The synthetic β-nitrostyrene derivative CYT-Rx20 induces breast cancer cell death and autophagy via ROS-mediated MEK/ERK pathway

Melatonin changes energy metabolism and reduces oncogenic signaling in ovarian cancer cells

Ovarian cancer (OC) adjusts energy metabolism in favor of its progression and dissemination. Because melatonin (Mel) has antitumor actions, we investigated its impact on energy metabolism and kinase signaling in OC cells (SKOV-3 and CAISMOV-24). Cells were divided into control and Mel-treated groups, in the presence or absence of the antagonist luzindole. There was a decrease in the levels of HIF-1α, G6PDH, GAPDH, PDH, and CS after Mel treatment even in the presence of luzindole in both OC cells. Mel treatment also reduced the activity of OC-related enzymes including PFK-1, G6PDH, LDH, CS, and GS whereas PDH activity was increased. Lactate and glutamine levels dropped after Mel treatment. Mel further promoted a reduction in the concentrations of CREB, JNK, NF-kB, p-38, ERK1/2, AKT, P70S6K, and STAT in both cell lines. Mel reverses Warburg-type metabolism and possibly reduces glutaminolysis, thereby attenuating various oncogenic molecules associated with OC progression and invasion.

Synthesis and Biochemical Evaluation of Ethanoanthracenes and Related Compounds: Antiproliferative and Pro-Apoptotic Effects in Chronic Lymphocytic Leukemia (CLL)

Chronic lymphocytic leukemia (CLL) is a malignancy of mature B cells, and it is the most frequent form of leukemia diagnosed in Western countries. It is characterized by the proliferation and accumulation of neoplastic B lymphocytes in the blood, lymph nodes, bone marrow and spleen. We report the synthesis and antiproliferative effects of a series of novel ethanoanthracene compounds in CLL cell lines. Structural modifications were achieved via the Diels-Alder reaction of 9-(2-nitrovinyl)anthracene and 3-(anthracen-9-yl)-1-arylprop-2-en-1-ones (anthracene chalcones) with dienophiles, including maleic anhydride and N-substituted maleimides, to afford a series of 9-(E)-(2-nitrovinyl)-9,10-dihydro-9,10-[3,4]epipyrroloanthracene-12,14-diones, 9-(E)-3-oxo-3-phenylprop-1-en-1-yl)-9,10-dihydro-9,10-[3,4]epipyrroloanthracene-12,14-diones and related compounds. Single-crystal X-ray analysis confirmed the structures of the novel ethanoanthracenes 23f, 23h, 24a, 24g, 25f and 27. The products were evaluated in HG-3 and PGA-1 CLL cell lines (representative of poor and good patient prognosis, respectively). The most potent compounds were identified as 20a, 20f, 23a and 25n with IC50 values in the ranges of 0.17-2.69 µM (HG-3) and 0.35-1.97 µM (PGA-1). The pro-apoptotic effects of the potent compounds 20a, 20f, 23a and 25n were demonstrated in CLL cell lines HG-3 (82-95%) and PGA-1 (87-97%) at 10 µM, with low toxicity (12-16%) observed in healthy-donor peripheral blood mononuclear cells (PBMCs) at concentrations representative of the compounds IC50 values for both the HG-3 and PGA-1 CLL cell lines. The antiproliferative effect of the selected compounds, 20a, 20f, 23a and 25n, was mediated through ROS flux with a marked increase in cell viability upon pretreatment with the antioxidant NAC. 25n also demonstrated sub-micromolar activity in the NCI 60 cancer cell line panel, with a mean GI50 value of 0.245 µM. This ethanoanthracene series of compounds offers potential for the further development of lead structures as novel chemotherapeutics to target CLL.

Therapeutic strategies of targeting non-apoptotic regulated cell death (RCD) with small-molecule compounds in cancer

Regulated cell death (RCD) is a controlled form of cell death orchestrated by one or more cascading signaling pathways, making it amenable to pharmacological intervention. RCD subroutines can be categorized as apoptotic or non-apoptotic and play essential roles in maintaining homeostasis, facilitating development, and modulating immunity. Accumulating evidence has recently revealed that RCD evasion is frequently the primary cause of tumor survival. Several non-apoptotic RCD subroutines have garnered attention as promising cancer therapies due to their ability to induce tumor regression and prevent relapse, comparable to apoptosis. Moreover, they offer potential solutions for overcoming the acquired resistance of tumors toward apoptotic drugs. With an increasing understanding of the underlying mechanisms governing these non-apoptotic RCD subroutines, a growing number of small-molecule compounds targeting single or multiple pathways have been discovered, providing novel strategies for current cancer therapy. In this review, we comprehensively summarized the current regulatory mechanisms of the emerging non-apoptotic RCD subroutines, mainly including autophagy-dependent cell death, ferroptosis, cuproptosis, disulfidptosis, necroptosis, pyroptosis, alkaliptosis, oxeiptosis, parthanatos, mitochondrial permeability transition (MPT)-driven necrosis, entotic cell death, NETotic cell death, lysosome-dependent cell death, and immunogenic cell death (ICD). Furthermore, we focused on discussing the pharmacological regulatory mechanisms of related small-molecule compounds. In brief, these insightful findings may provide valuable guidance for investigating individual or collaborative targeting approaches towards different RCD subroutines, ultimately driving the discovery of novel small-molecule compounds that target RCD and significantly enhance future cancer therapeutics.

IL17RB expression is associated with malignant cancer behaviors and poor prognosis in oral cancer

OBJECTIVES

Previously, we demonstrated that IL17RB plays an essential role in lung cancer progression. This study aimed to determine whether IL17RB correlates with oral cancer and promotes oral cancer progression.

SUBJECTS AND METHODS

IL17RB expression in oral cancer tissues and normal tissues was determined by immunohistochemistry staining, while the association of IL17RB expression with the clinicopathological characteristics of oral squamous cell carcinoma (OSCC) patients was analyzed and its correlation with progression-free survival and response to radiotherapy and chemotherapy in OSCC patients was also explored. Western blotting was performed to investigate the expression of IL17RB in various OSCC cell lines; moreover, transwell assay was performed to evaluate the effect of IL17RB expression on cell migration ability.

RESULTS

In this study, we found that IL17RB was expressed higher in OSCC tissues compared to normal oral mucosa tissues and its expression was positively correlated with tumor size, lymph node metastasis, advanced cancer stage, and poor prognosis. In vitro study showed that IL17RB expression in OSCC cell lines as determined by Western blotting, was positively correlated with their migration ability.

CONCLUSION

Clinical and in vitro studies suggest that IL17RB might serve as an independent risk factor and a therapeutic target for oral cancer.

Combination of Ethacrynic Acid and ATRA Triggers Differentiation and/or Apoptosis of Acute Myeloid Leukemia Cells through ROS

BACKGROUND AND OBJECTIVE

All-trans retinoic acid (ATRA), an effective differentiation inducer, has been applied clinically to treat acute promyelocytic leukemia (APL). Unfortunately, it is not as potent in other kinds of acute myeloid leukemia (AML). Ethacrynic acid (EA), a classical powerful diuretic, can increase reactive oxygen species (ROS) contents, which can assist ATRA in inducing differentiation in AML cells. Here, we investigated the effect of EA combined with ATRA (EA+RA) on some AML cells except APL.

METHODS

Apoptosis and differentiation were determined by morphology, cell viability, Annexin-V assay and CD11c expression. Western blot analysis and the detection of ROS and mitochondrial transmembrane potentials (MMP) were used to investigate the mechanisms.

RESULTS

AML cells exhibited differentiation and/or apoptosis after EA+RA treatment. EA+RA increased the intracellular ROS contents. EA+RA-induced apoptosis was accompanied by MMP attenuation and caspase-3/7 activation. EA+RA-induced differentiation was along with MEK/ERK and Akt activation and increased expression of PU.1, CCAAT/enhancer-binding protein β (C/EBPβ) and C/EBPε. N-acetyl-L-cysteine (NAC), an antioxidant, thoroughly reduced EA+RA-increased ROS, and also inhibited MMP attenuation, the activation of caspase- 3/7, MEK/ERK and Akt pathways, the elevation of PU.1 and C/EBPs, and apoptosis and differentiation. However, MEK or PI3K specific inhibitors only suppressed EA+RA-triggered differentiation and the elevation of PU.1 and C/EBPs, but not ROS levels.

CONCLUSION

EA+RA induced cell apoptosis through ROS dependent MMP attenuation and caspase 3/7 activation while inducing differentiation by ROS-MEK/ERK-PU.1/C/EBPs and ROS-Akt-PU.1/C/EBPs pathways. In summary, it may provide innovative ATRA-based combination therapy strategies for AML patients via ROS.

