Methyltransferase like 13 mediates the translation of Snail in head and neck squamous cell carcinoma

Methyltransferase like 13(METTL13),a kind of methyltransferase,is implicated in protein binding and synthesis.The upregulation of METTL13 has been reported in a variety of tumors.However,little was known about its potential function in head and neck squamous cell carcinoma(HNSCC)so far.In this study,we found that METTL13 was significantly upregulated in HNSCC at both mRNA and protein level.Increased METTL13 was negatively associated with clinical prognosis.And METTL13 markedly affected HNSCC cellular phenotypes in vivo and vitro.Further mechanism study revealed that METTL13 could regulate EMT signaling pathway by mediating enhancing translation efficiency of Snail,the key transcription factor in EMT,hence regulating the progression of EMT.Furthermore,Snail was verified to mediate METTL13-induced HNSCC cell malignant phenotypes.Altogether,our study had revealed the oncogenic role of METTL13 in HNSCC,and provided a potential therapeutic strategy.

Investigation of Linarinic acid and one of its derivatives against cerebral ischemia in mice

The study aims to investigate the effects of(-)-Linarinic acid(LA) and one of its derivatives(LAd) on brain injury induced by ischemia. Malonaldehyde(MDA) is determined as an index for lipid peroxidation both in vitro and vivo. Mice were pre-treated with LA and LAd for 3 d.Thereafter, they were induced to have incomplete cerebral ischemia with both bilateral carotid artery occlusion and hypotension(BCAOH). In the first part of the in vivo experiment, mice were divided into four groups: sham(control), ischemia, ischemia + LA(200 mg/kg, i.g.) and ischemia + LAd(200 mg/kg, i.g.). In the second part, the dose-response of LAd was investigated at 100, 200 and 400 mg/kg i.g., respectively. A modified neurological severity score was developed for evaluating behavioral deficits of the mice with ischemia. Brains of the mice were excised in order to determinate MDA after ischemia for 6 h. Survival time, survival rate, neurological injury score and MDA level in brains were observed. Results were: 1) The data in vitro showed that both LA and LAd could inhibit the generation of MDA. IC50 values obtained by Probit analysis were 2.9 mM for LAd and 4.88 mM for LA;2) BCAOH could significantly shorten the survival span, reduce the survival rate and cause neurological deficits,which were associated with high level of lipid hydroperoxide production in cerebral tissues;3) LAd decreased lipid peroxidation and improved the neurological outcome more than LA.It is concluded that LAd offers a better neuroprotection than LA against brain damage caused by cerebral ischemia.

A boronic acid conjugation integrates antitumor drugs into albumin-binding prodrugs-based nanoparticles with robust efficiency for cancer therapy

Despite great therapeutic effect of Abraxane®,complex preparation technology and unfavorable pharmacokinetics still restricted the clinical application of albumin-based paclitaxel(PTX)nanoparticles(NPs).Herein,we reported that an albumin-binding prodrug,phenylboronic acid-conjugated PTX(P-PTX),can form the uniform NPs with the diameters around 100 nm with the help of albumin via simple one-step nano-precipitation method.The albumin-based nanomedicines were stabilized by the integration of a single boronic acid with PTX due to the increased affinity based on multiple intermolecular interactions.We found that albumin-based P-PTX NPs exhibited superior colloidal stability over albumin-based PTX NPs through one-step nanoprecipitation approach,achieving longer in vivo circulation time and higher concentration in tumor than those of the marketed Abraxane®.Furthermore,the albumin-based P-PTX NPs with great stability and enhanced intratumoral enrichment,increased the maximum tolerated dose of PTX,remarkably suppressed the growth of breast tumor and lung metastasis,prolonged survival of melanoma tumors-bearing mice.Such a convenient and effective system gains an insight into the impact of phenylboronic acid group on the albumin-based PTX NPs,provides potent strategy for the rational design of albumin-based antitumor nanomedicines.

