize various secondary metabolites with bioactive properties that draw high attention in new drug discovery with beneficial uses for improving human well-being and life quality. Aspergillus genus members are widespread and cosmopolitan species with varying economic significance in the fields of industry, medicine, and agriculture. Its species are renowned for their biosynthesis of secondary metabolites, characterized by both potent biological activity and structural novelty, making them a substantial reservoir for the development of new pharmaceuticals. The current work aimed at focusing on one species of this genus, Aspergillus wentii Wehmer, including its reported secondary metabolites in the period from 1951 to November 2023. A total of 97 compounds, including nitro-compounds, terpenoids, anthraquinones, xanthones, benzamides, and glucans. A summary of their bioactivities, as well as their biosynthesis was highlighted. Additionally, the reported applications of this fungus and its enzymes have been discussed. This review offers a useful reference that can direct future research into this fungus and its active metabolites, as well as their possible pharmacological and biotechnological applications.

Redefining bioactive small molecules from microbial metabolites as revolutionary anticancer agents

Cancer treatment remains a significant challenge due to issues such as acquired resistance to conventional therapies and the occurrence of adverse treatment-related toxicities. In recent years, researchers have turned their attention to the microbial world in search of novel and effective drugs to combat this devastating disease. Microbial derived secondary metabolites have proven to be a valuable source of biologically active compounds, which exhibit diverse functions and have demonstrated potential as treatments for various human diseases. The exploration of these compounds has provided valuable insights into their mechanisms of action against cancer cells. In-depth studies have been conducted on clinically established microbial metabolites, unraveling their anticancer properties, and shedding light on their therapeutic potential. This review aims to comprehensively examine the anticancer mechanisms of these established microbial metabolites. Additionally, it highlights the emerging therapies derived from these metabolites, offering a glimpse into the immense potential they hold for anticancer drug discovery. Furthermore, this review delves into approved treatments and major drug candidates currently undergoing clinical trials, focusing on specific molecular targets. It also addresses the challenges and issues encountered in the field of anticancer drug research and development. It also presents a comprehensive exposition of the contemporary panorama concerning microbial metabolites serving as a reservoir for anticancer agents, thereby illuminating their auspicious prospects and the prospect of forthcoming strides in the domain of cancer therapeutics.

Phytochemicals in cervical cancer: an epigenetic overview

Cervical cancer is the fourth most common female malignancy worldwide and a complex disease that typically starts with HPV infection. Various genetic and epigenetic alterations are implicated in its development. The current cervical cancer therapies have unsatisfactory outcomes due to their serious adverse effects, necessitating the need for safe, effective preventive and therapeutic modalities. Phytochemicals have been addressed in cervical cancer prevention and treatment, and further understanding the epigenetics of cervical cancer pathogenesis is critical to investigate new preventive and therapeutic modalities. Addressing the epigenetic mechanisms of potential phytochemicals will provide an overview of their use individually or in combination. The primary aim of this review is to highlight the epigenetic effects of the phytochemicals addressed in cervical cancer therapy.

Design, Synthesis and Biological Evaluation of Quinazoline SOS1 Inhibitors

Son of sevenless 1 (SOS1) is a vital guanine nucleotide exchange factor (GEFs) that activates rat sarcoma (Ras) protein in cells. SOS1 inhibitors can effectively inhibit the expression of downstream signaling pathways by blocking the interaction between SOS1 and Ras protein. Here, we designed and synthesized a series of quinazoline-based compounds, and conducted subsequent evaluations of their biological activities. Among them, the comparable compounds I-2 (IC₅₀=20nM, against SOS1) I-5 (IC₅₀=18nM, against SOS1) and I-10 (IC₅₀=8.5nM, against SOS1) have kinase activity equivalent to BAY-293 (IC₅₀=6.6nM, against SOS1), and I-10 also has cell activity equivalent to BAY-293, providing a theoretical reference for subsequent related researches on SOS1 inhibitors.

Asperolide A induces apoptosis and cell cycle arrest of human hepatoma cells with p53-Y220C mutant through p38 mediating phosphorylation of p53 (S33)

Asperolides A (AA), one of the new tetranorlabdane diterpenoids, is proved to inhibit the proliferation of lung cancer cells and bone metastasis of breast cancer cells. Herein, we report that AA induces apoptosis and cell cycle arrest of hepatoma cells. It intensely inhibits proliferation of Huh-7 cell, compared with HepG-2 and L02 cells. AA elevates the activity of mitogen-activated protein kinases (MAPKs), in which the activation of ERK and JNK improves cell survival. However, phosphorylation of p53 at S33 by p38 activation could be a principal factor in the AA-induced apoptosis and G2/M cell cycle arrest of Huh-7 cells. The S33 site of p53-Y220C mutant, as the specific activation site of p38, reactivates the wild-type function of mutant p53 protein, which leads to a higher sensitivity of Huh-7 cells to AA. These results provide new insights into the molecular mechanisms of AA as a developing mutant p53 rescue drug.

Downregulation of Lysosome-Associated Membrane Protein-2A Contributes to the Pathogenesis of COPD

Background

Macroautophagy plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD), but the role of chaperone-mediated autophagy (CMA) has not been investigated. We investigated if and how CMA is involved in the pathogenesis of COPD.

Methods

We measured the level of lysosome-associated membrane protein-2A (LAMP-2A), which is a critical component of CMA that functions as a receptor for cytosolic substrate proteins, in total lung tissues and primary human bronchial epithelial cells (HBECs) from healthy never smokers, smokers, and COPD patients. We assessed the effects of LAMP-2A knock-down on cigarette smoke extract (CSE)-induced aging, cell cycle arrest, and apoptosis in BEAS-2B cells and the expression levels of apoptosis hallmarks in primary HBECs and lung tissue sections.

Results

We found that the protein levels of LAMP-2A in lung homogenates and primary HBECs from smokers and COPD patients were lower than those from never smokers. In addition, its level in primary HBECs was negatively correlated with years of smoking. CSE caused degradation of LAMP-2A protein via the lysosomal pathway by activating macroautophagy. Knock-down of LAMP-2A markedly enhanced CSE-induced expression of senescence markers such as p16, p21, p27, and p53. G2/M cell cycle arrest, up-regulation of cyclin B1, and apoptosis in BEAS-2B cells. Apoptosis was increased in CSE-treated primary HBECs and in lung tissues from smokers and COPD patients.

Conclusion

Cigarette smoke-induced down-regulation of LAMP-2A is involved in acceleration of aging and apoptosis of lung epithelial cells, which might at least partially contribute to COPD pathogenesis.

Holistic immunomodulation for small cell lung cancer

Small cell lung cancer (SCLC) is characterized by a high mortality rate, rapid growth, and early metastasis, which lead to a poor prognosis. Moreover, limited clinical treatment options further lower the survival rate of patients. Therefore, novel technology and agents are urgently required to enhance clinical efficacy. In this review, from a holistic perspective, we summarized the therapeutic targets, agents and strategies with the most potential for treating SCLC, including chimeric antigen receptor (CAR) T therapy, immunomodulating antibodies, traditional Chinese medicines (TCMs), and the microbiota, which have been found recently to improve the clinical outcomes and prognosis of SCLC. Multiomics technologies can be integrated to develop effective diagnostic methods and identify new targets for new drug discovery in SCLC. We discussed in depth the feasibility, potential, and challenges of these new strategies, as well as their combinational treatments, which may provide promising alternatives for enhancing the clinical efficacy of SCLC in the future.

