Discovery of Peptidic Ligands against the SARS-CoV-2 Spike Protein and Their Use in the Development of a Highly Sensitive Personal Use Colorimetric COVID-19 Biosensor.

In addition to efficacious vaccines and antiviral therapeutics, reliable and flexible in-home personal use diagnostics for the detection of viral antigens are needed for effective control of the COVID-19 pandemic. Despite the approval of several PCR-based and affinity-based in-home COVID-19 testing kits, many of them suffer from problems such as a high false-negative rate, long waiting time, and short storage period. Using the enabling one-bead-one-compound (OBOC) combinatorial technology, several peptidic ligands with a nanomolar binding affinity toward the SARS-CoV-2 spike protein (S-protein) were successfully discovered. Taking advantage of the high surface area of porous nanofibers, immobilization of these ligands on nanofibrous membranes allows the development of personal use sensors that can achieve low nanomolar sensitivity in the detection of the S-protein in saliva. This simple biosensor employing naked-eye reading exhibits detection sensitivity comparable to some of the current FDA-approved home detection kits. Furthermore, the ligand used in the biosensor was found to detect the S-protein derived from both the original strain and the Delta variant. The workflow reported here may enable us to rapidly respond to the development of home-based biosensors against future viral outbreaks.

Site-Specific Albumin-Selective Ligation to Human Serum Albumin under Physiological Conditions.

Human serum albumin (HSA) is the most abundant protein in human blood plasma. It plays a critical role in the native transportation of numerous drugs, metabolites, nutrients, and small molecules. HSA has been successfully used clinically as a noncovalent carrier for insulin (e.g., Levemir), GLP-1 (e.g., Liraglutide), and paclitaxel (e.g., Abraxane). Site-specific bioconjugation strategies for HSA only would greatly expand its role as the biocompatible, non-toxic platform for theranostics purposes. Using the enabling one-bead one-compound (OBOC) technology, we generated combinatorial peptide libraries containing myristic acid, a well-known binder to HSA at Sudlow I and II binding pockets, and an acrylamide. We then used HSA as a probe to screen the OBOC myristylated peptide libraries for reactive affinity elements (RAEs) that can specifically and covalently ligate to the lysine residue at the proximity of these pockets. Several RAEs have been identified and confirmed to be able to conjugate to HSA covalently. The conjugation can occur at physiological pH and proceed with a high yield within 1 h at room temperature. Tryptic peptide profiling of derivatized HSA has revealed two lysine residues (K225 and K414) as the conjugation sites, which is much more specific than the conventional lysine labeling strategy with N-hydroxysuccinimide ester. The RAE-driven site-specific ligation to HSA was found to occur even in the presence of other prevalent blood proteins such as immunoglobulin or whole serum. Furthermore, these RAEs are orthogonal to the maleimide-based conjugation strategy for Cys34 of HSA. Together, these attributes make the RAEs the promising leads to further develop in vitro and in vivo HSA bioconjugation strategies for numerous biomedical applications.

A pH-Driven Small-Molecule Nanotransformer Hijacks Lysosomes and Overcomes Autophagy-Induced Resistance in Cancer.

Smart conversion of supramolecular structures in vivo is an attractive strategy in cancer nanomedicine, which is usually achieved via specific peptide sequences. Here we developed a lysosomal targeting small-molecule conjugate, PBC, which self-assembles into nanoparticles at physiological pH and smartly converts to nanofibrils in lysosomes of tumor cells. Such a transformation mechanically leads to lysosomal dysfunction, autophagy inhibition, and unusual cytoplasmic vacuolation, thus granting PBC a unique anticancer activity as a monotherapy. Importantly, the photo-activated PBC elicits significant phototoxicity to lysosomes and shows enormous advantages in overcoming autophagy-caused treatment resistance frequently occurring in conventional phototherapy. This improved phototherapy achieves a complete cure of oral cancer xenografts upon limited administration. Our work provides a new paradigm for the construction of nonpeptide nanotransformers with biomedical activities.

Synthesis and biological evaluation of N, N-dialkylcarboxy coumarin-NO donor conjugates as potential anticancer agents.

A series of nitric oxide (NO) donor furoxan conjugates of N, N-dialkylcarboxy coumarins have been synthesized as potential anticancer agents. The synthesized compounds have been tested for their in vitro antiproliferative activities on various cancer and noncancerous cell lines. The candidate derivatives exhibit selectivity towards cancer cells with excellent activities in low nM to µM concentrations. In vitro mechanistic studies indicate that the candidate compounds generate substantial NO, inhibit colony formation, and cause apoptosis in cancer cells. A preliminary in vivo tolerance study of the lead candidate 10 in mice indicates that it is well-tolerated, evidenced by zero mortality and normal body weight gains in treated mice. Further translation of the lead derivative 10 using MDA-MB-231 based tumor xenograft model shows good tumor growth reduction.