SARS-CoV-2 Vaccination and the Multi-Hit Hypothesis of Oncogenesis

Cancer is a complex and dynamic disease. The "hallmarks of cancer" were proposed by Hanahan and Weinberg (2000) as a group of biological competencies that human cells attain as they progress from normalcy to neoplastic transformation. These competencies include self-sufficiency in proliferative signaling, insensitivity to growth-suppressive signals and immune surveillance, the ability to evade cell death, enabling replicative immortality, reprogramming energy metabolism, inducing angiogenesis, and activating tissue invasion and metastasis. Underlying these competencies are genome instability, which expedites their acquisition, and inflammation, which fosters their function(s). Additionally, cancer exhibits another dimension of complexity: a heterogeneous repertoire of infiltrating and resident host cells, secreted factors, and extracellular matrix, known as the tumor microenvironment, that through a dynamic and reciprocal relationship with cancer cells supports immortality, local invasion, and metastatic dissemination. This staggering intricacy calls for caution when advising all people with cancer (or a previous history of cancer) to receive the COVID-19 primary vaccine series plus additional booster doses. Moreover, because these patients were not included in the pivotal clinical trials, considerable uncertainty remains regarding vaccine efficacy, safety, and the risk of interactions with anticancer therapies, which could reduce the value and innocuity of either medical treatment. After reviewing the available literature, we are particularly concerned that certain COVID-19 vaccines may generate a pro-tumorigenic milieu (i.e., a specific environment that could lead to neoplastic transformation) that predisposes some (stable) oncologic patients and survivors to cancer progression, recurrence, and/or metastasis. This hypothesis is based on biological plausibility and fulfillment of the multi-hit hypothesis of oncogenesis (i.e., induction of lymphopenia and inflammation, downregulation of angiotensin-converting enzyme 2 (ACE2) expression, activation of oncogenic cascades, sequestration of tumor suppressor proteins, dysregulation of the RNA-G quadruplex-protein binding system, alteration of type I interferon responses, unsilencing of retrotransposable elements, etc.) together with growing evidence and safety reports filed to Vaccine Adverse Effects Report System (VAERS) suggesting that some cancer patients experienced disease exacerbation or recurrence following COVID-19 vaccination. In light of the above and because some of these concerns (i.e., alteration of oncogenic pathways, promotion of inflammatory cascades, and dysregulation of the renin-angiotensin system) also apply to cancer patients infected with SARS-CoV-2, we encourage the scientific and medical community to urgently evaluate the impact of both COVID-19 and COVID-19 vaccination on cancer biology and tumor registries, adjusting public health recommendations accordingly.

Synthesis, molecular docking, and binding Gibbs free energy calculation of β-nitrostyrene derivatives: Potential inhibitors of SARS-CoV-2 3CL protease

The outbreak of novel coronavirus disease 2019 (COVID-19), caused by the novel coronavirus (SARS-CoV-2), has had a significant impact on human health and the economic development. SARS-CoV-2 3CL protease (3CLpro) is highly conserved and plays a key role in mediating the transcription of virus replication. It is an ideal target for the design and screening of anti-coronavirus drugs. In this work, seven β-nitrostyrene derivatives were synthesized by Henry reaction and β-dehydration reaction, and their inhibitory effects on SARS-CoV-2 3CL protease were identified by enzyme activity inhibition assay in vitro. Among them, 4-nitro-β-nitrostyrene (compound a) showed the lowest IC₅₀ values of 0.7297 μM. To investigate the key groups that determine the activity of β-nitrostyrene derivatives and their interaction mode with the receptor, the molecular docking using the CDOCKER protocol in Discovery Studio 2016 was performed. The results showed that the hydrogen bonds between β-NO₂ and receptor GLY-143 and the π-π stacking between the aryl ring of the ligand and the imidazole ring of receptor HIS-41 significantly contributed to the ligand activity. Furthermore, the ligand-receptor absolute binding Gibbs free energies were calculated using the Binding Affinity Tool (BAT.py) to verify its correlation with the activity of β-nitrostyrene 3CLpro inhibitors as a scoring function. The higher correlation(r²=0.6) indicates that the absolute binding Gibbs free energy based on molecular dynamics can be used to predict the activity of new β-nitrostyrene 3CLpro inhibitors. These results provide valuable insights for the functional group-based design, structure optimization and the discovery of high accuracy activity prediction means of anti-COVID-19 lead compounds.

The Anti-Fungal Activity of Nitropropenyl Benzodioxole (NPBD), a Redox-Thiol Oxidant and Tyrosine Phosphatase Inhibitor

Phylogenetically diverse fungal species are an increasing cause of severe disease and mortality. Identification of new targets and development of new fungicidal drugs are required to augment the effectiveness of current chemotherapy and counter increasing resistance in pathogens. Nitroalkenyl benzene derivatives are thiol oxidants and inhibitors of cysteine-based molecules, which show broad biological activity against microorganisms. Nitropropenyl benzodioxole (NPBD), one of the most active antimicrobial derivatives, shows high activity in MIC assays for phylogenetically diverse saprophytic, commensal and parasitic fungi. NPBD was fungicidal to all species except the dermatophytic fungi, with an activity profile comparable to that of Amphotericin B and Miconazole. NPBD showed differing patterns of dynamic kill rates under different growth conditions for Candida albicans and Aspergillus fumigatus and was rapidly fungicidal for non-replicating vegetative forms and microconidia. It did not induce resistant or drug tolerant strains in major pathogens on long term exposure. A literature review highlights the complexity and interactivity of fungal tyrosine phosphate and redox signaling pathways, their differing metabolic effects in fungal species and identifies some targets for inhibition. A comparison of the metabolic activities of Amphotericin B, Miconazole and NPBD highlights the multiple cellular functions of these agents and the complementarity of many mechanisms. The activity profile of NPBD illustrates the functional diversity of fungal tyrosine phosphatases and thiol-based redox active molecules and contributes to the validation of tyrosine phosphatases and redox thiol molecules as related and complementary selective targets for antimicrobial drug development. NPBD is a selective antifungal agent with low oral toxicity which would be suitable for local treatment of skin and mucosal infections.

Regulated cell death (RCD) in cancer: key pathways and targeted therapies

Regulated cell death (RCD), also well-known as programmed cell death (PCD), refers to the form of cell death that can be regulated by a variety of biomacromolecules, which is distinctive from accidental cell death (ACD). Accumulating evidence has revealed that RCD subroutines are the key features of tumorigenesis, which may ultimately lead to the establishment of different potential therapeutic strategies. Hitherto, targeting the subroutines of RCD with pharmacological small-molecule compounds has been emerging as a promising therapeutic avenue, which has rapidly progressed in many types of human cancers. Thus, in this review, we focus on summarizing not only the key apoptotic and autophagy-dependent cell death signaling pathways, but the crucial pathways of other RCD subroutines, including necroptosis, pyroptosis, ferroptosis, parthanatos, entosis, NETosis and lysosome-dependent cell death (LCD) in cancer. Moreover, we further discuss the current situation of several small-molecule compounds targeting the different RCD subroutines to improve cancer treatment, such as single-target, dual or multiple-target small-molecule compounds, drug combinations, and some new emerging therapeutic strategies that would together shed new light on future directions to attack cancer cell vulnerabilities with small-molecule drugs targeting RCD for therapeutic purposes.

Assessment of the Therapeutic Potential of Melatonin for the Treatment of Osteoporosis Through a Narrative Review of Its Signaling and Preclinical and Clinical Studies

Melatonin is a bioamine produced primarily in the pineal gland, although peripheral sites, including the gut, may also be its minor source. Melatonin regulates various functions, including circadian rhythm, reproduction, temperature regulation, immune system, cardiovascular system, energy metabolism, and bone metabolism. Studies on cultured bone cells, preclinical disease models of bone loss, and clinical trials suggest favorable modulation of bone metabolism by melatonin. This narrative review gives a comprehensive account of the current understanding of melatonin at the cell/molecular to the systems levels. Melatonin predominantly acts through its cognate receptors, of which melatonin receptor 2 (MT2R) is expressed in mesenchymal stem cells (MSCs), osteoblasts (bone-forming), and osteoclasts (bone-resorbing). Melatonin favors the osteoblastic fate of MSCs, stimulates osteoblast survival and differentiation, and inhibits osteoclastogenic differentiation of hematopoietic stem cells. Produced from osteoblastic cells, osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) critically regulate osteoclastogenesis and melatonin by suppressing the osteoclastogenic RANKL, and upregulating the anti-osteoclastogenic OPG exerts a strong anti-resorptive effect. Although the anti-inflammatory role of melatonin favors osteogenic function and antagonizes the osteoclastogenic function with the participation of SIRT signaling, various miRNAs also mediate the effects of the hormone on bone cells. In rodent models of osteoporosis, melatonin has been unequivocally shown to have an anti-osteoporotic effect. Several clinical trials indicate the bone mass conserving effect of melatonin in aging/postmenopausal osteoporosis. This review aims to determine the possibility of melatonin as a novel class of anti-osteoporosis therapy through the critical assessment of the available literature.

