Photo-Induced C-H Methylation Reactions.

Direct C-H methylation is a highly valuable approach for introducing methyl groups into organic molecules, particularly in pharmaceutical chemistry. Among the various methodologies available, photo-induced methylation stands out as an exceptional choice due to its mild reaction conditions, energy efficiency, and compatibility with functional groups. This article offers a comprehensive review of photochemical strategies employed for the direct and selective methylation of C(sp3 )-H, C(sp2 )-H, and C(sp)-H bonds in various organic molecules. The discussed methodologies encompass transition-metal-based photocatalysis, organophotocatalysis, as well as other metal-free approaches, including electron donor-acceptor (EDA)-enabled transformations. Importantly, a wide range of easily accessible agents such as tert-butyl peroxide, methanol, DMSO, methyl tert-butyl ether, TsOMe, N-(acetoxy)phthalimide, acetic acid, methyl halides, and even methane can serve as effective methylating reagents for modifying diverse targets. These advancements in photochemical C-H methylation are anticipated to drive further progress in the fields of organic synthesis, photocatalysis, and pharmaceutical development, opening up exciting avenues for creating novel organic molecules and discovering new drug compounds.

A Review of the Regulatory Mechanisms of N-Myc on Cell Cycle.

Neuroblastoma has obvious heterogeneity. It is one of the few undifferentiated malignant tumors that can spontaneously degenerate into completely benign tumors. However, for its high-risk type, even with various intensive treatment options, the prognosis is still unsatisfactory. At the same time, a large number of research data show that the abnormal amplification and high-level expression of the MYCN gene are positively correlated with the malignant progression, poor prognosis, and mortality of neuroblastoma. In this context, this article explores the role of the N-Myc, MYCN gene expression product on its target genes related to the cell cycle and reveals its regulatory network in promoting tumor proliferation and malignant progression. We hope it can provide ideas and direction for the research and development of drugs targeting N-Myc and its downstream target genes.

Hepatocyte-derived VEGFA accelerates the progression of non-alcoholic fatty liver disease to hepatocellular carcinoma via activating hepatic stellate cells.

Non-alcoholic fatty liver disease (NAFLD) is emerging as an epidemic risk factor for hepatocellular carcinoma (HCC). The progression of NAFLD to HCC is closely associated with paracrine communication among hepatic cells. Vascular endothelial growth factor A (VEGFA) plays a key role in NAFLD and HCC; however, the cellular communication of VEGFA in the pathological transition from NAFLD to HCC remains unclear. Here, we found that VEGFA elevation was considerably distributed in hepatocytes of clinical and murine NAFLD-HCC specimens. Notably, progression from NAFLD to HCC was attenuated in hepatocyte-specific deletion of Vegfa (VegfaΔhep) mice. Mechanistically, VEGFA activated human hepatic stellate cell (HSC) LX2 into a fibrogenic phenotype via VEGF-VEGFR signaling in fatty acid medium, and HSC activation was largely attenuated in VegfaΔhep mice during NAFLD-HCC progression. Additionally, a positive correlation between VEGFA and hepatic fibrosis was observed in the NAFLD-HCC cohort, but not in the HBV-HCC cohort. Moreover, LX2 cells could be activated by conditioned medium from NAFLD-derived organoids, but not from HBV livers, whereas this activation was blocked by a VEGFA antibody. In summary, our findings reveal that hepatocyte-derived VEGFA contributes to NAFLD-HCC development by activating HSCs and highlight the potential of precisely targeting hepatocytic VEGFA as a promising therapeutic strategy for NAFLD-HCC.

Synthesis and Biological Evaluation of Amino Chalcone Derivatives as Antiproliferative Agents.

