Fimepinostat Impairs NF-κB and PI3K/AKT Signaling and Enhances Gemcitabine Efficacy in H3.3K27M-Diffuse Intrinsic Pontine Glioma.

Diffuse intrinsic pontine glioma (DIPG) is the most aggressive pediatric brain tumor, and the oncohistone H3.3K27M mutation is associated with significantly worse clinical outcomes. Despite extensive research efforts, effective approaches for treating DIPG are lacking. Through drug screening, we identified the combination of gemcitabine and fimepinostat as a potent therapeutic intervention for H3.3K27M DIPG. H3.3K27M facilitated gemcitabine-induced apoptosis in DIPG, and gemcitabine stabilized and activated p53, including increasing chromatin accessibility for p53 at apoptosis-related loci. Gemcitabine simultaneously induced a prosurvival program in DIPG through activation of RELB-mediated NF-κB signaling. Specifically, gemcitabine induced the transcription of long terminal repeat elements, activated cGAS-STING signaling, and stimulated noncanonical NF-κB signaling. A drug screen in gemcitabine-treated DIPG cells revealed that fimepinostat, a dual inhibitor of HDAC and PI3K, effectively suppressed the gemcitabine-induced NF-κB signaling in addition to blocking PI3K/AKT activation. Combination therapy comprising gemcitabine and fimepinostat elicited synergistic antitumor effects in vitro and in orthotopic H3.3K27M DIPG xenograft models. Collectively, p53 activation using gemcitabine and suppression of RELB-mediated NF-κB activation and PI3K/AKT signaling using fimepinostat is a potential therapeutic strategy for treating H3.3K27M DIPG. SIGNIFICANCE: Gemcitabine activates p53 and induces apoptosis to elicit antitumor effects in H3.3K27M DIPG, which can be enhanced by blocking NF-κB and PI3K/AKT signaling with fimepinostat, providing a synergistic combination therapy for DIPG.

Regeneration and proliferation of cardiomyocytes and its microRNA regulatory mechanisms.

Myocardial regeneration is identified as a concept at histological level. The core content is to increase the number of cardiomyocytes (CMs), so as to maintain the steady state of CMs under pathological or physiological conditions and ensure the normal cardiac function. In this review, we discussed the relevant factors involved in the regeneration of CMs, generalized in mice, large mammals and human. During different development stages of mammalian hearts, CMs showed several controlling and growth modes on the physiological or pathological state: mitosis, hypertrophy, nuclear polyploidy and multinucleation, amitosis and etc. We also discussed the mechanisms of specific microRNAs implicated in the cardiac development, as well as disease-induced apoptosis in CMs and the process of re-entering cell cycle after injury. It is hoped that this review will contribute to a deeper understanding of therapeutic approaches for myocardial regeneration after injury.

Context-dependent tumor-suppressive BMP signaling in diffuse intrinsic pontine glioma regulates stemness through epigenetic regulation of CXXC5.

The most lethal subtype of diffuse intrinsic pontine glioma (DIPG) is H3K27M. Although ACVR1 mutations have been implicated in the pathogenesis of this currently incurable disease, the impacts of bone morphogenetic protein (BMP) signaling on more than 60% of H3K27M DIPG carrying ACVR1 wild-type remain unknown. Here we show that BMP ligands exert potent tumor-suppressive effects against H3.3K27M and ACVR1 WT DIPG in a SMAD-dependent manner. Specifically, clinical data revealed that many DIPG tumors have exploited the capacity of CHRDL1 to hijack BMP ligands. We discovered that activation of BMP signaling promotes the exit of DIPG tumor cells from 'prolonged stem-cell-like' state to differentiation by epigenetically regulating CXXC5, which acts as a tumor suppressor and positive regulator of BMP signaling. Beyond showing how BMP signaling impacts DIPG, our study also identified the potent antitumor efficacy of Dacinostat for DIPG. Thus, our study delineates context-dependent features of the BMP signaling pathway in a DIPG subtype.

Inhibition of AKT induces p53/SIRT6/PARP1-dependent parthanatos to suppress tumor growth.