Cytotoxicity of synthetic derivatives against breast cancer and multi-drug resistant breast cancer cell lines: a literature-based perspective study

Cancer is the second most killer worldwide causing millions of people to lose their lives every year. In the case of women, breast cancer takes away the highest proportion of mortality rate than other cancers. Due to the mutation and resistance-building capacity of different breast cancer cell lines against conventional therapies, this death rate is on the verge of growth. New effective therapeutic compounds and treatment method is the best way to look out for in this critical time. For instance, new synthetic derivatives/ analogues synthesized from different compounds can be a ray of hope. Numerous synthetic compounds have been seen enhancing the apoptosis and autophagic pathway that directly exerts cytotoxicity towards different breast cancer cell lines. To cease the ever-growing resistance of multi-drug resistant cells against anti-breast cancer drugs (Doxorubicin, verapamil, tamoxifen) synthetic compounds may play a vital role by increasing effectivity, showing synergistic action. Many recent and previous studies have reported that synthetic derivatives hold potentials as an effective anti-breast cancer agent as they show great cytotoxicity towards cancer cells, thus can be used even vastly in the future in the field of breast cancer treatment. This review aims to identify the anti-breast cancer properties of several synthetic derivatives against different breast cancer and multi-drug-resistant breast cancer cell lines with their reported mechanism of action and effectivity.

Multiple strategies for the treatment of invasive breast carcinoma: A comprehensive prospective

In this review, we emphasize on evolving therapeutic strategies and advances in the treatment of breast cancer (BC). This includes small-molecule inhibitors under preclinical and clinical investigation, phytoconstituents with antiproliferative potential, targeted therapies as antibodies and antibody-drug conjugates (ADCs), vaccines as immunotherapeutic agents and peptides as a novel approach inhibiting the interaction of oncogenic proteins. We provide an update of molecules under different phases of clinical investigation which aid in the identification of loopholes or shortcomings that can be overcomed with future breast cancer research.

Oridonin induces autophagy-mediated cell death in pancreatic cancer by activating the c-Jun N-terminal kinase pathway and inhibiting phosphoinositide 3-kinase signaling

Background

Oridonin is a diterpenoid isolated from Rabdosia rubescens that has potent anticancer activity. This study set out to investigate the antitumor effects of oridonin in pancreatic carcinoma (PC) and their underlying mechanisms.

Methods

To investigate the antitumor effects of oridonin, we developed an orthotopic C57BL/6 mouse model of PC. After successful establishment of the model, the mice were given a daily intraperitoneal injection of phosphate-buffered saline containing 0.1% dimethyl sulfoxide or oridonin for 2 weeks. In vitro experiments including MTT assay and flow cytometry were performed to examine cell viability and apoptosis. Panc-1 and Panc02 cells were transfected with a green fluorescent protein (GFP)-LC3 plasmid. After the cells had been treated with or without 20 μM oridonin and 10 μM 3-MA, the formation of GFP-LC3 puncta was detected by fluorescence microscopy. The levels of the autophagy-related proteins Beclin-1, LC3, and p62 were measured by western blotting.

Results

Oridonin inhibited the proliferation of PC cells and induced their apoptosis in vitro and in vivo. Treatment with oridonin also led to an increase in the quantity of LC3B II protein and upregulation of the p62 and Beclin-1 levels in PC cells. The effects of oridonin on PC cell proliferation, apoptosis, and autophagy were mediated via the simultaneous inhibition of the phosphoinositide 3-kinase pathway and activation of the c-Jun N-terminal kinase pathway.

Conclusions

Our study is the first to confirm the antitumor and autophagy-activating effects of oridonin on PC cells. In light of these results, oridonin may be a promising therapeutic agent for PC.

COVID-19 infection and nanomedicine applications for development of vaccines and therapeutics: An overview and future perspectives based on polymersomes

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), which emerged in December 2019 and caused the coronavirus disease 2019 (COVID-19) pandemic, took the world by surprise with an unprecedented public health emergency. Since this pandemic began, extraordinary efforts have been made by scientists to understand the pathogenesis of COVID-19, and to fight the infection by providing various preventive, diagnostic and treatment opportunities based on either novel hypotheses or past experiences. Despite all the achievements, COVID-19 continues to be an accelerating health threat with no specifically approved vaccine or therapy. This review highlights the recent advances in COVID-19 infection, with a particular emphasis on nanomedicine applications that can help in the development of effective vaccines or therapeutics against COVID-19. A novel future perspective has been proposed in this review based on utilizing polymersome nano-objects for effectively suppressing the cytokine storm, which may reduce the severity of COVID-19 infection.

DNA damage response and breast cancer development: Possible therapeutic applications of ATR, ATM, PARP, BRCA1 inhibition

Breast cancer is the most common and significant cancers in females regarding the loss of life quality. Similar to other cancers, one of the etiologic factors in breast cancer is DNA damage. A plethora of molecules are responsible for sensing DNA damage and mediating actions which lead to DNA repair, senescence, cell cycle arrest and if damage is unbearable to apoptosis. In each of these, aberrations leading to unrepaired damage was resulted in uncontrolled proliferation and cancer. Another cellular function is autophagy defined as a process eliminating of unnecessary proteins in stress cases involved in pathogenesis of cancer. Knowing their role in cancer, scholars have tried to develop strategies in order to target DDR and autophagy. Further, the interactions of DDR and autophagy plus their regulatory role on each other have been focused simultaneously. The present review study has aimed to illustrate the importance of DDR and autophagy in breast cancer according to the related studies and uncover the relation between DDR and autophagy and its significance in breast cancer therapy.

AGEs induces apoptosis and autophagy via reactive oxygen species in human periodontal ligament cells

The apoptosis of human periodontal ligament cells (HPDLCs) may be an important factor of the negative effect of advanced glycation end products (AGEs) on the periodontal tissue of diabetic patients. However, the pathways or potential effects of apoptosis in AGEs-treated HPDLCs have not been fully elucidated. Autophagy is closely related to apoptosis. Herein, we investigated the potential mechanism of apoptosis and autophagy in HPDLCs treated with AGEs via an in vitro model. We found that AGEs-treated HPDLCs showed a time- and concentration-dependent reduction in the cell survival rate. The mitochondrial-dependent apoptosis was induced in AGEs-treated HPDLCs, as confirmed by the mitochondrial membrane potential depolarization, decreased Bcl-2 expression, increased Bax expression, and increased caspase-3 and PARP cleavage. Autophagy was also induced in AGEs-treated HPDLCs, as indicated by the conversion of LC3-II/LC3-I and the presence of autophagosomes. Interestingly, our study results suggested that apoptosis and autophagy were related to reactive oxygen species (ROS) production. In addition, AGEs-induced autophagy acted as a latent factor in decreasing the generation of ROS in HPDLCs and protecting against the AGEs-induced apoptosis. In summary, our study shows that ROS are essential in AGEs-induced HPDLCs apoptosis and autophagy, which may be a molecular mechanism for the repairment of ROS-induced damage in HPDLCs treated with AGEs to promote cell survival. The present study might provide new insights into the therapeutic targeting of HPDLCs autophagy, which could be an additional strategy for periodontitis in patients with diabetes mellitus.

Exopolysaccharide from Cryptococcus heimaeyensis S20 induces autophagic cell death in non-small cell lung cancer cells via ROS/p38 and ROS/ERK signalling

OBJECTIVES

Cryptococcus heimaeyensis S20 is found in Antarctica and can produce exopolysaccharides (CHEPS). Here, we explore the anti-tumour effects of CHEPS on non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Cell viability was assessed by CCK8 and colony formation assays. Flow cytometry was used to analyse the cell cycle, cell apoptosis and reactive oxygen species (ROS). Cell autophagy was detected by EGFP-LC3 puncta assay, Lyso-Tracker Red staining and transmission electron microscopy. mRNA and protein levels were analysed by qRT-PCR and Western blot. Related mechanisms were confirmed using appropriate inhibitors or shRNA. In vitro results were further confirmed by a tumour xenograft study.

RESULTS

CHEPS inhibited the proliferation of NSCLC cells by inducing S- and G2/M-phase arrest and autophagic cell death, but not apoptosis. CHEPS was less toxic to normal human embryonic lung fibroblasts. CHEPS activated the MAPK pathway in NSCLC cells, and p38 and ERK promoted CHEPS-induced cell death. Further studies showed that p38 and ERK promoted CHEPS-induced NSCLC cell autophagy and ERK promoted CHEPS-induced S- and G2/M-phase arrest. ROS were induced by CHEPS. A ROS scavenger attenuated CHEPS-induced p38 and ERK activation, autophagy and cell death. Finally, CHEPS reduced orthotopic lung tumour growth without organ-related toxicity. CHEPS also induced ROS, activated p38 and ERK, and triggered autophagy in vivo.

