Dichloroacetic acid and rapamycin synergistically inhibit tumor progression

Mammalian target of rapamycin(mTOR)controls cellular anabolism,and mTOR signaling is hyperactive in most cancer cells.As a result,inhibition of mTOR signaling benefits cancer patients.Rapamycin is a US Food and Drug Administration(FDA)-approved drug,a specific mTOR complex 1(mTORC1)inhibitor,for the treatment of several different types of cancer.However,rapamycin is reported to inhibit cancer growth rather than induce apoptosis.Pyruvate dehydrogenase complex(PDHc)is the gatekeeper for mitochondrial pyruvate oxidation.PDHc inactivation has been observed in a number of cancer cells,and this alteration protects cancer cells from senescence and nicotinamide adenine dinucleotide(NAD^(+))exhaustion.In this paper,we describe our finding that rapamycin treatment promotes pyruvate dehydrogenase E1 subunit alpha 1(PDHA1)phosphorylation and leads to PDHc inactivation dependent on mTOR signaling inhibition in cells.This inactivation reduces the sensitivity of cancer cells'response to rapamycin.As a result,rebooting PDHc activity with dichloroacetic acid(DCA),a pyruvate dehydrogenase kinase(PDK)inhibitor,promotes cancer cells'susceptibility to rapamycin treatment in vitro and in vivo.

Mitochondrial YBX1 promotes cancer cell metastasis by inhibiting pyruvate uptake

Pyruvate is an essential fuel for maintaining the tricarboxylic acid(TCA)cycle in the mitochondria.However,the precise mole-cular mechanism of pyruvate uptake by mitochondrial pyruvate carrier(MPC)is largely unknown.Here,we report that the DNA/RNA-binding protein Y-box binding protein 1(YBX1)is localized to the mitochondrial inter-membrane space by its C-terminal domain(CTD)in cancer cells.In mitochondria,YBX1 inhibits pyruvate uptake by associating with MPC1/2,thereby suppressing pyruvate-dependent TCA cycle flux.This association,in turn,promotes MPC-mediated glutaminolysis and histone lactylation.Our findings reveal that the YBX1-MPC axis exhibits a positive correlation with metastatic potential,while does not affect cell proliferation in both cultured cells and tumor xenografts.Therefore,the restricted pyruvate uptake into mitochondria potentially represents a hallmark of metastatic capacity,suggesting that the YBX1-MPC axis is a therapeutic target for combating cancer metastasis.

Identification of serum metabolites enhancing inflammatory responses in COVID-19

Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),is characterized by a strong production of inflammatory cytokines such as TNF and IL-6,which underlie the severity of the disease.However,the molecular mechanisms responsible for such a strong immune response remains unclear.Here,utilizing targeted tandem mass spectrometry to analyze serum metabolome and lipidome in COVID-19 patients at different temporal stages,we identified that 611 metabolites(of 1,039)were significantly altered in COVID-19 patients.Among them,two metabolites,agmatine and putrescine,were prominently elevated in the serum of patients;and 2-quinolinecarboxylate was changed in a biphasic manner,elevated during early COVID-19 infection but levelled off.When tested in mouse embryonic fibroblasts(MEFs)and macrophages,these 3 metabolites were found to activate the NF-κB pathway that plays a pivotal role in governing cytokine production.Importantly,these metabolites were each able to cause strong increase of TNF and IL-6 levels when administered to wildtype mice,but not in the mice lacking NF-κB.Intriguingly,these metabolites have little effects on the activation of interferon regulatory factors(IRFs)for the production of type I interferons(IFNs)for antiviral defenses.These data suggest that circulating metabolites resulting from COVID-19 infection may act as effectors to elicit the peculiar systemic inflammatory responses,exhibiting severely strong proinflammatory cytokine production with limited induction of the interferons.Our study may provide a rationale for development of drugs to alleviate inflammation in COVID-19 patients.

YB1 regulates miR-205/200b-ZEB1 axis by inhibiting microRNA maturation in hepatocellular carcinoma

