Class Of Conjugates Research Articles

A potent therapeutic scaffold fusing quinazolinone/melatonin for future colorectal cancer interventions: design, one-pot synthesis, biological and ADME-tox modeling studies

AbstractColorectal cancer is one of the most incident and lethal cancers in the world. The search for new compounds to treat this disease is being motivated by the occurrence of side effects and the rising in the resistance to chemotherapy. We synthesized a new class of conjugates bearing quinazolinone and melatonin which were prepared in good yields (63–93%) through one-pot three-component approach. quinazolinone/melatonin conjugates were proved against SW480 human colorectal adenocarcinoma cells and non-malignant colonic cells (NCM460). The cytotoxic and antiproliferative activities were determined through the sulforhodamine B assay. Compounds 1f, 1g and 1i–l displayed the best activity, being hybrids 1i–l the most selective against malignant cells, causing either a cytostatic and/or cytotoxic effect with evident morphological changes. Moreover, a theoretical drug-like/pharmacokinetics/toxicological study suggested that the hit-promising compounds 1i and 1j would have a great chance to advance to further preclinical studies as anti-cancer therapeutic candidate for oral oncological management. Our study evidently identified the potency of these quinazolinone/melatonin hybrids to be a prototype drug for further investigations toward novel therapeutics treatments of colorectal cancer.

Biguanide-Vancomycin Conjugates are Effective Broad-Spectrum Antibiotics against Actively Growing and Biofilm-Associated Gram-Positive and Gram-Negative ESKAPE Pathogens and Mycobacteria.

Strategies to increase the efficacy and/or expand the spectrum of activity of existing antibiotics provide a potentially fast path to clinically address the growing crisis of antibiotic-resistant infections. Here, we report the synthesis, antibacterial efficacy, and mechanistic activity of an unprecedented class of biguanide-antibiotic conjugates. Our lead biguanide-vancomycin conjugate, V-C6-Bg-PhCl (5e), induces highly effective cell killing with up to a 2 orders-of-magnitude improvement over its parent compound, vancomycin (V), against vancomycin-resistant enterococcus. V-C6-Bg-PhCl (5e) also exhibits improved activity against mycobacteria and each of the ESKAPE pathogens, including the Gram-negative organisms. Furthermore, we uncover broad-spectrum killing activity against biofilm-associated Gram-positive and Gram-negative bacteria as well as mycobacteria not observed for clinically used antibiotics such as oritavancin. Mode-of-action studies reveal that vancomycin-like cell wall synthesis inhibition with improved efficacy attributed to enhanced engagement at vancomycin binding sites through biguanide association with relevant cell-surface anions for Gram-positive and Gram-negative bacteria. Due to its potency, remarkably broad activity, and lack of acute mammalian cell toxicity, V-C6-Bg-PhCl (5e) is a promising candidate for treating antibiotic-resistant infections and notoriously difficult-to-treat slowly growing and antibiotic-tolerant bacteria associated with chronic and often incurable infections. More generally, this study offers a new strategy (biguanidinylation) to enhance antibiotic activity and facilitate clinical entry.

CyTOF analysis revealed platelet heterogeneity in breast cancer patients received T-DM1 treatment

T-DM1 (Trastuzumab Emtansine) belongs to class of Antibody-Drug Conjugates (ADC), where cytotoxic drugs are conjugated with the antibody Trastuzumab to specifically target HER2-positive cancer cells. Platelets, as vital components of the blood system, intricately influence the immune response to tumors through complex mechanisms. In our study, we examined platelet surface proteins in the plasma of patients before and after T-DM1 treatment, categorizing them based on treatment response. We identified a subgroup of platelets with elevated expression of CD63 and CD9 exclusively in patients with favorable treatment responses, while this subgroup was absent in patients with poor responses. Another noteworthy discovery was the elevated expression of CD36 in the platelet subgroups of patients exhibiting inadequate responses to treatment. These findings suggest that the expression of these platelet surface proteins may be correlated with the prognosis of T-DM1 treatment. These indicators offer valuable insights for predicting the therapeutic response to T-DM1 and may become important references in future clinical practice, contributing to a better understanding of the impact of ADC therapies and optimizing personalized cancer treatment strategies.

