Lx2-32c, a novel semi-synthetic taxane, exerts antitumor activity against prostate cancer cells in vitro and in vivo

Synthesis, biological evaluation and docking studies of N-substituted resveratrol derivatives

A total of 19 resveratrol derivatives, including 12 imines and 7 amines, were synthesized, among which compounds 1, 5, 6, 7', 11', and 13 are new compounds. The anti-inflammatory and antitumor activities of these compounds were evaluated in vitro. The results revealed that compounds 1, 6, 8', 12, and 12' exhibited significant inhibitory effects (> 50%) on NO production at the concentration of 10 μM and their NO production inhibitory activities have a significant concentration-dependent ability. Additionally, compounds 8' and 12' showed promising COX-2 inhibitory activity, and the molecular docking analysis indicated their stable binding to multiple amino acid residues within the active pocket of COX-2 through hydrogen bonding. Moreover, compound 12' exhibited inhibitory effects on various tumor cell lines and induced apoptosis in MCF-7 breast cancer cells, which was not observed with resveratrol alone. Therefore, the N-substituted structural modification of resveratrol would have possibly enhanced the bioactivity of resveratrol and facilitated its application.

Discovery of Pyxinol Amide Derivatives Bearing Amino Acid Residues as Nonsubstrate Allosteric Inhibitors of P-Glycoprotein-Mediated Multidrug Resistance

Nonsubstrate allosteric inhibitors of P-glycoprotein (Pgp), which are considered promising modulators for overcoming multidrug resistance (MDR), are relatively unknown. Herein, we designed and synthesized amino acids bearing amide derivatives of pyxinol, the main ginsenoside metabolite produced by the human liver, and examined their MDR reversal abilities. A potential nonsubstrate inhibitor (7a) was identified to undergo high-affinity binding to the putative allosteric site of Pgp at the nucleotide-binding domains. Subsequent assays confirmed that 7a (25 μM) was able to suppress both basal and verapamil-stimulated Pgp-ATPase activities (inhibition rates of 87 and 60%, respectively) and could not be pumped out by Pgp, indicating that it was a rare nonsubstrate allosteric inhibitor. Moreover, 7a interfered with Pgp-mediated Rhodamine123 efflux while exhibiting high selectivity for Pgp. Notably, 7a also markedly enhanced the therapeutic efficacy of paclitaxel, with a tumor inhibition ratio of 58.1%, when used to treat nude mice bearing KBV xenograft tumors.

The interaction between E3 ubiquitin ligase Parkin and mitophagy receptor PHB2 links inner mitochondrial membrane ubiquitination to efficient mitophagy

The autophagic clearance of mitochondria has been defined as mitophagy, which is triggered by mitochondrial damage and serves as a major pathway for mitochondrial homeostasis and cellular quality control. PINK1 and Parkin-mediated mitophagy is the most extensively studied form of mitophagy, which has been linked to the pathogenesis of neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. The current paradigm of this particular mitophagy pathway is that the ubiquitination of the outer mitochondrial membrane is the key step to enable the recognition of damaged mitochondria by the core autophagic component autophagosome. However, whether the inner mitochondrial membrane (IMM) is ubiquitinated by Parkin and its contribution to sufficient mitophagy remain unclear. Here, using molecular, cellular, and biochemical approaches, we report that prohibitin 2 (PHB2), an essential IMM receptor for mitophagy, is ubiquitinated by Parkin and thereby gains higher affinity to the autophagosome during mitophagy. Our findings suggest that Parkin directly binds to PHB2 through its RING1 domain and promotes K11- and K33-linked ubiquitination on K142/K200 sites of PHB2, thereby enhancing the interaction between PHB2 and MAP1LC3B/LC3B. Interestingly and importantly, our study allows us to propose a novel model in which IMM protein PHB2 serves as both a receptor and a ubiquitin-mediated base for autophagosome recruitment to ensure efficient mitophagy.

Thymoquinone Alterations of the Apoptotic Gene Expressions and Cell Cycle Arrest in Genetically Distinct Triple-Negative Breast Cancer Cells

Breast cancer (BC) is the most common cancer in women worldwide, and it is one of the leading causes of cancer death in women. triple-negative breast Cancer (TNBC), a subtype of BC, is typically associated with the highest pathogenic grade and incidence in premenopausal and young African American (AA) women. Chemotherapy, the most common treatment for TNBC today, can lead to acquired resistance and ineffective treatment. Therefore, novel therapeutic approaches are needed to combat medication resistance and ineffectiveness in TNBC patients. Thymoquinone (TQ) is shown to have a cytotoxic effect on human cancer cells in vitro. However, TQ's mode of action and precise mechanism in TNBC disease in vitro have not been adequately investigated. Therefore, TQ's effects on the genetically different MDA-MB-468 and MDA-MB-231 human breast cancer cell lines were assessed. The data obtained show that TQ displayed cytotoxic effects on MDA-MB-468 and MDA-MB-231 cells in a time- and concentration-dependent manner after 24 h, with IC50 values of 25.37 µM and 27.39 µM, respectively. Moreover, MDA-MB-231 and MDA-MB-468 cells in a scratched wound-healing assay displayed poor wound closure, inhibiting invasion and migration via cell cycle blocking after 24 h. TQ arrested the cell cycle phase in MDA-MB-231 and MDA-MB-468 cells. The three cell cycle stages in MDA-MB-468 cells were significantly affected at 15 and 20 µM for G0/G1 and S phases, as well as all TQ concentrations for G2/M phases. In MDA-MB-468 cells, there was a significant decrease in G0/G1 phases with a substantial increase in the S phase and G2/M phases. In contrast, MDA-MB-231 showed a significant effect only during the two cell cycle stages (S and G2/M), at concentrations of 15 and 20 µM for S phases and all TQ values for G2/M phases. The TQ effect on the apoptotic gene profiles indicated that TQ upregulated 15 apoptotic genes in MDA-MB-231 TNBC cells, including caspases, GADD45A, TP53, DFFA, DIABLO, BNIP3, TRAF2/3, and TNFRSF10A. In MDA-MB-468 cells, 16 apoptotic genes were upregulated, including TNFRSF10A, TNF, TNFRSF11B, FADD TNFRSF10B, CASP2, and TRAF2, all of which are important for the apoptotic pathway andsuppress the expression of one anti-apoptotic gene, BIRC5, in MDA-MB-231 cells. Compared to MDA-MB-231 cells, elevated levels of TNF and their receptor proteins may contribute to their increased sensitivity to TQ-induced apoptosis. It was concluded from this study that TQ targets the MDA-MB-231 and MDA-MB-468 cells differently. Additionally, due to the aggressive nature of TNBC and the lack of specific therapies in chemoresistant TNBC, our findings related to the identified apoptotic gene profile may point to TQ as a potential agent for TNBC therapy.

The regulatory role of MiR-203 in oxidative stress induced cell injury through the CBS/H2S pathway

Hydrogen Sulfide (H2S) mediates biological effects in a variety of ways. Due to its strong reducing potential, H2S has been recognized to have an important role in oxidative stress induced hypoxia. It has been reported that H2S production and miRNA can mutually regulate each other. H2S is produced by the catalytic activity of cystathionine-β-synthase (CBS), which is under the regulation of miRNAs. In this study, we used target gene prediction software, and identified miR-203 as a potential regulator of CBS. We verified this finding using an oxygen and glucose deprivation (OGD) hypoxia cell model in SH-SY5Y cells and pMIR-REPORT™ luciferase miRNA expression reporter vector. Furthermore, transfecting SH-SY5Y cells with miRNA agomir (agonist) and antagomir (antagonist) by lipofectamin RNAiMAX, we further validated miR-203 as a direct regulator of CBS. We also found that miR-203 protects from cell injury by regulating lipid peroxidation, cell apoptosis, and mitochondrial membrane potential. These findings suggest that while over-expression of miR-203 can aggravate OGD induced cell injury, inhibition of miR-203 can protect against OGD induced cell injury. Based on our data and that of others, we propose that miR-203 may regulate oxidative stress induced cell injury by regulating CBS expression and adjusting the levels of H2S production.