Chalcone is a common scaffold found in many biologically active compounds. The chalcone scaffold was also frequently utilized to design novel anticancer agents with potent biological efficacy. Aiming to continue the research of effective chalcone derivatives to treat cancers with potent anticancer activity, fourteen amino chalcone derivatives were designed and synthesized. The antiproliferative activity of amino chalcone derivatives was studied in vitro and 5-Fu as a control group. Some of the compounds showed moderate to good activity against three human cancer cells (MGC-803, HCT-116 and MCF-7 cells) and compound 13e displayed the best antiproliferative activity against MGC-803 cells, HCT-116 cells and MCF-7 cells with IC50 values of 1.52 µM (MGC-803), 1.83 µM (HCT-116) and 2.54 µM (MCF-7), respectively which was more potent than the positive control (5-Fu). Further mechanism studies were explored. The results of cell colony formatting assay suggested compound 10e inhibited the colony formation of MGC-803 cells. DAPI fluorescent staining and flow cytometry assay showed compound 13e induced MGC-803 cells apoptosis. Western blotting experiment indicated compound 13e induced cell apoptosis via the extrinsic/intrinsic apoptosis pathway in MGC-803 cells. Therefore, compound 13e might be a valuable lead compound as antiproliferative agents and amino chalcone derivatives worth further effort to improve amino chalcone derivatives' potency.

Spectroscopic investigation of the anticancer alkaloid piperlongumine binding to human serum albumin from the viewpoint of drug delivery.

Piperlongumine (PL) is a very promising natural agent with a high potential for cancer treatment. To overcome the poor water solubility of PL, there is a need to develop a novel water-soluble formulation in which PL is non-covalently bound to human serum albumin (HSA). PL binding to HSA was studied by various spectroscopic techniques under simulated physiological conditions. Spectroscopic evidence showed that the interaction of PL with HSA could form a PL-HSA complex. The binding constant (Ka ) values increased with increasing temperature, and a similar dependence was observed for the number of binding sites (n) values. The number of PL molecules bound to HSA reached 8.1 when the temperature was raised to 308 K. Thermodynamic calculation results suggested that the binding reaction occurred spontaneously but was an entropy-driven process, and hydrophobic forces played a major role in stabilizing the complex. Furthermore, PL binding induced conformational and microenvironmental changes in HSA. Displacement studies indicated that PL and warfarin had separate binding regions in site I. Therefore, it would be possible to develop a novel water-soluble formulation involving PL and HSA. This study may provide some valuable information in terms of improving the poor water solubility of PL.

Binding of fluphenazine with human serum albumin in the presence of rutin and quercetin: An evaluation of food-drug interaction by spectroscopic techniques.

The interactions between human serum albumin (HSA) and fluphenazine (FPZ) in the presence or absence of rutin or quercetin were studied by fluorescence, absorption and circular dichroism (CD) spectroscopy and molecular modeling. The results showed that the fluorescence quenching mechanism was static quenching by the formation of an HSA-FPZ complex. Entropy change (ΔS0 ) and enthalpy change (ΔH0 ) values were 68.42 J/(mol⋅K) and -4.637 kJ/mol, respectively, which indicated that hydrophobic interactions and hydrogen bonds played major roles in the acting forces. The interaction process was spontaneous because the Gibbs free energy change (ΔG0 ) values were negative. The results of competitive experiments demonstrated that FPZ was mainly located within HSA site I (sub-domain IIA). Molecular docking results were in agreement with the experimental conclusions of the thermodynamic parameters and competition experiments. Competitive binding to HSA between flavonoids and FPZ decreased the association constants and increased the binding distances of FPZ binding to HSA. The results of absorption, synchronous fluorescence, three-dimensional fluorescence, and CD spectra showed that the binding of FPZ to HSA caused conformational changes in HSA and simultaneous effects of FPZ and flavonoids induced further HSA conformational changes.

Visible light-triggered selective C(sp2)-H/C(sp3)-H coupling of benzenes with aliphatic hydrocarbons.