Microbially conjugated bile salts found in human bile activate the bile salt receptors TGR5 and FXR.

Bile salts of hepatic and microbial origin mediate interorgan cross talk in the gut-liver axis. Here, we assessed whether the newly discovered class of microbial bile salt conjugates (MBSCs) activate the main host bile salt receptors (Takeda G protein-coupled receptor 5 [TGR5] and farnesoid X receptor [FXR]) and enter the human systemic and enterohepatic circulation. N-amidates of (chenodeoxy) cholic acid and leucine, tyrosine, and phenylalanine were synthesized. Receptor activation was studied in cell-free and cell-based assays. MBSCs were quantified in mesenteric and portal blood and bile of patients undergoing pancreatic surgery. MBSCs were activating ligands of TGR5 as evidenced by recruitment of Gsα protein, activation of a cAMP-driven reporter, and diminution of lipopolysaccharide-induced cytokine release from macrophages. Intestine-enriched and liver-enriched FXR isoforms were both activated by MBSCs, provided that a bile salt importer was present. The affinity of MBSCs for TGR5 and FXR was not superior to host-derived bile salt conjugates. Individual MBSCs were generally not detected (ie, < 2.5 nmol/L) in human mesenteric or portal blood, but Leu-variant and Phe-variant were readily measurable in bile, where MBSCs comprised up to 213 ppm of biliary bile salts. MBSCs activate the cell surface receptor TGR5 and the transcription factor FXR and are substrates for intestinal (apical sodium-dependent bile acid transporter) and hepatic (Na+ taurocholate co-transporting protein) transporters. Their entry into the human circulation is, however, nonsubstantial. Given low systemic levels and a surplus of other equipotent bile salt species, the studied MBSCs are unlikely to have an impact on enterohepatic TGR5/FXR signaling in humans. The origin and function of biliary MBSCs remain to be determined.

Abstract 6352: Preclinical discovery of ARX622: A site-specific, TLR7 agonist, HER2-targeted immune-stimulatory antibody drug conjugate for treatment of multiple solid tumor types

Abstract Traditional antibody-drug conjugates leverage the specificity of antibodies to deliver cytotoxic payloads to tumor microenvironments (TMEs), thereby reducing systemic toxicities associated with non-targeted chemotherapeutics. Analogously, a novel class of immune-stimulating antibody conjugates (ISACs) has recently emerged to selectively deliver synthetic immune agonists to the TME without systemic immune activation. The first generation of ISACs and the majority of approved and investigational ADCs contain payloads linked to native lysine or cysteine residues, which can lead to heterogenous drug-antibody ratios (DARs), reduced antibody stability, and labile conjugation, all of which limit therapeutic index. Here we describe the generation and preclinical characterization of ARX622, a site-specific TLR7-selective agonist ISAC targeting HER2. To avoid the instability issues of previous generation ADCs and ISACs, ARX622 has a homogenous and stable DAR via oxime bond-mediated payload conjugation to a synthetic amino acid, para-acetyl phenylalanine (pAF), which is recombinantly incorporated at defined heavy chain positions. Similar to cytotoxic ADCs built on this site-specific conjugation platform, ARX622 ISAC and total mAb pharmacokinetic (PK) profiles in non-human primates (NHPs) are indistinguishable, demonstrating in vivo stability and minimal payload deconjugation. Accordingly, ARX622 displays an extended PK profile in mice compared to a DAR-matched random cysteine ISAC containing the same antibody and payload. In the presence of HER2-expressing cells, ARX622 selectively induces proinflammatory cytokine production, type I and III IFN secretion, and APC maturation. In a syngeneic tumor model, ARX622 promotes complete tumor regressions, immunologic memory, and epitope spreading. In xenograft systems, single doses of ARX622 induce complete regression of large, established tumors (&amp;gt;1000mm3), and robustly inhibit tumor growth in mice that have progressed through prior treatment with HER2-targeted mAbs or ADCs. In HER2-low xenografts, ARX622 monotherapy inhibits tumor growth, and promotes complete regression of late-stage (800mm3) tumors when sequentially combined with a HER2-ADC. Based on PK data at efficacious doses in mice and tolerated exposures in NHP toxicity studies, ARX622 has an estimated therapeutic index of ~60x. Taken together, ARX622’s mAb-like properties, high stability, broad immune mechanism induction, strong anti-tumor activity alone or in combination with ADCs, and wide therapeutic index make it a strong candidate for further development toward treating patients with a variety of HER2-expressing solid tumors. Citation Format: David Mills, Ji Young Kim, Erica Wood, Keith Tatsukawa, Nick Knudsen, Jay Nelson, Lillian Skidmore, Kedar GC, Hon Tran, Manoj Pal, Hamidreza Hashemi, Ying Buechler, Shawn Zhang, Dan O'Connor. Preclinical discovery of ARX622: A site-specific, TLR7 agonist, HER2-targeted immune-stimulatory antibody drug conjugate for treatment of multiple solid tumor types [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6352.