Protective Effect of Pyxinol, One Active Ingredient of Lichenes on Cisplatin-Induced Nephrotoxicity via Ameliorating DNA Damage Response

Background: Cisplatin is a valuable chemotherapeutic agent against malignant tumors. However, the clinical use of cisplatin is limited by its side effects such as renal injury. Pyxinol is an active constituent of Lichenes and its effects on cisplatin-induced nephrotoxicity is currently unknown. This study aims to examine the potential protective effects of pyxinol on cisplatin-induced renal injury and explore the underlying mechanisms.

Methods:In vivo rat model of cisplatin-induced nephrotoxicity was induced by intraperitoneal (i.p) administration of cisplatin. The blood urea nitrogen and creatinine levels were measured and renal histological analysis was conducted to evaluate the renal function; The TUNEL staining, western blotting and real-time PCR assays were conducted to examine related molecular changes. Finally, the in vivo anti-tumor efficacy was examined in the xenograft tumor model using nude mice.

Results: Pretreatment with pyxinol attenuated cisplatin-induced increase in blood urea nitrogen, creatinine and urinary protein excretion and the magnitude of injury in the renal tubules. Pyxinol ameliorated the activation of p53 via attenuating the DNA damage response, which then attenuated the tubular cell apoptosis. Finally, pyxinol could potentiate the in vivo anti-tumor efficacy of cisplatin against the xenograft tumor of cervical cancer cells in nude mice.

Conclusions: Combining pyxinol with cisplatin could alleviate cisplatin-induced renal injury without decreasing its therapeutic efficacy, which might represent a beneficial adjunct therapy for cisplatin-based chemotherapeutic regimens in the clinic.

A Novel Canine Mammary Cancer Cell Line: Preliminary Identification and Utilization for Drug Screening Studies

Canine malignant mammary tumor is a dangerously fatal neoplastic disease with poor survival in female dogs. The aim of this study was to preliminary characterize a novel canine mammary cancer cell line, B-CMT, from canine primary mammary gland tumor, and to utilize it as a cell model for in vitro screening of possible therapeutic drugs. The successfully established cell line, B-CMT, was cultured over 50 passages. B-CMT has a fast proliferation rate, and a population doubling time (PDT) of 33.6 h. The B-CMT cell line lacked human epidermal growth factor receptor-2 (HER-2), estrogen receptors (ER) and progesterone receptors (PR) expression by qRT-PCR. Compared with MDCK cells, CDH1 expression of CMT cell line was significantly decreased or even absent, but GATA3 expression dramatically increased, while TGF-β expression was at a similar level. Interestingly, the B-CMT cell line from canine primary tumor also showed positive hypoxia inducible factor-1α (HIF-1α) results in immunofluorescence (IF), western blot, and qRT-PCR analysis. Ten days post inoculation with EGFP-B-CMT (B-CMT cells stably expressing EGFP), the experimental mice developed palpable soft tissue masses which histologically resembled the canine primary tumor, and was approved to be derived from B-CMT cell line through detection of EGFP by immunohistochemical (IHC) analysis. Moreover, we investigated the cytotoxicity of five drugs to B-CMT cells, and the results showed that rapamycin and imatinib significantly inhibited the proliferation of the cells in vitro within a certain range of concentration. They also induced cell cycle arrest of B-CMT cells at G1 and G2 phase, respectively. In summary, the results of this report showed that B-CMT cell line might serve as a tool for future studies on tumor microenvironment and drug resistance.

Pyxinol bearing amino acid residues: Easily achievable and promising modulators of P-glycoprotein-mediated multidrug resistance

The P-glycoprotein (Pgp) is a major transporter involved in multidrug resistance (MDR) of cancer cells leading to chemotherapy failure. In our previous study, we demonstrated that the amide derivatives of pyxinol are promising modulators against Pgp-mediated MDR in cancer. In the present study, we designed and synthesized novel pyxinol derivatives linked to amino acid residues. We evaluated MDR (paclitaxel (Ptx) resistance) reversal potency of forty pyxinol derivatives in KBV cells and analyzed their structure-activity relationships. Half of our derivatives sensitized KBV cells to Ptx at non-toxic concentrations, among which the pyxinol compound bearing a methionine residue (3c) exhibited the best activity in MDR reversal. Compound 3c was found to possess high selectivity toward Pgp and sensitize the KBV cells to Pgp substrates by blocking the efflux function of Pgp. This manifestation may be attributed to its high binding affinity with Pgp, as suggested by docking studies. Overall, the biological profile and ease of synthesizing these pyxinol derivatives render them promising lead compounds for further development for Pgp-mediated MDR.

Design, synthesis, and biological evaluation of hederagenin derivatives with improved aqueous solubility and tumor resistance reversal activity

Multidrug resistance (MDR) has become a major obstacle to malignancies treatment by chemotherapeutic drugs, therefore, it is important to develop MDR reversal agents with high activity. We have previously found that the hederagenin (HD) derivative HBQ showed good tumor MDR reversal activity in vitro and in vivo but had poor solubility. In this study, to enhance the aqueous solubility and tumor MDR reversal activity of HBQ, three series of HD derivatives were designed and synthesized. Nitrogen-containing heterocyclic-substituted, PEGylated, and ring-A substituted derivatives significantly reversed the MDR phenotype of KBV (multidrug-resistant oral epidermoid carcinoma) cells toward paclitaxel at a concentration of 10 μM in MTT assays. The PEGylated derivatives 10c-10e had increased aqueous solubility compared with HBQ by 18-657 fold, while maintaining tumor MDR reversal activity. The most in vitro active compound 10c possessed good chemical stability to an esterase over 24 h and enhanced the sensitivity of KBV cells to paclitaxel and vincristine with IC₅₀ values of 4.58 and 0.79 nM, respectively. Mechanism studies indicated that compound 10c increased the accumulation of P-glycoprotein (P-gp) substrates rhodamine 123 and Flutax1 in KBV cells and MCF-7T (paclitaxel-resistant breast carcinoma) cells, that is to say, compound 10c exerted the reversal effect of tumor MDR by inhibiting the efflux function of P-gp. Finally, the structure-activity relationships were further investigated by analyzing the relationship between structure and tumor MDR reversal activity of HD derivatives. This study highlights the potential of PEGylated HD derivatives such as compound 10c for the development of tumor MDR reversal agents and provides information for the further improvement of the aqueous solubility and tumor MDR reversal activity of HD derivatives in the future.

Targeting castration-resistant prostate cancer with a novel RORγ antagonist elaiophylin

Prostate cancer (PCa) patients who progress to metastatic castration-resistant PCa (mCRPC) mostly have poor outcomes due to the lack of effective therapies. Our recent study established the orphan nuclear receptor RORγ as a novel therapeutic target for CRPC. Here, we reveal that elaiophylin (Elai), an antibiotic from Actinomycete streptomyces, is a novel RORγ antagonist and showed potent antitumor activity against CRPC in vitro and in vivo. We demonstrated that Elai selectively binded to RORγ protein and potently blocked RORγ transcriptional regulation activities. Structure–activity relationship studies showed that Elai occupied the binding pocket with several key interactions. Furthermore, Elai markedly reduced the recruitment of RORγ to its genomic DNA response element (RORE), suppressed the expression of RORγ target genes AR and AR variants, and significantly inhibited PCa cell growth. Importantly, Elai strongly suppressed tumor growth in both cell line based and patient-derived PCa xenograft models. Taken together, these results suggest that Elai is novel therapeutic RORγ inhibitor that can be used as a drug candidate for the treatment of human CRPC.

Combined treatment of mitoxantrone sensitizes breast cancer cells to rapalogs through blocking eEF-2K-mediated activation of Akt and autophagy

Oncogenic activation of the mTOR signaling pathway occurs frequently in tumor cells and contributes to the devastating features of cancer, including breast cancer. mTOR inhibitors rapalogs are promising anticancer agents in clinical trials; however, rapalogs resistance remains an unresolved clinical challenge. Therefore, understanding the mechanisms by which cells become resistant to rapalogs may guide the development of successful mTOR-targeted cancer therapy. In this study, we found that eEF-2K, which is overexpressed in cancer cells and is required for survival of stressed cells, was involved in the negative-feedback activation of Akt and cytoprotective autophagy induction in breast cancer cells in response to mTOR inhibitors. Therefore, disruption of eEF-2K simultaneously abrogates the two critical resistance signaling pathways, sensitizing breast cancer cells to rapalogs. Importantly, we identified mitoxantrone, an admitted anticancer drug for a wide range of tumors, as a potential inhibitor of eEF-2K via a structure-based virtual screening strategy. We further demonstrated that mitoxantrone binds to eEF-2K and inhibits its activity, and the combination treatment of mitoxantrone and mTOR inhibitor resulted in significant synergistic cytotoxicity in breast cancer. In conclusion, we report that eEF-2K contributes to the activation of resistance signaling pathways of mTOR inhibitor, suggesting a novel strategy to enhance mTOR-targeted cancer therapy through combining mitoxantrone, an eEF-2K inhibitor.

