Abdul Aziz, A. A. | Search bioRxiv

bioRxiv2025

RBPMS as a novel marker for cancer-associated fibroblasts in distinguishing left and right colorectal cancer sidedness

BackgroundColorectal cancer (CRC) can be classified into left-sided (LCRC) and right-sided CRC (RCRC). These CRC entities present different molecular phenotypes and prognosis. Accumulation of cancer-associated fibroblasts (CAFs) reflects poor prognosis and recurrence of CRC. CAF-cancer cell crosstalk regulates fibroblast activation and drives CRC progression, facilitated via secretomes including TGF{beta}1. CAF-cancer cell interplay according to colon sidedness have yet to be fully investigated due to the lack of robust marker for CAF. ObjectiveTo explore a novel CAF marker in differentiating the mechanisms of LCRC and RCRC. MethodsCAFs from cancerous tissues of LCRC and RCRC patients and normal fibroblasts from adjacent normal colon tissues were established. Profiling of these fibroblasts were performed. Gene expression of the fibroblasts was analyzed via Affymetrix Clariom S (Human) assay, validated using Western blot. The effect of TGF{beta}1 on protein expression of fibroblasts was also studied. Epithelial cancer cell lines were used as controls. ResultsFibroblast profiling showed differences in morphology and proliferation between CAFs and NFs, and pro-proliferative effect of CAFs on CRC cells. Molecular analyses revealed RNA-binding protein with multiple splicing (RBPMS) to be differentially expressed between CAFs and NFs from left and right colon. RBPMS was significantly upregulated in CAFs from LCRC compared to their respective NFs. In contrast, RBPMS was downregulated in CAFs from RCRC compared to their NFs (p<0.05). Furthermore, TGF{beta}1 induced RBPMS expression in CAFs and NFs from the left colon, whereas it suppressed RBPMS expression in fibroblasts from right colon. CAFs from LCRC resembled myCAFs with myofibroblast-related expression signatures, whereas those from RCRC signified iCAFs with inflammatory marker expression. ConclusionThis study highlighted RBPMS as a novel CAF marker in differentiating the mechanisms between LCRC and RCRC. This finding may be utilized in CAF-targeted therapy for CRC.

molecular biology↗

bioRxiv2024

OXPHOS TARGETING OF MYCN-AMPLIFIED NEUROBLASTOMA

SummaryHigh risk - neuroblastoma (HR-NB) is a pediatric solid tumor with high lethality. Half of HR-NB are driven by MYCN gene amplification (MNA). These HR-NBs require high dosage chemotherapy and often relapse. Moreover, current therapies can cause severe long-term side effects and new therapies are urgently needed. This study investigates a novel therapeutic approach targeting the metabolic vulnerabilities of MNA NB cells. We discovered that Diphenyleneiodonium chloride (DPI), an inhibitor of flavoprotein enzymes and mitochondrial complex I, synergizes with mitoquinone mesylate (MitoQ), a mitochondria-targeted antioxidant in 2D and 3D in vitro models of NB. Similarly to DPI, MitoQ affects MNA cells in a MYCN-dependent fashion, being more toxic when MYCN levels are high. Furthermore, low nanomolar concentrations of MitoQ significantly decrease MYCN protein expression and induce differentiation of MNA cells. The DPI and MitoQ combination further synergizes with vincristine, a chemotherapeutic agent used in NB treatment. Phosphoproteomics and proteomics analysis suggests that the drug combination induces MNA NB cell death by arresting the cell cycle and inhibiting oxidative phosphorylation (OXPHOS) in the mitochondria. Thus, interference with mitochondrial metabolism may represent an effective strategy to enhance the activity of chemotherapeutic drugs in MNA-NB.

cancer biology↗