DPAGT1 Inhibitors of Capuramycin Analogues and Their Antimigratory Activities of Solid Tumors

Capuramycin displays a narrow spectrum of antibacterial activity by targeting bacterial translocase I (MraY). In our program of development of new N-acetylglucosaminephosphotransferase1 (DPAGT1) inhibitors, we have identified that a capuramycin phenoxypiperidinylbenzylamide analogue (CPPB) inhibits DPAGT1 enzyme with an IC₅₀ value of 200 nM. Despite a strong DPAGT1 inhibitory activity, CPPB does not show cytotoxicity against normal cells and a series of cancer cell lines. However, CPPB inhibits migrations of several solid cancers including pancreatic cancers that require high DPAGT1 expression in order for tumor progression. DPAGT1 inhibition by CPPB leads to a reduced expression level of Snail but does not reduce E-cadherin expression level at the IC₅₀ (DPAGT1) concentration. CPPB displays a strong synergistic effect with paclitaxel against growth-inhibitory action of a patient-derived pancreatic adenocarcinoma, PD002: paclitaxel (IC₅₀: 1.25 μM) inhibits growth of PD002 at 0.0024–0.16 μM in combination with 0.10–2.0 μM CPPB (IC₅₀: 35 μM)

DPAGT1 Inhibitors of Capuramycin Analogues and Their Antimigratory Activities of Solid Tumors

Capuramycin displays a narrow spectrum of antibacterial activity by targeting bacterial translocase I (MraY). In our program of development of new N-acetylglucosaminephosphotransferase1 (DPAGT1) inhibitors, we have identified that a capuramycin phenoxypiperidinylbenzylamide analogue (CPPB) inhibits DPAGT1 enzyme with an IC₅₀ value of 200 nM. Despite a strong DPAGT1 inhibitory activity, CPPB does not show cytotoxicity against normal cells and a series of cancer cell lines. However, CPPB inhibits migrations of several solid cancers including pancreatic cancers that require high DPAGT1 expression in order for tumor progression. DPAGT1 inhibition by CPPB leads to a reduced expression level of Snail but does not reduce E-cadherin expression level at the IC₅₀ (DPAGT1) concentration. CPPB displays a strong synergistic effect with paclitaxel against growth-inhibitory action of a patient-derived pancreatic adenocarcinoma, PD002: paclitaxel (IC₅₀: 1.25 μM) inhibits growth of PD002 at 0.0024–0.16 μM in combination with 0.10–2.0 μM CPPB (IC₅₀: 35 μM)

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sity of differing M types is proposed. The vast majority of GAS infection is benign. Nonetheless, many divergent M types possess limited capacity to cause invasive infection. M1T1 GAS readily switch to a covRS mutant form that is neutrophil resistant and frequently associated with systemic infection. Whilst non-M1 GAS are shown in this study to less frequently accumulate covRS mutations in vivo, such mutants are isolated from invasive infections and exhibit neutrophil resistance and enhanced virulence. The reduced capacity of non-M1 GAS to switch to the hypervirulent covRS mutant form provides an explanation for the comparatively less frequent isolation of non-M1 serotypes from invasive human infections. Key Words Animal models ؒ Bacteriology ؒ Immunity ؒ Innate ؒ Neutrophils ؒ Streptococcus ؒ Virulence factors ؒ Invasive infection Abstract Group A Streptococcus (GAS) causes rare but life-threatening syndromes of necrotizing fasciitis and toxic shock-like syndrome in humans. The GAS serotype M1T1 clone has globally disseminated, and mutations in the control of virulence regulatory sensor kinase (covRS) operon correlate with severe invasive disease. Here, a cohort of non-M1 GAS was screened to determine whether mutation in covRS triggers systemic dissemination in divergent M serotypes. A GAS disease model defining parameters governing invasive propen

Parameters Governing Invasive Disease Propensity of Non-M1 Serotype Group A Streptococci