A red-light-activated sulfonamide porphycene for highly efficient photodynamic therapy against hypoxic tumor

Photodynamic therapy (PDT) is an emerging alternative cancer treatment modality that utilizes photo-sensitivity to cause cell death upon photo-irradiation. However, PDT efficiency has been hampered by tumor hypoxia, blue-shifted excitation wavelengths, and the high dark toxicity of photo-sensitizers. We designed and synthesized two novel porphycene-based photosensitizers (TBPoS-OH and TBPoS-2OH) with potent photo-cytotoxicity and a LD₅₀ in the nM range under both normoxic and hypoxic conditions in a variety of cell types after photo-irradiation (λ = 640 ± 15 nm). Further studies showed fast-cellular uptake for TBPoS-OH that localized lysosomes and subsequently induced cell apoptosis via the lysosomal-mitochondrial pathway. Moreover, TBPoS-OH significantly reduced tumor growth in two xenografted mouse models bearing melanoma A375 and B16 cells. Finally, TBPoS-OH exhibited no obvious immunogenicity and toxicity to blood cells and major organs in mice. These data demonstrated that these two porphycene-based photosensitizers, especially TBPoS-OH, could be developed as a potential PDT modality.

Structural and Biological Basis of Alphacoronavirus nsp1 Associated with Host Proliferation and Immune Evasion

Non-structural protein 1 (nsp1) is only characterized in alphacoronaviruses (α-CoVs) and betacoronaviruses (β-CoVs). There have been extensive researches on how the β-CoVs nsp1 regulates viral virulence by inhibiting host protein synthesis, but the regulatory mechanism of the α-CoVs nsp1 is still unclear. Here, we report the 2.1-Å full-length crystal structure of nsp1 in emerging porcine SADS-CoV and the 1.8-Å full-length crystal structure of nsp1 in the highly lethal cat FIPV. Although they belong to different subtypes of α-CoVs, these viruses all have a bucket-shaped fold composed of six β-sheets, similar to the crystal structure of PEDV and TGEV nsp1. Comparing the above four structures, we found that the structure of α-CoVs nsp1 in the same subtype was more conserved. We then selected mammalian cells that were treated with SADS-CoV and FIPV nsp1 for RNA sequencing analysis and found that nsp1 had a specific inhibitory effect on interferon (IFN) and cell cycle genes. Using the Renilla luciferase (Rluc) assay and Western blotting, we confirmed that seven representative α-CoVs nsp1s could significantly inhibit the phosphorylation of STAT1-S727 and interfere with the effect of IFN-I. Moreover, the cell cycle experiment confirmed that α-CoVs nsp1 could encourage host cells to stay in the G0/G1 phase. Based on these findings, we not only greatly improved the crystal structure data on α-CoVs nsp1, but we also speculated that α-CoVs nsp1 regulated host proliferation and immune evasion-related biological functions by inhibiting the synthesis of host proteins, thus creating an environment conducive to the virus.

Acute Nicotine Treatment Alleviates LPS-Induced Impairment of Fear Memory Reconsolidation Through AMPK Activation and CRTC1 Upregulation in Hippocampus

BACKGROUND

Fear memory is a fundamental capability for animals and humans to survive. Its impairment results in the disability to avoid danger. When memory is reactivated, a reconsolidation process, which can be disrupted by various stimuli, including inflammation, is required to become permanent. Nicotine has been shown to improve cognitive deficits induced by inflammation and other stimuli. Therefore, in the present study, we investigated the effect of nicotine on lipopolysaccharide (LPS)-induced impairment of fear memory reconsolidation and the underlying mechanism.

METHODS

Step-through inhibitory avoidance task was recruited to study fear memory of rat, i.p. LPS (0.5 mg/kg) treatment was used to induce inflammation, and western blot and immunostaining were applied to detect protein expression and distribution in medial prefrontal cortex and hippocampus.

RESULTS

Our data showed that LPS induced fear memory reconsolidation impairment without affecting retrieval. In addition, LPS significantly increased inflammation factors tumor necrosis factor-α and interleukin-1 beta and decreased CREB-regulated transcription coactivator 1 (CRTC1) expression and adenosine monophosphate-activated protein kinase (AMPK) activation in hippocampus. More importantly, LPS significantly decreased CRTC1 expression and AMPK activation in neurons by activating microglia cells. Of note, either nicotine treatment or activation of AMPK by intracerebroventricular infusion of metformin reduced LPS-induced impairment of fear memory reconsolidation and ameliorated inflammation factor tumor necrosis factor-α and interleukin-1 beta as well as the expression of CRTC1.

CONCLUSIONS

In conclusion, our results showed that acute nicotine treatment alleviates LPS-induced impairment of fear memory reconsolidation through activation of AMPK and upregulation of CRTC1 in hippocampus.

PCC0208023, a potent SHP2 allosteric inhibitor, imparts an antitumor effect against KRAS mutant colorectal cancer

The non-receptor tyrosine phosphatase SHP2, encoded by PTPN11, plays an indispensable role in tumors driven by oncogenic KRAS mutations, which frequently occur in colorectal cancer. Here, PCC0208023, a potent SHP2 allosteric inhibitor, was synthesized to evaluate its inhibitory effects against the SHP2 enzyme, and the KRAS mutant colorectal cancer in vitro and in vivo, and its impart on the RAS/MAPK pathway. Consistent with an allosteric mode of inhibition, PCC0208023 can non-competitively inhibit the activity of full-length SHP2 enzyme, but lacks activity against the free catalytic domain of SHP2. Furthermore, PCC0208023 inhibited the proliferation of KRAS mutation-driven human colorectal cancer cells by inhibiting the RAS/MAPK signaling pathway in vitro. Importantly, PCC0208023 displayed good anti-tumor efficacy against KRAS-driven LS180 and HCT116 xenograft models in nude mice with the decreased Ki67 and p-ERK level, and increased cleaved caspase-3 expression in tumors. Interestingly, PCC0208023 maintained high levels in LS180 tumors within 24 h after administration and was mainly distributed in both intestines and lungs. Molecular docking studies revealed a higher affinity of PCC0208023 with key residues in the SHP2 allosteric pocket than RMC-4550. PCC0208023 deserves further optimization to identify additional low-toxic and potent SHP2 allosteric inhibitors with novel scaffolds for the treatment of patients with KRAS mutation-positive colorectal cancer.

High plasma levels of pro-inflammatory factors interleukin-17 and interleukin-23 are associated with poor outcome of cardiac-arrest patients: a single center experience

Background

Systemic inflammation is an important feature of post-cardiac arrest syndrome (PCAS). This study was designed to determine whether the plasma concentrations of some circulating pro-inflammatory cytokines (interleukin-17 [IL-8], IL-22, IL-23 and IL-33) are of value in predicting the outcome of patients after return of spontaneous circulation (ROSC) during the post–cardiac arrest period.

Methods

This was a prospective observational clinical study. In total, 21 patients (survivors, n = 10; non-survivors, n = 11) who experienced cardiac arrest and successful ROSC with expected survival of at least 7 days were consecutively enrolled from January 2016 to December 2017. Of the 21 enrolled patients, ten survived were designated “survivors”. The other eleven patients died between 2 days and 1 months post ROSC. Venous blood was drawn at three time-points: baseline (< 1 h post ROSC), 2 days post ROSC and 7 days post ROSC. Plasma IL-8, IL-22, IL-23 and IL-33 were determined using commercial enzyme-linked immunosorbent assays.

Results

Plasma creatinine levels, but aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, were elevated in non-survivors compared with survivors. Plasma levels of IL-17, IL-22, IL-23 and IL-33 of the 21 total patients did not change at 2 or 7 days post ROSC compared to baseline. In survivors, the plasma levels of IL-17 and IL-23 at 2 or 7 days post ROSC were lower than baseline. In non-survivors, plasma levels of IL-17 increased compared with baseline. Receiver operating characteristic curve analysis showed that the plasma levels of IL-17 and IL-23 at 2 or 7 days post ROSC were able to predict the mortality of PCAS patients, and positively correlated with Acute Physiology and Chronic Health Evaluation (APACHE)-II score and time to ROSC.

