Search

Background: Even though prostate cancer (PCa) patients initially respond to androgen deprivation therapy, some will eventually develop castration resistant prostate cancer (CRPC). Androgen receptor (AR) mediated cell signaling is a major driver in the progression of CRPC while only a fraction of PCa becomes AR negative. This study aimed to understand the regulation of AR levels by N-myristoyltransferase in PCa cells., Methods: Two enantiomers, (1S,2S)- d-NMAPPD and (1R,2R)- d-NMAPPD (LCL4), were characterized by various methods ( 1 H and 13 C NMR, UHPLC, high-resolution mass spectra, circular dichroism) and evaluated for the ability to bind to N-myristoyltransferase 1 (NMT1) using computational docking analysis. structure-activity relationship analysis of these compounds led to the synthesis of (1R,2R)-LCL204 and evaluation as a potential NMT1 inhibitor utilizing the purified full length NMT1 enzyme. The NMT inhibitory activity wase determined by Click chemistry and immunoblotting. Regulation of NMT1 on tumor growth was evaluated in a xenograft tumor model., Results: (1R,2R)- d-NMAPPD, but not its enantiomer (1S,2S)- d-NMAPPD, inhibited NMT1 activity and reduced AR protein levels. (1R,2R)-LCL204, a derivative of (1R,2R)- d-NMAPPD, inhibited global protein myristoylation. It also suppressed protein levels, nuclear translocation, and transcriptional activity of AR full-length or variants in PCa cells. This was due to enhanced ubiquitin and proteasome-mediated degradation of AR. Knockdown of NMT1 levels inhibited tumor growth and proliferation of cancer cells., Conclusion: Inhibitory efficacy on N-myristoyltransferase activity by d-NMAPPD is stereospecific. (1R,2R)-LCL204 reduced global N-myristoylation and androgen receptor protein levels at low micromolar concentrations in prostate cancer cells. pharmacological inhibition of NMT1 enhances ubiquitin-mediated proteasome degradation of AR. This study illustrates a novel function of N-myristoyltransferase and provides a potential strategy for treatment of CRPC., (© 2023 The Authors. The Prostate published by Wiley Periodicals LLC.)

The triggering receptor expressed on myeloid cell 1 (TREM1) plays a critical role in development of chronic inflammatory disorders and the inflamed tumor microenvironment (TME) associated with most solid tumors. We examined whether loss of TREM1 signaling can abrogate the immunosuppressive TME and enhance cancer immunity. To investigate the therapeutic potential of TREM1 in cancer, we used mice deficient in Trem1 and developed a novel small molecule TREM1 inhibitor, VJDT. We demonstrated that genetic or pharmacological TREM1 silencing significantly delayed tumor growth in murine melanoma (B16F10) and fibrosarcoma (MCA205) models. Single-cell RNA-Seq combined with functional assays during TREM1 deficiency revealed decreased immunosuppressive capacity of myeloid-derived suppressor cells (MDSCs) accompanied by expansion in cytotoxic CD8+ T cells and increased PD-1 expression. Furthermore, TREM1 inhibition enhanced the antitumorigenic effect of anti-PD-1 treatment, in part, by limiting MDSC frequency and abrogating T cell exhaustion. In patient-derived melanoma xenograft tumors, treatment with VJDT downregulated key oncogenic signaling pathways involved in cell proliferation, migration, and survival. Our work highlights the role of TREM1 in cancer progression, both intrinsically expressed in cancer cells and extrinsically in the TME. Thus, targeting TREM1 to modify an immunosuppressive TME and improve efficacy of immune checkpoint therapy represents what we believe to be a promising therapeutic approach to cancer.

Phosphodiesterase-5 inhibitors (PDE5i) are under investigation for repurposing for colon cancer prevention. A drawback to conventional PDE5i are their side-effects and drug-drug interactions. We designed an analog of the prototypical PDE5i sildenafil by replacing the methyl group on the piperazine ring with malonic acid to reduce lipophilicity, and measured its entry into the circulation and effects on colon epithelium. This modification did not affect pharmacology as malonyl-sildenafil had a similar IC 50 to sildenafil but exhibited an almost 20-fold reduced EC 50 for increasing cellular cGMP. Using an LC-MS/MS approach, malonyl-sildenafil was negligible in mouse plasma after oral administration but was detected at high levels in the feces. No bioactive metabolites of malonyl-sildenafil were detected in the circulation by measuring interactions with isosorbide mononitrate. The treatment of mice with malonyl-sildenafil in the drinking water resulted in a suppression of proliferation in the colon epithelium that is consistent with results previously published for mice treated with PDE5i. A carboxylic-acid-containing analog of sildenafil prohibits the systemic delivery of the compound but maintains sufficient penetration into the colon epithelium to suppress proliferation. This highlights a novel approach to generating a first-in-class drug for colon cancer chemoprevention.

