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Colorectal cancer (CRC) is the second most common cause of cancer-related death in the world. The pro-viral integration site for Moloney murine leukemia virus 1 (PIM1) is a proto-oncogene and belongs to the serine/threonine kinase family, which are involved in cell proliferation, migration, and apoptosis. Fibroblast growth factor receptor 1 (FGFR1) is a tyrosine kinase that has been implicated in cell proliferation, differentiation and migration. Small molecule HCI-48 is a derivative of chalcone, a class of compounds known to possess anti-tumor, anti-inflammatory and antibacterial effects. However, the underlying mechanism of chalcones against colorectal cancer remains unclear. This study reports that HCI-48 mainly targets PIM1 and FGFR1 kinases, thereby eliciting antitumor effects on colorectal cancer growth in vitro and in vivo. HCI-48 inhibited the activity of both PIM1 and FGFR1 kinases in an ATP-dependent manner, as revealed by computational docking models. Cell-based assays showed that HCI-48 inhibited cell proliferation in CRC cells (HCT-15, DLD1, HCT-116 and SW620), and induced cell cycle arrest in the G2/M phase through modulation of cyclin A2. HCI-48 also induced cellular apoptosis, as evidenced by an increase in the expression of apoptosis biomarkers such as cleaved PARP, cleaved caspase 3 and cleaved caspase 7. Moreover, HCI-48 attenuated the activation of downstream components of the PIM1 and FGFR1 signaling pathways. Using patient-derived xenograft (PDX) murine tumor models, we found that treatment with HCI-48 diminished the PDX tumor growth of implanted CRC tissue expressing high protein levels of PIM1 and FGFR1. This study suggests that the inhibitory effect of HCI-48 on colorectal tumor growth is mainly mediated through the dual-targeting of PIM1 and FGFR1 kinases. This work provides a theoretical basis for the future application of HCI-48 in the treatment of clinical CRC. HCI-48 inhibits PIM1 and FGFR1 activity directly and attenuates their downstream signaling pathways, indicating that HCI-48 can inhibit the proliferation of colorectal cancer in vivo and in vitro. [Display omitted] [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a limited set of known driver mutations but considerable cancer cell heterogeneity. Phosphoproteomics provides a readout of aberrant signaling and has the potential to identify new targets and guide treatment decisions. Using two-step sequential phosphopeptide enrichment, we generate a comprehensive phosphoproteome and proteome of nine PDAC cell lines, encompassing more than 20,000 phosphosites on 5,763 phospho-proteins, including 316 protein kinases. By using integrative inferred kinase activity (INKA) scoring, we identify multiple (parallel) activated kinases that are subsequently matched to kinase inhibitors. Compared with high-dose single-drug treatments, INKA-tailored low-dose 3-drug combinations against multiple targets demonstrate superior efficacy against PDAC cell lines, organoid cultures, and patient-derived xenografts. Overall, this approach is particularly more effective against the aggressive mesenchymal PDAC model compared with the epithelial model in both preclinical settings and may contribute to improved treatment outcomes in PDAC patients. [Display omitted] • Phosphoproteomics uncovers multiple active kinases in PDAC • Top-ranking hyperactive kinases guide effective combinations • Low-dose 3-drug combinations inhibit tumor growth in vivo • Known molecular subtypes for PDAC align with phosphoproteomics profiles By profiling PDAC models, Vallés-Martí et al. show that profile-guided drug combinations at low doses are effective in vitro and in vivo. Most effective strategies must target both upstream and downstream effectors captured in the top 10 kinase profiles, with the precise combinations being associated with PDAC subtype. [ABSTRACT FROM AUTHOR]

Conformational changes associated to sensing mechanisms of heme-based protein sensors are a key molecular event that seems to modulate not only the protein activity but also the potential of the Fe III/II redox couple of the heme domain. In this work, midpoint potentials ( E m ) assigned to the Fe III/II redox couple of the heme domain of FixL from Rhizobium etli ( Re FixL) in the unliganded and liganded states were determined by spectroelectrochemistry in the presence of inorganic mediators. In comparison to the unliganded Re FixL protein (+ 19 mV), the binding to ligands that switch off the kinase activity induces a negative shift, i. e. E m = − 51, − 57 and − 156 mV for O 2 , imidazole and CN − , respectively. Upon binding to CO, which does not affect the kinase active, E m was observed at + 21 mV. The potential values observed for Fe III/II of the heme domain of Re FixL upon binding to CO and O 2 do not follow the expected trend based on thermodynamics, assuming that positive potential shift would be expected for ligands that bind to and therefore stabilize the Fe II state. Our results suggest that the conformational changes that switch off kinase activity upon O 2 binding have knock-on effects to the local environment of the heme, such as solvent rearrangement, destabilize the Fe II state and counterbalances the Fe II -stabilizing influence of the O 2 ligand. [ABSTRACT FROM AUTHOR]

Abstract: Brassinosteroids (BRs) are steroid hormones that participate in multiple biological processes. In this paper, we characterized a classic rice mutant Fn189 (dwarf54, d54) showing semi-dwarf stature and erect leaves. The coleoptile elongation and root growth was less affected in Fn189 than wild-type plant by the exogenous application of eBL, the most active form of BRs. Lamina joint inclination assay and morphological analysis in darkness further showed that Fn189 mutant plant was insensitive to exogenous eBL. Through map-based cloning, Fn189 was found to be a novel allelic mutant of the DWARF 61 (D61) gene, which encodes the putative BRs receptor OsBRI1. A single base mutation caused the I834F substitution in the OsBRI1 kinase domain. Consequently, kinase activity of OsBRI1 was found to decrease dramatically. Taken together, the kinase activity of OsBRI1 is essential for brassinosteroids to regulate normal plant growth and development in rice. [Copyright &y& Elsevier]