Conclusion

These results provide the first evidence that the elevated plasma IL-17 and IL-23 levels are associated with poor outcome in PCAS patients. The role of IL-17/IL-23 axis post ROSC is worth paying attention to in PCAS patients.

Trial registration

Clinicaltrial.govNCT02297776, 2014-11-21.

PCC0208025 (BMS202), a small molecule inhibitor of PD-L1, produces an antitumor effect in B16-F10 melanoma-bearing mice

The increased PD-L1 expression induces poorer prognosis in melanoma. The small molecule inhibitors of PD-1/PD-L1 pathways have been an encouraging drug development strategy because of good affinity and oral bioavailability without immunogenicity and immunotoxicities of PD-1/PD-L1 antibodies. In this study, we studied the effects of PCC0208025 (BMS202), a small molecule inhibitor of PD-L1, on PD-1/PD-L1 binding and the cytokines secretion in human CD3⁺ cells in vitro. We also investigated the antitumor and immunomodulatory activity of PCC0208025 and the pharmacokinetics properties in B16-F10 melanoma-bearing mice. The results showed that PCC0208025 inhibited the PD-1/PD-L1 proteins binding, and rescued PD-L1-mediated inhibition of IFN-γ production in human CD3⁺ T cells in vitro. Furthermore, in B16-F10 melanoma-bearing mice, PCC0208025 presented the antitumor effects, enhanced IFN-γ levels in plasma, increased the frequency of CD3⁺CD8⁺ T and CD8⁺IFN-γ⁺ T and the ratios of CD8⁺/Treg, and deceased the CD4⁺CD25⁺CD127^low/− (Treg) number in tumor. Pharmacokinetics study found that PCC0208025 was absorbed and distributed into the tumors with much higher concentrations than those of the blockade against PD-1/PD-L1 binding. Our work suggests that PCC0208025 exhibited anti-tumor effects through inhibiting Treg expansion and increasing cytotoxic activity of tumor-infiltrating CD8⁺ T cells by the blockade of PD-1/PD-L1 binding, which may provide the pharmacological basis to develop small molecule inhibitors of PD-1/PD-L1 binding for PCC0208025 as a lead compound.

PCC0208009, an indirect IDO1 inhibitor, alleviates neuropathic pain and co-morbidities by regulating synaptic plasticity of ACC and amygdala

BACKGROUND AND PURPOSE

Indoleamine 2, 3-dioxygenase 1 (IDO1) has been linked to neuropathic pain and IDO1 inhibitors have been shown to reduce pain in animals. Some studies have indicated that IDO1 expression increased after neuropathic pain in hippocampus and spinal cord, whether these changes existing in anterior cingulate cortex (ACC) and amygdala remains obscure and how IDO1 inhibition leads to analgesia is largely unknown. Here, we evaluated the antinociceptive effect of PCC0208009, an indirect IDO1 inhibitor, on neuropathic pain and examined the related neurobiological mechanisms.

EXPERIMENTAL APPROACH

The effects of PCC0208009 on pain, cognition and anxiogenic behaviors were evaluated in a rat model of neuropathic pain. Motor disorder, sedation and somnolence were also assessed. Biochemical techniques were used to measure IDO1-mediated signaling changes in ACC and amygdala.

KEY RESULTS

In rats receiving spinal nerve ligation (SNL), IDO1 expression level was increased in ACC and amygdala. PCC0208009 attenuated pain-related behaviors in the formalin test and SNL model and increased cognition and anxiogenic behaviors in SNL rats at doses that did not affect locomotor activity and sleeping. PCC0208009 inhibited IDO1 expression in ACC and amygdala by inhibiting the IL-6-JAK2/STAT3-IDO1-GCN2-IL-6 pathway. In addition, PCC0208009 reversed synaptic plasticity at the functional and structural levels by suppressing NMDA2B receptor and CDK5/MAP2 or CDK5/Tau pathway in ACC and amygdala.

CONCLUSION AND IMPLICATIONS

These results support the role of IDO1-mediated molecular mechanisms in neuropathic pain and suggest that the IDO1 inhibitor PCC0208009 demonstrates selective pain suppression and could be a useful pharmacological therapy for neuropathic pain.

PCC0208017, a novel small-molecule inhibitor of MARK3/MARK4, suppresses glioma progression in vitro and in vivo

Gliomas are the most common primary intracranial neoplasms among all brain malignancies, and the microtubule affinity regulating kinases (MARKs) have become potential drug targets for glioma. Here, we report a novel dual small-molecule inhibitor of MARK3 and MARK4, designated as PCC0208017. In vitro, PCC0208017 strongly inhibited kinase activity against MARK3 and MARK4, and strongly reduced proliferation in three glioma cell lines. This compound attenuated glioma cell migration, glioma cell invasion, and angiogenesis. Molecular mechanism studies revealed that PCC0208017 decreased the phosphorylation of Tau, disrupted microtubule dynamics, and induced a G2/M phase cell cycle arrest. In an in vivo glioma model, PCC0208017 showed robust anti-tumor activity, blood–brain barrier permeability, and a good oral pharmacokinetic profile. Molecular docking studies showed that PCC0208017 exhibited high binding affinity to MARK3 and MARK4. Taken together, our study describes for the first time that PCC0208017, a novel MARK3/MARK4 inhibitor, might be a promising lead compound for treatment of glioma.

Vitamin E-based prodrug self-delivery for nanoformulated irinotecan with synergistic antitumor therapeutics

Irinotecan (Ir) is a potent antitumor chemotherapeutics in clinic and used for the treatment of a various cancers, but the degree of its application is critically limited by toxic side-effects and marked heterogeneities. Nano-formulation of prodrugs, based on "all-in-one" carrier-free self-assemblies offers an effective approach to alter pharmacokinetics and safety profiles of cytotoxic agents. In this study, a novel vitamin E succinate-based formulation of Ir (VES-Ir) combined with nanoscaled characteristics and synergistic combination was constructed through esterification. The conjugation makes amphiphilic VES-Ir prodrug self-assemble into nanoparticles with a fine diameter (VES-Ir NPs, 75.4 nm) of spherical morphology. Furthermore, VES-Ir NPs with a 1:1 drug-to-drug ratio was demonstrated to possess respectable physiological stability within 72 h test, while can react to pH/esterase-sensitive drug release in lysosomes internalized into tumor cells, potentially highlighting their alleviating side effects. Compared with single and mixture drugs administration, the nanoformulated VES-Ir NPs codelivered both VES and Ir with different anticancer mechanisms to induce the highest suppress proliferation of MCF-7 (IC₅₀ 0.18 μM) and A549 (IC₅₀ 0.29 μM) cells in a synergistic way (CI < 1). More importantly, the formulating nanoparticulate Ir is to significantly enhance its bioavailability in vivo with long retention time in bloodstream and thereby, resulting the superior tumor inhibitory rate (TIR) of 85.2% versus controls. This simple nanoformulation of Ir drug deprived from VES conjugation, together with self-delivery and synergistic property, may provide an effective strategy for multiple chemotherapeutics delivery to treat cancers or other diseases.

Neochamaejasmin A Induces Mitochondrial-Mediated Apoptosis in Human Hepatoma Cells via ROS-Dependent Activation of the ERK1/2/JNK Signaling Pathway

The botanical constituents of Stellera chamaejasme Linn. exhibit various pharmacological and medicinal activities. Neochamaejasmin A (NCA), one main active constituent of S. chamaejasme, inhibits cell proliferation and induces cell apoptosis in several types of tumor cells. However, the antitumor effect of NCA on hepatocellular carcinoma cells is still unclear. In this study, NCA (36.9, 73.7, and 147.5 μM) significantly inhibited hepatoblastoma-derived HepG2 cell proliferation in a concentration-dependent manner. Hoechst 33258 staining and flow cytometry showed that apoptotic morphological changes were observed and the apoptotic rate was significantly increased in NCA-treated HepG2 cells, respectively. Additionally, the levels of Bax, cleaved caspase-3, and cytoplasmic cytochrome c were increased, while the level of Bcl-2 was decreased in NCA-treated HepG2 cells when compared with the control group. Moreover, we found that the reactive oxygen species (ROS) level was significantly higher and the mitochondrial membrane potential was remarkably lower in NCA-treated HepG2 cells than in the control group. Further studies demonstrated that the levels of p-JNK and p-ERK1/2 were significantly upregulated in NCA-treated HepG2 cells, and pretreatment with JNK and ERK1/2 inhibitors, SP600125 and PD0325901, respectively, suppressed NCA-induced cell apoptosis of HepG2 cells. In addition, NCA also significantly inhibited human hepatoma BEL-7402 cell proliferation and induced cell apoptosis through the ROS-mediated mitochondrial apoptotic pathway. These results implied that NCA induced mitochondrial-mediated cell apoptosis via ROS-dependent activation of the ERK1/2/JNK signaling pathway in HepG2 cells.