Astragaloside trigger autophagy: Implication a potential therapeutic strategy for pulmonary fibrosis

Pulmonary fibrosis is an abnormal wound-healing response to repeated alveolar injury, characterized by continuous inflammation and abnormal collagen deposition. Its treatment is problematic. Astragaloside (AST) is an active component of Astragalus membranaceus with anti-inflammatory and anti-tumor properties. Although the underlying mechanisms are unknown, AST is also used to treat fibrotic diseases. This study aimed to investigate the mechanisms of action of AST in pulmonary fibrosis treatment. We found that AST significantly improved restrictive ventilatory impairment, compliance, total lung capacity, and functional residual capacity. In mice with pulmonary fibrosis, extracellular matrix deposition in the pulmonary parenchyma and intemperate inflammation were reversed. This therapeutic effect can be attributed to autophagy, activating the genes for autophagy flux and autophagic vacuoles. Impaired autophagy increased susceptibility to pulmonary fibrosis by exacerbating collagen deposition in vitro and in vivo. Using a combination of molecular docking and network pharmacology, the Ras/Raf/MEK/ERK signaling pathway was identified as a possible candidate for the pharmacologic target of AST. Functional dephosphorylation of MEK and ERK inhibited the Ras/Raf/MEK/ERK signaling pathway, which converges at the rapamycin switch to initiate autophagy. Inhibitors of Ras and MEK regulated autophagy. These findings suggest that AST might treat pulmonary fibrosis by modulating the Ras/Raf/MEK/ERK signaling pathway mediated by depression.

Wentilactone A Reverses the NF-κB/ECM1 Signaling-Induced Cisplatin Resistance through Inhibition of IKK/IκB in Ovarian Cancer Cells

Wentilactone A (WA) is a tetranorditerpenoid isolated from marine algae. We previously found that WA inhibited cancer cell proliferation with little toxicity. In this study, we show that high expression of extracellular matrix protein-1 (ECM1) promotes cancer cell cisplatin resistance, and the secreted ECM1 activates normal fibroblasts (NFs) to transform cells with characteristics of cancer-associated fibroblasts (CAFs). Transcription of the ECM1 gene is regulated largely by NF-κB through EP881C/T-EP266C binding sites. WA supresses the phosphorylation of NF-κB through inhibition of the upstream IKK/IκB phoshorylation to block the expression of ECM1, which reverses the cisplatin-induced activation of NF-κB/ECM1. On the contrary, cisplatin facilitates phosphorylation of NF-κB to enhance the expression of ECM1. These results highlight ECM1 as a potential target for treatment of cisplatin-resistant cancers associated with the ECM1 activated signaling. In addition, WA reverses cisplatin resistance by targeting both tumor cells and the tumor microenvironment through IKK/IκB/NF-κB signaling to reduce the expression of the ECM1 protein.

Bioactive Microbial Metabolites in Cancer Therapeutics: Mining, Repurposing, and Their Molecular Targets

The persistence and resurgence of cancer, characterized by abnormal cell growth and differentiation, continues to be a serious public health concern critically affecting public health, social life, and the global economy. Hundreds of putative drug molecules of synthetic and natural origin were approved for anticancer therapy in the last few decades. Although conventional anticancer treatment strategies have promising aspects, several factors such as their limitations, drug resistance, and side effects associated with them demand more effort in repositioning or developing novel therapeutic regimens. The rich heritage of microbial bioactive components remains instrumental in providing novel avenues for cancer therapeutics. Actinobacteria, Firmicutes, and fungi have a plethora of bioactive compounds, which received attention for their efficacy in cancer treatment targeting different pathways responsible for abnormal cell growth and differentiation. Yet the full potential remains underexplored to date, and novel compounds from such microbes are reported regularly. In addition, the advent of computational tools has further augmented the mining of microbial secondary metabolites and identifying their molecular targets in cancer cells. Furthermore, the drug-repurposing strategy has facilitated the use of approved drugs of microbial origin in regulating cancer cell growth and progression. The wide diversity of microbial compounds, different mining approaches, and multiple modes of action warrant further investigations on the current status of microbial metabolites in cancer therapeutics. Hence, in this review, we have critically discussed the untapped potential of microbial products in mitigating cancer progression. The review also summarizes the impact of drug repurposing in cancer therapy and discusses the novel avenues for future therapeutic drug development against cancer.

Identification of a Unique Cytotoxic Thieno[2,3-c]Pyrazole Derivative with Potent and Selective Anticancer Effects In Vitro

In recent years, the thienopyrazole moiety has emerged as a pharmacologically active scaffold with antitumoral and kinase inhibitory activity. In this study, high-throughput screening of 2000 small molecules obtained from the ChemBridge DIVERset library revealed a unique thieno[2,3-c]pyrazole derivative (Tpz-1) with potent and selective cytotoxic effects on cancer cells. Compound Tpz-1 consistently induced cell death at low micromolar concentrations (0.19 μM to 2.99 μM) against a panel of 17 human cancer cell lines after 24 h, 48 h, or 72 h of exposure. Furthermore, an in vitro investigation of Tpz-1's mechanism of action revealed that Tpz-1 interfered with cell cycle progression, reduced phosphorylation of p38, CREB, Akt, and STAT3 kinases, induced hyperphosphorylation of Fgr, Hck, and ERK 1/2 kinases, and disrupted microtubules and mitotic spindle formation. These findings support the continued exploration of Tpz-1 and other thieno[2,3-c]pyrazole-based compounds as potential small-molecule anticancer agents.

Total syntheses of wentilactones A and B, and related norditerpene dilactones

A divergent approach toward the synthesis of A-ring functionalized tetranorditerpenoid dilactones has been developed, employing 3β-hydroxydilactone 6 as a common precursor which is readily derived from (S)-Wieland–Miescher ketone.

Total synthesis of bioactive tetracyclic norditerpene dilactones

Tetracyclic norditerpene dilactones are an important class of terpenoids that have been isolated from both terrestrial and marine sources, typically from Podocarpus plants and from filamentous fungi. This class of molecules shares a common 6/6/6/5 tetracyclic ring skeleton, which possesses a densely oxygenated carbon framework and contiguous stereocenters. What's more challenging for synthetic chemists are the consecutive sp2-hybridized carbon centers, which exacerbates the strain/rigidity of the whole molecule. In addition, many of these molecules display promising biological activities, such as antitumor, insecticidal, anti-feedant, allelopathic, and antibiotic activities. The unique structures and interesting biological profiles of norditerpene dilactones have attracted considerable attention from synthetic chemists. Herein we summarize the synthetic efforts with respect to tetranorditerpene dilactones.

Small molecule Son of Sevenless 1 (SOS1) inhibitors: a review of the patent literature

Introduction: Up to 30% of all human cancers are driven by the overactivation of RAS signaling. Son of Sevenless 1 (SOS1) is a central node in RAS signaling pathways and modulation of SOS1-mediated RAS activation represents a unique opportunity for treating RAS-addicted cancers. Several recent publications and patent documents have demonstrated the ability of small molecules to affect the activation of RAS by SOS1 and have shown their potential for the treatment of cancers driven by RAS mutants.Areas covered: Documents focusing on both small-molecule inhibitors and activators of the SOS1:RAS interaction and their potential use as cancer therapeutics are covered. A total of 10 documents from 4 applicants are evaluated with discussion focusing on structural modifications of these compounds as well as relevant preclinical data.Expert opinion: The last decade has seen a significant increase in research and disclosures in the development of small-molecule SOS1 inhibitors. Considering the promising data that have been disclosed, interest in this area of research will likely remain strong for the foreseeable future. With the first SOS1 inhibitor currently in phase I clinical trials, the outcome of these trials will likely influence future development of SOS1 inhibitors for treatment of RAS-driven cancers.

