Discovery of a novel quinoxalinhydrazide with a broad-spectrum anticancer activity

Previously, we discovered a novel class of salicylhydrazide compounds with remarkable activity in hormone-dependent and -independent human cancer cells. We then designed and synthesized numerous analogues. Among these analogues, a quinoxalinhydrazide compound, SC144, exhibited desirable physicochemical and drug-like properties and therefore was selected for further preclinical investigation. In the present study, we evaluated the in vitro activity of SC144 in a range of drug-sensitive and -resistant cancer cell lines as well as its in vivo efficacy in MDA-MB-435 and HT29 mice xenograft models. The broad-spectrum cytotoxicity of SC144 is especially highlighted by its potency in ovarian cancer cells resistant to cisplatin, breast-cancer cells resistant to doxorubicin, and colon cancer cells resistant to oxaliplatin. Furthermore, its activity was independent of p53, HER-2, estrogen and androgen receptor expressions. We also examined the effect of SC144 on cell cycle progression and apoptosis in select cell lines. Considering its cytotoxicity profile in a variety of in vitro and in vivo cancer models as well as its effects on cell cycle regulation and apoptosis, SC144 appears to represent a promising agent for further clinical development

Phenotype plasticity and altered sensitivity to chemotherapeutic agents in aggressive prostate cancer cells

In 2023, approximately 288,300 new diagnoses of prostate cancer will occur, with 34,700 disease-related deaths. Death from prostate cancer is associated with metastasis, enabled by progression of tumor phenotypes and successful extracapsular extension to reach Batson’s venous plexus, a specific route to the spine and brain. Using a mouse-human tumor xenograft model, we isolated an aggressive muscle invasive cell population of prostate cancer, called DU145J7 with a distinct biophysical phenotype, elevated histone H3K27, and increased matrix metalloproteinase 14 expression as compared to the non-aggressive parent cell population called DU145WT. Our goal was to determine the sensitivities to known chemotherapeutic agents of the aggressive cells as compared to the parent population. High-throughput screening was performed with 5,578 compounds, comprising of approved and investigational drugs for oncology. Eleven compounds were selected for additional testing, which revealed that vorinostat, 5-azacitidine, and fimepinostat (epigenetic inhibitors) showed 2.6-to-7.5-fold increases in lethality for the aggressive prostate cancer cell population as compared to the parent, as judged by the concentration of drug to inhibit 50% cell growth (IC50). On the other hand, the DU145J7 cells were 2.2-to-4.0-fold resistant to mitoxantrone, daunorubicin, and gimatecan (topoisomerase inhibitors) as compared to DU145WT. No differences in sensitivities between cell populations were found for docetaxel or pirarubicin. The increased sensitivity of DU145J7 prostate cancer cells to chromatin modifying agents suggests a therapeutic vulnerability occurs after tumor cells invade into and through muscle. Future work will determine which epigenetic modifiers and what combinations will be most effective to eradicate early aggressive tumor populations

Ruthenium arene complexes as HIV-1 integrase strand transfer inhibitors

The quinolone HL1 and the hydroxypyrimidine-carboxamide HL2 were designed and synthesized as models of the HIV integrase strand transfer inhibitors Elvitegravir and Raltegravir (brand name Isentress), with the aim to study their complexing behavior and their biological activity. The Ru(arene) complexes [RuCl(η6-p-cym)L1], [RuCl(η6-p-cym)L2] and [RuCl(hexamethylbenzene)L2] were also synthesized and spectroscopically characterized and their X-ray diffraction structures were discussed. The ligands and the complexes showed inhibition potency in the sub/low-micromolar concentration range in anti-HIV-1 integrase enzymatic assays, with selectivity toward strand transfer catalytic process, without any significant cytotoxicity on cancer cells