Group A Streptococcus (GAS) causes rare but life-threatening syndromes of necrotizing fasciitis and toxic shock-like syndrome in humans. The GAS serotype M1T1 clone has globally disseminated, and mutations in the control of virulence regulatory sensor kinase (covRS) operon correlate with severe invasive disease. Here, a cohort of non-M1 GAS was screened to determine whether mutation in covRS triggers systemic dissemination in divergent M serotypes. A GAS disease model defining parameters governing invasive propensity of differing M types is proposed. The vast majority of GAS infection is benign. Nonetheless, many divergent M types possess limited capacity to cause invasive infection. M1T1 GAS readily switch to a covRS mutant form that is neutrophil resistant and frequently associated with systemic infection. Whilst non-M1 GAS are shown in this study to less frequently accumulate covRS mutations in vivo, such mutants are isolated from invasive infections and exhibit neutrophil resistance and enhanced virulence. The reduced capacity of non-M1 GAS to switch to the hypervirulent covRS mutant form provides an explanation for the comparatively less frequent isolation of non-M1 serotypes from invasive human infections

Role of TGF-β in pancreatic ductal adenocarcinoma progression and PD-L1 expression

The transforming growth factor-beta (TGF-β) pathway plays a paradoxical, context-dependent role in pancreatic ductal adenocarcinoma (PDAC): a tumor-suppressive role in non-metastatic PDAC and a tumor-promotive role in metastatic PDAC. We hypothesize that non-SMAD-TGF-β signaling induces PDAC progression. We investigated the expression of non-SMAD-TGF-β signaling proteins (pMAPK14, PD-L1, pAkt and c-Myc) in patient-derived tissues, cell lines and an immunocompetent mouse model. Experimental models were complemented by comparing the signaling proteins in PDAC specimens from patients with various survival intervals. We manipulated models with TGF-β, gemcitabine (DNA synthesis inhibitor), galunisertib (TGF-β receptor inhibitor) and MK-2206 (Akt inhibitor) to investigate their effects on NF-κB, β-catenin, c-Myc and PD-L1 expression. PD-L1 expression was also investigated in cancer cells and tumor associated macrophages (TAMs) in a mouse model. We found that tumors from patients with aggressive PDAC had higher levels of the non-SMAD-TGF-β signaling proteins pMAPK14, PD-L1, pAkt and c-Myc. In PDAC cells with high baseline β-catenin expression, TGF-β increased β-catenin expression while gemcitabine increased PD-L1 expression. Gemcitabine plus galunisertib decreased c-Myc and NF-κB expression, but induced PD-L1 expression in some cancer models. In mice, gemcitabine plus galunisertib treatment decreased metastases (p = 0.018), whereas galunisertib increased PD-L1 expression (p < 0.0001). In the mice, liver metastases contained more TAMs compared to the primary pancreatic tumors (p = 0.001), and TGF-β increased TAM PD-L1 expression (p < 0.05). In PDAC, the non-SMAD-TGF-β signaling pathway leads to more aggressive phenotypes, TAM-induced immunosuppression and PD-L1 expression. The divergent effects of TGF-β ligand versus receptor inhibition in tumor cells versus TAMs may explain the TGF-β paradox. Further evaluation of each mechanism is expected to lead to the development of targeted therapies

DNase Sda1 provides selection pressure for a switch to invasive group A streptococcal infection

Most invasive bacterial infections are caused by species that more commonly colonize the human host with minimal symptoms. Although phenotypic or genetic correlates underlying a bacterium's shift to enhanced virulence have been studied, the in vivo selection pressures governing such shifts are poorly understood. The globally disseminated M1T1 clone of group A Streptococcus (GAS) is linked with the rare but life-threatening syndromes of necrotizing fasciitis and toxic shock syndrome. Mutations in the GAS control of virulence regulatory sensor kinase (covRS) operon are associated with severe invasive disease, abolishing expression of a broad-spectrum cysteine protease (SpeB) and allowing the recruitment and activation of host plasminogen on the bacterial surface. Here we describe how bacteriophage-encoded GAS DNase (Sda1), which facilitates the pathogen's escape from neutrophil extracellular traps, serves as a selective force for covRS mutation. The results provide a paradigm whereby natural selection exerted by the innate immune system generates hypervirulent bacterial variants with increased risk of systemic dissemination