CONCLUSIONS

CHEPS induces autophagic cell death and S- and G2/M-phase arrest in NSCLC cells via ROS/p38 and ROS/ERK signalling.

Myricetin induces apoptosis and autophagy by inhibiting PI3K/Akt/mTOR signalling in human colon cancer cells

BACKGROUND

The compound 3,3',4',5,5',7-hexahydroxyflavone (myricetin) is a natural flavonoid with antitumour activity. Most of the studies on myricetin have focused on the induction of tumour cell apoptosis, and little is known about the regulatory effects of myricetin on autophagy in colorectal cancer.

METHODS

Here, we studied the effects of myricetin on colon cancer cell proliferation, apoptosis and autophagy. We detected colon cancer cell apoptosis induced by myricetin via flow cytometry and Hoechst 33258 staining. Transmission electron microscopy was performed to observe the morphological changes associated with autophagy. The expression levels of apoptosis-, autophagy- and PI3K/Akt/mTOR signalling-related proteins were measured by Western blot analysis.

RESULTS

This study confirmed that myricetin inhibits the proliferation of 4 kinds of colon cancer cell lines. Myricetin induced cell apoptosis and autophagy by inhibiting PI3K/Akt/mTOR signalling pathway. In addition, the inhibition of autophagy with 3-methyladenine (3-MA) promoted the apoptosis of myricetin-treated colon cancer cells.

CONCLUSIONS

Considering that myricetin induces apoptosis and autophagy in colon cancer cells, myricetin may become a viable candidate for chemotherapy; it could be used to exert tumour inhibitory effects alone or as adjuvant chemotherapy to inhibit autophagy. These studies may provide further evidence for the potential use of myricetin in the treatment of colon cancer.

Irinotecan Induces Autophagy-Dependent Apoptosis and Positively Regulates ROS-Related JNK- and P38-MAPK Pathways in Gastric Cancer Cells

Background

Irinotecan (IRI) is considered an option for second-line treatment of advanced gastric cancer; however, acquired drug resistance currently limits its clinical application. Recently, many researchers have shown that autophagy plays a crucial role in the resistance of tumor cells to chemotherapy and radiotherapy. In this study, we investigated the relationship between autophagy and antitumor activity of IRI in gastric cancer cells.

Methods

We used MTT assay, flow cytometry and immunofluorescence staining to detect viability, apoptosis and autophagy in gastric cancer. Western blotting assay was used to determine the expression of LC3, Beclin-1, P62, cleaved PARP and Caspase 3. In vivo animal study was performed finally.

Results

We found that IRI treatment dose- and time-dependently inhibited growth and induced apoptosis in gastric cancer cells. Moreover, IRI treatment caused autophagy in these cells, whereas autophagy inhibitors—3-methyladenine (3-MA), chloroquine (CQ), and Beclin-1 small interfering RNA (siRNA)—suppressed cytotoxicity of IRI. A mechanistic analysis showed that IRI-induced autophagy and apoptosis were related to increased reactive oxygen species (ROS) accumulation and activation of the JNK- and p38-MAPK pathways. Further in vivo experiments revealed that IRI suppressed tumor growth, induced autophagy, and stimulated the JNK- and p38-MAPK pathways, whereas 3-MA attenuated these effects.

Conclusion

Taken together, these results indicate that IRI stimulates the ROS-related JNK- and p38-MAPK pathways to promote autophagy-dependent apoptosis. Thus, a combination of IRI with a pharmacological autophagy enhancer may be a promising therapeutic strategy against gastric cancer.

Autophagy suppresses resveratrol-induced apoptosis in renal cell carcinoma 786-O cells

As a polyphenolic compound, resveratrol (Res) is widely distributed in a variety of plants. Previous studies have demonstrated that Res can inhibit various different types of tumor growth. However, its role in renal cell carcinoma (RCC) remains largely unknown. The present study first demonstrated that Res inhibited cell viability and induced apoptosis in RCC 786-O cells. Further experiments revealed that Res damaged the mitochondria and activated caspase 3. In contrast, Z-VAD-FMK, a pan-caspase inhibitor, suppressed Res-induced apoptosis. Reactive oxygen species (ROS) were involved in the process of Res-induced apoptosis, and antioxidant N-acetyl cysteine could significantly attenuate this. Furthermore, Res activated c-Jun N-terminal kinase via ROS to induce autophagy, whereas inhibition of autophagy with chloroquine or Beclin 1 small interfering RNA aggravated Res-induced apoptosis, indicating that autophagy served as a pro-survival mechanism to protect 786-O cells from Res-induced apoptosis. Therefore, a combination of Res and autophagy inhibitors could enhance the inhibitory effect of Res on RCC.

Design, Synthesis and Biochemical Evaluation of Novel Ethanoanthracenes and Related Compounds to Target Burkitt's Lymphoma

Lymphomas (cancers of the lymphatic system) account for 12% of malignant diseases worldwide. Burkitt’s lymphoma (BL) is a rare form of non-Hodgkin’s lymphoma in which the cancer starts in the immune B-cells. We report the synthesis and preliminary studies on the antiproliferative activity of a library of 9,10-dihydro-9,10-ethanoanthracene based compounds structurally related to the antidepressant drug maprotiline against BL cell lines MUTU-1 and DG-75. Structural modifications were achieved by Diels-Alder reaction of the core 9-(2-nitrovinyl)anthracene with number of dienophiles including maleic anhydride, maleimides, acrylonitrile and benzyne. The antiproliferative activity of these compounds was evaluated in BL cell lines EBV⁻ MUTU-1 and EBV⁺ DG-75 (chemoresistant). The most potent compounds 13j, 15, 16a, 16b, 16c, 16d and 19a displayed IC₅₀ values in the range 0.17–0.38 μM against the BL cell line EBV⁻ MUTU-1 and IC₅₀ values in the range 0.45–0.78 μM against the chemoresistant BL cell line EBV⁺ DG-75. Compounds 15, 16b and 16c demonstrated potent ROS dependent apoptotic effects on the BL cell lines which were superior to the control drug taxol and showed minimal cytotoxicity to peripheral blood mononuclear cells (PBMCs). The results suggest that this class of compounds merits further investigation as antiproliferative agents for BL.

The cardiotoxicity of the common carp (Cyprinus carpio) exposed to environmentally relevant concentrations of arsenic and subsequently relieved by zinc supplementation

Waterborne exposure to arsenic trioxide (As₂O₃) is inevitable due to its widespread industrial and agricultural applications. Oxidative stress and cascaded programmed cell death is now hypothesized to be the dominant mechanisms of arseniasis evidenced in vivo and in vitro. This study aimed to explore the interaction of divalent zinc ion (Zn²⁺), an efficient reactive oxygen species (ROS) scavenger with arsenite in the heart of common carp, and extensively investigated the exact signaling molecules involved. Significant induction of cardiotoxicity including oxidative stress, apoptosis and autophagy was evident in heart tissues following arsenite exposure (P < 0.05). The dissipation of antioxidant enzymes (SOD and CAT) was induced by ROS burst, leading to oxidative damage and lipid peroxidation (MDA). Arsenite induced classic apoptotic hallmarks, characterized by chromatin degradation and subsequent formation of clumps adjacent, and elevated expression of Bax/Bcl-2 and Caspase family, and also increased autophagic flux evidenced by accelerated formation (LC3) and degradation (p62) of autophagosomes. PI3K/Akt/mTOR pathway was phosphorylated inhibited, while MAPK signaling (p38, ERK and JNK) displayed elevated phosphorylation levels in arsenite-exposed heart tissues. In contrast, above phenomena were effectively inhibited by Zn²⁺, which supplement attenuated arsenite-induced myocardial toxicity through inhibition of apoptosis and autophagy via PI3K/Akt/mTOR pathway, as well as suppressing intracellular ROS cluster via activating antioxidative system via MAPK pathway. Our results provided experimental explanation and evidences for cardiotoxicity of arsenite. Furthermore, our findings hint that the application of zinc preparations may provide a candidate for the prevention and treatment for arsenic poisoning.