An organometallic swap strategy for bottlebrush polymer-protein conjugate synthesis.

Polymer-protein bioconjugation offers a powerful strategy to alter the physical properties of proteins, and various synthetic polymer compositions and architectures have been investigated for this purpose. Nevertheless, conjugation of molecular bottlebrush polymers (BPs) to proteins remains an unsolved challenge due to the large size of BPs and a general lack of methods to transform the chain ends of BPs into functional groups suitable for bioconjugation. Here, we present a strategy to address this challenge in the context of BPs prepared by "graft-through" ring-opening metathesis polymerization (ROMP), one of the most powerful methods for BP synthesis. Quenching ROMP of PEGylated norbornene macromonomers with an activated enyne terminator facilitates the transformation of the BP Ru alkylidene chain ends into Pd oxidative addition complexes (OACs) for facile bioconjugation. This strategy is shown to be effective for the synthesis of two BP-protein conjugates (albumin and ERG), setting the stage for a new class of BP-protein conjugates for future therapeutic and imaging applications.

Design, synthesis and structure-activity relationship (SAR) studies of an unusual class of non-cationic fatty amine-tripeptide conjugates as novel synthetic antimicrobial agents.

Cationic ultrashort lipopeptides (USLPs) are promising antimicrobial candidates to combat multidrug-resistant bacteria. Using DICAMs, a newly synthesized family of tripeptides with net charges from -2 to +1 and a fatty amine conjugated to the C-terminus, we demonstrate that anionic and neutral zwitterionic USLPs can possess potent antimicrobial and membrane-disrupting activities against prevalent human pathogens such as Streptococcus pneumoniae and Streptococcus pyogenes. The strongest antimicrobials completely halt bacterial growth at low micromolar concentrations, reduce bacterial survival by several orders of magnitude, and may kill planktonic cells and biofilms. All of them comprise either an anionic or neutral zwitterionic peptide attached to a long fatty amine (16-18 carbon atoms) and show a preference for anionic lipid membranes enriched in phosphatidylglycerol (PG), which excludes electrostatic interactions as the main driving force for DICAM action. Hence, the hydrophobic contacts provided by the long aliphatic chains of their fatty amines are needed for DICAM's membrane insertion, while negative-charge shielding by salt counterions would reduce electrostatic repulsions. Additionally, we show that other components of the bacterial envelope, including the capsular polysaccharide, can influence the microbicidal activity of DICAMs. Several promising candidates with good-to-tolerable therapeutic ratios are identified as potential agents against S. pneumoniae and S. pyogenes. Structural characteristics that determine the preference for a specific pathogen or decrease DICAM toxicity have also been investigated.

Design, synthesis and bioactivity evaluation of novel fusion peptides and their CPT conjugates inducing effective anti-tumor responses on HER2 positive tumors