Glioblastoma (GBM) is a hypervascular and aggressive primary malignant tumor of the central nervous system. Recent investigations showed that traditional therapies along with antiangiogenic therapies failed due to the development of post-therapy resistance and recurrence. Previous investigations showed that there were changes in the cellular and metabolic compositions in the tumor microenvironment (TME). It can be said that tumor cell-directed therapies are ineffective and rethinking is needed how to treat GBM. It is hypothesized that the composition of TME-associated cells will be different based on the therapy and therapeutic agents, and TME-targeting therapy will be better to decrease recurrence and improve survival. Therefore, the purpose of this study is to determine the changes in the TME in respect of T-cell population, M1 and M2 macrophage polarization status, and MDSC population following different treatments in a syngeneic model of GBM. In addition to these parameters, tumor growth and survival were also studied following different treatments. The results showed that changes in the TME-associated cells were dependent on the therapeutic agents, and the TME-targeting therapy improved the survival of the GBM bearing animals. The current GBM therapies should be revisited to add agents to prevent the accumulation of bone marrow-derived cells in the TME or to prevent the effect of immune-suppressive myeloid cells in causing alternative neovascularization, the revival of glioma stem cells, and recurrence. Instead of concurrent therapy, a sequential strategy would be better to target TME-associated cells., Competing Interests: The authors have declared that no competing interests exist.

Background: Glioblastoma (GBM) was shown to relapse faster and displayed therapeutic resistance to antiangiogenic therapies (AATs) through an alternative tumor cell-driven mechanism of neovascularization called vascular mimicry (VM). We identified highly upregulated interleukin 8 (IL-8)-CXCR2 axis in tumor cells in high-grade human glioma and AAT-treated orthotopic GBM tumors., Methods: Human GBM tissue sections and tissue array were used to ascertain the clinical relevance of CXCR2-positive tumor cells in the formation of VM. We utilized U251 and U87 human tumor cells to understand VM in an orthotopic GBM model and AAT-mediated enhancement in VM was modeled using vatalanib (anti-VEGFR2) and avastin (anti-VEGF). Later, VM was inhibited by SB225002 (CXCR2 inhibitor) in a preclinical study., Results: Overexpression of IL8 and CXCR2 in human datasets and histological analysis was identified as a bonafide candidate to validate VM through in vitro and animal model studies. AAT-treated tumors displayed a higher number of CXCR2-positive GBM-stem cells with endothelial-like phenotypes. Stable knockdown of CXCR2 expression in tumor cells led to decreased tumor growth as well as incomplete VM structures in the animal models. Similar data were obtained following SB225002 treatment., Conclusions: The present study suggests that tumor cell autonomous IL-8-CXCR2 pathway is instrumental in AAT-mediated resistance and VM formation in GBM. Therefore, CXCR2 can be targeted through SB225002 and can be combined with standard therapies to improve the therapeutic outcomes in clinical trials., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Fibroblast growth factor (FGF)/FGF receptor (FGFR) signaling facilitates tumor initiation and progression. Although currently approved inhibitors of FGFR kinase have shown therapeutic benefit in clinical trials, overexpression or mutations of FGFRs eventually confer drug resistance and thereby abrogate the desired activity of kinase inhibitors in many cancer types. In this study, we report that loss of myristoylation of fibroblast growth factor receptor substrate 2 (FRS2α), a scaffold protein essential for FGFR signaling, inhibits FGF/FGFR-mediated oncogenic signaling and FGF10-induced tumorigenesis. Moreover, a previously synthesized myristoyl-CoA analog, B13, which targets the activity of N -myristoyltransferases, suppressed FRS2α myristoylation and decreased the phosphorylation with mild alteration of FRS2α localization at the cell membrane. B13 inhibited oncogenic signaling induced by WT FGFRs or their drug-resistant mutants (FGFRs DRM ). B13 alone or in combination with an FGFR inhibitor suppressed FGF-induced WT FGFR- or FGFR DRM -initiated phosphoinositide 3-kinase (PI3K) activity or MAPK signaling, inducing cell cycle arrest and thereby inhibiting cell proliferation and migration in several cancer cell types. Finally, B13 significantly inhibited the growth of xenograft tumors without pathological toxicity to the liver, kidney, or lung in vivo In summary, our study suggests a possible therapeutic approach for inhibiting FGF/FGFR-mediated cancer progression and drug-resistant FGF/FGFR mutants., (© 2018 by The American Society for Biochemistry and Molecular Biology, Inc.)