Structure-based inhibitor design of mutant RAS proteins-a paradigm shift

As a member of small GTPase family, KRAS protein is a key physiological modulator of various cellular activities including proliferation. However, mutations of KRAS present in numerous cancer types, most frequently in pancreatic (> 60%), colorectal (> 40%), and lung cancers, drive oncogenic processes through overactivation of proliferation. The G12C mutation of KRAS protein is especially abundant in the case of these types of malignancies. Despite its key importance in human disease, KRAS was assumed to be non-druggable for a long time since the protein seemingly lacks potential drug-binding pockets except the nucleotide-binding site, which is difficult to be targeted due to the high affinity of KRAS for both GDP and GTP. Recently, a new approach broke the ice and provided evidence that upon covalent targeting of the G12C mutant KRAS, a highly dynamic pocket was revealed. This novel targeting is especially important since it serves with an inherent solution for drug selectivity. Based on these results, various structure-based drug design projects have been launched to develop selective KRAS mutant inhibitors. In addition to the covalent modification strategy mostly applicable for G12C mutation, different innovative solutions have been suggested for the other frequently occurring oncogenic G12 mutants. Here we summarize the latest advances of this field, provide perspectives for novel approaches, and highlight the special properties of KRAS, which might issue some new challenges.

Resveratrol reduces drug resistance of SCLC cells by suppressing the inflammatory microenvironment and the STAT3/VEGF pathway

DNA‐damaging agents, such as doxorubicin (Adriamycin), are widely used for the treatment of small cell lung cancer (SCLC). However, drug resistance is one of the major challenges for treatment of SCLC. Herein, we investigated the mechanisms underlying drug resistance in SCLC cells and the effects of resveratrol (Res) on drug resistance. We report that Adriamycin treatment of H69AR (multidrug resistance phenotype) cells resulted in a lower rate of growth inhibition, up‐regulation of MRP1 and P‐glycoprotein (P‐gp), and higher P‐gp activity as compared with susceptible H69 cells treated with Adriamycin. Moreover, the signal transducer and activator of transcription 3/vascular endothelial growth factor (STAT3/VEGF) pathway was overactivated in H69AR cells, especially after interleukin‐23 treatment. The inflammatory microenvironment promoted the drug resistance of H69AR cells by activating the STAT3/VEGF pathway. The addition of Res suppressed the expression levels of inflammatory mediators, inhibited the STAT3/VEGF pathway, impeded P‐gp activity, and decreased the drug resistance of H69AR cells. H69AR cells exhibited Adriamycin resistance through activation of the STAT3/VEGF pathway, and Res ameliorated the inflammatory microenvironment to suppress the STAT3/VEGF pathway to reduce drug resistance. Our results suggest that Res may have therapeutic potential for SCLC treatment.

Molecular and biological functions of gingerol as a natural effective therapeutic drug for cervical cancer

Cervical cancer is one of the most common and important gynecological cancers, which has a global concern with an increasing number of patients and mortality rates. Today, most women in the world who suffer from cervical cancer are developing advanced stages of the disease. Smoking and even exposure to secondhand smoke, infections caused by the human papillomavirus, immune system dysfunction and high-risk individual-social behaviors are among the most important predisposing factors for this type of cancer. In addition, papilloma virus infection plays a more prominent role in cervical cancer. Surgery, chemotherapy or radical hysterectomy, and radiotherapy are effective treatments for this condition, the side effects of these methods endanger a person's quality of life and cause other problems in other parts of the body. Studies show that herbal medicines, including taxol, camptothecin and combretastatins, have been shown to be effective in treating cervical cancer. Ginger (Zingiber officinale, Zingiberaceae) is one of the plants with valuable compounds such as gingerols, paradols and shogoals, which is a rich source of antioxidants, anti-cancer and anti-inflammatory agents. Numerous studies have reported the therapeutic effects of this plant through various pathways in cervical cancer. In this article, we look at the signaling mechanisms and pathways in which ginger is used to treat cervical cancer.

Development of Potential Antitumor Agents from the Scaffolds of Plant-Derived Terpenoid Lactones

Naturally occurring terpenoid lactones and their synthetic derivatives have attracted increasing interest for their promising antitumor activity and potential utilization in the discovery and design of new antitumor agents. In the present perspective article, selected plant-derived five-membered γ-lactones and six-membered δ-lactones that occur with terpenoid scaffolds are reviewed, with their structures, cancer cell line cytotoxicity and in vivo antitumor activity, structure-activity relationships, mechanism of action, and the potential for developing cancer chemotherapeutic agents discussed in each case. The compounds presented include artemisinin (ART, 1), parthenolide (PTL, 2), thapsigargin (TPG, 3), andrographolide (AGL, 4), ginkgolide B (GKL B, 5), jolkinolide B (JKL B, 6), nagilactone E (NGL E, 7), triptolide (TPL, 8), bruceantin (BRC, 9), dichapetalin A (DCT A, 10), and limonin (LMN, 11), and their naturally occurring analogues and synthetic derivatives. It is hoped that this contribution will be supportive of the future development of additional efficacious anticancer agents derived from natural products.

The Role of ERBB2/HER2 Tyrosine Kinase Receptor in the Regulation of Cell Death

HER2 (Human Epidermal Growth Factor Receptor 2), also known as ERBB2, CD340, and Neu protooncogene, is a member of the epidermal growth factor receptor (EGRF) family. Members of the ERBB family, including HER2, activate molecular cascades that stimulate proliferation and migration of cancer cells, as well as their resistance to the anticancer therapy. These proteins are often overexpressed and/or mutated in various cancer types and represent promising targets for the anti-cancer therapy. Currently, anti-HER2 drugs have been approved for the treatment of several types of solid tumors. HER2-specific therapy includes monoclonal antibodies and low-molecular weight inhibitors of tyrosine kinase receptors, such as lapatinib, neratinib, and pyrotinib. In addition to the activation of molecular pathways responsible for cell proliferation and survival under stress conditions, HER2 directly regulates programmed cell death. Here, we review the studies focused on the involvement of HER2 in various signaling pathways and its role in the regulation of apoptosis.

Chemistry, biosynthesis and biological activity of terpenoids and meroterpenoids in bacteria and fungi isolated from different marine habitats

The marine environment with its vast biological diversity encompasses many organisms that produce bioactive natural products. Marine microorganisms are rich sources of compounds from many structural classes with a multitude of biological activities. The biosynthesis of microbial natural products depends on a variety of biotic and abiotic factors in the marine environment, including temperature, nutrients, salinity and interaction with other microorganisms. Terpenoids, as one of the most important groups of natural products in terrestrial microorganisms are important metabolites for marine microorganisms. Here, we have reviewed the chemistry, biosynthesis and pharmacological activities of terpenoids, extracted from marine microbes, and then survey their potential applications in drug development. We also discussed the different habitats in which marine microorganisms are found including sediments, the flora, such as seaweeds, sea grasses, and mangroves as well as the fauna like sponges and corals. Amongst these habitats, marine sediments are the major source for terpenoids producing microorganisms. The marine bacteria produce mostly meroterpenoids, while the fungi are well known for production of isoprenoids. Interestingly, marine-derived microbial terpenoids have some structural characteristics such as halogenation, which are catalyzed by specific enzymes with distinct substrate specificity. These compounds have anticancer, antibacterial, antifungal, antimalarial and anti-inflammatory properties. The information collected here might provide useful clues for developing new medications.