Synthesis and biological evaluation of a novel anticancer agent CBISC that induces DNA damage response and diminishes levels of mutant-p53.

A novel nitrogen mustard CBISC has been synthesized and evaluated as an anticancer agent. CBISC has been shown to exhibit enhanced cell proliferation inhibition properties against mutant p53 cell lines colorectal cancer WiDr, pancreatic cancer (MIAPaCa-2 and PANC-1), and triple negative breast cancer (MDA-MB-231 and MDA-MB-468). In vitro mechanism of action studies revealed perturbations in the p53 pathway and increased cell death as evidenced by western blotting, immunofluorescent microscopy and MTT assay. Further, in vivo studies revealed that CBISC is well tolerated in healthy mice and exhibited significant in vivo tumor growth inhibition properties in WiDr and MIAPaCa-2 xenograft models. These studies illustrate the potential utility of CBISC as an anticancer agent.

Synthesis, in vitro, and in vivo evaluation of novel N-phenylindazolyl diarylureas as potential anti-cancer agents.

Novel N-phenylindazole based diarylureas have been designed, synthesized and evaluated as potential anticancer agents. In vitro cell viability studies of these derivatives illustrate good potency with IC50 values in the range of 0.4-50 µM in several cancer cell lines including murine metastatic breast cancer 4T1, murine glioblastoma GL261, human triple negative breast cancer MDA-MB-231, human pancreatic cancer MIAPaCa-2, and human colorectal cancer cell line WiDr. The ester group in the lead compound 8i was modified to incorporate amino-amides to increase solubility and stability while retaining biological activity. Further in vitro studies reveal that lead candidates inhibit tube length in HUVEC cells. In vivo systemic toxicity studies indicate that these candidate compounds are well tolerated in mice without any significant side effects. Anticancer efficacy studies in WiDr tumor xenograft and 4T1 tumor syngraft models demonstrate that the lead candidate 11 exhibits significant antitumor properties as a single agent in these tumor models.

Pharmacophore hybridisation and nanoscale assembly to discover self-delivering lysosomotropic new-chemical entities for cancer therapy.

Integration of the unique advantages of the fields of drug discovery and drug delivery is invaluable for the advancement of drug development. Here we propose a self-delivering one-component new-chemical-entity nanomedicine (ONN) strategy to improve cancer therapy through incorporation of the self-assembly principle into drug design. A lysosomotropic detergent (MSDH) and an autophagy inhibitor (Lys05) are hybridised to develop bisaminoquinoline derivatives that can intrinsically form nanoassemblies. The selected BAQ12 and BAQ13 ONNs are highly effective in inducing lysosomal disruption, lysosomal dysfunction and autophagy blockade and exhibit 30-fold higher antiproliferative activity than hydroxychloroquine used in clinical trials. These single-drug nanoparticles demonstrate excellent pharmacokinetic and toxicological profiles and dramatic antitumour efficacy in vivo. In addition, they are able to encapsulate and deliver additional drugs to tumour sites and are thus promising agents for autophagy inhibition-based combination therapy. Given their transdisciplinary advantages, these BAQ ONNs have enormous potential to improve cancer therapy.

Development of Novel Silyl Cyanocinnamic Acid Derivatives as Metabolic Plasticity Inhibitors for Cancer Treatment.

Novel silyl cyanocinnamic acid derivatives have been synthesized and evaluated as potential anticancer agents. In vitro studies reveal that lead derivatives 2a and 2b have enhanced cancer cell proliferation inhibition properties when compared to the parent monocarboxylate transporter (MCT) inhibitor cyano-hydroxycinnamic acid (CHC). Further, candidate compounds exhibit several-fold more potent MCT1 inhibition properties as determined by lactate-uptake studies, and these studies are supported by MCT homology modeling and computational inhibitor-docking studies. In vitro effects on glycolysis and mitochondrial metabolism also illustrate that the lead derivatives 2a and 2b lead to significant effects on both metabolic pathways. In vivo systemic toxicity and efficacy studies in colorectal cancer cell WiDr tumor xenograft demonstrate that candidate compounds are well tolerated and exhibit good single agent anticancer efficacy properties.

Novel N,N-dialkyl cyanocinnamic acids as monocarboxylate transporter 1 and 4 inhibitors.