Human epidermal growth factor receptor 2 (HER2) represents an ideal target for antibody drug development, abnormal expression of the HER2 gene is associated with multiple tumor types. Pertuzumab, as the first monoclonal antibody inhibitor of HER2 dimerization, has been FDA-approved for HER2-positive patients. In order to enhance the activity of HER2-targeted peptide-drug conjugates (PDCs) developed based on pertuzumab, a novel class of conjugates 1–9 was designed and synthesized by fusing the N-terminal peptide sequence of the second mitochondria-derived activator of caspases (SMAC) with P1, followed by conjugation with CPT molecules. Compound 4 exhibited excellent in vitro anti-tumor activity across the three HER2-positive cell lines, comparable to the activity of CPT. Apoptosis induction assays indicated that the synergistic effect of the SMAC sequence enhanced the pro-apoptotic activity of the conjugate. Western Blot analysis and Caspase activity studies validated the mechanism through which SMAC peptides, in synergy with CPT, enhance the activity of PDCs. In vivo studies demonstrated that compound 4 possesses superior anti-tumor activity compared to CPT and can effectively mitigate potential renal toxicity associated with free SMAC peptides. In conclusion, conjugate 4 exhibited excellent anti-tumor activity both in vitro and in vivo, offering potential for further development as a novel peptide-conjugated drug.

A Novel Natural Siderophore Antibiotic Conjugate Reveals a Chemical Approach to Macromolecule Coupling.

Inspired by natural sideromycins, the conjugation of antibiotics to siderophores is an attractive strategy to facilitate "Trojan horse" delivery of antibiotics into bacteria. Genome analysis of a soil bacterium, Dactylosporangium fulvum, found a "hybrid" biosynthetic gene cluster responsible for the production of both an antibiotic, pyridomycin, and a novel chlorocatechol-containing siderophore named chlorodactyloferrin. While both of these natural products were synthesized independently, analysis of the culture supernatant also identified a conjugate of both molecules. We then found that the addition of ferric iron to purified chlorodactyloferrin and pyridomycin instigated their conjugation, leading to the formation of a covalent bond between the siderophore-catechol and the pyridomycin-pyridine groups. Using model reactants, this iron-based reaction was found to proceed through a Michael-type addition reaction, where ferric iron oxidizes the siderophore-catechol group into its quinone form, which is then attacked by the antibiotic pyridyl-nitrogen to form the catechol-pyridinium linkage. These findings prompted us to explore if other "cargo" molecules could be attached to chlorodactyloferrin in a similar manner, and this was indeed confirmed with a pyridine-substituted TAMRA fluorophore as well as with pyridine-substituted penicillin, rifampicin, and norfloxacin antibiotic analogues. The resultant biomimetic conjugates were demonstrated to effectively enter a number of bacteria, with TAMRA-chlorodactyloferrin conjugates causing fluorescent labeling of the bacteria, and with penicillin and rifampicin conjugates eliciting antibiotic activity. These findings open up new opportunities for the design and facile synthesis of a novel class of biomimetic siderophore conjugates with antibiotic activity.

Antibody-drug conjugates as new therapeutic agents in uro-oncology

Antibody-drug conjugates represent anew class of therapeutic agents that are already being used in the field of uro-oncology. They consist of an antibody directed against aspecific tumour antigen linked to acytotoxic substance ("payload") which acts after internalisation into the tumour cell and its release. Currently, approval in the European Union is restricted to enfortumab vedotin which is directed against nectin‑4 and carries the microtubule-inhibiting active ingredient monomethyl auristatinE (MMAE). Enfortumab vedotin is approved for locally advanced or metastatic urothelial carcinoma in the third line of therapy after platinum-based chemotherapy and after therapy with aprogrammed cell death (ligand)1 (PD-[L]1) immune checkpoint inhibitor. However, an expansion of the indication of enfortumab vedotin as monotherapy and in combination with PD-(L)1 immune checkpoint inhibitors, as well as approval of other antibody-drug conjugates is expected in the future. This could sustainably change the therapy sequence in urothelial carcinoma. Currently, several clinical trials are recruiting in different therapeutic settings. This article presents the new substance class of antibody-drug conjugates, their mechanism of action, their representatives and clinical studies, and points out practice-relevant side effects and how to deal with them.

Rapid Phase Transitions of Thermotropic Glycolipid Quasicrystal and Frank-Kasper Mesophases: A Mechanistic Rosetta Stone.