CS-PEI/Beclin-siRNA Downregulate Multidrug Resistance Proteins and Increase Paclitaxel Therapeutic Efficacy against NSCLC

Paclitaxel (PTX) is a widely used chemotherapy drug; however, frequent use causes multidrug resistance (MDR), which limits the utility of PTX against advanced non-small-cell lung cancer (NSCLC). PTX-resistant subline (NCI-H23-TXR) was established in vitro by exposing NCI-H23 cells to gradually increased concentrations of PTX in culture medium. Distinct Beclin expression of autophagy level was observed between resistant NCI-H23-TXR and parental NCI-H23 cells. Beclin-small interfering RNA (siRNA) was selected to restore sensitivity of PTX against NCI-H23-TXR. Chondroitin sulfate-polyethylenimine (CS-PEI) was constructed for delivery and protection of Beclin-siRNA. To delineate the underlying molecular mechanism of Beclin knockdown, we analyzed different MDR expression proteins of two cells using western blot, and the corresponding genes were confirmed by real-time PCR. Compared with NCI-H23, NCI-H23-TXR had higher expression levels in P-glycoprotein (P-gp) and multidrug resistance protein 7 (ABCC10). Knockdown of Beclin simultaneously inhibited P-gp and ABCC10, and renewed the sensitivity of PTX against NCI-H23-TXR. Research on zebrafish embryos revealed that tumor sizes decreased in NCI-H23 tumor xenografts but remained intact in NCI-H23-TXR tumor xenografts as zebrafish were treated with 1 μg/mL PTX. In contrast, the tumor sizes decreased in NCI-H23-TXR tumor xenografts with zebrafish pre-transfected with CS-PEI/Beclin-siRNA followed by the same treatment of PTX. The role of autophagy was associated with MDR development. This study paves the way for a new avenue of PTX in MDR-related lung cancer therapy using CS-PEI as a gene delivery carrier.

Celastrol mediates autophagy and apoptosis via the ROS/JNK and Akt/mTOR signaling pathways in glioma cells

Background

Celastrol, a triterpene compound derived from the traditional Chinese medicine Tripterygium wilfordii, has been reported to possess potential antitumor activity towards various malignancies. However, the effect of celastrol on glioma cells and the underlying molecular mechanisms remain elusive.

Methods

Glioma cells, including the U251, U87-MG and C6 cell lines and an animal model were used. The effects of celastrol on cells were evaluated by flow cytometry, confocal microscopy, reactive oxygen species production assay and immunoblotting after treatment of celastrol. Fisher’s exact test, a one-way ANOVA and the Mann-Whitney U-test were used to compare differences between groups. All data were analyzed using SPSS version 21.0 software.

Results

Here, we found that exposure to celastrol induced G2/M phase arrest and apoptosis. Celastrol increased the formation of autophagosomes, accumulation of LC3B and the expression of p62 protein. Celastrol-treated glioma cells exhibited decreased cell viability after the use of autophagy inhibitors. Additionally, autophagy and apoptosis caused by celastrol in glioma cells inhibited each other. Furthermore, celastrol induced JNK activation and ROS production and inhibited the activities of Akt and mTOR kinases. JNK and ROS inhibitors significantly attenuated celastrol-trigged apoptosis and autophagy, while Akt and mTOR inhibitors had opposite effects.

Conclusions

In conclusion, our study revealed that celastrol caused G2/M phase arrest and trigged apoptosis and autophagy by activating ROS/JNK signaling and blocking the Akt/mTOR signaling pathway.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1173-4) contains supplementary material, which is available to authorized users.

Stimulation of pulmonary vagal C-fibers by trans-4-methyl-β-nitrostyrene induces bradycardiac and depressor reflex in rats: Role of vanilloid TRPV1 receptors

Previously, we showed that the synthetic nitroderivative trans-4-methyl-β-nitrostyrene (T4MeN) induced vasorelaxant effects in rat isolated aortic rings. Here, we investigated the mechanisms underlying the cardiovascular effects of T4MeN in normotensive rats. In pentobarbital-anesthetized rats, intravenous (i.v.) injection of T4MeN (0.03-0.5 mg/kg) induced a rapid (onset time of 1-2 s) and dose-dependent bradycardia and hypotension. These cardiovascular responses to T4MeN were abolished by bilateral cervical vagotomy or selective blockade of neural conduction of vagal C-fiber afferents by perineural treatment of both cervical vagus nerves with capsaicin. Hypotension and bradycardia were also recorded when T4MeN was directly injected in the right, but not into the left ventricle. Furthermore, they were significantly reduced by i.v. pretreatment with capsazepine but remained unaltered by ondansetron or suramin. In conscious rats, the dose-dependent hypotension and bradycardia evoked by T4MeN were abolished by i.v. methylatropine pretreatment. In conclusion, bradycardiac and depressor responses induced by T4MeN has a vago-vagal reflex origin resulting from the vagal pulmonary afferents stimulation. The transduction mechanism seems to involve the activation of vanilloid TRPV₁, but not purinergic (P2X) or 5-HT₃ receptors located on vagal pulmonary sensory nerves.

PKP3 interactions with MAPK-JNK-ERK1/2-mTOR pathway regulates autophagy and invasion in ovarian cancer

Armadillo-related proteins function in both signal transduction and cell adhesion, it also plays a central role in tumorigenesis. Plakophilin 3 (PKP3) is a member of the armadillo protein family. PKP3 has demonstrated a role in melanoma, breast cancer, gastric cancer, and other kind of cancers; however its role in ovarian cancer was not fully understood. In this study we explored the function and mechanisms of PKP3 in ovarian cancer. An elevated level of PKP3 was found in ovarian cancer tissues compared with normal tissues. PKP3 also modulate cellular proliferation and invasion in ovarian cancer. The ability of cellular proliferation, formation, and invasion was significantly decreased after the silencing of PKP3 in SKOV3 cells. While an over-expression of PKP3 in A2780 cells up-regulates the ability of cellular proliferation, formation, and invasion. As for the mechanism of PKP3, mTOR pathway was activated to regulate autophagy according to the interaction of PKP3 with the upstream of MAPK pathway. The result of this study support PKP3 as the oncogene candidate and a potential target for the treatment of ovarian cancer.

Glutamine Deficiency Promotes PCV2 Infection through Induction of Autophagy via Activation of ROS-Mediated JAK2/STAT3 Signaling Pathway

Porcine circovirus type 2 (PCV2) is an important pathogen in swine herds. We previously reported that glutamine (Gln) deficiency promoted PCV2 infection in vitro. Here, we established a Gln deficiency model in vivo and further investigated the detailed molecular mechanisms. In vivo and in vitro, Gln deficiency promoted PCV2 infection, which was evident through increased viral yields and PCV2 Cap protein synthesis. It also induced autophagy, as demonstrated by the increases in LC3-II conversion, SQSTM1 degradation, and GFP-LC3 dot accumulation. Autophagy inhibition abolished the effects of Gln deficiency on PCV2 infection. Inhibition of ROS generation alleviated the Gln deficiency-activated JAK2/STAT3 signaling pathway, thereby inhibiting autophagy induction. In vitro, the inhibition of STAT3 by an inhibitor or RNA interference blocked autophagy, thus reversing the effects of Gln deficiency on PCV2 infection. These results indicate that Gln deficiency activates autophagy by upregulating ROS-medicated JAK2/STAT3 signaling and thereby promoting PCV2 infection.

A new xanthatin analogue 1β-hydroxyl-5α-chloro-8-epi-xanthatin induces apoptosis through ROS-mediated ERK/p38 MAPK activation and JAK2/STAT3 inhibition in human hepatocellular carcinoma

1β-hydroxyl-5α-chloro-8-epi-xanthatin (XTT), a sesquiterpene lactone isolated from Xanthium sibiricum, possessed potent cytotoxicity on cancer cells in vitro. The objective of this study was to investigate the anti-tumor effect and underlying mechanisms of XTT on human hepatocellular carcinoma (HCC). Firstly, XTT inhibited the cell growth and induced apoptosis in human HCC cells, which was associated with the induction of Bax and cleaved-caspase-3, inhibition of Bcl-2 and survivin expression. Importantly, XTT induced the generation of reactive oxygen species (ROS) and malondialdehyde (MDA), and depletion of glutathione (GSH) in HCC cells through covalently modification of GSH. Furthermore, XTT caused obvious activation of extracellular regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (p38 MAPK) and inactivation of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) in HCC cells. ROS scavenger N-acetyl cysteine abrogated the effects of XTT on ERK/p38 MAPK activation and JAK2/STAT3 inhibition, and rescued HCC cells from XTT-induced apoptosis. Additionally, inhibitors of ERK/p38 MAPKs or activator of JAK2/STAT3 partially abolished XTT-mediated effect. In summary, XTT inhibited cell growth and induced apoptosis in HCC cells through ROS-mediated ERK/p38 MAPK activation and JAK2/STAT3 inhibition by GSH depletion. These findings also show the therapeutic potential of XTT in HCC.

Attenuation of everolimus-induced cytotoxicity by a protective autophagic pathway involving ERK activation in renal cell carcinoma cells

Aim

The mammalian target of rapamycin (mTOR) pathway is a critical target for cancer treatment and the mTOR inhibitor everolimus (RAD001) has been approved for treatment of renal cell carcinoma (RCC). However, the limited efficacy of RAD001 has led to the development of drug resistance. Autophagy is closely related to cell survival and death, which may be activated under RAD001 stimulation. The aim of the present study was to identify the underlying mechanisms of RAD001 resistance in RCC cells through cytoprotective autophagy involving activation of the extracellular signal-regulated kinase (ERK) pathway.