CAVIN2 is frequently silenced by CpG methylation and sensitizes lung cancer cells to paclitaxel and 5-FU

Aim: To explore the biological functions and clinical significance of CAVIN2 in lung cancer. Materials & methods: Methylation-specific PCR was used to measure promoter methylation of CAVIN2. The function of CAVIN2 was tested by Cell Counting Kit-8, colony formation, Transwell, flow cytometric analysis, acridine orange/ethidium bromide, chemosensitivity assay and xenograft assay. Results: CAVIN2 is significantly downregulated by promoter methylation in lung cancer. CAVIN2 overexpression inhibits lung cancer cell migration and invasion. Furthermore, ectopic expression of CAVIN2 inhibits cell proliferation in vivo and in vitro by inducing G2/M cell cycle arrest, which sensitizes the chemosensitivity of lung cancer cells to paclitaxel and 5-fluorouracil, but not cisplatin. Conclusion: CAVIN2 is a tumor suppressor in non-small-cell lung cancer and can sensitize lung cancer cells to paclitaxel and 5-fluorouracil.

Asperolide A prevents bone metastatic breast cancer via the PI3K/AKT/mTOR/c-Fos/NFATc1 signaling pathway

Background

Breast cancer is the leading cause of death among women with malignant tumors worldwide. Bone metastasis is the main factor affecting the prognosis of breast cancer. Therefore, both antitumor and anti‐breast‐cancer‐induced osteolysis agents are urgently needed.

Methods

We examined the effect of Asperolide A (AA), a marine‐derived agent, on osteolysis and RANKL‐induced phosphoinositide 3‐kinase (PI3K)/AKT/mTOR/c‐FOS/nuclear factor‐activated T cell 1 (NFATc1) pathway activation, F‐actin ring formation, and reactive oxygen species (ROS) generation in vitro. We evaluated AA effect on breast cancer MDA‐MB‐231 and MDA‐MB‐436 cells in vitro through CCK8 assay, wound healing assay, transwell assay, Annexin V‐FITC/PI staining for cell apoptosis, and cell cycle assay. Furthermore, we assessed the effect of AA in vivo using a breast cancer‐induced bone osteolysis nude mouse model, followed by micro‐computed tomography, tartrate‐resistant acid phosphatase staining, and hematoxylin and eosin staining.

Results

Asperolide A inhibited osteoclast formation and differentiation, bone resorption, F‐actin belt formation, ROS activity, and osteoclast‐specific gene and protein expressions and prevented PI3K/AKT/mTOR/c‐FOS/NFATc1 signaling activation in a dose‐dependent manner in vitro. AA also inhibited breast cancer growth and breast cancer‐induced bone osteolysis by reducing osteoclast formation and function and inactivated PI3K/AKT/mTOR signaling in vivo.

Conclusions

Our study demonstrated that AA suppressed bone metastatic breast cancer. These findings indicate AA as a potential, novel curative drug candidate for patients with bone metastatic breast cancer.

Marine compounds targeting the PI3K/Akt signaling pathway in cancer therapy

Cancer is a disease characterized by overproliferation, including that due to transformation, apoptosis disorders, proliferation, invasion, angiogenesis and metastasis, and is one of the deadliest diseases. Currently, conservative chemotherapy is used for cancer treatment due to a lack of effective drugs. The PI3K/Akt signaling pathway plays a very essential role in the pathogenesis of many cancers, and abnormal activation of this pathway leads to abnormal expression of a series of downstream proteins, which ultimately results in the excessive proliferation of cancer cells. Therefore, the PI3K/Akt signaling pathway is a critical target in cancer treatment. Marine drugs have attracted much attention in recent years, and studies have found that many extracts from oceanic animals, plants and microorganisms or their metabolites exert antitumor effects, including antiproliferative effects or the induction of cell cycle arrest, apoptosis or autophagy. However, most anticancer targets and the mechanisms of marine compounds remain unclear. The great potential of the development of marine drugs provides a new direction for cancer treatment. This review focuses on marine compounds that target the PI3K/Akt signaling pathway for the prevention and treatment of cancer and provides comprehensive information for those interested in research on marine drugs.

Dual effects of active ERK in cancer: A potential target for enhancing radiosensitivity

Ionizing radiation (IR) is an important cancer treatment approach. However, radioresistance eventually occurs, resulting in poor outcomes in patients with cancer. Radioresistance is associated with multiple signaling pathways, particularly pro-survival signaling pathways. The extracellular signal-regulated kinase 1/2 (ERK1/2) cascade is an important signaling pathway that initiates several cellular processes and is regulated by various stimuli, including IR. Although numerous studies have demonstrated the pro-survival effects of active ERK, activation of ERK has also been associated with cell death, indicating that radiosensitization may occur by ERK stimulation. In this context, the present review describes the associations between ERK signaling, cancer and IR, and discusses the association between ERK and its pro-survival function in cancer cells, including stimuli, molecular mechanisms, clinical use of inhibitors and underlying limitations. Additionally, the present review introduces the view that active ERK may induce cell death, and describes the potential factors associated with this process. This review describes the various outcomes induced by active ERK to prompt future studies to aim to enhance radiosensitivity in the treatment of cancer.

BRC-mediated RNAi targeting of USE1 inhibits tumor growth in vitro and in vivo

USE1 has been demonstrated to play crucial roles in the development and progression of human lung cancer. However, the antitumor efficacy of RNA interference (RNAi) targeting of USE1 has not yet been evaluated as a possible clinical application. We here synthesized USE1 targeting bubbled RNA-based cargo (BRC) composed of densely packed multimeric pre-siRNAs with specific Dicer cleavage sites to enable efficient siRNA release upon entry to target cells. The physical entanglement and continuous networking of RNAs via hybridization during enzymatic replication serve as a driving force for the self-assembly of BRCs. These molecules effectively suppressed the transcription of their target genes, leading to tumor growth suppression in vitro and in vivo. Moreover, their repeated intravenous administration efficiently inhibited the growth of A549 tumor xenografts. Based on these findings of a reduced cancer cell viability following a USE1 knockdown, we further explored cell cycle arrest and apoptosis pathways. The observed tumor cell growth suppression was found to be controlled by cell cycle arrest and apoptosis signals induced by the USE1 reduction. These results suggest that USE1 BRCs may have future clinical applications as an RNAi-based cancer therapy.

Antitumor Potential of Seaweed Derived-Endophytic Fungi

The marine environment presents a high biodiversity and a valuable source of bioactive compounds with therapeutic and biotechnological potential. Among the organisms present in marine environment, the endophytic fungi isolated from seaweed stand out. These microorganisms have aroused interest in the scientific community regarding its various activities such as antiviral, antimicrobial, antioxidant, photoprotective, cytotoxic, genotoxic, anti-inflammatory, and anticancer, besides establishing important ecological relations with its hosts. Anticancer molecules derived from marine natural sources are a promising target against different types of cancer. The disease's high rates of morbidity and mortality affect millions of people world wild and the search for new therapeutic alternatives is needed. Thus, this review partially summarizes the methodologies for the isolation of seaweed-derived endophytic fungi, as well as describes the anticancer compounds isolated from such microorganisms, reported in the literature from 2009 to the present. In addition, it describes how some biotechnological processes can help in the discovery of bioactive compounds, especially with anticancer activity.

Novel compound cedrelone inhibits hepatocellular carcinoma progression via PBLD and Ras/Rap1

Although it is known that Phenazine biosynthesis-like domain-containing protein (PBLD) expression is downregulated in hepatocellular carcinoma (HCC), its biological function is unclear. Additionally, no agents capable of upregulating PBLD exist. In the current study, the relationship between PBLD and HCC was analyzed using clinicopathological specimens. A HCC cell model, microarray analysis and an animal model were used to verify the therapeutic effect of cedrelone on HCC. The present study demonstrated that PBLD inhibited HCC progression. Furthermore, the present study revealed that cedrelone possessed treated-HCC capabilities via targeted PBLD overexpression. The epithelial-mesenchymal transition phenotype and growth rate were inhibited and the apoptosis ratio was promoted by cedrelone following PBLD overexpression. The Ras and Ras-proximate-1 signaling pathways were also determined to be regulated by cedrelone via PBLD activation in HCC. PBLD may therefore be an independent predictor of HCC progression and a novel target for HCC treatment. Additionally, the PBLD activator, cedrelone, may be a potential drug for HCC treatment in the future.