Experimental results are presented that serve to lower the barrier for developing the science and technology of non-classical thermotropic glycolipid mesophases, which now include dodecagonal quasicrystal (DDQC) and Frank-Kasper (FK) A15 and σ mesophases that can be produced under mild conditions from a versatile class of sugar-polyolefin conjugates. By employing "alloys" comprised of mono- and disaccharide-polyolefin conjugates, and optionally with vitamin E as a small molecule phase modulator, we report the spontaneous formation of stable A15 mesophases at ambient temperature. We further document a rich thermotropic phase map that includes DDQC, A15, and σ mesophases of tunable periodicity that are connected through rapid thermotropic phase transitions as a function of increasing temperature in the order: liquid-like packing (LLP)→DDQC → A15→σ→ disorder. This first direct observation of a rapid thermotropic A15→σ phase transition provides support for a diffusionless martensitic process proceeding through strain-induced introduction of planar defects into the A15 lattice.

Synthesis of novel ciprofloxacin-avibactam conjugates for the development of second-generation non-β-lactam-β-lactamase inhibitors

To overcome the antibiotic resistance challenge, we synthesized a novel class of conjugates based on ciprofloxacin and avibactam, covalently linked by diverse amino acids. In vitro studies of these conjugates have shown improved antibacterial efficacy of avibactam when used alone against some ESKAPE pathogens, i.e., S. aureus, E. coli, and A. baumannii. Further, ceftazidime was screened in combination with all conjugates and found to be less synergistically effective than avibactam-ceftazidime co-dosing against K. pneumoniae and E. coli bacterial strains. Subsequently, the top-ranked active conjugates were investigated against the commercially available β-lactamase-II (Penicillinase from Bacillus cereus) through in vitro studies. These studies elucidated two conjugates i.e, 9 (IC50 = 1.69±0.35 nM) and 24b (IC50 = 57.37±5.39 nM), which have higher inhibition profile than avibactam (IC50 = 141.08±12.20 nM). These outcomes allude to avibactam integration with ciprofloxacin is a novel and fruitful approach to discovering clinically valuable next-generation non-β-lactam-β-lactamase inhibitors.

Abstract 2636: Amanitin-based ADCs targeting Guanylyl cyclase C (GCC) as novel therapeutic modality for treatment of colorectal cancer

Abstract Background: Amatoxin-based antibody drug conjugates (so called ATAC®s) constitute a new class of antibody-drug conjugates (ADCs) which utilize amanitin as toxic payload. Amanitin binds to the RNA pol II and thereby efficiently inhibits cellular transcription. In the current study, in vitro and in vivo data of an ATAC® targeting GCC (guanylyl cyclase C) are presented. GCC is a cell surface receptor expressed in &amp;gt;95% of colorectal cancer, and in approximately 65% of esophageal, gastric, and pancreatic tumors. In healthy conditions GCC expression is restricted to the gastrointestinal tract, and more specific to the apical brush border of the intestinal epithelium (luminal site). Thus, GCC in healthy tissue is not exposed to the circulation but upon tumor progression in GI malignancies it becomes accessible for i.v. injected targeted therapeutics. This tumor-specific accessibility for drugs in circulation makes GCC a highly attractive target for ATAC®s. Material and Methods: ATAC®s: Cysteine-reactive amanitin-linker constructs were synthesized at Heidelberg Pharma and conjugated site-specifically to engineered cysteine residues of a proprietary anti-GCC antibody yielding ATAC®s with a DAR of 2.0. Animal models: Subcutaneous (s.c.) mouse xenograft models with the GCC overexpressing cell line HEK293-GUCY2C mono2 or colon cancer PDX models (Charles River) were performed in single-dose and multiple-dosing experiments. Tolerability was assessed in NMRI nude mice and non-human primates (NHP). Results: All anti-GCC ATAC®s with amanitin-linker derivatives, optimized for use in solid tumors, showed favorable in vitro cytotoxicity with picomolar activity on GCC+ cell lines and no cytotoxic activity on target-negative cells. In mouse xenograft models, the optimized anti-GCC ATAC®s caused dose-dependent tumor regression in HEK293-GUCY2C mono2 s.c. xenografts. Even in colorectal cancer PDX models, anti- GCC ATAC®s led to a substantial anti-tumor effect. Multiple dosing improved this anti-tumor efficacy even further without negative impact on toxicity. The MTD of the ATAC®s tested in mice differed between 7.5 and 50 mg/kg depending on linker chemistry. Safety profiling in cynomolgus monkeys revealed good tolerability for all selected ATAC®s. Hematology and clinical chemistry parameters were unaffected apart from a moderate and transient increase in liver enzymes. Conclusions: Targeted cytotoxic drug delivery to GCC+ cell lines was achieved by using anti-GCC ATAC®s optimized for the use in solid tumors. The mode of action of the payload amanitin led to a pronounced anti-tumor effect in vitro and in vivo in PDX models with good tolerability in non-human primates. The use of anti-GCC ATAC®s with their novel mode of action in the therapy of GCC positive cancers, such as colorectal cancer represents a promising approach in cancer therapy. Citation Format: Alexandra Braun, Andreas Pelz, Franziska Ebeling, Kristin Decker, Anikó Pálfi, Michael Kulke, Andreas Pahl, Torsten Hechler. Amanitin-based ADCs targeting Guanylyl cyclase C (GCC) as novel therapeutic modality for treatment of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2636.