The title compound, C 24 H 18 N 2 O 4 S, crystallizes in the ortho-rhom-bic P 2 1 2 1 2 1 space group, indicating the existence of only one enanti-omer with an S configuration of the chiral center in the crystal phase. The di-hydro-pyrimidine ring adopts a twist-boat conformation while the quinone ring is slightly non-planar. In the crystal, mol-ecules are linked by weak C-H⋯O and C-H⋯S hydrogen bonds and C-H⋯π inter-actions. In addition, a short inter-molecular S⋯N contact of 3.250 (3) Å indicates an inter-action between the S atom and the π-system of the thia-zole ring.

Protein N -myristoylation enables localization to membranes and helps maintain protein conformation and function. N -myristoyltransferases (NMT) catalyze co- or posttranslational myristoylation of Src family kinases and other oncogenic proteins, thereby regulating their function. In this study, we provide genetic and pharmacologic evidence that inhibiting the N -myristoyltransferase NMT1 suppresses cell-cycle progression, proliferation, and malignant growth of prostate cancer cells. Loss of myristoylation abolished the tumorigenic potential of Src and its synergy with androgen receptor in mediating tumor invasion. We identified the myristoyl-CoA analogue B13 as a small-molecule inhibitor of NMT1 enzymatic activity. B13 exposure blocked Src myristoylation and Src localization to the cytoplasmic membrane, attenuating Src-mediated oncogenic signaling. B13 exerted its anti-invasive and antitumor effects against prostate cancer cells, with minimal toxic side-effects in vivo Structural optimization based on structure-activity relationships enabled the chemical synthesis of LCL204, with enhanced inhibitory potency against NMT1. Collectively, our results offer a preclinical proof of concept for the use of protein myristoylation inhibitors as a strategy to block prostate cancer progression. Cancer Res; 77(24); 6950-62. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Distant metastasis is the primary cause of death in the majority of the cancer types. Recently, much importance has been given to tumor microenvironment (TME) in the development of invasive malignant tumors, as well as the metastasis potential. The ability of tumor cells to modulate TME and to escape immune-mediated attack by releasing immunosuppressive cytokines has become a hallmark of breast cancer. Our study shows the effect of IV formulation of HET0016 (HPßCD-HET0016) a selective inhibitor of 20-HETE synthesis, administered intravenously in immune-competent in vivo mouse model of murine breast cancer. 4T1 luciferase positive cells were implanted to the mammary fat pad in Balb/c mice. Treatment started on day 15, and was administered for 5 days a week for 3 weeks. The development of metastasis was detected via optical imaging. Blood, spleen, lungs, bone marrow and tumor were collected for flow cytometry, to investigate changes in myeloid-derived suppressive cells (MDSCs) populations and endothelial phenotype. Tumor and lungs were collected for protein analysis. Our results show that HPßCD-HET0016: (1) decreased tumor volume and lung metastasis compared to the vehicle group; (2) reduced migration and invasion of tumor cells and levels of metalloproteinases in the lungs of animals treated with HPßCD-HET0016 via PI3K/AKT pathway; and (3) decreased expression of pro-inflammatory cytokines, growth factors and granulocytic MDSCs population in the lung microenvironment in treated animals. Thus, HPßCD-HET0016 showed potential in treating lung metastasis in a preclinical mouse model and needs further investigations on TME.

Glioblastoma (GBM) is a hypervascular primary brain tumor with poor prognosis. HET0016 is a selective CYP450 inhibitor, which has been shown to inhibit angiogenesis and tumor growth. Therefore, to explore novel treatments, we have generated an improved intravenous (IV) formulation of HET0016 with HPßCD and tested in animal models of human and syngeneic GBM. Administration of a single IV dose resulted in 7-fold higher levels of HET0016 in plasma and 3.6-fold higher levels in tumor at 60 min than that in IP route. IV treatment with HPßCD-HET0016 decreased tumor growth, and altered vascular kinetics in early and late treatment groups (p < 0.05). Similar growth inhibition was observed in syngeneic GL261 GBM (p < 0.05). Survival studies using patient derived xenografts of GBM811, showed prolonged survival to 26 weeks in animals treated with focal radiation, in combination with HET0016 and TMZ (p < 0.05). We observed reduced expression of markers of cell proliferation (Ki-67), decreased neovascularization (laminin and αSMA), in addition to inflammation and angiogenesis markers in the treatment group (p < 0.05). Our results indicate that HPßCD-HET0016 is effective in inhibiting tumor growth through decreasing proliferation, and neovascularization. Furthermore, HPßCD-HET0016 significantly prolonged survival in PDX GBM811 model., Competing Interests: The authors declare no competing financial interests.

