ABSTRACT
Rationale: Doublecortin-like kinase 1 (DCLK1) is a serine/threonine kinase that selectively marks cancer stem-like cells (CSCs) and promotes malignant progression in colorectal cancer (CRC). However, the exact molecular mechanism by which DCLK1 drives the aggressive phenotype of cancer cells is incompletely determined. Methods: Here, we performed comprehensive genomics and proteomics analyses to identify binding proteins of DCLK1 and discovered X-ray repair cross-complementing 5 (XRCC5). Thus, we explored the biological role and downstream events of the DCLK1/XRCC5 axis in human CRC cells and CRC mouse models. Results: The results of comprehensive bioinformatics analyses suggested that DCLK1-driven CRC aggressiveness is linked to inflammation. Mechanistically, DCLK1 bound and phosphorylated XRCC5, which in turn transcriptionally activated cyclooxygenase-2 expression and enhanced prostaglandin E2 production; these events collectively generated the inflammatory tumor microenvironment and enhanced the aggressive behavior of CRC cells. Consistent with the discovered mechanism, inhibition of DCLK1 kinase activity strongly impaired the tumor seeding and growth capabilities in CRC mouse models. Conclusion: Our study illuminates a novel mechanism that mediates the pro-inflammatory function of CSCs in driving the aggressive phenotype of CRC, broadening the biological function of DCLK1 in CRC.
Subject(s)
Colorectal Neoplasms , Doublecortin-Like Kinases , Animals , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Complement C5/metabolism , Cyclooxygenase 2/genetics , Cyclooxygenase 2/metabolism , Doublecortin-Like Kinases/metabolism , Epithelial-Mesenchymal Transition/genetics , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Ku Autoantigen/metabolism , Mice , Neoplastic Stem Cells/metabolism , Protein Serine-Threonine Kinases/genetics , Tumor Microenvironment/genetics , X-RaysABSTRACT
Recurrence and metastasis remain major obstacles in colorectal cancer (CRC) treatment. Recent studies suggest that a small subpopulation of cells with a self-renewal ability, called cancer stem-like cells (CSCs), promotes recurrence and metastasis in CRC. Unfortunately, no CSC inhibitor has been demonstrated to be more effective than existing chemotherapeutic drugs, resulting in a significant unmet need for effective CRC therapies. In this study, transcriptomic profiling of metastatic tumors from CRC patients revealed significant upregulation in the Wnt pathway and stemness genes. Thus, we examined the therapeutic effect of the small-molecule Wnt inhibitor ICG-001 on cancer stemness and metastasis. The ICG-001 treatment efficiently attenuated self-renewal activity and metastatic potential. Mechanistically, myeloid ecotropic viral insertion site 1 (MEIS1) was identified as a target gene of ICG-001 that is transcriptionally regulated by Wnt signaling. A series of functional analyses revealed that MEIS1 enhanced the CSC behavior and metastatic potential of the CRC cells. Collectively, our findings suggest that ICG-001 efficiently inhibits CRC stemness and metastasis by suppressing MEIS1 expression. These results provide a basis for the further clinical investigation of ICG-001 as a targeted therapy for CSCs, opening a new avenue for the development of novel Wnt inhibitors for the treatment of CRC metastasis.
Subject(s)
Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Colorectal Neoplasms/drug therapy , Myeloid Ecotropic Viral Integration Site 1 Protein/metabolism , Neoplastic Stem Cells/drug effects , Pyrimidinones/pharmacology , Small Molecule Libraries/pharmacology , Wnt Signaling Pathway/drug effects , Animals , Cell Line, Tumor , Colorectal Neoplasms/metabolism , Gene Expression Profiling/methods , HCT116 Cells , HT29 Cells , Humans , Male , Mice , Mice, Inbred NOD , Transcription, Genetic/drug effectsABSTRACT
Tofacitinib is an oral disease-modifying anti-rheumatic drug to selectively inhibit Janus kinases. Tofacitinib is a representative small molecule inhibitor that is used to treat many diseases including rheumatoid arthritis and various autoimmune conditions. Unlike biological agents, tofacitinib has several advantages, including the ability to be administered orally and a short half-life. This study aimed to evaluate the bioequivalence of the pharmacokinetics (PK) between tofacitinib aspartate 7.13 mg (test formulation) and tofacitinib citrate 8.08 mg (reference formulation; Xeljanz®) in healthy subjects. A randomized, open-label, single-dose, 2-sequence, 2-period, 2-treatment crossover trial was conducted in 41 healthy volunteers. A total of 5 mg of tofacitinib as the test or the reference formulation was administered, and serial blood samples were collected up to 14 hours after dosing for PK analyses. The plasma concentration of tofacitinib was determined by ultra-performance liquid chromatography-tandem mass spectrometry. A non-compartmental analysis was used to estimate the PK parameters. A total of 35 subjects completed the study and the study drug was well-tolerated. The mean maximum concentration (Cmax) and area under the concentration-time curve from time zero to the time of the last quantifiable concentration (AUClast) for the test formulation were 52.67 ng/mL and 133.86 ngâh/mL, respectively, and 50.61 ng/mL and 133.49 hâng/mL for the reference formulation, respectively. The geometric mean ratios (90% confidence intervals) of the Cmax and AUClast between the 2 formulations were 1.041 (0.944-1.148) and 1.003 (0.968-1.039), respectively. Tofacitinib aspartate exhibited bioequivalent PK profiles to those of the reference formulation. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04278391.