Isotalatizidine, a C19-diterpenoid alkaloid, attenuates chronic neuropathic pain through stimulating ERK/CREB signaling pathway-mediated microglial dynorphin A expression

Background

Isotalatizidine is a representative C₁₉-diterpenoid alkaloid extracted from the lateral roots of Aconitum carmichaelii, which has been widely used to treat various diseases on account of its analgesic, anti-inflammatory, anti-rheumatic, and immunosuppressive properties. The aim of this study was to evaluate the analgesic effect of isotalatizidine and its underlying mechanisms against neuropathic pain.

Methods

A chronic constrictive injury (CCI)-induced model of neuropathic pain was established in mice, and the limb withdrawal was evaluated by the Von Frey filament test following isotalatizidine or placebo administration. The signaling pathways in primary or immortalized microglia cells treated with isotalatizidine were analyzed by Western blotting and immunofluorescence.

Results

Intrathecal injection of isotalatizidine attenuated the CCI-induced mechanical allodynia in a dose-dependent manner. At the molecular level, isotalatizidine selectively increased the phosphorylation of p38 and ERK1/2, in addition to activating the transcription factor CREB and increasing dynorphin A production in cultured primary microglia. However, the downstream effects of isotalatizidine were abrogated by the selective ERK1/2 inhibitor U0126-EtOH or CREB inhibitor of KG-501, but not by the p38 inhibitor SB203580. The results also were confirmed in in vivo experiments.

Conclusion

Taken together, isotalatizidine specifically activates the ERK1/2 pathway and subsequently CREB, which triggers dynorphin A release in the microglia, eventually leading to its anti-nociceptive action.

Withaferin A triggers G2/M arrest and intrinsic apoptosis in glioblastoma cells via ATF4-ATF3-CHOP axis

OBJECTIVE

Withaferin A (WA) is a bioactive compound with a remarkable anti-cancer effect derived from Withania somnifera, commonly known as ashwagandha. However, the anti-cancer mechanisms of WA in glioblastoma multiforme (GBM) are still unclear.

MATERIALS AND METHODS

Cell viability assays and xenografted nude mice were used to evaluate the effects of WA, along with flow cytometry to detect apoptosis and cell cycle of GBM. RNA-seq analysis, Western blotting, immunofluorescence staining, qRT-PCR and siRNA gene silencing were carried out to determine the signalling pathways affected by WA.

RESULTS

Withaferin A significantly inhibited the growth of GBM in vitro and in vivo and triggered the intrinsic apoptosis of GBM cells by up-regulating expression of Bim and Bad. WA arrested GBM cells at the G2/M phase of the cell cycle through dephosphorylating Thr161 of CDK1 by activating p53-independent p21 up-regulation. Knockdown of p21 restored cell cycle progression and cell viability by down-regulating the expression of Bad rather than Bim. We demonstrated that endoplasmic reticulum (ER) stress induced by WA through the ATF4-ATF3-CHOP axis, initiated apoptosis and G2/M arrest in GBM cells.

CONCLUSION

We revealed a novel pathway that elucidated WA activation of apoptosis and G2/M arrest in GBM cells through the ATF4-ATF3-CHOP axis. This discovery is important for optimization of WA-based regimens for prevention and/or treatment of GBM.

Somatic and germline mutations in the tumor suppressor gene PARK2 impair PINK1/Parkin-mediated mitophagy in lung cancer cells

PARK2, which encodes Parkin, is a disease-causing gene for both neurodegenerative disorders and cancer. Parkin can function as a neuroprotector that plays a crucial role in the regulation of mitophagy, and germline mutations in PARK2 are associated with Parkinson's disease (PD). Intriguingly, recent studies suggest that Parkin can also function as a tumor suppressor and that somatic and germline mutations in PARK2 are associated with various human cancers, including lung cancer. However, it is presently unknown how the tumor suppressor activity of Parkin is affected by these mutations and whether it is associated with mitophagy. Herein, we show that wild-type (WT) Parkin can rapidly translocate onto mitochondria following mitochondrial damage and that Parkin promotes mitophagic clearance of mitochondria in lung cancer cells. However, lung cancer-linked mutations inhibit the mitochondrial translocation and ubiquitin-associated activity of Parkin. Among all lung cancer-linked mutants that we tested, A46T Parkin failed to translocate onto mitochondria and could not recruit downstream mitophagic regulators, including optineurin (OPTN) and TFEB, whereas N254S and R275W Parkin displayed slower mitochondrial translocation than WT Parkin. Moreover, we found that deferiprone (DFP), an iron chelator that can induce mitophagy, greatly increased the death of A46T Parkin-expressing lung cancer cells. Taken together, our results reveal a novel mitophagic mechanism in lung cancer, suggesting that lung cancer-linked mutations in PARK2 are associated with impaired mitophagy and identifying DFP as a novel therapeutic agent for PARK2-linked lung cancer and possibly other types of cancers driven by mitophagic dysregulation.

Cinobufagin induces cell cycle arrest at the S phase and promotes apoptosis in nasopharyngeal carcinoma cells

Emerging evidence suggests that cinobufagin, an active ingredient in Venenum Bufonis, inhibits cell proliferation in several tumor cells. However, the anti-tumor effect of cinobufagin on nasopharyngeal carcinoma and the underlying molecular mechanisms are still unclear. In this study, we found that cinobufagin significantly inhibits the proliferation of nasopharyngeal carcinoma HK-1 cells. Further analyses demonstrated that cinobufagin induces cell cycle arrest at the S phase in HK-1 cells through downregulating the levels of CDK2 and cyclin E. Moreover, cinobufagin significantly downregulates the protein level of Bcl-2 and upregulates the levels of Bax, subsequently increasing the levels of cytoplasmic cytochrome c, Apaf-1, cleaved PARP1, cleaved caspase-3, and cleaved caspase-9, leading to HK-1 apoptosis. Furthermore, we found that cinobufagin significantly increases ROS levels and decreases the mitochondrial membrane potential in HK-1 cells. Collectively, these data imply that cinobufagin induces cell cycle arrest at the S phase and induces apoptosis through increasing ROS levels, thereby inhibiting cell proliferation in HK-1 cells. Therefore, cinobufagin is a promising bioactive agent that may contribute to the development of treatment strategies of nasopharyngeal carcinoma.

Oxidation of multiple MiT/TFE transcription factors links oxidative stress to transcriptional control of autophagy and lysosome biogenesis

Significant evidences indicate that reactive oxygen species (ROS) can induce macroautophagy/autophagy under both physiological and pathological conditions. Although the relationship between ROS and autophagy regulation has been well studied, the basic mechanism by which ROS affects autophagy and the biological role of this regulation are still not fully understood. In the present study we show that multiple MiT-TFE transcription factors including TFEB, TFE3 and MITF, which are master regulators of autophagy and lysosomal biogenesis, can be activated upon direct cysteine oxidation by ROS. Oxidation promotes the nuclear translocation of these MiT-TFE transcription factors by inhibiting the association of them with RRAG GTPases, which in turn leads to enhanced global gene expression level in autophagy-lysosome system. Our study highlights the role of oxidation of MiT-TFE transcription factors in ROS-linked autophagy, and provides novel mechanism that MiT-TFE transcription factors-mediated transcriptional control of autophagy may govern cell homeostasis in response to oxidative stress, a biological process tightly linked to human diseases including neurodegenerative diseases and cancer.