Aberrant translation regulated by METTL1/WDR4-mediated tRNA N7-methylguanosine modification drives head and neck squamous cell carcinoma progression

Background:Cancer cells selectively promote the translation of oncogenic tran-scripts to stimulate cancer progression.Although growing evidence has revealed that tRNA modifications and related genes participate in this process,their roles in head and neck squamous cell carcinoma(HNSCC)remain largely unchar-acterized.Here,we sought to investigate the function and mechanisms of the transfer RNA(tRNA)N7-methylguanosine(m'G)modification in regulating the occurrence and development of HNSCC.Methods:Cell lost of-function and gain-of function assays,xenograft models,conditional knockout and knockin mouse models were used to study the physi-ological functions of tRNA m'G modification in HNSCC tumorigenesis.tRNA modification and expression profiling,mRNA translation profiling and res-cue assays were performed to uncover the underlying molecular mechanisms.Single-cell RNA sequencing(scRNA seq)was conducted to explore the tumor microenvironment changes.Results:The tRNA.m7G methyltransferase complex components Methyltransferase-like 1(METTL1)/WD repeat domain 4(WDR4)were upregulated in HNSCC and associated with a poor prognosis.Functionally,METTL1/WDR4 promoted HNSCC progression and metastasis in cell-based and transgenic mouse models.Mechanistically,ablation of METTL1 reduced the m'G levels of 16 tRNAS,inhibiting the translation of a subset of oncogenic transcripts,including genes related to the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin(PI3K/AKT/mTOR)signaling pathway.In addition,chemical modulators of the PI3K/Akt/mTOR signaling pathway reversed the effects of Mettll in mouse HNSCC.Furthermore,scRNA-seq results revealed that Mettll knockout in mouse tumor cells altered the immune landscape and cell-cell interaction between the tumor and stromal compartment.Conclusions:The tRNA m?G methyltransferase METTLI was found to promote the development and malignancy of HNSCC through regulating global mRNA translation,including the PI3K/AKT/mTOR signaling pathway,and found to alter immune landscape.METTLI could be a promising treatment target for HNSCC patients.

Discovery of a series of dimethoxybenzene FGFR inhibitors with 5H-pyrrolo[2,3-b]pyrazine scaffold: structure–activity relationship, crystal structural characterization and in vivo study

Genomic alterations are commonly found in the signaling pathways of fibroblast growth factor receptors(FGFRs). Although there is no selective FGFR inhibitors in market, several promising inhibitors have been investigated in clinical trials, and showed encouraging efficacies in patients. By designing a hybrid between the FGFR-selectivity-enhancing motif dimethoxybenzene group and our previously identified novel scaffold, we discovered a new series of potent FGFR inhibitors, with the best one showing sub-nanomolar enzymatic activity. After several round of optimization and with the solved crystal structure, detailed structure–activity relationship was elaborated. Together with in vitro metabolic stability tests and in vivo pharmacokinetic profiling, a representative compound(35) was selected and tested in xenograft mouse model, and the result demonstrated that inhibitor 35 was effective against tumors with FGFR genetic alterations, exhibiting potential for further development.

Synthesis of selective PAK4 inhibitors for lung metastasis of lung cancer and melanoma cells

The p21 activated kinase 4(PAK4) is serine/threonine protein kinase that is critical for cancer progression.Guided by X-ray crystallography and structure-based optimization,we report a novel subseries of C-3-substituted 6-ethynyl-1 H-indole derivatives that display high potential and specificity towards group Ⅱ PAKs.Among these inhibitors,compound 55 exhibited excellent inhibitory activity and kinase selectivity,displayed superior anti-migratory and anti-invasive properties against the lung cancer cell line A549 and the melanoma cell line B16.Compound 55 exhibited potent in vivo antitumor metastatic efficacy,with over 80% and 90% inhibition of lung metastasis in A549 or B16-BL6 lung metastasis models,respectively.Further mechanistic studies demonstrated that compound 55 mitigated TGF-β1-induced epithelial-mesenchymal transition(EMT).

Structurally defined tandem-responsive nanoassemblies composed of dipeptide-based photosensitive derivatives and hypoxia-activated camptothecin prodrugs against primary and metastatic breast tumors

Substantial progress in the use of chemo-photodynamic nano-drug delivery systems(nanoDDS) for the treatment of the malignant breast cancer has been achieved. The inability to customize precise nanostructures, however, has limited the therapeutic efficacy of the prepared nano-DDS to date. Here,we report a structurally defined tandem-responsive chemo-photosensitive co-nanoassembly to eliminate primary breast tumor and prevent lung metastasis. This both-in-one co-nanoassembly is prepared by assembling a biocompatible photosensitive derivative(pheophorbide-diphenylalanine peptide, PPADA) with a hypoxia-activated camptothecin(CPT) prodrug [(4-nitrophenyl) formate camptothecin, NCPT]. According to computational simulations, the co-assembly nanostructure is not the classical core-shell type, but consists of many small microphase regions. Upon exposure to a 660 nm laser,PPA-DA induce high levels of ROS production to effectively achieve the apoptosis of normoxic cancer cells. Subsequently, the hypoxia-activated N-CPT and CPT spatially penetrate deep into the hypoxic region of the tumor and suppress hypoxia-induced tumor metastasis. Benefiting from the rational design of the chemo-photodynamic both-in-one nano-DDS, these nanomedicines exhibit a promising potential in the inhibition of difficult-to-treat breast tumor metastasis in patients with breast cancer.