Design of cell-permeable nanoneedles as HIV-1 integrase inhibitors

DESIGN OF CELL-PERMEABLE NANONEEDLES AS HIV-1 INTEGRASE INHIBITORS Ya-Qiu Long*,†, Shao-Xu Huang†, ‡, Zahrah Zawahir§,‡, Huiyuan Li†, Tino W. Sanchez§, Ying Zhi†, Frauke Christ¶, Zeger Debyser¶, Nouri Neamati*,§ †State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China; §Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033; ¶The Laboratory for Molecular Virology and Gene Therapy, KULeuven and IRC KULAK, Kapucijnenvoer 33, B-3000 Leuven, Flanders, Belgium HIV-1 integrase (IN) is an essential enzyme in the viral life cycle and catalyzes the integration of viral DNA into the host genome. It is an attractive therapeutic target for developing HIV-specific drugs because no mammalian counterpart exists for this enzyme. For successful integration of reverse-transcribed viral DNA into the host genome to occur, several interactions with host proteins are required. We have previously demonstrated HIV-1 IN inhibition in vitro with peptides derived from naturally occurring alpha-helical regions of the protein. Two peptides, NL6 and NL9, with low micromolar IC50 values for inhibition of HIV-1 IN catalysis were discovered. Each peptide was derived from the α1 and α3 helical domains of the IN protein, respectively. Alanine scanning on these peptides further pinpointed amino acid residues that were later proven to be critical for IN dimerization and LEDGF/p75-IN interaction. Here we show that hydrocarbon-stapling of these peptides to stabilize their helical structure enables enhanced enzyme inhibitory potency and cell permeability while demonstrating selective inhibition of HIV-1 replication in cell culture. Furthermore, the stabilized peptides demonstrate inhibition of the LEDGF/p75 interaction. The corresponding unstapled peptides do not show inhibition of replication in vivo, although each pair of peptides has similar activity against IN in our in vitro assay. Given their enhanced potency and cell permeability they may serve as prototypical biochemical probes for development into ‘nanoneedles’ for the elucidation of HIV-1 IN and host co-factor interactions within their native cellular environment. To our knowledge this is the first report attempting to design and synthesize stapled-peptides targeting integration events either by directly inhibiting IN or inhibiting its interaction with LEDGF/p75.status: publishe

The significance of autoantibodies to DFS70/LEDGFp75 in health and disease: integrating basic science with clinical understanding

Antinuclear autoantibodies (ANAs) displaying the nuclear dense fine speckled immunofluorescence (DFS-IIF) pattern in HEp-2 substrates are commonly observed in clinical laboratory referrals. They target the dense fine speckled autoantigen of 70 kD (DFS70), most commonly known as lens epithelium-derived growth factor p75 (LEDGFp75). Interesting features of these ANAs include their low frequency in patients with systemic autoimmune rheumatic diseases (SARD), elevated prevalence in apparently healthy individuals, IgG isotype, strong trend to occur as the only ANA specificity in serum, and occurrence in moderate to high titers. These autoantibodies have also been detected at varied frequencies in patients with diverse non-SARD inflammatory and malignant conditions such as atopic diseases, asthma, eye diseases, and prostate cancer. These observations have recently stimulated vigorous research on their clinical and biological significance. Some studies have suggested that they are natural, protective antibodies that could serve as biomarkers to exclude a SARD diagnosis. Other studies suggest that they might be pathogenic in certain contexts. The emerging role of DFS70/LEDGFp75 as a stress protein relevant to human acquired immunodeficiency syndrome, cancer, and inflammation also points to the possibility that these autoantibodies could be sensors of cellular stress and inflammation associated with environmental factors. In this comprehensive review, we integrate our current knowledge of the biology of DFS70/LEDGFp75 with the clinical understanding of its autoantibodies in the contexts of health and disease.NIH/NIMHDNIH/NIMGSRoche Tissue Diagnost, Ventana Med, Tucson, AZ USAInova Diagnost Inc, Dept Res, San Diego, CA USALoma Linda Univ, Dept Basic Sci, Ctr Hlth Dispar & Mol Med, Sch Med, Mortensen Hall 142,11085 Campus St, Loma Linda, CA 92350 USAUniv Fed Sao Paulo, Div Rheumatol, Sao Paulo, BrazilFleury Med & Hlth Labs, Div Immunol, Sao Paulo, BrazilUniv Calgary, Fac Med, Calgary, AB, CanadaLoma Linda Univ, Sch Med, Dept Med, Div Rheumatol, Loma Linda, CA 92354 USAUniv Fed Sao Paulo, Div Rheumatol, Sao Paulo, BrazilNIH/NIMHD: P20MD006988NIH/NIMGS: R25GM060507Web of Scienc