ABBREVIATIONS

Bafi A1: bafilomycin A₁; EBSS: Earle's balanced salt solution; EGFP: enhanced green fluorescent protein; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MTORC1: mechanistic target of rapamycin kinase complex 1; ROS: reactive oxygen species; RPS6KB/p70S6K: ribosomal protein S6 kinase B; TFEB: transcription factor EB; WT: wild type.

Survivin Promotes Piperlongumine Resistance in Ovarian Cancer

Ovarian cancer is one of the most fatal female malignancies while targeting apoptosis is critical for improving ovarian cancer patients' lives. Survivin is regarded as the most robust anti-apoptosis protein, and its overexpression in ovarian cancer is related to poor survival and apoptosis resistance. Piperlongumine (PL) extracted from peppers is defined as an active alkaloid/amide and exhibits a broad spectrum of antitumor effects. Here, we demonstrate that PL induces the rapid depletion of survivin protein levels via reactive oxygen species (ROS)-mediated proteasome-dependent pathway in vitro, while exerting a remarkable inhibitory influence on the proliferation of ovarian cancer cells. Overexpression of survivin raises the survival rate of ovarian cancer cells to PL. Moreover, PL inhibits ovarian cancer cells xenograft tumor growth and downregulates survivin in vivo. Our findings reveal a previously unrecognized mechanism of PL in suppressing survivin expression as well as survivin promotes piperlongumine resistance in ovarian cancer and suggest that ROS-mediated proteasome-dependent pathway can be exploited to overcome apoptosis resistance triggered by aberrant expression of survivin.

Neuroprotective Effect of SCM-198 through Stabilizing Endothelial Cell Function

Leonurine, also named SCM-198, which was extracted from Herba leonuri, displayed a protective effect on various cardiovascular and brain diseases, like ischemic stroke. Ischemic stroke which is the leading cause of morbidity and mortality, ultimately caused irreversible neuron damage. This study is aimed at exploring the possible therapeutic potential of SCM-198 in the protection against postischemic neuronal injury and possible underlying mechanisms. A transient middle cerebral artery occlusion (tMCAO) rat model was utilized to measure the protective effect of SCM-198 on neurons. TEM was used to determine neuron ultrastructural changes. The brain slices were stained with Nissl staining solution for Nissl bodies. Fluoro-Jade B (FJB) was used for staining the degenerating neurons. In the oxygen-glucose deprivation and re-oxygenation (OGD/R) model of bEnd.3 cells treated with SCM-198 (0.1, 1, 10 μM). Then, the bEnd.3 cells were cocultured with SH-SY5Y cells. Cell viability, MDA level, CAT activity, and apoptosis were examined to evaluate the cytotoxicity of these treatments. Western blot and immunofluorescent assays were used to examine the expression of protein related to the p-STAT3/NOX4/Bcl-2 signaling pathway. Coimmunoprecipitation was performed to determine the interaction between p-STAT3 and NOX4. In the transient middle cerebral artery occlusion (tMCAO) rat model, we found that treatment with SCM-198 could ameliorate neuron morphology and reduce the degenerating cell and neuron loss. In the in vitro model of bEnd.3 cell oxygen-glucose deprivation and reoxygenation (OGD/R), treatment with SCM-198 restored the activity of catalase (CAT), improved the expression of Cu-Zn superoxide dismutase (SOD1), and decreased the malondialdehyde (MDA) production. SCM-198 treatment prevented OGD/R-induced cell apoptosis as indicated by increased cell viability and decreased the number of TUNEL-positive cells, accompanied with upregulation of Bcl-2 and Bcl-xl protein and downregulation Bax protein. The results were consistent with SH-SY5Y cells which coculture with bEnd.3 cells. The forthcoming study revealed that SCM-198 activated the p-STAT3/NOX4/Bcl-2 signaling pathway. All the data indicated that SCM-198 protected against oxidative stress and neuronal damage in in vivo and in vitro injury models via the p-STAT3/NOX4/Bcl-2 signaling pathway. Our results suggested that SCM-198 could be the potential drug for neuroprotective effect through stabilizing endothelial cell function.

Autophagy and Ubiquitin-Proteasome System Coordinate to Regulate the Protein Quality Control of Neurodegenerative Disease-Associated DCTN1

Motor neuron diseases are neurodegenerative diseases that are characterized by degeneration of the upper and lower motor neurons in the central nervous system. Mutations in Dynactin 1 (DCTN1), a component in the Dynein/Dynactin motor complex, have been previously identified to cause motor neuron diseases and other neurodegenerative disorders. Recent studies showed that motor neuron disease-linked mutation, such as G59S mutation, could lead to dysfunction and protein aggregation of DCTN1. However, the cellular pathway involved in the clearance of DCTN1 aggregates is still not fully elucidated. In this study, we employed a culture cell model of DCTN1-linked neurodegeneration and explored the role of cellular protein control systems in the regulation of wild type and mutant DCTN1. We find that the ubiquitin-proteasome system, but not autophagy, is the primary protein degradation system for the turnover of both wild type and G59S DCTN1 under normal conditions. However, it turns out that autophagy can play a role in the clearance of protein aggregates of G59S DCTN1 when the proteasome activity is inhibited. Importantly, overexpression of TFEB, a master regulator of autophagy, promotes the autophagic clearance of G59S DCTN1 aggregates and ameliorates G59S DCTN1-induced cytotoxicity when the proteasomes are impaired. In conclusion, autophagy may play as a backup system to protect cells against the cytotoxicity induced by aggregate-prone DCTN1 when proteasomal function is damaged.

Cinobufagin Induces Cell Cycle Arrest at the G2/M Phase and Promotes Apoptosis in Malignant Melanoma Cells

Emerging evidence has shown that cinobufagin, as an active ingredient of Venenum Bufonis, inhibits tumor development. The aim of this study was to investigate the inhibitory effects of cinobufagin on A375 human malignant melanoma cells. MTT and colony formation assays showed that cinobufagin significantly inhibited A375 cell proliferation and cell colony formation. Additional studies demonstrated that cinobufagin markedly increased the levels of ATM serine/threonine kinase (ATM) and checkpoint kinase 2 (Chk2) and decreased the levels of cell division cycle 25C (CDC25C), cyclin-dependent kinase 1 (CDK1), and cyclin B, subsequently inducing G2/M cell cycle arrest in A375 cells. Moreover, cinobufagin clearly inhibited the levels of phosphoinositide 3-kinase (PI3K), phosphorylated PI3K (p-PI3K), AKT, p-AKT, and B-cell lymphoma 2 (Bcl-2). By contrast, it increased the levels of Bcl-2-associated death promoter, Bcl-2-associated X, cytoplasmic cytochrome C, and apoptotic protease activating factor 1, leading to increased levels of cleaved caspase-9 and cleaved caspase-3, resulting in the apoptosis of A375 cells. Together, these results indicate that cinobufagin can induce cell cycle arrest at the G2/M phase and apoptosis, leading to inhibition of A375/B16 cell proliferation. Thus, cinobufagin may be useful for melanoma treatment.

PDE3A inhibitor anagrelide activates death signaling pathway genes and synergizes with cell death-inducing cytokines to selectively inhibit cancer cell growth

We performed a drug repurposing screening of a US Food and Drug Administration (FDA)-approved drug compound library and identified Anagrelide (ANA), a known phosphodiesterase 3A (PDE3A) inhibitor, that selectively and potently inhibited the growth of cancer cells. However, inactivation of PDE3A or knocking-down its gene expression did not inhibit cancer cell growth. It was the interaction of ANA with PDE3A that created a new function of PDE3A to alter the activities of another unknown function protein SLFN12 to cause the inhibition of cancer cell growth. The expressions of both PDE3A and SLFN12 were required for ANA to inhibit cancer cell growth. Depletion of PDE3A or SLFN12 led to ANA resistance. Furthermore, the effects of ANA on different cancer cells were different depending on the expression levels of PDE3A and SLFN12, causing G0/G1 cell cycle arrest in the cells expressing lower levels of SLFN12, but apoptosis in the cells expressing higher levels of the two proteins. Further investigation into the molecular mechanisms of the ANA-induced cell cycle arrest and apoptosis identified a set of cell cycle and apoptosis-related genes whose expressions were altered by ANA treatment. ANA also synergized with the cell death-inducing cytokines IFN-α, IFN-γ, TNF-α, or TRAIL, which regulated the same set of genes as ANA did, to induce apoptosis of the cancer cells. Our study uncovered new activities, functions, and mechanisms of ANA and SLFN12 and provided a diagnosis method to precisely use ANA as an anti-cancer drug. It also revealed PDE3A and SLFN12 as new anti-cancer drug targets for developing novel anti-cancer therapies.