DNA methylation-regulated QPCT promotes sunitinib resistance by increasing HRAS stability in renal cell carcinoma

Rationale: Although sunitinib has been shown to improve the survival rate of advanced renal cell carcinoma (RCC) patients, poor drug response is a major challenge that reduces patient benefit. It is important to elucidate the underlying mechanism so that the therapeutic response to sunitinib can be restored. Methods: We used an Illumina HumanMethylation 850K microarray to find methylation-differentiated CpG sites between sunitinib-nonresponsive and -responsive RCC tissues and Sequenom MassARRAY methylation analysis to verify the methylation chip results. We verified glutaminyl peptide cyclotransferase (QPCT) expression in sunitinib-nonresponsive and -responsive RCC tissues via qRT-PCR, western blot and immunohistochemical assays. Then, cell counting kit 8 (CCK-8), plate colony formation and flow cytometric assays were used to verify the function of QPCT in RCC sunitinib resistance after QPCT intervention or overexpression. Chromatin immunoprecipitation (ChIP) was performed to clarify the upstream regulatory mechanism of QPCT. A human proteome microarray assay was used to identify downstream proteins that interact with QPCT, and co-immunoprecipitation (co-IP) and confocal laser microscopy were used to verify the protein chip results. Results: We found that the degree of methylation in the QPCT promoter region was significantly different between sunitinib-nonresponsive and -responsive RCC tissues. In the sunitinib-nonresponsive tissues, the degree of methylation in the QPCT promoter region was significantly reduced, and the expression of QPCT was upregulated, which correlated with a clinically poor response to sunitinib. A knockdown of QPCT conferred sunitinib sensitivity traits to RCC cells, whereas an overexpression of QPCT restored sunitinib resistance in RCC cells. Mechanistically, reducing the methylation degree of the QPCT promoter region by 5-aza-2'-deoxycytidine (decitabine) in RCC cells could increase the expression of QPCT and NF-κB (p65) bound to the QPCT promoter region, positively regulating its expression, while the hypermethylation in the QPCT promoter region could inhibit the binding of NF-κB (p65). QPCT could bind to HRAS and attenuate the ubiquitination of HRAS, thus increasing its stability and leading to the activation of the ERK pathway in RCC cells. Conclusion: QPCT may be a novel predictor of the response to sunitinib therapy in RCC patients and a potential therapeutic target.

Marine Fungi: Biotechnological Perspectives from Deep-Hypersaline Anoxic Basins

Deep-sea hypersaline anoxic basins (DHABs) are one of the most hostile environments on Earth. Even though DHABs have hypersaline conditions, anoxia and high hydrostatic pressure, they host incredible microbial biodiversity. Among eukaryotes inhabiting these systems, recent studies demonstrated that fungi are a quantitatively relevant component. Here, fungi can benefit from the accumulation of large amounts of organic material. Marine fungi are also known to produce bioactive molecules. In particular, halophilic and halotolerant fungi are a reservoir of enzymes and secondary metabolites with valuable applications in industrial, pharmaceutical, and environmental biotechnology. Here we report that among the fungal taxa identified from the Mediterranean and Red Sea DHABs, halotolerant halophilic species belonging to the genera Aspergillus and Penicillium can be used or screened for enzymes and bioactive molecules. Fungi living in DHABs can extend our knowledge about the limits of life, and the discovery of new species and molecules from these environments can have high biotechnological potential.

Discovery and Structure-Based Optimization of Benzimidazole-Derived Activators of SOS1-Mediated Nucleotide Exchange on RAS

Son of sevenless homologue 1 (SOS1) is a guanine nucleotide exchange factor that catalyzes the exchange of GDP for GTP on RAS. In its active form, GTP-bound RAS is responsible for numerous critical cellular processes. Aberrant RAS activity is involved in ∼30% of all human cancers; hence, SOS1 is an attractive therapeutic target for its role in modulating RAS activation. Here, we describe a new series of benzimidazole-derived SOS1 agonists. Using structure-guided design, we discovered small molecules that increase nucleotide exchange on RAS in vitro at submicromolar concentrations, bind to SOS1 with low double-digit nanomolar affinity, rapidly enhance cellular RAS-GTP levels, and invoke biphasic signaling changes in phosphorylation of ERK 1/2. These compounds represent the most potent series of SOS1 agonists reported to date.

Wentilactone A induces cell apoptosis by targeting AKR1C1 gene via the IGF-1R/IRS1/PI3K/AKT/Nrf2/FLIP/Caspase-3 signaling pathway in small cell lung cancer

Wentilactone A (WA), a marine-derived compound, inhibits proliferation of NCI-H446, as demonstrated by previous research; however, the anti-SCLC mechanism underlying WA was not fully investigated. The present study aimed to investigate the anti-SCLC mechanism underlying WA in vitro and in vivo. Cell Counting Kit-8 was used to assay cell growth, flow cytometry was conducted to analyze cell apoptosis and nude mice xenografts were used to examine SCLC growth following WA treatment. Bioinformatics was used for verification of the target gene of WA. Reverse transcription-quantitative polymerase chain reaction and western blot were used to examine aldo-keto reductase family 1 member C1 (AKR1C1) mRNA and protein levels, and AKR1C1-associated proteins prior to and following WA treatment. Cell growth, apoptosis and growth of nude mice xenografts were assayed prior to and following transfection with AKR1C1 knockdown or overexpression carriers, respectively. It was determined that AKR1C1 was a target gene of WA. Decreased AKR1C1 expression and WA treatment promoted apoptosis in SCLC via the insulin like growth factor-1 receptor/insulin receptor substrate 1/phosphoinositide 3-kinase/AKT/nuclear factor-erythroid 2-associated factor 2/Fas-associated death domain-like interleukin-1-converting enzyme-like inhibitory protein/Caspase-3 pathway. WA attenuated the proliferation and induced the apoptosis of SCLC cells in vitro and in vivo by targeting the AKR1C1 gene. WA may be a novel AKR1C1-targeted drug candidate for the treatment of SCLC in the future.

Resveratrol promotes the sensitivity of small-cell lung cancer H446 cells to cisplatin by regulating intrinsic apoptosis

The aim of the present study was to evaluate the effects of resveratrol on small-cell lung cancer (SCLC) cell proliferation and apoptosis. The results demonstrated that resveratrol concentration- and time-dependently reduced H446 cell viability. In addition, cells treated with resveratrol displayed higher apoptotic rates, in association with mitochondrial depolarization, cytochrome c release from the mitochondrial compartment to the cytoplasm, apoptosis-inducing factor translocation from the mitochondrial compartment to the nucleus, and altered protein levels of Bcl-2, Bcl-xL and Bax. Furthermore, resveratrol promoted H446 cell inhibition by cisplatin, as reflected by reduced viability and increased apoptosis. These findings suggest that resveratrol exerts antitumor effects on SCLC H446 cells and promotes H446 cell killing by cisplatin via modulation of intrinsic apoptosis.