Abstract 967: Real-world transcriptomic biomarkers as replacement for immunohistochemistry and FISH studies in breast cancer

Abstract Background: Human epidermal growth factor receptor-2 (HER2) and hormone receptors are typically used as binary biomarkers for selecting breast cancer therapy. There is a need to explore the clinical relevance of these biomarkers as continuous variables. This is particularly relevant for the new class of antibody-drug conjugates (ADC), in which a relatively low HER2 expression level is adequate for targeting tumor cells. We explored the potential of RNA profiling, determined by next generation sequencing (NGS), to provide more flexible clinical biomarkers as compared with immunohistochemistry (IHC) or fluorescent in situ hybridization (FISH). Methods: Clinical and laboratory data from 57 breast cancers collected by the COTA real-world data company were used to study biomarker levels as detected by routine clinical transcriptomic tests. HER2 (ERBB2), estrogen receptor alpha (ESR1), and androgen receptor (AR) mRNA levels were compared with reported HER2 and estrogen receptor (ER) IHC and FISH results. Results: RNA levels accurately reflected and predicted HER2 amplification (see table below). Importantly, RNA data showed significant variation and overlap in the levels of ERBB2 mRNA between cases scored by IHC as zero, 1+, and 2+. This variation correlated with progression-free survival (PFS). Similarly, the ESR1 RNA levels accurately reflected ER status and demonstrated significant variation between positive cases. RNA data also showed significant variations in the AR levels. Patients wssith high AR mRNA levels had significantly better PFS (P=0.05). Patients expressing high ER and AR levels had significantly better PFS than those expressing low ESR1 and AR levels (P=0.03). Conclusions: These findings suggest that RNA analysis using NGS is an alternative to IHC and FISH. RNA provides continuous data that can determine cut-off points predicting response to therapy and should be explored in predicting ADC response. ERBB2 mRNA levels (FPKM) in various HER2 IHC groupss IHC Score Valid N Mean Median Minimum Maximum Quartile Range Std.Dev. Zero 19 231 243 63 537 170 110 Zero vs one 3 151 155 45 253 208 104 Zero to one vs one 18 397 302 172 845 365 222 One Vs two 13 495 423 159 1094 273 284 Two vs three 4 7523 7649 937 13859 7183 5310 Citation Format: Maher Albitar, Andre Goy, Andrew Pecora, Deena Graham, Donna Donna McNamara, Ahmad Ahmad Charifa, Andrew IP, Wanlong Ma, Stanley Waintraub. Real-world transcriptomic biomarkers as replacement for immunohistochemistry and FISH studies in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 967.

Design, Synthesis, and Biological Evaluation of Androgen Receptor (AR) Antagonist-Heat Shock Protein 90 (Hsp90) Inhibitor Conjugates for Targeted Therapy of Castration-Resistant Prostate Cancer.

Androgen deprivation in cases of castration-resistant prostate cancer (CRPC) leads to adverse effects, including loss of muscle and bone mass and gain of subcutaneous fat. The tumor-specific suppression of androgen receptor (AR) signaling, while not global, may reduce side effects. We present a class of small-molecular conjugates consisting of an AR antagonist linked to a heat shock protein 90 (Hsp90) inhibitor. We demonstrate that the high accumulation of Hsp90 on the surface of CRPC cells allows uptake of conjugates and increases the enrichment of drugs in the tumor cells. After penetrating prostate cancer cells, the conjugates not only inhibit AR function by the antagonist component but also bind to Hsp90 and suppress the AR protein level. Compared to AR antagonists, these conjugates showed improved tumor-targeting ability and enhanced potency against Enzalutamide-resistant 22Rv1 cells.

