Efflux inhibition by IWR-1-endo confers sensitivity to doxorubicin effects in osteosarcoma cells

METTL3/YTHDF1 stabilizes CORO6 expression promoting osteosarcoma progression through glycolysis

This study investigates the role of CORO6 (Coronin 6) in the development of osteosarcoma. Osteosarcoma is a common malignant bone tumor in children and adolescents, characterized by rapid and irregular bone growth and a high risk of distant lung metastasis. CORO6 is a member of the Coronin family, known for its conserved WD40 repeat domain. This structure allows CORO6 to inhibit actin dynamics through interactions with F-actin and Arp2/3, thereby affecting the organization of the cytoskeleton. Our research found that in osteosarcoma patients, the levels of CORO6 are significantly elevated. Experimental observations showed that reducing the expression of CORO6 significantly inhibits the growth, migration, and invasion abilities of osteosarcoma cells. Moreover, in vivo experiments demonstrated that the absence of CORO6 effectively inhibits the growth of osteosarcoma in animal models. We also discovered that CORO6 promotes the proliferation, migration and invasion capabilities of osteosarcoma cells by activating the Wnt/β-catenin signaling pathway. Moreover, CORO6 plays a critical important role in glycolysis of osteosarcoma cells. Mechanically, we found that METTL3/YTHDF1 induced m6A modification of CORO6 mRNA promoted the expression of CORO6 by enhancing its stability. These findings offer new directions for the treatment of osteosarcoma, suggesting that CORO6 could be a novel prognostic biomarker and an effective therapeutic target for patients. In summary, CORO6, as an oncogene, plays a key role in the development of osteosarcoma, providing a crucial theoretical basis for the development of new osteosarcoma treatment strategies.

FATS inhibits the Wnt pathway and induces apoptosis through degradation of MYH9 and enhances sensitivity to paclitaxel in breast cancer

Breast cancer is one of the most prevalent and diverse malignancies, and, with global cases increasing, the need for biomarkers to inform individual sensitivity to chemotherapeutics has never been greater. Our retrospective clinical analysis predicted that the expression of the fragile site-associated tumor suppressor (FATS) gene was associated with the sensitivity of breast cancer to neoadjuvant chemotherapy with paclitaxel. In vitro experiments subsequently demonstrated that FATS significantly increased the inhibitory effects of paclitaxel on breast cancer cells' migration, growth, and survival. An interaction screen revealed that FATS interacted with MYH9 and promoted its degradation via the ubiquitin-proteasome pathway, thereby downregulating Wnt signaling. By overexpressing FATS and MYH9, we demonstrated that FATS enhanced paclitaxel-induced apoptosis in breast cancer cells by degrading MYH9 to downregulate the Wnt pathway. We also demonstrated in a mouse xenograft model that FATS significantly increased the chemosensitivity of breast cancer cells to paclitaxel in vivo. This study presents a new mechanism by which FATS interacts with MYH9 to suppress the Wnt/β-catenin signaling pathway and induce apoptosis, thus enhancing the sensitivity of breast cancer cells to paclitaxel chemotherapy. The results also propose novel biomarkers for predicting breast cancer sensitivity to neoadjuvant chemotherapy with paclitaxel. Finally, we provide in vivo evidence that the combination of paclitaxel with IWR-1, a novel Wnt pathway inhibitor, synergistically suppresses breast cancer growth, laying the foundation for future trials with this drug combination. These results therefore provide a number of potential solutions for more precise treatment of patients with breast cancer in the future.

Development and Validation of a Sensitive and Specific LC-MS/MS Method for IWR-1-Endo, a Wnt Signaling Inhibitor: Application to a Cerebral Microdialysis Study

IWR-1-endo, a small molecule that potently inhibits the Wnt/β-catenin signaling pathway by stabilizing the AXIN2 destruction complex, can inhibit drug efflux at the blood−brain barrier. To conduct murine cerebral microdialysis research, validated, sensitive, and reliable liquid chromatography−tandem mass spectrometry (LC-MS/MS) methods were used to determine IWR-1-endo concentration in the murine plasma and brain microdialysate. IWR-1-endo and the internal standard (ISTD) dabrafenib were extracted from murine plasma and microdialysate samples by a simple solid-phase extraction protocol performed on an Oasis HLB µElution plate. Chromatographic separation was executed on a Kinetex C18 (100A, 50 × 2.1 mm, 4 µm particle size) column with a binary gradient of water and acetonitrile, each having 0.1% formic acid, pumped at a flow rate of 0.6 mL/min. Detection by mass spectrometry was conducted in the positive selected reaction monitoring ion mode by monitoring mass transitions 410.40 > 344.10 (IWR-1-endo) and 520.40 > 307.20 (ISTD). The validated curve range of IWR-1-endo was 5−1000 ng/mL for the murine plasma method (r2 ≥ 0.99) and 0.5−500 ng/mL for the microdialysate method (r2 ≥ 0.99). The lower limit of quantification (LLOQ) was 5 ng/mL and 0.5 ng/mL for the murine plasma and microdialysate sample analysis method, respectively. Negligible matrix effects were observed in murine plasma and microdialysate samples. IWR-1-endo was extremely unstable in murine plasma. To improve the stability of IWR-1-endo, pH adjustments of 1.5 were introduced to murine plasma and microdialysate samples before sample storage and processing. With pH adjustment of 1.5 to the murine plasma and microdialysate samples, IWR-1-endo was stable across several tested conditions such as benchtop, autosampler, freeze−thaw, and long term at −80 °C. The LC-MS/MS methods were successfully applied to a murine pharmacokinetic and cerebral microdialysis study to characterize the unbound IWR-1-endo exposure in brain extracellular fluid and plasma.