Mechanistic Investigation of Thiazole-Based Pyruvate Kinase M2 Inhibitor Causing Tumor Regression in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is a deadly breast cancer with a poor prognosis. Pyruvate kinase M2 (PKM2), a key rate-limiting enzyme in glycolysis, is abnormally highly expressed in TNBC. Overexpressed PKM2 amplifies glucose uptake, enhances lactate production, and suppresses autophagy, thereby expediting the progression of oncogenic processes. A high mortality rate demands novel chemotherapeutic regimens at once. Herein, we report the rational development of an imidazopyridine-based thiazole derivative 7d as an anticancer agent inhibiting PKM2. Nanomolar range PKM2 inhibitors with favorable drug-like properties emerged through enzyme assays. Experiments on two-dimensional (2D)/three-dimensional (3D) cell cultures, lactate release assay, surface plasmon resonance (SPR), and quantitative real-time polymerase chain reaction (qRT-PCR) validated 7d preclinically. In vivo, 7d outperformed lapatinib in tumor regression. This investigation introduces a lead-based approach characterized by its clear-cut chemistry and robust efficacy in designing an exceptionally potent inhibitor targeting PKM2, with a focus on combating TNBC.

Polystyrene-Based Slippery Surfaces Enable the Generation and Easy Retrieval of Tumor Spheroids.

Multicellular tumor spheroids are the most well-characterized organotypic models for cancer research. Generally, scaffold-based and scaffold-free techniques are widely used for culturing spheroids. In scaffold-free techniques, the hanging drop (HD) method is a more versatile technique, but the retrieval of three-dimensional (3D) cell spheroids in the hanging drop method is usually labor-intensive. We developed oil-coated polystyrene nanofiber-based reusable slippery surfaces for the generation and easy retrieval of 3D spheroids. The developed slippery surfaces facilitated the rolling and gliding of the cell medium drops as well as holding the hydrophilic drops for more than 72 h by the virtue of surface tension as in the hanging drop method. In this study, polystyrene nanofibers were developed by the facile technique of electrospinning and the morphological evaluation was performed by scanning electron microscopy (SEM) and cryo-FESEM. We modeled the retrieval process of 3D spheroids with the ingredients of 3D spheroid generation, such as water, cell culture media, collagen, and hyaluronic acid solution, demonstrating the faster and easy retrieval of 3D spheroids within a few seconds. We created MCF-7 spheroids as a proof of concept with a developed slippery surface. 3D spheroids were characterized for their size, homogeneity, reactive oxygen species, proliferative marker (Ki-67), and hypoxic inducing factor 1ά (HIF-1ά). These 3D tumor spheroids were further tested for evaluating the cellular toxicity of the doxorubicin drug. Hence, the proposed slippery surfaces demonstrated the potential alternative of culturing 3D tumor spheroids with an easy retrieval process with intact 3D spheroids.

Novel imidazopyrimidines-based molecules induce tetramerization of tumor pyruvate kinase M2 and exhibit potent antiproliferative profile.

Discovery of novel and potent lead molecules for the specific therapeutic targets by de novo drug design is still in infancy. Here, we disclose the unprecedented development of imidazopyri(mi)dine-based tumor pyruvate kinase M2 (PKM2) modulators by subsequent link and grow strategy. The most potent modulator 15n acts as a PKM2 activator with an AC50 of 90 nM, with considerable cancer cell-selectivity and membrane-permeability. NMR metabolomics studies also revealed that treatment with 15n results in diminution in lactate concentrations in MCF-7 cells. 15n binds to a previously reported site at PKM2 adjacent to the interface of two monomers. In molecular dynamics (MD) simulation studies, it was observed that 15n stabilizes the PKM2 at the dimeric interface, assisting in the formation of a biologically active tetramer conformation. 15n was also screened on MCF-7 breast cancer cell lines grown on 3-D scaffolds, and the results exhibited better anticancer potential compared to control, paving the way for future clinical studies.