Overexpression of the Ubiquilin-4 (UBQLN4) is Associated with Cell Cycle Arrest and Apoptosis in Human Normal Gastric Epithelial Cell Lines GES-1 Cells by Activation of the ERK Signaling Pathway

BACKGROUND Ubiquilin-4 (UBQLN4) is a component of the ubiquitin-proteasome system and regulates the degradation of many proteins implicated in pathological conditions. The aim of this study was to determine the role of UBQLN4 in regulating the proliferation and survival of the normal gastric epithelial cell line GES-1. MATERIAL AND METHODS We constructed GES-1 lines stably overexpressing UBQLN4 by lentiviral infection. Cell proliferation, apoptosis, and the cell cycle were analyzed using the MTT assay and flow cytometric assays. Phosphorylation of ERK, JNK, p38, and expression of cyclin D1 were detected by western blot analysis. RESULTS Overexpression of UBQLN4 significantly reduced proliferation and induced G2/M phase arrest and apoptosis in GES-1 cells. Moreover, upregulation of UBQLN4 increased the expression of cyclin D1 and phosphorylated ERK, but not JNK or p38. CONCLUSIONS These data suggest that UBQLN4 may induce cell cycle arrest and apoptosis via activation of the ERK pathway and upregulation of cyclin D1 in GES-1 cells.

Pseudo-Ginsenoside Rh2 induces A549 cells apoptosis via the Ras/Raf/ERK/p53 pathway

Ginsenoside Rh2, a major effective constituent of ginseng, has been suggested to have a pro-apoptotic effect in a variety of cancer cells. Pseudo-Ginsenside-Rh2 (pseudo-G-Rh2) is a novel derivative of ginsenoside Rh2. The aim of the present study was to evaluate the effect of pseudo-G-Rh2 on the apoptosis of lung adenocarcinoma A549 cells. The cytotoxicity of pseudo-G-Rh2 on A549 cells was evaluated using an MTT assay. Apoptosis was detected using DAPI staining and flow cytometry. The expression of apoptosis associated proteins was identified by western blot analysis. The results demonstrated that pseudo-G-Rh2 inhibits the proliferation of A549 cells in a dose-dependent manner. DAPI staining revealed topical morphological changes in apoptotic bodies following pseudo-G-Rh2 treatment. Flow cytometric analysis revealed that the percentage of Annexin V-fluorescein isothiocyanate-positive cells, which are apoptotic, increased with pseudo-G-Rh2 treatment in a dose-dependent manner. Furthermore, treatment with pseudo-G-Rh2 increased the level of reactive oxygen species in A549 cells as well as the activation of caspase-9, caspase-3 and poly ADP-ribose polymerase. Pseudo-G-Rh2 treatment was observed to induce mitochondrial membrane potential loss. Furthermore, the results of western blotting revealed that B-cell lymphoma 2 (Bcl-2) expression was significantly decreased while Bcl-2-associated X protein expression was significantly upregulated in A549 cells with pseudo-G-Rh2 treatment. Pseudo-G-Rh2-induced apoptosis was accompanied by sustained phosphorylation of Ras, Raf, extracellular signal-regulated kinase (ERK) and p53. In conclusion, the results of the present study suggest that pseudo-G-Rh2 induces mitochondrial apoptosis in A549 cells and is responsible for excessive activation of the Ras/Raf/ERK/p53 pathway.

Scutellarin Increases Cisplatin-Induced Apoptosis and Autophagy to Overcome Cisplatin Resistance in Non-small Cell Lung Cancer via ERK/p53 and c-met/AKT Signaling Pathways

Cisplatin, as the first-line anti-tumor agent, is widely used for treatment of a variety of malignancies including non-small cell lung cancer (NSCLC). However, the acquired resistance has been a major obstacle for the clinical application. Scutellarin is a active flavone extracted from Erigeron breviscapus Hand-Mazz that has been shown to exhibit anticancer activities on various types of tumors. Here, we reported that scutellarin was capable of sensitizing A549/DDP cells to cisplatin by enhancing apoptosis and autophagy. Mechanistic analyses indicated that cisplatin-induced caspase-3-dependent apoptosis was elevated in the presence of scutellarin through activating extracellular signal-regulated kinases (ERK)-mediated p53 pathway. Furthermore, scutellarin also promoted cisplatin-induced cytotoxic autophagy, downregulated expression of p-AKT and c-met. Deficiency of c-met reduced p-AKT level, and inhibition of p-AKT or c-met improved autophagy in A549/DDP cells. Interestingly, loss of autophagy attenuated the synergism of this combination. In vivo, the co-treatment of cisplatin and scutellarin notably reduced the tumor size when compared with cisplatin treatment alone. Notably, scutellarin significantly reduced the toxicity generated by cisplatin in tumor-bearing mice. This study identifies the unique role of scutellarin in reversing cisplatin resistance through apoptosis and autophagy, and suggests that combined cisplatin and scutellarin might be a novel therapeutic strategy for patients with NSCLC.

Diepoxybutane-induced apoptosis is mediated through the ERK1/2 pathway

Diepoxybutane (DEB) is the most potent active metabolite of butadiene, a regulated air pollutant. We previously reported the occurrence of DEB-induced, p53-dependent, mitochondrial-mediated apoptosis in human lymphoblasts. The present study investigated the role of the extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) pathway in DEB-induced apoptotic signaling in exposed human lymphoblasts. Activated ERK1/2 and mitogen-activated protein (MAP) kinase/ERK1/2 kinase (MEK) levels were significantly upregulated in DEB-exposed human lymphoblasts. The MEK inhibitor PD98059 and ERK1/2 siRNA significantly inhibited apoptosis, ERK1/2 activation, as well as p53 and phospho-p53 (serine-15) levels in human lymphoblasts undergoing DEB-induced apoptosis. Collectively, these results demonstrate that DEB induces apoptotic signaling through the MEK-ERK1/2-p53 pathway in human lymphoblasts. This is the first report implicating the activation of the ERK1/2 pathway and its subsequent role in mediating DEB-induced apoptotic signaling in human lymphoblasts. These findings contribute towards the understanding of DEB toxicity, as well as the signaling pathways mediating DEB-induced apoptosis in human lymphoblasts.

Marine Fungi: A Source of Potential Anticancer Compounds

Metabolites from marine fungi have hogged the limelight in drug discovery because of their promise as therapeutic agents. A number of metabolites related to marine fungi have been discovered from various sources which are known to possess a range of activities as antibacterial, antiviral and anticancer agents. Although, over a thousand marine fungi based metabolites have already been reported, none of them have reached the market yet which could partly be related to non-comprehensive screening approaches and lack of sustained lead optimization. The origin of these marine fungal metabolites is varied as their habitats have been reported from various sources such as sponge, algae, mangrove derived fungi, and fungi from bottom sediments. The importance of these natural compounds is based on their cytotoxicity and related activities that emanate from the diversity in their chemical structures and functional groups present on them. This review covers the majority of anticancer compounds isolated from marine fungi during 2012-2016 against specific cancer cell lines.

Macrovipecetin, a C-type lectin from Macrovipera lebetina venom, inhibits proliferation migration and invasion of SK-MEL-28 human melanoma cells and enhances their sensitivity to cisplatin

BACKGROUND

The resistance of melanoma cells to cisplatin restricts its clinical use. Therefore, the search for novel tumor inhibitors and effective combination treatments that sensitize tumor cells to this drug are still needed. We purified macrovipecetin, a novel heterodimeric C-type lectin, from Macrovipera lebetina snake venom and investigated its anti-tumoral effect on its own or combined with cisplatin, in human melanoma cells.

METHODS

Biochemical characterization, in vitro cells assays such as viability, apoptosis, adhesion, migration, invasion, Western blotting and in silico analysis were used in this study.

