技术资料

AMPK is a master regulator of cellular metabolism that exerts either oncogenic or tumor suppressor activity depending on context. Here,we report that the specific AMPK agonist GSK621 selectively kills acute myeloid leukemia (AML) cells but spares normal hematopoietic progenitors. This differential sensitivity results from a unique synthetic lethal interaction involving concurrent activation of AMPK and mTORC1. Strikingly,the lethality of GSK621 in primary AML cells and AML cell lines is abrogated by chemical or genetic ablation of mTORC1 signaling. The same synthetic lethality between AMPK and mTORC1 activation is established in CD34-positive hematopoietic progenitors by constitutive activation of AKT or enhanced in AML cells by deletion of TSC2. Finally,cytotoxicity in AML cells from GSK621 involves the eIF2$\alpha$/ATF4 signaling pathway that specifically results from mTORC1 activation. AMPK activation may represent a therapeutic opportunity in mTORC1-overactivated cancers. View Publication

A leading pharmacological strategy toward HIV cure requires shock" or activation of HIV gene expression in latently infected cells with latency reversal agents (LRAs) followed by their subsequent clearance. In a screen for novel LRAs we used fungal secondary metabolites as a source of bioactive molecules. Using orthogonal mass spectrometry (MS) coupled to latency reversal bioassays we identified gliotoxin (GTX) as a novel LRA. GTX significantly induced HIV-1 gene expression in latent ex vivo infected primary cells and in CD4+ T cells from all aviremic HIV-1+ participants. RNA sequencing identified 7SK RNA the scaffold of the positive transcription elongation factor b (P-TEFb) inhibitory 7SK small nuclear ribonucleoprotein (snRNP) complex to be significantly reduced upon GTX treatment of CD4+ T cells. GTX directly disrupted 7SK snRNP by targeting La-related protein 7 (LARP7) releasing active P-TEFb which phosphorylated RNA polymerase II (Pol II) C-terminal domain (CTD) inducing HIV transcription." View Publication

Cystic fibrosis (CF) cells display a more cancer-like phenotype vs. non-CF cells. KLF4 overexpression has been described in CF and this transcriptional factor acts as a negative regulator of wt-CFTR. KLF4 is described as exerting its effects in a cell-context-dependent fashion,but it is generally considered a major regulator of proliferation,differentiation,and wound healing,all the processes that are also altered in CF. Therefore,it is relevant to characterize the differential role of KLF4 in these processes in CF vs. non-CF cells. To this end,we used wt- and F508del-CFTR CFBE cells and their respective KLF4 knockout (KO) counterparts to evaluate processes like cell proliferation,polarization,and wound healing,as well as to compare the expression of several epithelial differentiation markers. Our data indicate no major impact of KLF4 KO in proliferation and a differential impact of KLF4 KO in transepithelial electrical resistance (TEER) acquisition and wound healing in wt- vs. F508del-CFTR cells. In parallel,we also observed a differential impact on the levels of some differentiation markers and epithelial-mesencymal transition (EMT)-associated transcription factors. In conclusion,KLF4 impacts TEER acquisition,wound healing,and the expression of differentiation markers in a way that is partially dependent on the CFTR-status of the cell. View Publication

Cancer stem cells (CSC) are purported to initiate and maintain tumor growth. Deregulation of normal stem cell signaling may lead to the generation of CSCs; however,the molecular determinants of this process remain poorly understood. Here we show that the transcriptional coactivator YAP1 is a major determinant of CSC properties in nontransformed cells and in esophageal cancer cells by direct upregulation of SOX9. YAP1 regulates the transcription of SOX9 through a conserved TEAD binding site in the SOX9 promoter. Expression of exogenous YAP1 in vitro or inhibition of its upstream negative regulators in vivo results in elevated SOX9 expression accompanied by the acquisition of CSC properties. Conversely,shRNA-mediated knockdown of YAP1 or SOX9 in transformed cells attenuates CSC phenotypes in vitro and tumorigenicity in vivo. The small-molecule inhibitor of YAP1,verteporfin,significantly blocks CSC properties in cells with high YAP1 and a high proportion of ALDH1(+). Our findings identify YAP1-driven SOX9 expression as a critical event in the acquisition of CSC properties,suggesting that YAP1 inhibition may offer an effective means of therapeutically targeting the CSC population. View Publication