Methods and results:

RAD001 strongly induced autophagy of RCC cells in a dose- and time-dependent manner, as confirmed by Western blot analysis. Importantly, suppression of autophagy by the pharmacological inhibitor chloroquine effectively enhanced RAD001-induced apoptotic cytotoxicity, as demonstrated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Western blot analysis, indicating a cytoprotective role for RAD001-induced autophagy. In addition, as was shown by the MTT assay, flow cytometry, and Western blot analysis, RAD001 robustly activated ERK, but not c-Jun N-terminal kinase and p38. Activation of ERK was inhibited by the pharmacological inhibitor selumetinib (AZD6244), which effectively promoted RAD001-induced cell death. Moreover, employing AZD6244 markedly attenuated RAD001-induced autophagy and enhanced RAD001-induced apoptosis, which play a central role in RAD001-induced cell death. Furthermore, RAD001-induced autophagy is regulated by ERK-mediated phosphorylation of Beclin-1 and B-cell lymphoma 2, as confirmed by Western blot analysis.

Conclusion

These results suggest that RAD001-induced autophagy involves activation of the ERK, which may impair cytotoxicity of RAD001 in RCC cells. Thus, inhibition of the activation of ERK pathway-mediated autophagy may be useful to overcome chemoresistance to RAD001.

Juglone induces apoptosis and autophagy via modulation of mitogen-activated protein kinase pathways in human hepatocellular carcinoma cells

Juglone (JG), a naturally-occurring naphthoquinone of Manchurian walnut (Juglans mandshurica) was shown to inhibit proliferation in various tumor types. However, the molecular mechanisms of JG on the induction of apoptosis and autophagy in HepG2 cells have not been examined. Herein, we investigated that JG could inhibit cell proliferation by induction of G2/M phase arrest. Also, occurrence of apoptosis was closely related with loss of mitochondrial membrane potential, the changes of apoptosis-related proteins after treatment with JG. In addition, we found that JG caused autophagy, as evidenced by increased expressions of LC3-II and Beclin-1. Interestingly, inhibition of JG-induced autophagy by 3-methyladenine (3-MA) and wortmannin (WT) significantly decreased apoptosis, whereas the apoptosis inhibitor z-VAD-fmk slightly enhanced autophagy. Furthermore, the induction of autophagy and apoptosis was associated with activation of MAPK family members (p38 and JNK) and production of reactive oxygen species (ROS). Both JNK inhibitor (SP600125) and ROS scavenger (N-acetylcysteine, NAC) could attenuate JG-induced autophagy and apoptosis. However, the p38-specific inhibitor SB203580 enhanced autophagic and apoptotic death. Moreover, the ROS scavenger NAC prevented phosphorylation of both p38 and JNK. Collectively, our data revealed that JG induced G2/M phase arrest, apoptosis, and autophagy through the ROS-dependent signaling pathway.

The TLR7 agonist imiquimod induces anti-cancer effects via autophagic cell death and enhances anti-tumoral and systemic immunity during radiotherapy for melanoma

Toll-like receptor (TLR) ligands are strongly considered immune-adjuvants for cancer immunotherapy and have been shown to exert direct anti-cancer effects. This study was performed to evaluate the synergistic anti-cancer and anti-metastatic effects of the TLR7 agonist imiquimod (IMQ) during radiotherapy for melanoma. The pretreatment of B16F10 or B16F1 cells with IMQ combined with γ-ionizing radiation (IR) led to enhanced cell death via autophagy, as demonstrated by increased expression levels of autophagy-related genes, and an increased number of autophagosomes in both cell lines. The results also confirmed that the autophagy process was accelerated via the reactive oxygen species (ROS)-mediated MAPK and NF-κB signaling pathway in the cells pretreated with IMQ combined with IR. Mice subcutaneously injected with melanoma cells showed a reduced tumor growth rate after treatment with IMQ and IR. Treatment with 3-methyladenine (3-MA), ameliorated the anti-cancer effect of IMQ combined with IR. Additionally, the combination therapy enhanced anti-cancer immunity, as demonstrated by an increased number of CD8⁺ T cells and decreased numbers of regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSCs) in the tumor lesions. Moreover, the combination therapy decreased the number of metastatic nodules in the lungs of mice that were injected with B16F10 cells via the tail vein. In addition, the combination therapy enhanced systemic anti-cancer immunity by increasing the abundances of T cell populations expressing IFN-γ and TNF-α. Therefore, these findings suggest that IMQ could serve as a radiosensitizer and immune booster during radiotherapy for melanoma patients.

Short hairpin RNA-mediated gene silencing of ADAM17 inhibits the growth of breast cancer MCF‑7 cells in vitro and in vivo and its mechanism of action

A disintegrin and metalloprotease 17 (ADAM17) is highly expressed in many malignant tumors and is closely related to their development. We showed in a previous study that silencing of ADAM17 by siRNA inhibited the growth of MCF-7 breast cancer cells in vitro and in vivo. In the present study, we investigated the effects of ADAM17-short hairpin RNA (ADAM17-shRNA) on MCF-7 breast cancer cells and explored the potential action pathway. In vitro, transfection of shRNAs was performed using a lentivirus, and the effects of ADAM17-shRNA on invasion, proliferation and cell cycle distribution of MCF-7 cells were assessed by Boyden chamber method, real-time cell analysis and flow cytometry, respectively. In vivo, MCF-7 cells with different administrations were transplanted subcutaneously into nude mice, and the effect of ADAM17-shRNA on the growth of transplanted tumors was assessed. In addition, the morphological structures were observed by H&E staining, and the expression of ADAM17 and Ki-67 was assessed by immunohistochemistry; expression of ADAM17, EGFR, p-EGFR, AKT, p-AKT, ERK and p-ERK proteins was assessed by western blotting, respectively. Our data showed that ADAM17-shRNA successfully inhibited ADAM17 mRNA expression, invasion and proliferation of MCF-7 cells resulting in G0/G1 phase arrest, and significantly inhibited the growth of transplanted tumors with larger areas of necrosis, low expression of ADAM17 and Ki-67 and reduced protein expression of ADAM17, EGFR, p-EGFR, AKT, p-AKT, ERK, and p-ERK in the tumor tissues. The present research suggests that ADAM17-shRNA can inhibit MCF-7 cell invasion and proliferation in vitro and inhibit MCF-7 xenograft growth in vivo through the EGFR/PI3K/AKT and EGFR/MEK/ERK signaling pathways.

Melatonin suppresses autophagy in type 2 diabetic osteoporosis

Type 2 diabetes mellitus is often complicated by osteoporosis, a process which may involve osteoblast autophagy. As melatonin suppresses autophagy under certain conditions, we its investigated the effects on bone autophagy during diabetes. We first assessed different body parameters in a diabetic rat model treated with various concentrations of melatonin. Dynamic biomechanicalmeasurements, bone organization hard slice dyeing and micro-CT were used to observe the rat bone microstructure, and immunohistochemistry was used to determine levels of autophagy biomarkers. We also performed in vitro experiments on human fetal osteoblastic (hFOB1.19) cells cultured with high glucose, different concentrations of melatonin, and ERK pathway inhibitors. And we used Western blotting and immunofluorescence to measure the extent of osteogenesis and autophagy. We found that melatonin improved the bone microstructure in our rat diabetes model and reduced the level of autophagy(50 mg/kg was better than 100 mg/kg). Melatonin also enhanced osteogenesis and suppressed autophagy in osteoblasts cultured at high glucose levels (10 μM was better than 1 mM). This suggests melatonin may reduce the level of autophagy in osteoblasts and delay diabetes-induced osteoporosis by inhibiting the ERK signaling pathway.

β-Nitrostyrene derivatives attenuate LPS-mediated acute lung injury via the inhibition of neutrophil-platelet interactions and NET release

Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) are high-mortality and life-threatening diseases that are associated with neutrophil activation and accumulation within lung tissue. Emerging evidence indicates that neutrophil-platelet aggregates (NPAs) at sites of injury increase acute inflammation and contribute to the development of ALI. Although numerous studies have increased our understanding of the pathophysiology of ALI, there is still a lack of innovative and useful treatments that reduce mortality, emphasizing that there is an urgent need for novel treatment strategies. In this study, a new series of small compounds of β-nitrostyrene derivatives (BNSDs) were synthesized, and their anti-inflammatory bioactivities on neutrophils and platelets were evaluated. The new small compound C7 modulates neutrophil function by inhibiting superoxide generation and elastase release. Compound C7 elicits protective effects on LPS-induced paw edema and acute lung injury via the inhibition of neutrophil accumulation, proinflammatory mediator release, platelet aggregation, myeloperoxidase activity, and neutrophil extracellular trap (NET) release. NET formation was identified as the bridge for the critical interactions between neutrophils and platelets by confocal microscopy and flow cytometry. This research provides new insights for elucidating the complicated regulation of neutrophils and platelets in ALI and sheds further light on future drug development strategies for ALI/ARDS and acute inflammatory diseases.