Potent and dual monocarboxylate transporter (MCT) 1 and 4 inhibitors have been developed for the first time as potential anticancer agents based on α-cyanocinnamic acid structural template. Candidate inhibitors 1-9 have been evaluated for in vitro cell proliferation against MCT1 and MCT4 expressing cancer cell lines. Potential MCT1 and MCT4 binding interactions of the lead compound 9 have been studied through homology modeling and molecular docking prediction. In vitro effects on extracellular flux via glycolysis and mitochondrial stress tests suggest that candidate compounds 3 and 9 disrupt glycolysis and OxPhos efficiently in MCT1 expressing colorectal adenocarcinoma WiDr and MCT4 expressing triple negative breast cancer MDA-MB-231 cells. Fluorescence microscopy analyses in these cells also indicate that compound 9 is internalized and concentrated near mitochondria. In vivo tumor growth inhibition studies in WiDr and MDA-MB-231 xenograft tumor models in mice indicate that the candidate compound 9 exhibits a significant single agent activity.

Synthesis and biological evaluation of 2-alkoxycarbonylallyl esters as potential anticancer agents.

The reaction of carboxylic acids with Baylis-Hillman reaction derived α-bromomethyl acrylic esters readily provide 2-(alkoxycarbonyl)allyl esters in good to excellent yields. These functionalized allyl esters have been evaluated for their cell proliferation inhibition properties against breast cancer (MDA-MB-231 and 4T1) and pancreatic cancer (MIAPaCa-2) cell lines to explore their potential as anticancer agents. Several of the synthesized derivatives exhibit good potency against all three cancer cell lines. Our structure activity relationship (SAR) studies on 2-carboxycarbonyl allyl esters indicate that substituted aromatic carboxylic acids provide enhanced activity compared to substituted aliphatic carboxylic acid analogs. Di- and tri-allyl esters derived from di-and tri-carboxylic acids exhibit higher inhibition of cell proliferation than mono esters. Further SAR studies indicate that the double bond in the 2-(alkoxycarbonyl)allyl ester is required for its activity, and there is no increase in activity with increased chain length of the alkoxy group. Two lead candidate compounds have been identified from the cell proliferation inhibition studies and their preliminary mechanism of action as DNA damaging agents has been evaluated using epifluorescence and western blot analysis. One of the lead compounds has been further evaluated for its systemic toxicity in healthy CD-1 mice followed by anticancer efficacy in a triple negative breast cancer MDA-MB-231 xenograft model in NOD-SCID mice. These two in vivo studies indicate that the lead compound is well tolerated in healthy CD-1 mice and exhibits good tumor growth inhibition compared to breast cancer drug doxorubicin.

Coumarin carboxylic acids as monocarboxylate transporter 1 inhibitors: In vitro and in vivo studies as potential anticancer agents.

Novel N,N-dialkyl carboxy coumarins have been synthesized as potential anticancer agents via inhibition of monocarboxylate transporter 1 (MCT1). These coumarin carboxylic acids have been evaluated for their in vitro MCT1 inhibition, MTT cancer cell viability, bidirectional Caco-2 cell permeability, and stability in human and liver microsomes. These results indicate that one of the lead candidate compounds 4a has good absorption, metabolic stability, and a low drug efflux ratio. Systemic toxicity studies with lead compound 4a in healthy mice demonstrate that this inhibitor is well tolerated based on zero animal mortality and normal body weight gains compared to the control group. In vivo tumor growth inhibition studies in mice show that the candidate compound 4a exhibits significant single agent activity in MCT1 expressing GL261-luc2 syngraft model but doesn't show significant activity in MCT4 expressing MDA-MB-231 xenograft model, indicating the selectivity of 4a for MCT1 expressing tumors.

Synthesis, in vitro, and in vivo evaluation of novel functionalized quaternary ammonium curcuminoids as potential anti-cancer agents.

Novel functionalized quaternary ammonium curcuminoids have been synthesized from piperazinyl curcuminoids and Baylis-Hillman reaction derived allyl bromides. These molecules are found to be highly water soluble with increased cytotoxicity compared to native curcumin against three cancer cell lines MIAPaCa-2, MDA-MB-231, and 4T1. Preliminary in vivo toxicity evaluation of a representative curcuminoid 5a in healthy mice indicates that this molecule is well tolerated based on normal body weight gains compared to control group. Furthermore, the efficacy of 5a has been tested in a pancreatic cancer xenograft model of MIAPaCa-2 and has been found to exhibit good tumor growth inhibition as a single agent and also in combination with clinical pancreatic cancer drug gemcitabine.