Identification of Novel Isatin Derivative Bearing a Nitrofuran Moiety as Potent Multi-Isoform Aldehyde Dehydrogenase Inhibitor.

Aldehyde dehydrogenases (ALDHs) are a family of enzymes that aid in detoxification and are overexpressed in several different malignancies. There is a correlation between increased expression of ALDH and a poor prognosis, stemness, and resistance to several drugs. Several ALDH inhibitors have been generated due to the crucial role that ALDH plays in cancer stem cells. All of these inhibitors, however, are either ineffective, very toxic, or have yet to be subjected to rigorous testing on their effectiveness. Although various drug-like compounds targeting ALDH have been reported in the literature, none have made it to routine use in the oncology clinic. As a result, new potent, non-toxic, bioavailable, and therapeutically effective ALDH inhibitors are still needed. In this study, we designed and synthesized potent multi-ALDH isoform inhibitors based on the isatin and indazole pharmacophore. Molecular docking studies and enzymatic tests revealed that among all of the synthesized analogs, compound 3 is the most potent inhibitor of ALDH1A1, ALDH3A1, and ALDH1A3, exhibiting 51.32%, 51.87%, and 36.65% inhibition, respectively. The ALDEFLUOR assay further revealed that compound 3 acts as an ALDH broad spectrum inhibitor at 500 nM. Compound 3 was also the most cytotoxic to cancer cells, with an IC50 in the range of 2.1 to 3.8 µM for ovarian, colon, and pancreatic cancer cells, compared to normal and embryonic kidney cells (IC50 7.1 to 8.7 µM). Mechanistically, compound 3 increased ROS activity due to potent multi-ALDH isoform inhibition, which increased apoptosis. Taken together, this study identified a potent multi-isoform ALDH inhibitor that could be further developed as a cancer therapeutic.

One- and Two-Photon Uncaging of Carbon Monoxide (CO) with Real-Time Monitoring: On-Demand Carbazole-Based Dual CO-Releasing Platform to Test over Single and Combinatorial Approaches for the Efficient Regression of Orthotopic Murine Melanoma In Vivo.

Herein, we report three new metal-free, photochemically active single, dual, and combinatorial CORMs (photoCORMs) based on a carbazole-fused 1,3-dioxol-2-one moiety which released one equivalent of CO, two equivalent of CO, and a combination of one equivalent of each CO and anticancer drug upon one- and two-photon excitation, respectively. The photoCORMs exhibited good cellular uptake and real-time monitoring ability of CO uncaging by a color change approach in cancerous B16F10 cells. Interestingly, the cytotoxicity assay on B16F10 cells indicated that the dual photoCORM has increased anticancer activity over the single and combinatorial photoCORMs upon irradiation. Our results also showed that CO could accelerate the effectiveness of the well-known anticancer drug (chlorambucil). Finally, the in vivo evaluation of the dual photoCORM on an established murine melanoma tumor (C57BL/6J mouse model) manifested a significant regression of tumor volume and led to significant improvement (>50%) in the overall survivability.

Combating Glioblastoma by Codelivering the Small-Molecule Inhibitor of STAT3 and STAT3siRNA with α5ß1 Integrin Receptor-Selective Liposomes.

Glioblastoma multiforme (GBM) is one of the most aggressive tumors with a median survival of only 15 months. Effective therapeutics need to overcome the formidable challenge of crossing the blood-brain barrier (BBB). Receptors and transporters overexpressed on BCECs are being used for designing liposomes, polymers, polymeric micelles, peptides, and dendrimer-based drug carriers for combating brain tumors. Herein, using the orthotopic mouse glioblastoma model, we show that codelivering a small-molecule inhibitor of the JAK/STAT pathway (WP1066) and STAT3siRNA with nanometric (100-150 nm) α5ß1 integrin receptor-selective liposomes of RGDK-lipopeptide holds therapeutic promise in combating glioblastoma. Rh-PE (red)-labeled liposomes of RGDK-lipopeptide were found to be internalized in GL261 cells via integrin α5ß1 receptors. Intravenously administered near-infrared (NIR)-dye-labeled α5ß1 integrin receptor-selective liposomes of RGDK-lipopeptide were found to be accumulated preferentially in the mouse brain tumor tissue. Importantly, we show that iv injection of WP1066 (a commercially sold small-molecule inhibitor of the JAK/STAT pathway) and STAT3siRNA cosolubilized within the liposomes of RGDK-lipopeptide leads to significant inhibition (>350% compared to the untreated mice group) of orthotopically growing mouse glioblastoma. The present strategy may find future use in combating GBM.

A lysosome-specific near-infrared fluorescent probe for in vitro cancer cell detection and non-invasive in vivo imaging.

Near-infrared (NIR) fluorescent probes have been developed as potential bio-materials having profound applications in diagnosis and clinical practice. Herein, we wish to disclose a highly photostable ultra-bright NIR probe for the specific detection of lysosomes in numerous cell lines. Furthermore, the applicability of the developed NIR probe was evaluated for in vivo imaging.

Large Amino Acid Transporter 1 Selective Liposomes of l-DOPA Functionalized Amphiphile for Combating Glioblastoma.

Despite significant progress in neurosurgery and radiation therapy during the past decade, overall survivability (OS) of glioblastoma patients continues to be less than 2 years. The scope of systemic chemotherapy is greatly limited by poor drug transport across the blood brain barrier (BBB) and, thereby, suboptimal drug accumulation in glioma tissue. To this end, use of large amino acid transporter-1 (LAT1) overexpressed both on brain capillary endothelial cells (BCECs) and glioma cells has begun. Prior reports on the use of LAT1 mediated delivery of model drugs showed their brain accumulations. However, in depth in vivo glioblastoma regression studies aimed at examining the therapeutic potential of LAT1 mediated delivery of potent chemotherapeutics to brain tumor tissues have not yet been undertaken. Herein, we report on the development of a nanometric (100-135 nm) promising LAT1 selective liposomal drug carrier prepared from a novel l-3,4-dihydroxyphenylalanine (l-DOPA) functionalized amphiphile (Amphi-DOPA). In vitro studies using Rh-PE labeled liposomes of Amphi-DOPA both in untreated glioma (GL261) cells and in GL261cells preincubated with LAT1 antibody revealed LAT1 mediated cellular uptake. Intravenously administered NIR-dye labeled liposomes of Amphi-DOPA in glioblastoma-bearing mice showed preferential accumulation of the dye in brain tissue. Notably iv administration of WP1066-loaded liposomes of Amphi-DOPA enhanced the overall survivability of C57BL/6J mice bearing orthotopically established mouse glioblastoma by ∼60% compared to that for the untreated mouse group. Furthermore, we show that the OS of established glioblastoma-bearing mice can be significantly enhanced (by >300% compared to that for the untreated mouse group) when the presently described LAT1 mediated targeted chemotherapy with WP1066-loaded liposomes of Amphi-DOPA is combined with in vivo DC-targeted DNA vaccination using a survivin (a glioblastoma antigen) encoded DNA vaccine. The present findings open a new door for LAT1 mediated systemic chemotherapy of glioblastoma.

Redox-responsive xanthene-coumarin-chlorambucil-based FRET-guided theranostics for "activatable" combination therapy with real-time monitoring.

A FRET donor-acceptor xanthene-coumarin conjugate has been designed for redox-regulated synergic treatment of photodynamic therapy and chemotherapy with real-time monitoring. The "locked" FRET pair was selectively "unlocked" by biological reducing thiols via rupture of a sacrificial disulfide linker. A distinct change in fluorescence color and selective cancer cell toxicity were observed in vitro.