Identification of (1S,4S)-2,5-diazabicyclo[2.2.1]heptane-dithiocarbamate-nitrostyrene hybrid as potent antiproliferative and apoptotic inducing agent against cervical cancer cell lines

The present study seeks to describe the design and synthesis of six new Michael adducts of (1S,4S)-2,5-diazabicyclo[2.2.1]heptane-dithiocarbamate with nitrostyrenes and their in vitro antiproliferative activity against human cervical cancer cell lines [HeLa (HPV 18 positive), CaSki (HPV 16 positive) and ViBo (HPV negative) cervical cancer cell lines]. Virtual screening of the physicochemical properties of all compounds have also been presented. All the compounds exploited significant antiproliferative activity on the three cervical cancer cell lines. Compound 8a was found to be most potent, displaying in vitro antiproliferative activity against HeLa, CaSki and ViBo cervical cancer cell lines superior to Cisplatin and Paclitaxel with IC₅₀ values 0.99 ± 0.007, 2.36 ± 0.016 and 0.73 ± 0.002 μM respectively. In addition, compound 8a did not trigger the necrosis cell death to the test cancer cell lines. Further mechanistic study revealed that compound 8a could inhibit the cancer cell proliferation by inducing apoptosis through caspase-3 activation. Moreover, cell cycle analysis indicated that compound 8a could arrest the cell cycle at the G1 phase for HeLa and CaSki cancer cells. At the predetermined IC₅₀ values on cancer cells, compound 8a did not induce any necrotic (cytotoxic) death to the normal human lymphocytes. In the present design, (1S,4S)-2,5-diazabicyclo[2.2.1]heptane system was found to be superior than the piperazine counterpart 11.

Alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone inhibits cell proliferation, invasion, and migration in gastric cancer in part via autophagy

Gastric cancer is a leading cause of mortality worldwide. Alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone is a type of limonoid mainly isolated from Cedrela odorata (Meliaceae) that has been shown to suppress cell proliferation in several human carcinoma cell lines. In this study, we investigated the anti-cancer ability of alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone and its underlying mechanism in MKN45 cells. Alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone induced excess reactive oxygen species (ROS) accumulation. Transwell and wound healing assays demonstrated that alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone inhibited the invasion and migration ability of MKN45 cells. Moreover, autophagy-related proteins Beclin-1, Atg5, and Atg7 were up-regulated. Light chain 3 (LC3)-I protein was converted into LC3-II under alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone exposure. Transmission electron microscopy demonstrated that alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone treatment resulted in the formation of autophagosomes. Immunofluorescence assays suggested that alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone treatment elicited dot formation of green fluorescent protein (GFP)-LC3. 3-methyladenine (3-MA), an autophagy inhibitor, demonstrated that autophagy promoted death in MKN45 cells. Western blotting showed that ROS/mitogen activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways play crucial roles in the intrinsic mechanism of alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone's activity. The combined use of N-acetyl-_L-cysteine (NAC) or U0126 validated the regulatory role of ROS/MEK/ERK signaling pathways. Alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone administration inhibited the growth of MKN45 xenograft tumors in nude mice and suppressed Ki67 expression. More importantly, a similar effect was achieved in a patient-derived xenograft (PDX) model, which is more relevant to clinical application. Taken together, alpha, 2'-dihydroxy-4,4'-dimethoxydihydrochalcone has the potential to be further developed into an anti-tumor agent for clinical treatment of gastric cancer.

High Nrf2 expression in alveolar type I pneumocytes is associated with low recurrences in primary spontaneous pneumothorax

Recurrent primary spontaneous pneumothorax (PSP) is a troublesome problem and a major concern for the patients. This study examined whether nuclear factor erythroid 2-related factor 2 (Nrf2) expression in alveolar type I pneumocytes was associated with the clinical manifestations of PSP patients including disease recurrence. Eighty-eight PSP patients who were managed with needlescopic video-assisted thoracoscopic surgery (NVATS) were included in this study. Immunohistochemistry (IHC) was assessed to determine Nrf2 expression in resected lung tissues and the results were correlated with clinicopathological characteristics by the chi-square or the Fisher's exact test. The prognostic value of Nrf2 for overall recurrence was evaluated by univariate and multivariable Cox regression model. The expression of Nrf2 was observed in type I pneumocytes of lung tissues from PSP patients by IHC. We found that low Nrf2 expression in PSP patients, especially in young (age ≤ 20, p = 0.033) and body mass index (BMI) ≥18 kg/m² (p = 0.019) groups, was significantly correlated with PSP recurrence. In the univariate and multivariate analyses, high Nrf2 expression was a significant protective factor for overall recurrence in PSP patients (univariate: p = 0.026; multivariate: p = 0.004). The expression level of Nrf2 in alveolar type I pneumocytes was a potential factor involved in PSP recurrence. Our findings suggest that elevated Nrf2 expression in PSP patients may be a promising way for reducing PSP recurrence.

3'-hydroxy-4'-methoxy-β-methyl-β-nitrostyrene inhibits tumorigenesis in colorectal cancer cells through ROS-mediated DNA damage and mitochondrial dysfunction

The β-nitrostyrene family has been shown to suppress cell proliferation and induce apoptosis in types of various cancers. However, the mechanisms underlying the anticancer effects of β-nitrostyrenes in colorectal cancer remain poorly understood. In this study, we synthesized a β-nitrostyrene derivative, CYT-Rx20 (3'-hydroxy-4'-methoxy-β-methyl-β-nitrostyrene), and investigated its anticancer activities in human colorectal cancer cells both in vitro and in vivo. Our findings showed that treatment with CYT-Rx20 reduced cell viability and induced DNA damage in colorectal cancer cells. In addition, CYT-Rx20 induced cell cycle arrest of colorectal cancer cells at the G2/M phase and upregulated the protein expression of phospho-ERK, cyclin B1, phospho-cdc2 (Tyr15), aurora A, and aurora B, while it downregulated the expression of cdc25A and cdc25C. Furthermore, we found that CYT-Rx20 caused accumulation of intracellular reactive oxygen species (ROS) and reduction of mitochondrial membrane potential. The effects of CYT-Rx20 on cell viability, DNA damage, and mitochondrial membrane potential were reversed by pretreatment with the thiol antioxidant N-acetyl-L-cysteine (NAC), suggesting that ROS-mediated DNA damage and mitochondrial dysregulation play a critical role in these events. Finally, the nude mice xenograft study showed that CYT-Rx20 significantly reduced tumor growth of implanted colorectal cancer cells accompanied by elevated protein expression of aurora A, aurora B, γH2AX, phosphor-ERK, and MDA in the tumor tissues. Taken together, these results suggest that CYT-Rx20 may potentially be developed as a novel β-nitrostyrene-based anticancer agent for colorectal cancer.

CYT-Rx20 Inhibits Cervical Cancer Cell Growth and Migration Through Oxidative Stress-Induced DNA Damage, Cell Apoptosis, and Epithelial-to-Mesenchymal Transition Inhibition

OBJECTIVE

The β-nitrostyrene family has been reported to possess anticancer properties. However, the anticancer activity of β-nitrostyrenes on cervical cancer cells and the underlying mechanisms involved remain unexplored. In this study, a β-nitrostyrene derivative CYT-Rx20 (3'-hydroxy-4'-methoxy-β-methyl-β-nitrostyrene) was synthesized, and its anticancer activity on cervical cancer cells and the mechanisms involved were investigated.

METHODS

The effect of CYT-Rx20 on human cervical cancer cell growth was evaluated using cell viability assay. Reactive oxygen species (ROS) generation and annexin V staining were detected by flow cytometry. The protein expression levels of cleaved caspase-3, cleaved caspase-9, cleaved poly (ADPribose) polymerase, γH2AX, β-catenin, Vimentin, and Twist were measured by Western blotting. DNA double-strand breaks were determined by γ-H2AX foci formation and neutral comet assay. Migration assay was used to determine cancer cell migration. Nude mice xenograft was used to investigate the antitumor effects of CYT-Rx20 in vivo.

RESULTS

CYT-Rx20 induced cytotoxicity in cervical cancer cells by promoting cell apoptosis via ROS generation and DNA damage. CYT-Rx20-induced cell apoptosis, ROS generation, and DNA damage were reversed by thiol antioxidants. In addition, CYT-Rx20 inhibited cervical cancer cell migration by regulating the expression of epithelial-to-mesenchymal transition markers. In nude mice, CYT-Rx20 inhibited cervical tumor growth accompanied by increased expression of DNA damage marker γH2AX and decreased expression of mesenchymal markers β-catenin and Twist.