Catalytic cleavage activities of 10–23 DNAzyme analogs functionalized with an amino group in its catalytic core

Functionalization of the catalytic loop of 10–23 DNAzyme with an amino group was performed by incorporation of 7-(3-aminopropyl)-8-aza-7-deaza-20-deoxyadenosine in different single positions.Among the nine modified positions in the catalytic loop,A9 is the unique position with positive contribution by such modification.These results indicated that more efficient deoxyribozymes remain to be explored by introduction of exogenous functional groups in an appropriate position in the catalytic loop of 10–23 DNAzyme,such as the combination of 7-functional group substituted 8-aza-7-deaza-20-deoxyadenosine analogs and A9 position.

Au(Ⅰ)-Catalyzed 6-endo-dig Cyclizations of Aromatic 1,5-Enynes to 2-(Naphthalen-2-yl)anilines Leading to Divergent Syntheses of Benzo[α]carbazole, Benzo[c,h]cinnoline and Dibenzo[i]phenanthridine Derivatives

A gold(Ⅰ)-catalyzed 6-endo-dig cyclization of aromatic 1,5-enynes was developed to synthesize 2-(naphthalen-2-yl)anilines.The functional group tolerance of this cyclization was examined systematically and a possible mechanism was proposed.The derivatization of 2-(naphthalen-2-yl)aniline was carried out to facile access to benzo[α]carbazole,benzo[c,h]cinnoline and dibenzo[i]phenanthridine derivatives in a divergent way.

Mettl5 mediated 18S rRNA N6-methyladenosine(m^(6)A)modification controls stem cell fate determination and neural function

Ribosome RNA(rRNA)accounts for more than 80%of the cell's total RNA,while the physiological functions of rRNA modifications are poorly understood.Mutations of 18S rRNA m6A methyltransferase METTL5 cause intellectual disability,microcephaly,and facial dysmorphisms in patients,however,little is known about the underlying mechanisms.In this study,we identified METTL5 protein complex and revealed that METTL5 mainly interacts with RNA binding proteins and ribosome proteins.Functionally,we found that Mettl5 knockout in mESCs leads to the abnormal craniofacial and nervous development.Moreover,using Mettl5 knockout mouse model,we further demonstrated that Mettl5 knockout mice exhibit intellectual disability,recapitulating the human phenotype.Mechanistically,we found that Mettl5 maintains brain function and intelligence by regulating the myelination process.Our study uncovered the causal correlation between mis-regulated 18S rRNA m6A modification and neural function defects,supporting the important physiological functions of rRNA modifications in human diseases.

Novel Pt(IV) complex OAP2 induces STING activation and pyroptosis via mitochondrial membrane remodeling for synergistic chemo-immunotherapy

Mitochondrial membrane remodeling can trigger the release of mitochondrial DNA (mtDNA), leading to the activation of cellular oxidative stress and immune responses. While the role of mitochondrial membrane remodeling in promoting inflammation in hepatocytes is well-established, its effects on tumors have remained unclear. In this study, we designed a novel Pt(IV) complex, OAP2, which is composed of oxaliplatin (Oxa) and acetaminophen (APAP), to enhance its anti-tumor effects and amplify the immune response. Our findings demonstrate that OAP2 induces nuclear DNA damage, resulting in the production of nuclear DNA. Additionally, OAP2 downregulates the expression of mitochondrial Sam50, to promote mitochondrial membrane remodeling and trigger mtDNA secretion, leading to double-stranded DNA accumulation and ultimately synergistically activating the intracellular cGAS-STING pathway. The mitochondrial membrane remodeling induced by OAP2 overcomes the limitations of Oxa in activating the STING pathway and simultaneously promotes gasdermin-D-mediated cell pyroptosis. OAP2 also promotes dendritic cell maturation and enhances the quantity and efficacy of cytotoxic T cells, thereby inhibiting cancer cell proliferation and metastasis. Briefly, our study introduces the first novel small-molecule inhibitor that regulates mitochondrial membrane remodeling for active immunotherapy in anti-tumor research, which may provide a creative idea for targeting organelle in anti-tumor therapy.