The direct and selective coupling of benzenes with aliphatic hydrocarbons is a promising strategy for C(sp2)-C(sp3) bond formation using readily available starting materials, yet it remains a significant challenge. In this study, we have developed a simplified photochemical system that incorporates catalytic amounts of iron(III) halides as multifunctional reagents and air as a green oxidant to address this synthetic problem. Under mild conditions, the reaction between a strong C(sp2)-H bond and a robust C(sp3)-H bond has been achieved, affording a broad range of cross-coupling products with high yields and commendable chemo-, site-selectivity. The iron halide acts as a multifunctional reagent that responds to visible light, initiates C-centered radicals, induces single-electron oxidation to carbocations, and participates in a subsequent Friedel-Crafts-type process. The gradual release of radical species and carbocation intermediates appears to be critical for achieving desirable reactivity and selectivity. This eco-friendly, cost-efficient approach offers access to various building blocks from abundant hydrocarbon feedstocks, and demonstrates the potential of iron halides in sustainable synthesis.

Selectfluor®-enabled photochemical selective C(sp3)-H(sulfonyl)amidation.

Transition metal- and photosensitizer-free C(sp3)-H (sulfonyl)amidation reactions have been realized by employing Selectfluor® as a versatile reagent, functioning as a photoactive component, a HAT precursor and an oxidant. Various toluene derivatives, cycloalkanes, natural products and bioactive molecules can be converted into N-containing products under mild conditions in good yield and with high chemo- and site-selectivity.

Hypomethylation of Thyroid Peroxidase as a Biomarker for Hepatocellular Carcinoma with Tumor Thrombosis.

OBJECTIVE: Thyroid hormones (THs) regulate multiple physiological activities in the liver, including cellular metabolism, differentiation, and cell growth, and play important roles in the pathogenesis of hepatocellular carcinoma (HCC). Thyroid peroxidase (TPO) is a key molecule involved in the THs synthesis and signaling pathway. As an epigenetic modification, DNA methylation has a critical role in tumorigenesis with diagnostic potential. However, the connection between THs and DNA methylation has been rarely investigated. METHODS: The methylation of key TH-related genes was analyzed by in-house epigenome-wide scanning, and we further analyzed the methylation levels of the TPO promotor in 164 sample pairs of HCC and adjacent non-cancerous tissues by Sequenom EpiTYPER assays, and evaluated their clinical implications. RESULTS: We identified that the methylation of the TPO promoter was downregulated in the HCC tissues (P<0.0001) with a mean difference ranging from 18.5% to 22.3%. This methylation pattern correlated with several clinical factors, including a multi-satellite tumor, fibrous capsule, and the presence of tumor thrombus. The receiver operator characteristic (ROC) curve analysis further confirmed that the percent methylated reference (PMR) values for TPO were predictive of the tumor [the area under the curve (AUC) ranged from 0.755 to 0.818] and the thrombosis in the HCC patients (the AUC ranged from 0.706 to 0.777). CONCLUSION: These findings demonstrated that epigenetic alterations of TPO, as indicated by the PMR values, were a potential biomarker for HCC patients with tumor thrombosis.

A review: hippo signaling pathway promotes tumor invasion and metastasis by regulating target gene expression.

BACKGROUND: The Hippo pathway is widely considered to inhibit cell growth and play an important role in regulating the size of organs. However, recent studies have shown that abnormal regulation of the Hippo pathway can also affect tumor invasion and metastasis. Therefore, finding out how the Hippo pathway promotes tumor development by regulating the expression of target genes provides new ideas for future research on targeted drugs that inhibit tumor progression. METHODS: PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched. RESULTS: The search strategy identified 1892 hits and 196 publications were finally included in this review. As the core molecule of the Hippo pathway, YAP/TAZ are usually highly expressed in tumors that undergo invasion and migration and are accompanied by abnormally strong nuclear metastasis. Through its interaction with nuclear transcription factors TEADs, it directly or indirectly regulates and the expressions of target genes related to tumor metastasis and invasion. These target genes can induce the formation of invasive pseudopodia in tumor cells, reduce intercellular adhesion, degrade extracellular matrix (ECM), and cause epithelial-mesenchymal transition (EMT), or indirectly promote through other signaling pathways, such as mitogen-activated protein kinases (MAPK), TGF/Smad, etc, which facilitate the invasion and metastasis of tumors. CONCLUSION: This article mainly introduces the research progress of YAP/TAZ which are the core molecules of the Hippo pathway regulating related target genes to promote tumor invasion and metastasis. Focus on the target genes that affect tumor invasion and metastasis, providing the possibility for the selection of clinical drug treatment targets, to provide some help for a more in-depth study of tumor invasion and migration mechanism and the development of clinical drugs.