CONCLUSIONS

CYT-Rx20 inhibits cervical cancer cells in vitro and in vivo and has the potential to be further developed into an anti-cervical cancer drug clinically.

Reactive Oxygen Species-Regulating Polymersome as an Antiviral Agent against Influenza Virus

Reactive oxygen species (ROS) produced during mitochondrial oxidative phosphorylation play an important role as signal messengers in the immune system and also regulate signal transduction. ROS production, initiated as a consequence of microbial invasion, if generated at high levels, induces activation of the MEK (mitogen-activated protein kinase kinase)/ERK (extracellular signal-regulated kinase) pathway to promote cell survival and proliferation. However, viruses hijack the host cells' pathways, causing biphasic activation of the MEK/ERK cascade. Thus, regulation of ROS leads to concomitant inhibition of virus replication. In the present study, poly(aniline-co-pyrrole) polymerized nanoregulators (PASomes) to regulate intracellular ROS levels are synthesized, exploiting their oxidizing-reducing characteristics. Poly(aniline-co-pyrrole) embedded within an amphiphilic methoxy polyethylene glycol-block-polyphenylalanine copolymer (mPEG-b-pPhe) are used. It is demonstrated that the PASomes are water soluble, biocompatible, and could control ROS levels successfully in vitro, inhibiting viral replication and cell death. Furthermore, the effects of homopolymerized nanoregulators (polypyrrole assembled with mPEG-b-pPhe or polyaniline assembled with mPEG-b-pPhe) are compared with those of the PASomes. Consequently, it is confirmed that the PASomes can regulate intracellular ROS levels successfully and suppress viral infection, thereby increasing the cell survival rate.

Natural Compounds from Herbs that can Potentially Execute as Autophagy Inducers for Cancer Therapy

Accumulated evidence indicates that autophagy is a response of cancer cells to various anti-cancer therapies. Autophagy is designated as programmed cell death type II, and is characterized by the formation of autophagic vacuoles in the cytoplasm. Numerous herbs, including Chinese herbs, have been applied to cancer treatments as complementary and alternative medicines, supplements, or nutraceuticals to dampen the side or adverse effects of chemotherapy drugs. Moreover, the tumor suppressive actions of herbs and natural products induced autophagy that may lead to cell senescence, increase apoptosis-independent cell death or complement apoptotic processes. Hereby, the underlying mechanisms of natural autophagy inducers are cautiously reviewed in this article. Additionally, three natural compounds—curcumin, 16-hydroxycleroda-3,13-dien-15,16-olide, and prodigiosin—are presented as candidates for autophagy inducers that can trigger cell death in a supplement or alternative medicine for cancer therapy. Despite recent advancements in therapeutic drugs or agents of natural products in several cancers, it warrants further investigation in preclinical and clinical studies.

CYT-Rx20 inhibits ovarian cancer cells in vitro and in vivo through oxidative stress-induced DNA damage and cell apoptosis

PURPOSE

The β-nitrostyrene family has been previously reported to possess anticancer property. However, the biological effects of β-nitrostyrenes on ovarian cancer and the underlying mechanisms involved remain unclear. In the present study, we synthesized a β-nitrostyrene derivative, CYT-Rx20 3'-hydroxy-4'-methoxy-β-methyl-β-nitrostyrene), and investigated its anticancer effects and the putative pathways of action in ovarian cancer.

METHODS

The effects of CYT-Rx20 were analyzed using cell viability assay, reactive oxygen species (ROS) generation assay, FACS analysis, annexin V staining, immunostaining, comet assay, immunoblotting, soft agar assay, migration assay, nude mice xenograft study and immunohistochemistry.

RESULTS

CYT-Rx20 induced cytotoxicity in ovarian cancer cells by promoting cell apoptosis via ROS generation and DNA damage. CYT-Rx20-induced cell apoptosis, ROS generation and DNA damage were reversed by thiol antioxidants. In addition, CYT-Rx20 inhibited ovarian cancer cell migration by regulating the expression of epithelial to mesenchymal transition (EMT) markers. In nude mice, CYT-Rx20 inhibited ovarian tumor growth accompanied by increased expression of DNA damage marker γH2AX and decreased expression of EMT marker Vimentin.

CONCLUSIONS

CYT-Rx20 inhibits ovarian cancer cells in vitro and in vivo, and has the potential to be further developed into an anti-ovarian cancer drug clinically.

HMGB1-mediated autophagy attenuates gemcitabine-induced apoptosis in bladder cancer cells involving JNK and ERK activation

High-mobility group box 1 (HMGB1) has been found to mediate autophagy during chemotherapy in several cancers. However, whether HMGB1plays a role in autophagy and chemoresistance in bladder cancer is elusive. In this report, HMGB1 expression was found to be increased in 30 primary bladder cancer tissue specimens compared to their matched adjacent non-tumor tissues. While gemcitabine induced apoptotic cell death, it also induced HMGB1 expression and autophagy in bladder cancer T24 and BIU-87 cells. Suppressing HMGB1 expression with siRNA strongly potentiated gemcitabine-induced apoptosis. HMGB1 siRNA or autophagy inhibitors suppressed gemcitabine-induced autophagy. Further, gemcitabine activated c-Jun N-terminal kinase (JNK) and extracellular regulated protein kinase (ERK) and Bcl-2 phosphorylation, and blocking ERK and JNK inhibited autophagy and increased apoptosis in gemcitabine-treated cells. Interestingly, suppressing HMGB1 expression attenuated gemcitabine-induced ERK and JNK activation and Bcl-2 phosphorylation. Thus, our results suggest that while gemcitabine kills bladder cancer cells through apoptosis, a cytoprotective autophagy is also induced involving HMGB1-mediated JNK and ERK to counteract the cytotoxicity of gemcitabine, and intervention targeting this pathway may improve the anticancer efficacy of gemcitabine against bladder cancer.

Synthetic β-nitrostyrene derivative CYT-Rx20 as inhibitor of oral cancer cell proliferation and tumor growth through glutathione suppression and reactive oxygen species induction

BACKGROUND

The β-nitrostyrene family possesses anticancer properties. In this study, β-nitrostyrene derivative CYT-Rx20 (3'-hydroxy-4'-methoxy-β-methyl-β-nitrostyrene) was synthesized and investigated its anticancer activity in oral cancer.

METHODS

Anticancer activity of CYT-Rx20 and the underlying mechanisms were analyzed using cell viability assay, reactive oxygen species (ROS) generation assay, fluorescence-activated cell sorter analysis, annexin V staining, comet assay, glutathione (GSH)/glutathione disulfide (GSSG) ratio, immunoblotting, soft agar assay, nude mice xenograft study, and immunohistochemistry.

RESULTS

CYT-Rx20-induced cell apoptosis via ROS generation and mitochondrial membrane potential reduction, associated with release of mitochondrial cytochrome C to cytosol and activation of downstream caspases and poly ADP-ribose polymerase (PARP). Furthermore, CYT-Rx20 induced mitochondrial ROS accumulation and mitochondrial dysfunction, followed by GSH downregulation. CYT-Rx20-induced cell apoptosis, ROS generation, and DNA damage were reversed by thiol antioxidants. In nude mice, CYT-Rx20 inhibited oral tumor growth accompanied by increased expression of γH2AX, GSH reductase, and cleaved-caspase-3.

CONCLUSION

CYT-Rx20 has the potential to be further developed into an antioral cancer drug clinically. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1055-1064, 2017.

Ndrg3 gene regulates DSB repair during meiosis through modulation the ERK signal pathway in the male germ cells

The N-myc downstream regulated gene (NDRG) family consists of 4 members, NDRG-1, -2, -3, -4. Physiologically, we found Ndrg3, a critical gene which led to homologous lethality in the early embryo development, regulated the male meiosis in mouse. The expression of Ndrg3 was enhanced specifically in germ cells, and reached its peak level in the pachytene stage spermatocyte. Haplo-insufficiency of Ndrg3 gene led to sub-infertility during the male early maturation. In the Ndrg3^+/- germ cells, some meiosis events such as DSB repair and synaptonemal complex formation were impaired. Disturbances on meiotic prophase progression and spermatogenesis were observed. In mechanism, the attenuation of pERK1/2 signaling was detected in the heterozygous testis. With our primary spermatocyte culture system, we found that lactate promoted DSB repair via ERK1/2 signaling in the male mouse germ cells in vitro. Deficiency of Ndrg3 gene attenuated the activation of ERK which further led to the aberrancy of DSB repair in the male germ cells in mouse. Taken together, we reported that Ndrg3 gene modulated the lactate induced ERK pathway to facilitate DSB repair in male germ cells, which further regulated meiosis and subsequently fertility in male mouse.