Background:Y-box binding protein 1(YB1 or YBX1)plays a critical role in tumorigenesis and cancer progression.However,whether YB1 affects malignant transformation by modulating non-codingRNAs remains largely unknown.This study aimed to investigate the relationship between YB1 and microRNAs and reveal the underlying mechanism by which YB1 impacts on tumor malignancy via miRNAs-mediated regulatory network.Methods:The biological functions of YB1 in hepatocellular carcinoma(HCC)cells were investigated by cell proliferation,wound healing,and transwell invasion assays.The miRNAs dysregulated by YB1 were screened by microarray analysis in HCC cell lines.The regulation of YB1 on miR-205 and miR-200b was determined by quantitative real-time PCR,dual-luciferase reporter assay,RNA immunoprecipitation,and pull-down assay.The relationships of YB1,DGCR8,Dicer,TUT4,and TUT1 were identified by pull-down and coimmunoprecipitation experiments.The cellular co-localization of YB1,DGCR8,and Dicer were detected by immunofluorescent staining.The in vivo effect of YB1 on tumor metastasis was determined by injecting MHCC97H cells transduced with YB1 shRNA or shControl via the tail vein in nude BALB/c mice.The expression levels of epithelial tomesenchymal transition markerswere detected by immunoblotting and immunohistochemistry assays.Results:YB1 promoted HCC cell migration and tumor metastasis by regulating miR-205/200b‒ZEB1 axis partially in a Snail-independent manner.YB1 suppressedmiR-205 and miR-200b maturation by interacting with the microprocessors DGCR8 and Dicer as well as TUT4 and TUT1 via the conserved cold shock domain.Subsequently,the downregulation of miR-205 and miR-200b enhanced ZEB1 expression,thus leading to increased cell migration and invasion.Furthermore,statistical analyses on gene expression data from HCC and normal liver tissues showed that YB1 expression was positively associated with ZEB1 expression and remarkably correlated with clinical prognosis.Conclusion:This study reveals a previously undescribed mechanism by which YB1 promotes cancer progression by regulating the miR-205/200b‒ZEB1 axis in HCC cells.Furthermore,these results highlight that YB1 may play biological functions via miRNAs-mediated gene regulation,and it can serve as a potential therapeutic target in human cancers.

Cholesterol as a functional metabolite cooperates with metadherin in cancer cells

Protein-metabolite interactions(PMIs)play important roles in various biological processes,especially in disease progression.However,due to the complexity of living cells,it is very difficult to identify specific PMIs.Herein,we chose one oncogenic factor,metadherin(MTDH),as a bait to identify its in vivo interacting metabolites in cancer cells.Cholesterol is an important metabolite and essential structural component of cell membranes.It could also drive several diseases including cancer.Interestingly,we found that cholesterol robustly interacted with MTDH and downregulated the expression of MTDH in cancer cells.Furthermore,MTDH disturbed metabolite alterations under cholesterol treatment in MTDH transduced cancer cells.Collectively,our results uncover an undescribed PMI where MTDH,as an oncogenic factor,might positively regulate cancer progression by interacting with choleste rol.This study interprets the theoretical basis of PMI-oriented cancer progression and targeting therapies in clinic.

Semi-Quantitatively Designing Two-Photon High-Performance Fluorescent Probes for Glutathione S-Transferases

Glutathione S-transferases(GSTs),detoxification enzymes that catalyze the addition of glutathione(GSH)to diverse electrophilic molecules,are often overexpressed in various tumor cells.While fluorescent probes for GSTs have often adopted the 2,4-dinitrobenzenesulfonyl(DNs)group as the receptor unit,they usually suffer from considerable background reaction noise with GSH due to excessive electron deficiency.However,weakening this reactivity is generally accompanied by loss of sensitivity for GSTs,and therefore,finely turning down the reactivity while maintaining certain sensitivity is critical for developing a practical probe.Here,we report a rational semiquantitative strategy for designing such a practical two-photon probe by introducing a parameter adopted from the conceptual density functional theory(CDFT),the local electrophilicityω_(k),to characterize this reactivity.As expected,kinetic studies establishedω_(k)as efficient to predict the reactivity with GSH,and probe NI3 showing the best performance was successfully applied to detecting GST activities in live cells and tissue sections with high sensitivity and signal-to-noise ratio.Photoinduced electron transfer of naphthalimide-based probes,captured by femtosecond transient absorption for the first time and unraveled by theoretical calculations,also contributes to the negligible background noise.

Biochemical reactions in metabolite-protein interaction

Active endogenous metabolites regulate the viability of cells. This process is controlled by a series ofinteractions between small metabolites and large proteins. Previously, several studies had reported thatmetabolite regulates the protein functions, such as diacylglycerol to protein kinase C, lactose regulationof the lac repressor, and HIF-1α stabilization by 2-hydroxyglutarate. However, decades old traditionalbiochemical methods are insufficient to systematically investigate the bio-molecular reactions for a high-throughput discovery. Here, we have reviewed an update on the recently developed chemical proteomicscalled activity-based protein profiling （ABPP）. ABPP is able to identify proteins interacted eithercovalently or non-covalently with metabolites significantly. Thus, ABPP will facilitate the characteriza-tion of specific metabolite regulating; proteins in human disease progression.