Regulation of the epithelial sodium channel (ENaC), which regulates fluid homeostasis and blood pressure, is complex and remains incompletely understood. The TIP peptide, a mimic of the lectin-like domain of TNF, activates ENaC by binding to glycosylated residues in the extracellular loop of ENaC-α, as well as to a hitherto uncharacterized internal site. Molecular docking studies suggested three residues, Val 567 , Glu 568 , and Glu 571 , located at the interface between the second transmembrane and C-terminal domains of ENaC-α, as a critical site for binding of the TIP peptide. We generated Ala replacement mutants in this region of ENaC-α and examined its interaction with TIP peptide (3M, V567A/E568A/E571A; 2M, V567A/E568A; and 1M, E571A). 3M and 2M ENaC-α, but not 1M ENaC-α, displayed significantly reduced binding capacity to TIP peptide and to TNF. When overexpressed in H441 cells, 3M mutant ENaC-α formed functional channels with similar gating and density characteristics as the WT subunit and efficiently associated with the β and γ subunits in the plasma membrane. We subsequently assayed for increased open probability time and membrane expression, both of which define ENaC activity, following addition of TIP peptide. TIP peptide increased open probability time in H441 cells overexpressing wild type and 1M ENaC-α channels, but not 3M or 2M ENaC-α channels. On the other hand, TIP peptide-mediated reduction in ENaC ubiquitination was similar in cells overexpressing either WT or 3M ENaC-α subunits. In summary, this study has identified a novel site in ENaC-α that is crucial for activation of the open probability of the channel, but not membrane expression, by the lectin-like domain of TNF., (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)

Objective: To study whether efficient transduction and subsequent elimination of fibroid tumor-initiating stem cells during debulking of tumor cells will aid in completely eradicating the tumor as well as decreasing the likelihood of recurrence., Design: Case control study., Setting: Research laboratory., Patient(s): None., Intervention(s): Magnetic nanoparticles (MNPs) complexed to adenovirus (Ad-GFP) or (Ad-LacZ) used to transfect differentiated human fibroid cells in vitro., Main Outcome Measure(s): Rate of transduction and tumor growth inhibition., Result(s): We have developed a localized nonsurgical adenovirus-based alternative for the treatment of uterine fibroids that combines viral-based gene delivery with nanotechnology for more efficient targeting. Magnetic nanoparticles complexed to adenovirus, in the presence of an external magnetic field, accelerate adenovirus transduction. We observed a statistically significant increase in transduction efficiency among differentiated human fibroid cells at two different multiplicities of infection (MOI), 1 and 10, respectively, with MNPs as compared with adenovirus alone. Human fibroid stem cells transfected with Ad-LacZ expressed β-galactosidaze at a MOI of 1, 10, and 50 at 19%, 62%, and 90%, respectively, which were statistically significantly enhanced with MNPs., Conclusion(s): When applied with adenovirus herpes simplex thymidine kinase, magnetofection statistically significantly suppressed proliferation and induced apoptosis in both cell types. Through the use of magnetofection, we will prove that a lower viral dose will effectively increase the overall safety profile of suicide gene therapy against fibroid tumors., (Published by Elsevier Inc.)

A procedure for the cyclization of dipeptidoyl benzotriazolides containing proline derivatives promoted by triethylamine under MW activation is introduced. The reaction is general for a variety of dipeptidoyl benzotriazolides and represents a very practical and convenient method for the preparation of Pro- or Hyp-derived 2,5-diketopiperazines (2,5-DKPs) and bis-DKPs with a disulfide linker. This method can be used for the construction of 2,5-DKP compound libraries and for the synthesis of natural products with diketopiperazine cores.

Natural tetrapeptide Goralatide inhibits primitive hematopoietic cell proliferation but reported to be rather unstable in solution (half-life 4.5 min). In this work, we report the synthesis of an aminoxy analog of Goralatide. Aminoxy moiety is expected to provide increased stability and bioavailability of the Goralatide analog., (Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.)

Dimerization-macrocyclization has been a long-standing problem in the cyclization of peptides since, together with the desired cyclic product, many cyclic oligomers and linear polymers may also be formed during the reaction. Therefore, the development of a process that affords the cyclic dimer predominantly is difficult. A novel and versatile strategy for the synthesis of symmetric cyclo-tetrapeptides by palladium-promoted tandem deprotection/cyclo-dimerization from readily available Cbz-dipeptidoyl benzotriazolides is reported (Cbz=carboxybenzyl)., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Taurine-containing water-soluble peptidomimetics were designed and synthesized. N-terminal taurine acylations allowed synthesis of a number of taurine-containing peptides. N-protection of taurine with Cbz and SO2-activation with benzotriazole followed by coupling with various amino esters, dipeptides and nucleophiles provided taurine N- and O-conjugates and sulfonopeptides.

Open-chain N-Cbz-protected-peptidoyl benzotriazolides are converted by a novel lactamization strategy using proline as a turn introducer into both symmetrical (5a-c and 11a-c) and unsymmetrical (19a-e) bis-2,5-diketopiperazines (bis-2,5-DKPs), previously recognized as difficult targets.