Real-Time Impedance-Based Monitoring of the Growth and Inhibition of Osteomyelitis Biofilm Pathogen Staphylococcus aureus Treated with Novel Bisphosphonate-Fluoroquinolone Antimicrobial Conjugates.

Osteomyelitis is a limb- and life-threatening orthopedic infection predominantly caused by Staphylococcus aureus biofilms. Bone infections are extremely challenging to treat clinically. Therefore, we have been designing, synthesizing, and testing novel antibiotic conjugates to target bone infections. This class of conjugates comprises bone-binding bisphosphonates as biochemical vectors for the delivery of antibiotic agents to bone minerals (hydroxyapatite). In the present study, we utilized a real-time impedance-based assay to study the growth of Staphylococcus aureus biofilms over time and to test the antimicrobial efficacy of our novel conjugates on the inhibition of biofilm growth in the presence and absence of hydroxyapatite. We tested early and newer generation quinolone antibiotics (ciprofloxacin, moxifloxacin, sitafloxacin, and nemonoxacin) and several bisphosphonate-conjugated versions of these antibiotics (bisphosphonate-carbamate-sitafloxacin (BCS), bisphosphonate-carbamate-nemonoxacin (BCN), etidronate-carbamate-ciprofloxacin (ECC), and etidronate-carbamate-moxifloxacin (ECX)) and found that they were able to inhibit Staphylococcus aureus biofilms in a dose-dependent manner. Among the conjugates, the greatest antimicrobial efficacy was observed for BCN with an MIC of 1.48 µg/mL. The conjugates demonstrated varying antimicrobial activity depending on the specific antibiotic used for conjugation, the type of bisphosphonate moiety, the chemical conjugation scheme, and the presence or absence of hydroxyapatite. The conjugates designed and tested in this study retained the bone-binding properties of the parent bisphosphonate moiety as confirmed using high-performance liquid chromatography. They also retained the antimicrobial activity of the parent antibiotic in the presence or absence of hydroxyapatite, albeit at lower levels due to the nature of their chemical modification. These findings will aid in the optimization and testing of this novel class of drugs for future applications to pharmacotherapy in osteomyelitis.

Self-Assembly of Tunable Intrinsically Disordered Peptide Amphiphiles.

Intrinsically disordered peptide amphiphiles (IDPAs) present a novel class of synthetic conjugates that consist of short hydrophilic polypeptides anchored to hydrocarbon chains. These hybrid polymer-lipid block constructs spontaneously self-assemble into dispersed nanoscopic aggregates or ordered mesophases in aqueous solution due to hydrophobic interactions. Yet, the possible sequence variations and their influence on the self-assembly structures are vast and have hardly been explored. Here, we measure the nanoscopic self-assembled structures of four IDPA systems that differ by their amino acid sequence. We show that permutations in the charge pattern along the sequence remarkably alter the headgroup conformation and consequently alter the pH-triggered phase transitions between spherical, cylindrical micelles and hexagonal condensed phases. We demonstrate that even a single amino acid mutation is sufficient to tune structural transitions in the condensed IDPA mesophases, while peptide conformations remain unfolded and disordered. Furthermore, alteration of the peptide sequence can render IDPAs to become susceptible to enzymatic cleavage and induce enzymatically activated phase transitions. These results hold great potential for embedding multiple functionalities into lipid nanoparticle delivery systems by incorporating IDPAs with the desired properties.

Targeting the Phosphatidylserine-Immune Checkpoint with a Small-Molecule Maytansinoid Conjugate.