RESULTS

Macrovipecetin decreased melanoma cell viability 100 times more than cisplatin. Interestingly, when combined with the drug, macrovipecetin enhanced the sensitivity of SK-MEL-28 cells by augmenting their apoptosis through increased expression of the apoptosis inducing factor (AIF) and activation of ERK_1/2, p38, AKT and NF-κB. Moreover, macrovipecetin alone or combined with cisplatin induced the expression of TRADD, p53, Bax, Bim and Bad and down-regulated the Bcl-2 expression and ROS levels in SK-MEL-28 cells. Interestingly, these treatments impaired SK-MEL-28 cell adhesion, migration and invasion through modulating the function and expression of αvβ3 integrin along with regulating E-cadherin, vimentin, β-catenin, c-Src and RhoA expression. In silico study suggested that only the α chain of macrovipecetin interacts with a region overlapping the RGD motif binding site on this integrin.

CONCLUSIONS

We validated the antitumor effect of macrovipecetin when combined, or not, with cisplatin on SK-MEL-28 cells.

GENERAL SIGNIFICANCE

The presented work proposes the potential use of macrovipecetin and cisplatin in combination as an effective anti-melanoma treatment.

Surface Plasmon Resonance Sensing of Biorecognition Interactions within the Tumor Suppressor p53 Network

Surface Plasmon Resonance (SPR) is a powerful technique to study the kinetics of biomolecules undergoing biorecognition processes, particularly suited for protein-protein interactions of biomedical interest. The potentiality of SPR was exploited to sense the interactions occurring within the network of the tumor suppressor p53, which is crucial for maintaining genome integrity and whose function is inactivated, mainly by down regulation or by mutation, in the majority of human tumors. This study includes p53 down-regulators, p53 mutants and also the p53 family members, p63 and p73, which could vicariate p53 protective function. Furthermore, the application of SPR was extended to sense the interaction of p53 with anti-cancer drugs, which might restore p53 function. An extended review of previous published work and unpublished kinetic data is provided, dealing with the interaction between the p53 family members, or their mutants and two anticancer molecules, Azurin and its cell-penetrating peptide, p28. All the kinetic results are discussed in connection with those obtained by a complementary approach operating at the single molecule level, namely Atomic Force Spectroscopy and the related literature data. The overview of the SPR kinetic results may significantly contribute to a deeper understanding of the interactions within p53 network, also in the perspective of designing suitable anticancer drugs.

Cardamonin induces ROS-mediated G2/M phase arrest and apoptosis through inhibition of NF-κB pathway in nasopharyngeal carcinoma

Cardamonin has been demonstrated to have an inhibitory effect in many cancers, but its underlying mechanism remains elusive. Here, we studied, for the first time, the mechanism of cardamonin-induced nasopharyngeal carcinoma cell death both in vitro and in vivo. In our study, we showed that cardamonin inhibited cancer cell growth by inducing G2/M phase cell cycle arrest and apoptosis via accumulation of ROS. NF-κB activation was involved in breaking cellular redox homeostasis. Therefore, our results provided new insight into the mechanism of the antitumor effect of cardamonin, supporting cardamonin as a prospective therapeutic drug in nasopharyngeal carcinoma by modulating intracellular redox balance.

Mertensene, a Halogenated Monoterpene, Induces G2/M Cell Cycle Arrest and Caspase Dependent Apoptosis of Human Colon Adenocarcinoma HT29 Cell Line through the Modulation of ERK-1/-2, AKT and NF-κB Signaling

Conventional treatment of advanced colorectal cancer is associated with tumor resistance and toxicity towards normal tissues. Therefore, development of effective anticancer therapeutic alternatives is still urgently required. Nowadays, marine secondary metabolites have been extensively investigated due to the fact that they frequently exhibit anti-tumor properties. However, little attention has been given to terpenoids isolated from seaweeds. In this study, we isolated the halogenated monoterpene mertensene from the red alga Pterocladiella capillacea (S.G. Gmelin) Santelices and Hommersand and we highlight its inhibitory effect on the viability of two human colorectal adenocarcinoma cell lines HT29 and LS174. Interestingly, exposure of HT29 cells to different concentrations of mertensene correlated with the activation of MAPK ERK-1/-2, Akt and NF-κB pathways. Moreover, mertensene-induced G2/M cell cycle arrest was associated with a decrease in the phosphorylated forms of the anti-tumor transcription factor p53, retinoblastoma protein (Rb), cdc2 and chkp2. Indeed, a reduction of the cellular level of cyclin-dependent kinases CDK2 and CDK4 was observed in mertensene-treated cells. We also demonstrated that mertensene triggers a caspase-dependent apoptosis in HT29 cancer cells characterized by the activation of caspase-3 and the cleavage of poly (ADP-ribose) polymerase (PARP). Besides, the level of death receptor-associated protein TRADD increased significantly in a concentration-dependent manner. Taken together, these results demonstrate the potential of mertensene as a drug candidate for the treatment of colon cancer.

The CDK4/6 inhibitor palbociclib synergizes with irinotecan to promote colorectal cancer cell death under hypoxia

Hypoxia is an inherent impediment to cancer therapy. Palbociclib, a highly selective inhibitor for CDK4/6, has been tested in numerous clinical trials and has been approved by the FDA. We previously reported that CDK inhibitors can destabilize HIF1α regardless of the presence of hypoxia and can sensitize tumor cells to TRAIL through dual blockade of CDK1 and GSK-3β. To translate this knowledge into a cancer therapeutic strategy, we investigated the therapeutic effects and molecular mechanisms of CDK inhibition against colon cancer cells under normoxia and hypoxia. We found that palbociclib sensitizes colon cancer cells to hypoxia-induced apoptotic resistance via deregulation of HIF-1α accumulation. In addition to inhibition of cell proliferation, we observed that palbociclib promotes colon cancer cell death regardless of the presence of hypoxia at a comparatively high concentration via regulating ERK/GSK-3β signaling and GSK-3β expression. Furthermore, palbociclib synergized with irinotecan in a variety of colon cancer cell lines with various molecular subtypes via deregulating irinotecan-induced Rb phosphorylation and reducing HIF-1α accumulation under normoxia or hypoxia. Collectively, our findings provide a novel combination therapy strategy against hypoxic colon cancer cells that may be further translated in the clinic.

Proteasome inhibition mediates p53 reactivation and anti-cancer activity of 6-gingerol in cervical cancer cells

Human papilloma virus (HPV) expressing E6 and E7 oncoproteins, is known to inactivate the tumor suppressor p53 through proteasomal degradation in cervical cancers. Therefore, use of small molecules for inhibition of proteasome function and induction of p53 reactivation is a promising strategy for induction of apoptosis in cervical cancer cells. The polyphenolic alkanone, 6-Gingerol (6G), present in the pungent extracts of ginger (Zingiber officinale Roscoe) has shown potent anti-tumorigenic and pro-apoptotic activities against a variety of cancers. In this study we explored the molecular mechanism of action of 6G in human cervical cancer cells in vitro and in vivo. 6G potently inhibited proliferation of the HPV positive cervical cancer cells. 6G was found to: (i) inhibit the chymotrypsin activity of proteasomes, (ii) induce reactivation of p53, (iii) increase levels of p21, (iv) induce DNA damage and G2/M cell cycle arrest, (v) alter expression levels of p53-associated apoptotic markers like, cleaved caspase-3 and PARP, and (vi) potentiate the cytotoxicity of cisplatin. 6G treatment induced significant reduction of tumor volume, tumor weight, proteasome inhibition and p53 accumulation in HeLa xenograft tumor cells in vivo. The 6G treatment was devoid of toxic effects as it did not affect body weights, hematological and osteogenic parameters. Taken together, our data underscores the therapeutic and chemosensitizing effects of 6G in the management and treatment of cervical cancer.