Endothelial Yes-Associated Protein 1 Promotes Astrocyte Proliferation and Maturation via Cytoplasmic Leukemia Inhibitory Factor Secretion in Oxygen-Induced Retinopathy.

Purpose: Purpose The role of endothelial Yes-associated protein 1 (YAP) in the pathogenesis of retinal angiogenesis and the astrocyte network in the mouse oxygen-induced retinopathy (OIR) model is unknown. Methods: For in vivo studies, OIR was induced in conditional endothelial YAP knockout mice and their wild-type littermates. Retinal vascularization and the astrocyte network were evaluated by whole-mount fluorescence and Western blotting. In vitro experiments were performed in astrocytes cultured with human microvascular endothelial cell-1-conditioned medium to analyze the mechanisms underlying the effect of endothelial YAP on astrocytes.

Vps35 Deficiency Impairs Cdk5/p35 Degradation and Promotes the Hyperphosphorylation of Tau Protein in Retinal Ganglion Cells.

PURPOSE: Vacuolar protein sorting 35 (Vps35) mutations and protein dysfunction have been linked to the hyperphosphorylation and accumulation of tau protein in a number of central neurodegenerative disorders. The aims of the present study were to investigate the mechanism underlying the tau hyperphosphorylation caused by Vps35 deficiency. METHODS: The cells used in this study were primary retinal ganglion cells (RGCs). The rat retinal glutamate excitotoxicity model was used in vivo. Fresh retinal tissues or eyeballs were collected at different time points. The expression and interactions of Vps35, Cdk5/p35, tau hyperphosphorylation, LAMP1, EEA1 and UBE1 in RGCs were studied by immunofluorescence staining, Western blotting, and immunoprecipitation. RESULTS: The downregulation and overexpression of Vps35 increased and decreased the expression of p35 and tau hyperphosphorylation, respectively. More important, roscovitine, a Cdk5 inhibitor, could effectively decrease the hyperphosphorylated tau level induced by Vps35 deficiency. Furthermore, this study confirmed that the inhibition of Vps35 could increase the activity of Cdk5/p35 by affecting the lysosomal degradation of p35 and lead to the degeneration of RGCs. CONCLUSIONS: These findings demonstrate the possibility that Cdk5/p35 acts as a "cargo" of Vps35 and provide new insights into the pathogenesis of RGC degeneration caused by hyperphosphorylated tau protein. Vps35 is a potential target for basic research and clinical treatment of RGC degeneration in many ocular diseases such as glaucoma.

Retinal blood vessel-origin yes-associated protein (YAP) governs astrocytic maturation via leukaemia inhibitory factor (LIF).

OBJECTIVES: To testify that endothelial cells (ECs) induce astrocyte maturation by leukaemia inhibitory factor (LIF) secretion. MATERIALS AND METHODS: In vivo experiments, mice bearing floxed alleles of YAP were crossed with mice expressing a Cre recombinase driven by the endothelial Tek promoter (Tek-Cre) to finally obtain the following three genotypes: YAPf/f , Tek-Cre; YAPf/w , Tek-Cre; and YAPf/f . Retinal vascularization and astrocyte network were evaluated by whole-mount fluorescence and Western blotting. In vitro, experiments were performed in an astrocyte and human microvascular endothelial cell (HMEC-1) coculture model to analyse the mechanisms underlying the effect of endothelial YAP on astrocytes. RESULTS: In vivo, YAPf/f ;Tek-Cre mice showed delayed angiogenesis, sparse vessels and decreased glial fibrillary acidic protein (GFAP)+ astrocytes but aberrant growth of endothelial networks and immature astrocytes (platelet-derived growth factor A, PDGFRA+ astrocytes) overgrowth. In vitro, Yap deletion attenuated the LIF release that delayed the maturation of retinal astrocyte which was consistent with the results of HMEC-1-astrocyte coculture. The effect of YAP overexpression on LIF-LIFR axis in HMEC-1 interferes the GFAP expression of astrocyte. In contrast, LIF protein rescues the astrocytic GFAP expression when EC YAP was inhibited by siRNAs. CONCLUSIONS: We show that EC yes-associated protein (YAP) is not only a critical coactivator of Hippo signalling in retinal vessel development but also plays an essential role in retinal astrocyte maturation by regulating LIF production.