BACKGROUND: Targeting AKT suppresses tumor growth through inducing apoptosis, however, during which whether other forms of cell death occurring is poorly understood. METHODS: The effects of increasing PARP1 dependent cell death (parthanatos) induced by inhibiting AKT on cell proliferation were determined by CCK-8 assay, colony formation assay, Hoechst 33,258 staining and analysis of apoptotic cells by flow cytometry. For the detailed mechanisms during this process, Western blot analysis, qRT-PCR analysis, immunofluorescence and co-immunoprecipitation were performed. Moreover, the inhibition of tumor growth by inducing p53/SIRT6/PARP1-dependent parthanatos was further verified in the xenograft mouse model. RESULTS: For the first time, we identified that inhibiting AKT triggered parthanatos, a new form of regulated cell death, leading to colon cancer growth suppression. For the mechanism investigation, we found that after pharmacological or genetic AKT inhibition, p53 interacted with SIRT6 and PARP1 directly to activate it, and promoted the formation of PAR polymer. Subsequently, PAR polymer transported to outer membrane of mitochondria and resulted in AIF releasing and translocating to nucleus thus promoting cell death. While, blocking PARP1 activity significantly rescued colon cancer from death. Furthermore, p53 deletion or mutation eliminated PAR polymer formation, AIF translocation, and PARP1 dependent cell death, which was promoted by overexpression of SIRT6. Meanwhile, reactive oxygen species production was elevated after inhibition of AKT, which might also play a role in the occurrence of parthanatos. In addition, inhibiting AKT initiated protective autophagy simultaneously, which advanced tumor survival and growth. CONCLUSION: Our findings demonstrated that AKT inhibition induced p53-SIRT6-PARP1 complex formation and the activation of parthanatos, which can be recognized as a novel potential therapeutic strategy for cancer. Video Abstract.

Directed evolution of the PobR allosteric transcription factor to generate a biosensor for 4-hydroxymandelic acid.

Hydroxy-mandelic acid (HMA) is widely applied in pharmaceuticals, food and cosmetics. In this study, we aimed to develop an allosteric transcription factors (aTFs) based biosensor for HMA. PobR, an aTF for HMA analog 4-hydroxybenzoic acid, was used to alter its selectivity and create novel aTFs responsive to HMA by directed evolution. We established a PobR mutant library with a capacity of 550,000 mutants using error-prone PCR and Megawhop PCR. Through our screening, two mutants were obtained with responsiveness to HMA. Analysis of each missense mutation indicating residues 122-126 were involved in its PobR ligand specificity. These results showed the effectiveness of directed evolution in switching the ligand specificity of a biosensor and improving HMA production.

Noncoding RNAs in Drug Resistance of Gastrointestinal Stromal Tumor.

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the gastrointestinal tracts and a model for the targeted therapy of solid tumors because of the oncogenic driver mutations in KIT and PDGDRA genes, which could be effectively inhibited by the very first targeted agent, imatinib mesylate. Most of the GIST patients could benefit a lot from the targeted treatment of this receptor tyrosine kinase inhibitor. However, more than 50% of the patients developed resistance within 2 years after imatinib administration, limiting the long-term effect of imatinib. Noncoding RNAs (ncRNAs), the non-protein coding transcripts of human, were demonstrated to play pivotal roles in the resistance of various chemotherapy drugs. In this review, we summarized the mechanisms of how ncRNAs functioning on the drug resistance in GIST. During the drug resistance of GIST, there were five regulating mechanisms where the functions of ncRNAs concentrated: oxidative phosphorylation, autophagy, apoptosis, drug target changes, and some signaling pathways. Also, these effects of ncRNAs in drug resistance were divided into two aspects. How ncRNAs regulate drug resistance in GIST was further summarized according to ncRNA types, different drugs and categories of resistance. Moreover, clinical applications of these ncRNAs in GIST chemotherapies concentrated on the prognostic biomarkers and novel therapeutic targets.

The diagnostic value of 3.0T MRI in cesarean scar pregnancy.