Mifepristone is a potent antagonist of steroid hormone receptors such as glucocorticoid and progesterone receptors. We investigated the potential for mifepristone to act as an antiandrogen and compared it with partial androgen receptor (AR) agonists and antagonists,in particular bicalutamide. Mifepristone was an effective antiandrogen in vitro that inhibited transcription from three androgen-responsive promoters and blocked the agonist R1881 in a dose-dependent manner. Like bicalutamide,mifepristone also antagonized the action of androgen receptor with a (T877A) mutation. Mifepristone competed effectively with R1881 with a relative binding affinity comparable to that of cyproterone acetate,and much higher than that of hydroxyflutamide and bicalutamide in a binding assay. Mifepristone could effectively induce the binding of the herpes simplex viral protein 16/AR fusion protein to the hormone response elements in the murine mammary tumor virus-luciferase reporter. With either wild-type or T877A mutant AR,mifepristone alone was unable to induce any detectable interaction with coactivators transcriptional intermediary factor-2 or beta-catenin but could inhibit the R1881-induced binding of AR to transcriptional intermediary factor-2 and beta-catenin. Similarly,mifepristone could inhibit the R1881-induced N/C-terminal interaction in a dose-dependent manner even though mifepristone alone has no effect on the N/C-terminal interaction of AR. We found that mifepristone could induce a strong interaction between AR and corepressors nuclear receptor corepressor and silencing mediator for retinoid and thyroid hormone receptors in both transactivation and two-hybrid assays to a greater degree than hydroxyflutamide,cyproterone acetate,and bicalutamide. The AR-corepressor interaction was also seen in coimmunoprecipitation assays. Finally,mifepristone at high concentrations induced a low level of prostate-specific antigen expression in LNCaP and antagonized prostate-specific antigen expression induced by R1881. Mifepristone also antagonized R1881 action on the growth of LNCaP prostate cancer cells. View Publication

Enterotoxin-mediated secretory diarrheas such as cholera involve chloride secretion by enterocytes into the intestinal lumen by the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel. We previously identified glycine hydrazide CFTR blockers that by electrophysiological studies appeared to block the CFTR anion pore at its lumen-facing surface. Here,we synthesize highly water-soluble,nonabsorbable malondihydrazides by coupling 2,4-disulfobenzaldehyde,4-sulfophenylisothiocyante,and polyethylene glycol (PEG) moieties to 2-naphthalenylamino-[(3,5-dibromo-2,4-dihydroxyphenyl) methylene] propanedioic acid dihydrazide,and aminoacethydrazides by coupling PEG to [(N-2-naphthalenyl)-2-(2-hydroxyethyl)]-glycine-2-[(3,5-dibromo-2,4-dihydroxyphenyl) methylene] hydrazide. Compounds rapidly,fully and reversibly blocked CFTR-mediated chloride current with Ki of 2-8 microM when added to the apical surface of epithelial cell monolayers. Compounds did not pass across Caco-2 monolayers,and were absorbed by {\textless}2{\%}/hr in mouse intestine. Luminally added compounds blocked by {\textgreater}90{\%} cholera toxin-induced fluid secretion in mouse intestinal loops,without inhibiting intestinal fluid absorption. These orally administered,nonabsorbable,nontoxic CFTR inhibitors may reduce intestinal fluid losses in cholera. View Publication

Drug-induced resistance,or tolerance,is an emerging yet poorly understood failure of anticancer therapy. The interplay between drug-tolerant cancer cells and innate immunity within the tumor,the consequence on tumor growth,and therapeutic strategies to address these challenges remain undescribed. Here we elucidate the role of taxane-induced resistance on natural killer (NK) cell tumor immunity in triple-negative breast cancer (TNBC) and the design of spatio-temporally controlled nanomedicines,which boost therapeutic efficacy and invigorate 'disabled' NK. Drug tolerance limited NK cell immune surveillance via drug-induced depletion of the NK-activating ligand receptor axis,NKG2D and MHC class I polypeptide-related sequence A,B (MICA/B). Systems biology supported by empirical evidence revealed the heat shock protein 90 (Hsp90) simultaneously controls immune surveillance and persistence of drug-treated tumor cells. Based on this evidence,we engineered a 'chimeric' nano-therapeutic tool comprising taxanes and a cholesterol-tethered Hsp90 inhibitor,radicicol,which targets the tumor,reduces tolerance,and optimally re-primes NK cells via prolonged induction of NK-activating ligand receptors via temporal control of drug release in vitro and in vivo. A human ex-vivo TNBC model confirmed the importance of NK cells in drug-induced death under pressure of clinically-approved agents. These findings highlight a convergence between drug-induced resistance,the tumor-immune contexture,and engineered approaches that considers the tumor and microenvironment to improve the success of combinatorial therapy. View Publication

The recent approvals of anticancer therapeutic agents targeting the histone deacetylases and DNA methyltransferases have highlighted the important role that epigenetics plays in human diseases,and suggested that the factors controlling gene expression are novel drug targets. Protein arginine deiminase 4 (PAD4) is one such target because its effects on gene expression parallel those observed for the histone deacetylases. We demonstrated that F- and Cl-amidine,two potent PAD4 inhibitors,display micromolar cytotoxic effects towards several cancerous cell lines (HL-60,MCF7 and HT-29); no effect was observed in noncancerous lines (NIH 3T3 and HL-60 granulocytes). These compounds also induced the differentiation of HL-60 and HT29 cells. Finally,these compounds synergistically potentiated the cell killing effects of doxorubicin. Taken together,these findings suggest PAD4 inhibition as a novel epigenetic approach for the treatment of cancer,and suggest that F- and Cl-amidine are candidate therapeutic agents for this disease. View Publication