Targeting MK2 Is a Novel Approach to Interfere in Multiple Myeloma

MAPKAPK2 (MK2), the direct substrate of p38 MAPK, has been well-acknowledged as an attractive drug target for cancer therapy. However, few studies have assessed the functions of it in multiple myeloma (MM). In the present study, MK2 expression of MM patients was analyzed by gene expression profiling (GEP) and array-based comparative genomic hybridization (aCGH). Several experiments in vitro including MTT assay, Western blot and flow cytometry analysis were performed to identify the function of MK2 in MM. In addition, we conducted mouse survival experiments to explain the effects of MK2 on MM in vivo. mRNA level of MK2 and chromosomal gain of MK2 locus in MM cells significantly increased compared to normal samples. Furthermore, MM patients with high expression of MK2 were associated with a poor outcome. Follow-up studies showed that MK2 exerted a remarkably positive effect on MM cell proliferation and drug-resistance. Further exploration focusing on MK2 inhibitor IV revealed its inhibitory action on MM growth and drug-resistance, as well as improving survival in mouse models. In addition, a combination of MK2 inhibitor IV and the key MM therapeutic agents including bortezomib, doxorubicin, or dexamethasone facilitated curative effects on inhibiting MM cell proliferation. Taken together, our study reveals the clinical relevance of MK2 inhibition in MM and demonstrates that targeting MK2 may afford a new therapeutic approach to MM.

PCC0208018 exerts antitumor effects by activating effector T cells

Poor prognosis is associated with melanoma due to immunosuppression profiles, suggesting that immune alterations have an important role in the occurrence, growth, and metastasis of melanoma. Here, we found that PCC0208018, a small-molecule compound, enhanced T cell proliferation and activation to release interferon gamma (IFN-γ) and interleukin-2 (IL-2) without blocking the programmed cell death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) binding and did not directly affect tumor cell viability in vitro. Furthermore, PCC0208018 increased the phosphorylation of protein kinase B (PKB/AKT) as well as extracellular regulated protein kinases (ERK) in human peripheral blood mononuclear cells (PBMCs) in vitro. The secretion of cytokines induced by PCC0208018 was significantly suppressed by the PI3K inhibitor GDC-0941. In B16-F10 melanoma-harboring mice, PCC0208018 significantly inhibited tumor growth as well as increasing CD3⁺, CD3⁺CD4⁺, and CD3⁺CD8⁺ T cell abundance in tumors without affecting PD-L1 expression. This study showed that PCC0208018 potentially increased PBMCs proliferation and function by activating the phosphatidylinositol 3 kinase (PI3K)/AKT and mitogen-activated protein kinase (MEK)/ERK pathways to exert antitumor effects.

Cannabidiol Induces Cell Cycle Arrest and Cell Apoptosis in Human Gastric Cancer SGC-7901 Cells

The main chemical component of cannabis, cannabidiol (CBD), has been shown to have antitumor properties. The present study examined the in vitro effects of CBD on human gastric cancer SGC-7901 cells. We found that CBD significantly inhibited the proliferation and colony formation of SGC-7901 cells. Further investigation showed that CBD significantly upregulated ataxia telangiectasia-mutated gene (ATM) and p53 protein expression and downregulated p21 protein expression in SGC-7901 cells, which subsequently inhibited the levels of CDK2 and cyclin E, thereby resulting in cell cycle arrest at the G0–G1 phase. In addition, CBD significantly increased Bax expression levels, decreased Bcl-2 expression levels and mitochondrial membrane potential, and then upregulated the levels of cleaved caspase-3 and cleaved caspase-9, thereby inducing apoptosis in SGC-7901 cells. Finally, we found that intracellular reactive oxygen species (ROS) increased after CBD treatment. These results indicated that CBD could induce G0–G1 phase cell cycle arrest and apoptosis by increasing ROS production, leading to the inhibition of SGC-7901 cell proliferation, thereby suggesting that CBD may have therapeutic effects on gastric cancer.

BTK induces CAM-DR through regulation of CXCR4 degradation in multiple myeloma

Cellular adhesion-mediated drug resistance (CAM-DR) occurs frequently in patients with relapsed or refractory multiple myeloma (MM). Elucidating the mechanism underlying CAM-DR and developing the corresponding treatment may prove to be promising for the clinical management of MM. Bruton's tyrosine kinase (BTK) has been attracting attention in relation to MM progression and drug resistance. BTK was reported to be associated with cell surface CXCR4, a classic cell adhesion molecule and homing factor. However, the exact association between BTK and CAM-DR in MM remains elusive. In this study, we demonstrated that promoting BTK expression induced MM cell adherence to the extracellular matrix (ECM) and stromal cells in vitro and in vivo, and that CAM-DR could be reversed by separating MM cells from ECM or stromal cells. Enhancing BTK expression levels increased CXCR4 expression in MM cells. In addition, BTK may bind directly with CXCR4 and prevent its ubiquitination-induced degradation. Finally, a BTK inhibitor exerted synergistic therapeutic effects with bortezomib in a 5TMM3VT MM mouse model. These findings revealed a novel role of BTK in CAM-DR and may provide a promising approach to MM treatment.

Ailanthone Induces Cell Cycle Arrest and Apoptosis in Melanoma B16 and A375 Cells

Malignant melanoma is the most lethal type of skin cancer. Previous studies have shown that ailanthone has potent antitumor activity in a variety of cell lines. However, the anti-tumor effect of ailanthone on malignant melanoma remains unclear. To investigate the anti-tumor mechanisms of ailanthone in human melanoma B16 and mouse melanoma A375 cells, the cell counting kit-8 assay, colony formation assay, DNA content analysis, Hoechst 33258, and Annexin V-FITC/PI staining were used to assess cell proliferation, cell cycle distribution, and cell apoptosis, respectively. Western blotting was performed to evaluate the expression of cell cycle- and apoptosis-related proteins and regulatory molecules. The results showed that ailanthone significantly inhibited melanoma B16 and A375 cell proliferation as well as remarkably induced cell cycle arrest at the G0–G1 phase in B16 cells and the G2–M phase in A375 cells in a dose-dependent manner. Further investigation revealed that ailanthone promoted the expression of p21 and suppressed the expression of cyclin E in B16 cells or cyclin B in A375 cells through the PI3K-Akt signaling pathway. In addition, ailanthone induced B16 and A375 cell apoptosis via a caspase-dependent mechanism. Further studies showed that ailanthone remarkably downregulated Bcl-2 and upregulated Apaf-1 and Bax, and subsequently increased mitochondrial membrane permeabilization and released cytochrome c from the mitochondria in B16 cells and A375 cells. Taken together, ailanthone induces cell cycle arrest via the PI3K-Akt signaling pathway as well as cell apoptosis via the mitochondria-mediated apoptotic signaling pathway. Ailanthone may be potentially utilized as an anti-tumor agent in the management of malignant melanoma.

ATF3 promotes erastin-induced ferroptosis by suppressing system Xc

The amino acid antiporter system Xc⁻ is important for the synthesis of glutathione (GSH) that functions to prevent lipid peroxidation and protect cells from nonapoptotic, iron-dependent death (i.e., ferroptosis). While the activity of system Xc⁻ often positively correlates with the expression level of its light chain encoded by SLC7A11, inhibition of system Xc⁻ activity by small molecules (e.g., erastin) causes a decrease in the intracellular GSH level, leading to ferroptotic cell death. How system Xc⁻ is regulated during ferroptosis remains largely unknown. Here we report that activating transcription factor 3 (ATF3), a common stress sensor, can promote ferroptosis induced by erastin. ATF3 suppressed system Xc⁻, depleted intracellular GSH, and thereby promoted lipid peroxidation induced by erastin. ATF3 achieved this activity through binding to the SLC7A11 promoter and repressing SLC7A11 expression in a p53-independent manner. These findings thus add ATF3 to a short list of proteins that can regulate system Xc⁻ and promote ferroptosis repressed by this antiporter.