Long non-coding RNA FEZF1-AS1 promotes cell growth in multiple myeloma via miR-610/Akt3 axis.

Increasing evidence showed that long non-coding RNAs (lncRNAs) play critical roles in tumor progression. FEZF1-AS1 is a cancer-associated lncRNA which upregulated and associated with poor prognosis in patients with cancer. However, the roles of FEZF1-AS1 in multiple myeloma (MM) remains unclear. In the present study, our data revealed that FEZF1-AS1 expression was increased both in MM samples and cell lines. Loss of functional assays indicated that FEZF1-AS1 suppression inhibited MM cells proliferation, arrested cell cycle in G0/G1 phase and induced cell apoptosis in vitro. Furthermore, our data indicated that FEZF1-AS1 functioned as a competing endogenous RNA in MM cells that regulated miR-610 expression, which suppressed Akt3. Those data showed that FEZF1-AS1 promoted MM cells proliferation through regulating miR-610/Akt3 axis, suggesting FEZF1-AS1 could be served as a potential target for cancer therapeutics in MM.

Exploration of the glutamate-mediated retinal excitotoxic damage: a rat model of retinal neurodegeneration.

AIM: To explore the more suitable concentration of glutamate or N-methyl-D-aspartic acid (NMDA) for intravitreal injection to establish a rat model of retinal neurodegeneration. METHODS: We injected different doses of glutamate (20 or 50 nmol) or NMDA (40 nmol) into the vitreous chambers of rats, then measured the concentration of glutamate and retinal thickness, quantified apoptotic cells and determined the degree of tau hyperphosphorylation at different time points. T-test was used for comparison of two groups. One-way ANOVA and Turkey's multiple comparisons test were used for comparisons of different groups, and P values below 0.05 were considered statistically significant. RESULTS: The glutamate level in the rats treated with 50 nmol of glutamate was twice that of the control group and persisted two weeks. Seven days after intravitreal injection of 50 nmol of glutamate, three parameters [inner retinal thickness (IRT), retinal thickness (RT) and ganglion cell layer (GCL) cell number] were reduced significantly. Furthermore, numerous TUNEL-positive cells were observed in the GCL one day after intravitreal injection of 50 nmol of glutamate, the expression of the apoptosis-related factor cleaved casepase-3 was markedly increased compared with the expression levels in the other treatment groups, and the expression levels of tau s396 and tau s404 were significantly increased compared with those in the control group. CONCLUSION: This study demonstrates that the intravitreal injection of 50 nmol of glutamate can establish the more effective retinal neurodegeneration animal model relative to other treatment groups.

[Application of the improved MTT assay in predicting the intrinsic drug resistance of liver cancer].

OBJECTIVE: To investigate the role of the improved MTT assay in prediction of intrinsic drug resistance of liver cancer. METHODS: The convenient MTT colorimetry was innovated to test the effects of 4'-epi-adriamycin (E-ADM), carboplatin (CBP), and 5-Fluorouracil(5-Fu), used alone or in combination, on 30 specimens of primary liver cancer without chemotherapy. All of the 30 paraffin-embedded tissues were assembled in a microarray. The used terminal concentrations of drugs were one twentieth those of the plasma peak concentrations calculated by using the liver cancer cells of the line SMMC-7721. The expression of P-glycoprotein (P-gp), multidrug resistant protein (MRP)-3, lung resistance-related protein (LRP), glutathione S-transferase (GST)-pi, and 2 kinds of cyclin-related protein: p16(INK4a) and p21WAF1, were detected by immunohistochemistry. RESULTS: Sixteen of the 30 specimens (53.3%) were drug-resistant and 14 of the 30 specimens (46.7%) were drug-sensitive. The sequence of drug -sensitivity was in the order of combination chemotherapy, E-ADM, 5-Fu, and CBP. The positive rate of P-gp in the drug-resistant group was 56.3%, significantly higher than that of the drug-sensitive group (14.3%, P < 0.05). CONCLUSION: An improved MTT assay has been developed that is more scientific and worth spreading clinically. Intrinsic drug resistance of liver cancer is popular. P-gp is a good predictive marker in intrinsic drug resistance of liver cancer.