Thyromimetics that specifically target TR$\beta$ have been shown to reduce plasma cholesterol levels and avoid atherosclerosis through the promotion of reverse cholesterol transport in an animal model. We designed novel thyromimetics with high receptor (TR$\beta$) and organ (liver) selectivity based on the structure of eprotirome (3) and molecular modeling. We found that indane derivatives are potent and dual-selective thyromimetics expected to avoid hypothyroidism in some tissues as well as heart toxicity. KTA-439 (29),a representative indane derivative,showed the same high human TR$\beta$ selectivity in a binding assay as 3 and higher liver selectivity than 3 in a cholesterol-fed rat model. View Publication

PURPOSE PARP-3 is member of the PARP family of poly (ADP-ribose) polymerases involved in ADPribosylation. PARPs are involved in the basic mechanisms of DNA repair. PARP3,a critical player for efficient mitotic progression,is required for the stabilization of the mitotic spindle by regulation of the mitotic components,NuMA and Tankyrase 1. METHODS The sensitization effect of vinorelbine on PARP3 inhibition-induced cytotoxicity was assessed by the SRB assay. The contribution of programed cell death and cell cycle arrest to the sensitization effect were determined by assessing changes in Annexin V,a marker of apoptosis. Alterations in cell cycle progression were assessed by cell cycle analysis. We used immunofluorescence to assess the effect of vinorelbine and/or PARP3 inhibitors on tubulin and microtubule depolarization. The PARP3 chemiluminescent assay kit was used for PARP3 activity. RESULTS PARP3 inhibitors sensitize breast cancer cells to vinorelbine,a vinca alkaloid used in the treatment of metastatic breast cancer. Olaparib which was originally described as a PARP1 and 2 inhibitor has recently been shown to be a potent PARP3 inhibitor while ME0328 is a more selective PARP3 inhibitor. The combination of vinorelbine with nontoxic concentrations of ME0328 or olaparib reduces vinorelbine resistance by 10 and 17 fold,respectively,potentiating vinorelbine-induced arrest at the G2/M boundary. In addition,PARP3 inhibition potentiates vinorelbine interaction with tubulin. Furthermore,olaparib or ME0328 potentiates vinorelbine-induced PARP3 inhibition,mitotic arrest,and apoptosis. CONCLUSION Our results indicated this approach with PARP3 inhibitors and vinorelbine is unique and promising for breast cancer patients with metastases. This combination could significantly increase the survival of breast cancer patients with metastases. View Publication

Small molecules that promote the metabolic activity of the pyruvate kinase isoform PKM2,such as TEPP-46 and DASA-58,limit tumorigenesis and inflammation. To understand how these compounds alter T cell function,we assessed their therapeutic activity in a mouse model of T cell-mediated autoimmunity that mimics multiple sclerosis (MS). TH17 cells are believed to orchestrate MS pathology,in part,through the production of two proinflammatory cytokines: interleukin-17 (IL-17) and GM-CSF. We found that both TEPP-46 and DASA-58 suppressed the development of IL-17-producing TH17 cells but increased the generation of those producing GM-CSF. This switch redirected disease pathology from the spinal cord to the brain. In addition,we found that activation of PKM2 interfered with TGF-$\beta$1 signaling,which is necessary for the development of TH17 and regulatory T cells. Collectively,our data clarify the therapeutic potential of PKM2 activators in MS-like disease and how these agents alter T cell function. View Publication

The airway epithelium contains ionocytes,a rare cell type with high expression of Forkhead Box I1 (FOXI1) transcription factor and Cystic Fibrosis Transmembrane conductance Regulator (CFTR),a chloride channel that is defective in cystic fibrosis (CF). Our aim was to verify if ionocyte development is altered in CF and to investigate the relationship between ionocytes and CFTR-dependent chloride secretion. We collected nasal cells by brushing to determine ionocyte abundance. Nasal and bronchial cells were also expanded in vitro and reprogrammed to differentiated epithelia for morphological and functional studies. We found a relatively high ({\~{}}3{\%}) ionocyte abundance in ex vivo nasal samples,with no difference between CF and control individuals. In bronchi,ionocytes instead appeared very rarely as previously reported,thus suggesting a possible proximal-distal gradient in human airways. The difference between nasal and bronchial epithelial cells was maintained in culture,which suggests an epigenetic control of ionocyte development. In the differentiation phase of the culture procedure,we used two media that resulted in a different pattern of CFTR expression: confined to ionocytes or more broadly expressed. CFTR function was similar in both conditions,thus indicating that chloride secretion equally occurs irrespective of CFTR expression pattern. View Publication