Effects of 17-AAG on the cell cycle and apoptosis of H446 cells and the associated mechanisms

As a heat shock protein 90 inhibitor, 17-allyl-amino-17-demethoxygeldanamycin (17-AAG) has been studied in numerous types of cancer, however the effects of 17-AAG on apoptosis and the cell cycle of H446 cells remain unclear. In the current study, the MTT method was used to evaluate the inhibitory effects of different durations and doses of 17-AAG treatment on the proliferation of H446 cells. The cells were stained with Annexin-fluorescein isothiocyanate/propidium iodide and measured by flow cytometry, and the gene and protein expression levels of signal transducer and activator of transcription 3 (STAT3), survivin, cyclin D1, cyt-C, caspase 9 and caspase 3 were determined by reverse transcription-quantitative polymerase chain reaction and western blot analysis. The results indicated that with treatment with 1.25–20 mg/l 17-AAG for 24 and 48 h, significant inhibition of H446 cell proliferation was observed in a time- and dose-dependent manner. With treatment of 3.125, 6.25 and 12.5 mg/l 17-AAG for 48 h, significant apoptosis and cell cycle arrest was observed. The results indicated that the gene and protein expression levels of STAT3, survivin and cyclin D1 were downregulated, and cyt-C, caspase 9 and caspase 3 were upregulated by 17-AAG in a dose-dependent manner when the cells were treated with 3.125 and 6.25 mg/l 17-AAG for 48 h. The results indicated that 17-AAG is able to inhibit the cell proliferation, induce apoptosis and G₂/M arrest and downregulate the gene and protein expression levels of STAT3, survivin and cyclin D1, and upregulate gene and protein expression of cyt-C, caspase 9, caspase 3.

Aspewentins D-H, 20-Nor-isopimarane Derivatives from the Deep Sea Sediment-Derived Fungus Aspergillus wentii SD-310

Five new 20-nor-isopimarane diterpenoids, aspewentins D-H (1-5), along with a related known congener, aspewentin A (6), were isolated from the culture extract of Aspergillus wentii SD-310, a fungal strain obtained from a deep-sea sediment sample. The structures of these compounds were established on the basis of spectroscopic interpretation, and the absolute configurations of compounds 1-5 were determined by X-ray crystallographic analysis and TDDFT-ECD calculations. The isolated compounds were evaluated for antimicrobial activity against nine human and aquatic pathogenic bacteria and four plant pathogenic fungi as well as for lethality against brine shrimp (Artemia salina). 20-Nor-isopimarane derivatives rarely occur in fungi, and only three (aspewentins A-C) have previously been reported from a marine-derived fungus.

Desmethylanhydroicaritin isolated from Sophora flavescens, shows antitumor activities in U87MG cells via inhibiting the proliferation, migration and invasion

This study is the first report of the antitumor activities of desmethylanhydroicaritin (DMAI) isolated from Sophora flavescens on U87MG cells. Human glioblastoma is one of the most aggressive malignant type of brain tumors and highly diffuses to around normal brain tissues. DMAI showed anti-proliferation effects on U87MG cells at the concentration of 30μM, however did not affect to HEK-293 cells. DMAI induced anti-proliferation effects via ERK/MAPK, PI3K/Akt/mTOR signal pathway and G2/M phase cell cycle arrest. DMAI led to morphological change and inhibition of filapodia formation through regulation of Rac 1 and Cdc 42. In addition, migration and invasion of U87MG cells were inhibited by DMAI via down-regulation of matrix metalloproteinase (MMP) -2 and MMP -9 expressions and activities. Our results suggest that DMAI has a potential as a therapeutic agent against glioblastoma cells.

Lebein, a snake venom disintegrin, suppresses human colon cancer cells proliferation and tumor-induced angiogenesis through cell cycle arrest, apoptosis induction and inhibition of VEGF expression

Lebein, is an heterodimeric disintegrin isolated from Macrovipera lebetina snake venom that was previously characterized as an inhibitor of ADP-induced platelet aggregation. In this study, we investigated the effect of Lebein on the p53-dependent growth of human colon adenocarcinoma cell lines. We found that Lebein significantly inhibited LS174 (p53wt), HCT116 (p53wt), and HT29 (p53mut) colon cancer cell viability by inducing cell cycle arrest through the modulation of expression levels of the tumor suppression factor p53, cell cycle regulating proteins cyclin D1, CDK2, CDK4, retinoblastoma (Rb), CDK1, and cyclin-dependent kinase inhibitors p21 and p27. Interestingly, Lebein-induced apoptosis of colon cancer cells was dependent on their p53 status. Thus, in LS174 cells, cell death was associated with PARP cleavage and the activation of caspases 3 and 8 while in HCT116 cells, Lebein induced caspase-independent apoptosis through increased expression of apoptosis inducing factor (AIF). In LS174 cells, Lebein triggers the activation of the MAPK ERK1/2 pathway through induction of reactive oxygen species (ROS). It also decreased cell adhesion and migration to fibronectin through down regulation of α5β1 integrin. Moreover, Lebein significantly reduced the expression of two angiogenesis stimulators, Vascular Endothelial Growth Factor (VEGF) and Neuropilin 1 (NRP1). It inhibited the VEGF-induced neovascularization process in the quail embryonic CAM system and blocked the development of human colon adenocarcinoma in nude mice. Overall, our work indicates that Lebein may be useful to design a new therapy against colon cancer. © 2016 Wiley Periodicals, Inc.

Characterization of a Newly Isolated Marine Fungus Aspergillus dimorphicus for Optimized Production of the Anti-Tumor Agent Wentilactones

The potential anti-tumor agent wentilactones were produced by a newly isolated marine fungus Aspergillus dimorphicus. This fungus was derived from deep-sea sediment and identified by polyphasic approach, combining phenotypic, molecular, and extrolite profiles. However, wentilactone production was detected only under static cultures with very low yields. In order to improve wentilactone production, culture conditions were optimized using the response surface methodology. Under the optimal static fermentation conditions, the experimental values were closely consistent with the prediction model. The yields of wentilactone A and B were increased about 11-fold to 13.4 and 6.5 mg/L, respectively. The result was further verified by fermentation scale-up for wentilactone production. Moreover, some small-molecule elicitors were found to have capacity of stimulating wentilactone production. To our knowledge, this is first report of optimized production of tetranorlabdane diterpenoids by a deep-sea derived marine fungus. The present study might be valuable for efficient production of wentilactones and fundamental investigation of the anti-tumor mechanism of norditerpenoids.

Magnolol inhibits growth of gallbladder cancer cells through the p53 pathway

Magnolol, the major active compound found in Magnolia officinalis has a wide range of clinical applications due to its anti-inflammation and anti-oxidation effects. This study investigated the effects of magnolol on the growth of human gallbladder carcinoma (GBC) cell lines. The results indicated that magnolol could significantly inhibit the growth of GBC cell lines in a dose- and time-dependent manner. Magnolol also blocked cell cycle progression at G0 /G1 phase and induced mitochondrial-related apoptosis by upregulating p53 and p21 protein levels and by downregulating cyclin D1, CDC25A, and Cdk2 protein levels. When cells were pretreated with a p53 inhibitor (pifithrin-a), followed by magnolol treatment, pifithrin-a blocked magnolol-induced apoptosis and G0 /G1 arrest. In vivo, magnolol suppressed tumor growth and activated the same mechanisms as were activated in vitro. In conclusion, our study is the first to report that magnolol has an inhibitory effect on the growth of GBC cells and that this compound may have potential as a novel therapeutic agent for the treatment of GBC.