Genomic expression profiling and bioinformatics analysis of pancreatic cancer.

Pancreatic cancer is a polygenic disease and the fourth leading cause of cancer-associated mortality worldwide; however, the tumorigenesis of pancreatic cancer remains poorly understood. Research at a molecular level, which includes the exploration of biomarkers for early diagnosis and specific targets for therapy, may effectively aid in the diagnosis of pancreatic cancer in its early stages and in the development of targeted molecular­biological approaches for treatment, thus improving prognosis. By conducting expression profiling in para­carcinoma, carcinoma and relapse of human pancreatic tissues, 319 genes or transcripts with differential expression levels >3­fold between these tissue types were identified. Further analysis with Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes demonstrated that the translation, nucleus assembly processes and molecular functions associated with vitamin B6 and pyridoxal phosphate binding in pancreatic carcinoma were abnormal. Pancreatic cancer was additionally identified to be closely associated with certain autoimmune diseases, including type I diabetes mellitus and systemic lupus erythematosus.

Hypoxia inducible factor-1α suppresses Peroxiredoxin 3 expression to promote proliferation of CCRCC cells.

Peroxiredoxin 3 (Prx3) is a mitochondrial member of the antioxidant family of thioredoxin peroxidases that uses mitochondrial thioredoxin 2 as a source of reducing equivalents to scavenge hydrogen peroxide (H2O2). Here, we report that the protein levels of Prx3 are significantly reduced in VHL-deficient clear cell renal cell carcinoma (CCRCC). Furthermore, stabilization of HIF-1α protein, caused either by VHL deficiency under normoxia, or by hypoxia, significantly reduced Prx3 expression. Luciferase-reporter and chromatin-immunoprecipitation assays indicated that HIF-1α binds to the hypoxia-responsive elements of PRDX3 promoter and represses its transcription. Finally, shRNA-based assays suggested that Prx3 downregulation is required for the HIF-1α-dependent proliferation of CCRCC cells. Taken together, our results shed new light onto the mechanism of HIF-1α-dependent proliferation in CCRCC cells.

[Inhibitory effect of PD98059 on MAPK signaling pathway in acute lymphocytic leukemia cells].

This study was purposed to investigate the effect of blocking Ras/Erk signaling pathway on expression of important transcription factor c-fos, c-jun and TAK1 gene in primary acute lymphocytic leukemia (ALL) cells. The best effective concentration and effect time of PD98059 were screened; the expression levels of c-fos, c-jun and TAK1 in primary cultured cells of normal persons, primary cultured ALL cells and primary cultured ALL cells treated by PD98059 were detected by SYBR GreenI real-time quantitative-PCR. The results showed that before treatment by PD98059 the expression levels of c-fos and TAK1 mRNA were significantly up-regulated in primary cultured ALL cells as compared with primary cultured cells of normal persons (P = 0.014 and P = 0.017 respectively). After treatment by PD98059, the expression levels of c-fos, c-jun mRNA decreased in all 7 serum samples, while expression of TAK1 was down-regulated in 5 samples, and up-regulated in 2 samples. After treatment with PD98059, there was no statistical difference of c-fos, c-jun and TAK1 expression levels in primary cultured ALL cells and primary cultured normal cells. It is concluded that the c-fos and TAK1 activity of primary cultured ALL cells increases, and blocking the Ras/Erk signaling pathway of ALL cells can lead to obvious decrease of important transcription factors c-fos, c-jun, TAK1 genes expression.