Investigating the role of metal chelation in HIV-1 integrase strand transfer inhibitors

HIV-1 integrase (IN) has been validated as an attractive target for the treatment of HIV/AIDS. Several studies have confirmed that the metal binding function is a crucial feature in many of the reported IN inhibitors. To provide new insights on the metal chelating mechanism of IN inhibitors, we prepared a series of metal complexes of two ligands (HL1 and HL2), designed as representative models of the clinically used compounds raltegravir and elvitegravir. Potentiometric measurements were conducted for HL2 in the presence of Mg(II), Mn(II), Co(II), and Zn(II) in order to delineate a metal speciation model. We also determined the X-ray structures of both of the ligands and of three representative metal complexes. Our results support the hypothesis that several selective strand transfer inhibitors preferentially chelate one cation in solution and that the metal complexes can interact with the active site of the enzyme

Racial differences in the expression of inhibitors of apoptosis (IAP) proteins in extracellular vesicles (EV) from prostate cancer patients - Fig 1

<p>A. Survivin levels were detected in sera derived from European American (EA) (n = 17) and African American (AA) (n = 21) patients with prostate cancer (PCa), as well as from control sera (n = 10) from individuals with no diagnosis of cancer. Comparisons between groups were analyzed by MANOVA (** p < 0.01). B. Survivin levels were detected in plasma derived from EA (n = 10) and AA (n = 12) patients with PCa. Comparisons were analyzed by Student’s t-test (*** p < 0.001). (*N6 and *N14 are Hispanics; *N12 is Asian, we have excluded those from the analysis).</p

Representative Western blots showing the IAP levels in EV derived from individual European American (EA) (N1-N5) & (N7-N9), *N6 and African American (AA) (N1-N9) patients with prostate cancer (PCa).

<p>Specific antibodies against Survivin, XIAP, cIAP-1, cIAP-2, and Lamp1 were used for the Western blotting analysis of total exosomal proteins. The blots from both patient groups were processed under identical conditions; Lamp 1 was used as loading control. (*N6, Hispanic.) (Both blots were done side by side in the same gel running and transferring apparatus, blocking, washing buffers, and antibody incubations were done in the same time, in the same incubating trays under the identical exposure to keep the consistencies.)</p

Design of Cell-Permeable Stapled Peptides as HIV‑1 Integrase Inhibitors

HIV-1 integrase (IN) catalyzes the integration of viral DNA into the host genome, involving several interactions with the viral and cellular proteins. We have previously identified peptide IN inhibitors derived from the α-helical regions along the dimeric interface of HIV-1 IN. Herein, we show that appropriate hydrocarbon stapling of these peptides to stabilize their helical structure remarkably improves the cell permeability, thus allowing inhibition of the HIV-1 replication in cell culture. Furthermore, the stabilized peptides inhibit the interaction of IN with the cellular cofactor LEDGF/p75. Cellular uptake of the stapled peptide was confirmed in four different cell lines using a fluorescein-labeled analogue. Given their enhanced potency and cell permeability, these stapled peptides can serve as not only lead IN inhibitors but also prototypical biochemical probes or “nanoneedles” for the elucidation of HIV-1 IN dimerization and host cofactor interactions within their native cellular environment