OBJECTIVE: The purpose was to evaluate the diagnostic value of 3.0T MRI in cesarean scar pregnancy (CSP). METHODS: 56 patients with suspected CSP treated in our hospital from August 2018 to July 2020 were recruited as the study cohort and diagnosed using ultrasound and 3.0T MRI. With the pathological examination results as the gold standard and the ultrasound examination results as a comparison, the diagnostic value of 3.0T MRI was evaluated according to the diagnostic accuracy, sensitivity, specificity, and positive and negative misdiagnosis rates, etc. Results: The pathological examination showed that 33 patients were positive for CSP but the other 23 were negative. The accuracy, sensitivity, and specificity of 3.0T MRI in the CSP diagnoses were significantly higher than the accuracy, sensitivity, and specificity of the ultrasound diagnoses (P<0.05), and the positive and negative misdiagnosis rates were significantly lower than the misdiagnosis rates of the ultrasound diagnosis (P<0.05). Moreover, the images from two patients showed that 3.0T MRI can provide clear images of the patients' lesion locations. CONCLUSION: Compared with ultrasound diagnoses, 3.0TMRI has significant advantages in diagnosing CSP and has a high clinical value.

Curcumin protects thymus against D-galactose-induced senescence in mice.

Senescence-related decline of thymus affects immune function in the elderly population and contributes to the prevalence of many relevant diseases like cancer, autoimmune diseases, and other chronic diseases. In this study, we investigated the therapeutic effects of curcumin, an agent that could counter aging, and explored its optimal intake and the alteration of autoimmune regulator (Aire) after curcumin treatment in the D-galactose (D-gal)-induced accelerated aging mice. ICR mice were intraperitoneally injected with D-gal for 8 weeks to establish the accelerated aging model and given curcumin with 50, 100, and 200 mg/kg body weight per day by gavage, respectively, for 6 weeks. It indicated that the D-gal-treated mice developed structural changes in the thymi compared with the control group without D-gal and curcumin treatment. As the supplements of curcumin, it resulted in a restoration of the normal thymic anatomy with an increase of proliferating cells and a reduction of apoptotic cells in the thymi of the D-gal-induced aging model mice. Curcumin administration could also expand the expression level of Aire from mRNA level and protein level. The current study demonstrated that curcumin could ameliorate senescence-related thymus involution via upregulating Aire expression, suggesting that curcumin can rejuvenate senescence-associated alterations of thymus induced by D-gal accumulation.

Effect of Dahuang Danpi Decoction on Lactobacillus bulgaricus growth and metabolism: In vitro study.

Gut flora plays an essential role in disease and health. A traditional Chinese herb formula, Dahuang Danpi Decoction (DDD) can alleviate several gastrointestinal diseases.In the present study, we assessed the effect of DDD on the growth and metabolism of Lactobacillus bulgaricus. L bulgaricus was cultured in MRS with 40 mg/ml (high), 10 mg/ml (medium), and 2.5 mg/ml (low) of DDD, Ceftriaxone and blank (control). The growth of L bulgaricus was measured by optical density. The levels of L-lactic acid and D-lactic acid were also measured.Compared to the control group, the concentrations of L bulgaricus in the medium and the high concentrations DDD groups were significantly higher (P < .001 for all), while the concentrations of L bulgaricus in the ceftriaxone groups were significantly lower. In the 3 DDD groups, the L- lactic acid levels were significantly higher than those in the control group and the ceftriaxone groups (P < .001 for all), and the L-lactic acid level was the highest in the high DDD group. Similarly, the D-lactic acid level in the high concentration DDD group was significantly higher than those in the medium and low concentration DDD groups, the control group and the ceftriaxone groups. Both the L-lactic acid and D-lactic acid levels were lower than those in the control group and the DDD groups.DDD could dose-dependently promote the growth of L bulgaricus and enhance the secretion of L-lactic acid and D-lactic acid, which suggests DDD may be able to interact with the probiotics, improve the gut microbiota, and serve in the prevention and treatment of dysbiosis.