PCC0208027, a novel tyrosine kinase inhibitor, inhibits tumor growth of NSCLC by targeting EGFR and HER2 aberrations

PCC-0208027 is a novel tyrosine kinase inhibitor that has a strong inhibitory effect on epidermal growth factor receptor (EGFR)- or HER2-driven cancers. The aim is to assess the anti-tumor activity of PCC0208027 and related mechanisms in non-small cell lung cancer (NSCLC). We examined the activity of PCC0208027 on various mutated EGFRs, HER2, and HER4. MTT assays, flow cytometry, and Western blotting were used to examine the effects of PCC0208027 on NSCLC cells with different genetic characteristics and relevant molecular mechanisms. Nude mouse xenograft models with HCC827, NCI-H1975, and Calu-3 cells were used to evaluate the in vivo anti-tumor activity of PCC0208027. Results showed that PCC0208027 effectively inhibited the enzyme activity of EGFR family members, including drug-sensitive EGFR mutations, acquired drug-resistant EGFR T790M and EGFR C797S mutations, and wild-type (WT) HER2. PCC0208027 blocked EGFR phosphorylation, thereby downregulating downstream PI3K/AKT and MAPK/ERK signaling pathways and inducing G0/G1 arrest in NSCLC cells. PCC0208027 inhibited tumor growth in mouse xenograft models of HCC827, NCI-H1975, and Calu-3 cells. In summary, our findings suggest that PCC0208027 has the potential to become an oral antineoplastic drug for NSCLC treatment and is worthy of further development.

Dynasore Suppresses mTORC1 Activity and Induces Autophagy to Regulate the Clearance of Protein Aggregates in Neurodegenerative Diseases

Autophagy is an important cellular protein control process, which plays a key role in the regulation of cell homeostasis and pathogenesis of many human diseases including neurodegenerative diseases. Reduced autophagic activity and abnormal protein aggregation are common features of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease. Therefore, pharmacological regulation of overall autophagy may be helpful for effective treatment of neurodegenerative diseases. In the present study, we find Dynasore, a potent inhibitor of dynamin, can repress the lysosomal localization of mTOR and block the activity of mTORC1, which in turn enhances the nuclear translocation of the master regulators of autophagy including TFE3 and TFEB. We find that autophagic flux is upregulated in Dynasore-treated cells. Moreover, treatment of Dynasore significantly promotes the clearance of protein aggregates formed by mutant huntingtin protein containing expanded polyglutamine (polyQ), but not damaged mitochondria. In contrast, treatment with Dynasore has no effect on the clearance of polyQ aggregates of mutant huntingtin in ATG5-depleted cells, in which autophagy is defective. Taken together, our results indicate that Dynasore affects autophagic degradation of neurodegenerative disease-associated proteins by regulating mTORC1-TFEB signaling.

Synthesis, Characterization, and Anticancer Activities Evaluation of Compounds Derived from 3,4-Dihydropyrimidin-2(1H)-one

3,4-dihydropyrimidin-2(1H)-one compounds (DHPMs) possess extensive biological activities and are mainly prepared via Biginelli reaction and N-alkylation. In the present study, selective alkylation of N¹ was investigated by using tetrabutylammonium hydroxide. In vitro cytotoxicity study on all synthesized compounds demonstrated that introduction of the aryl chain in the R³ as well as the low electron-donating group in the R¹ of DHPMs contributed to the anti-proliferative potency. A larger value of the partition coefficient (Log P) and suitable polar surface area (PSA) values were both found to be important in order to maintain the antitumor activity. The results from in vivo study indicated the great potential of compound 3d to serve as a lead compound for novel anti-tumor drugs to treat glioma. Pharmacophore study regarding the structure-activity relations of DHPMs were also conducted. Our results here could provide a guide for the design of novel bioactive 3,4-dihydropyrimidin-2(1H)-one compounds.

Design, Synthesis, and Biological Evaluation of Novel Nitrogen Heterocycle-Containing Ursolic Acid Analogs as Antitumor Agents

Nineteen ursolic acid analogues were designed, synthesized, and evaluated for their antiproliferative activity against the Hela and MKN45 cell lines. Some compounds containing a piperazine moiety displayed moderate to high levels of antitumor activities against the tested cancer cell lines. The most potent compound shares the IC50 value of 2.1 µM and 2.6 µM for the Hela and MKN45 cell lines, respectively. Further mechanism studies and in vivo antitumor studies have shown that it decreased the apoptosis regulator (BCL2/BAX) ratio, disrupted mitochondrial potential and induced apoptosis, and suppressed the growth of Hela xenografts in nude mice.

Discovery and evaluation of ZT55, a novel highly-selective tyrosine kinase inhibitor of JAK2V617F against myeloproliferative neoplasms

BACKGROUND

The JAK2-STAT signaling pathway plays a critical role in myeloproliferative neoplasms (MPN). An activating mutation in JAK2 (V617F) is present in ~ 95% of polycythemia vera, essential thrombocythemia, and primary myelofibrosis cases. This study aims to explore the selective JAK2^V617F inhibitor, evaluate the efficacy and possible mechanism of ZT55 on MPN.

METHODS

HTRF assays were conducted to evaluate the selective inhibition of ZT55 for JAKs. Cell apoptosis, proliferation, and cycle arrest assays were performed to examine the effect of ZT55 on HEL cell line with JAK2^V617F mutation in vitro. Western analysis was used to monitor the expression and activity of proteins on JAK2/STAT pathway. A mice xenograft model was established to evaluate the antitumor efficacy of ZT55 in vivo. Peripheral blood samples from patients with the JAK2^V617F mutation were collected to estimate the effect of ZT55 on erythroid colony formation by colony-forming assay.

RESULTS

We found that ZT55 showed a selective inhibition of a 0.031 μM IC₅₀ value against JAK2. It exhibited potent effects on the cellular JAK-STAT pathway, inhibiting tyrosine phosphorylation in JAK2^V617F and downstream STAT3/5 transcription factors. ZT55 inhibited the proliferation of the JAK2^V617F-expressing HEL cell line, leading to cell cycle arrest at the G₂/M phase and induction of caspase-dependent apoptosis. Notably, ZT55 also significantly suppressed the growth of HEL xenograft tumors in vivo. Further evaluation indicated that ZT55 blocked erythroid colony formation of peripheral blood hematopoietic progenitors from patients carrying the JAK2^V617F mutation.

CONCLUSION

These results suggest that ZT55 is a highly-selective JAK2 inhibitor that can induce apoptosis of human erythroleukemia cells by inhibiting the JAK2-STAT signaling.

Echinacoside protects against MPTP/MPP+-induced neurotoxicity via regulating autophagy pathway mediated by Sirt1

Parkinson's disease (PD) is a common chronic neurodegenerative disease and greatly affects the quality of PD patients' life. Current symptomatic treatment of PD is limited. There are no effective treatment and drugs that could radically cure PD. Increasing experimental evidence has proven a causal relationship between alpha-synuclein (α-synuclein, α-syn) and the neuropathology of Parkinson's diseases, although the exact pathophysiological role of α-synuclein is not fully clarified. Previous studies showed that monomers and polymers of α-synuclein were secreted from damaged nerve cells via exocytosis and occupied healthy nerve cells via endocytosis, which afford evidence for the prion-like role of α-synuclein. Autophagy is the known mechanism for eukaryotic cells to degrade protein polymers and damaged organelles that proteasome does not cope with. Therefore, promoting the clearance of α-synuclein by enhancing autophagy in neuronal cells could be a promising treatment in the early stage of PD. SIRT1 is a potent regulator of autophagy, because it deacetylates a mass of important transcription factors such as Forkhead Box subgroup O (FoxO) transcription factors family. SIRT1's action relates to FoxO, because FoxO transcription factors are involved in various molecular pathways underlying neuronal protection and autophagy. Moreover, Sirt1 deacetylates proautophagic proteins such as Atg5, Atg7, and Atg8. Echinacoside (ECH) is the main active ingredient of a widely used Chinese herb cistanche, which has been proven to elicit neuroprotective effects in models of neurodegenerative diseases. In this study, we found that ECH could improve PD-like symptoms in MPTP-lesioned mouse model. We further showed that the underlying mechanism of the action of ECH was associated with enhancing autophagy in neurons via bind to Sirt1 directly and affect FoxO expression. Our study demonstrated ECH as a potential therapeutic agent against PD.