Ligand-targeting drug delivery systems have made significant strides for disease treatments with numerous clinical approvals in this era of precision medicine. Herein, we report a class of small molecule-based immune checkpoint-targeting maytansinoid conjugates. From the ligand targeting ability, pharmacokinetics profiling, in vivo anti-pancreatic cancer, triple-negative breast cancer, and sorafenib-resistant liver cancer efficacies with quantitative mRNA analysis of treated-tumor tissues, we demonstrated that conjugate 40a not only induced lasting regression of tumor growth, but it also rejuvenated the once immunosuppressive tumor microenvironment to an “inflamed hot tumor” with significant elevation of gene expressions that were not accessible in the vehicle-treated tumor. In turn, the immune checkpoint-targeting small molecule drug conjugate from this work represents a new pharmacodelivery strategy that can be expanded with combination therapy with existing immune-oncology treatment options.

A novel BMP2 secretagogue ameliorates glucocorticoid induced oxidative stress in osteoblasts by activating NRF2 dependent survival while promoting Wnt/β-catenin mediated osteogenesis.

In our previous study, a novel BMP2 secretagogue was synthesized belonging to a class of galloyl conjugates of flavanones, with remarkable osteogenic potential that promoted bone regeneration. We aimed to establish the protective effect of our compound against bone loss that co-exists with excess Glucocorticoid (GC) therapy. GC therapy induces osteoblast damage leading to apoptosis by increasing reactive oxygen species (ROS). Our results delineate that compound 5e (a BMP2 secretagogue) activates NRF2 signalling to counter the disturbed cellular redox homeostasis and escalate osteoblast survival as assessed by Western blot and immunocytochemistry. Depletion of NRF2 by siRNA blocked activation of the NRF2/HO-1 pathway, magnified oxidative stress, increased apoptosis and abrogated the protective effects of compound 5e. 5e, on the other hand, increased ALP, mineralization activity, and promoted osteoblast differentiation by activating WNT/β-catenin signalling in BMP2 dependent manner, validated by Western blot of WNT3A, SOST, GSK3-β and β-catenin nuclear translocation. Treatment of 5e in presence of BMP inhibitor noggin attenuated the osteogenic efficacy and minimized Wnt//β-catenin signalling in presence of dexamethasone. Our compound prevents GC challenged trabecular and cortical bone loss assessed by micro-CT and promotes bone formation and osteocyte survival determined by calcein labelling and TUNEL assay in GC treated animals. The osteogenic potential of the compound was authenticated by bone turnover markers. On a concluding note, compounds with BMP upregulation can be potential therapeutics for the prevention and treatment of glucocorticoid-induced osteoporosis.

Comparative clinical and economic assessment of polatuzumab vedotin therapy in combination with bendamustine and rituximab for adult transplantation-ineligible patients with relapsed/refractory diffuse large B-cell lymphoma

Aim. To evaluate the pharmacoeconomic feasibility of using polatuzumab vedotin in combination with bendamustine and rituximab for the treatment of adult transplantation-ineligible patients with relapsed/refractory diffuse large B-cell lymphoma.Materials and methods. Study design - retrospective analysis of literature data. Pharmacoeconomic research methods - clinical and economic analysis (incremental cost-effectiveness analysis, case-based approach) using sensitivity assessment. The sources of the drug efficacy data were publications on conducted clinical trials; on the drugs cost -the State register of maximum selling prices, data from the manufacturer's company.Results. Polatuzumab vedotin is the unique drug from the class of monoclonal antibody-antimitotic agent conjugates registered in Russia for the treatment of adult transplantation-ineligible patients with relapsed/refractory diffuse large B-cell lymphoma. for this reason a case-based approach was applied as part of the cost-effectiveness analysis. As a result of clinical and economic analysis, it was found that the cost of progression free life-year added when using polatuzumab vedotin in combination with bendamustine and rituximab in patients with relapsed/refractory diffuse large b-cell lymphoma by 50.7 %, or by 11.4 million rubles, lower than the cost of progression free life-year added when using brentuximab vedotin in patients with relapsed/refractory Hodgkin's lymphoma. The sensitivity assessment showed the stability of the obtained results to changes in the input parameters of treatment cost and efficacy in a wide range of values.Conclusion. Use of polatuzumab vedotin in combination with bendamustine and rituximab for the treatment of adult transplantation-ineligible patients with diffuse large B-cell non-Hodgkin's lymphoma is pharmacoeconomically justified and appropriate.