Integrative Modeling of Signaling Network Dynamics Identifies Cell Type-selective Therapeutic Strategies for FGFR4-driven Cancers.

Oncogenic FGFR4 signaling represents a potential therapeutic target in various cancer types, including triple negative breast cancer (TNBC) and hepatocellular carcinoma (HCC). However, resistance to FGFR4 single-agent therapy remains a major challenge, emphasizing the need for effective combinatorial treatments. Our study sought to develop a comprehensive computational model of FGFR4 signaling and provide network-level insights into resistance mechanisms driven by signaling dynamics. An integrated approach, combining computational network modeling with experimental validation, uncovered potent AKT reactivation following FGFR4 targeting in TNBC cells. Analyzing the effects of co-targeting specific network nodes by systematically simulating the model predicted synergy of co-targeting FGFR4 and AKT or specific ErbB kinases, which was subsequently confirmed through experimental validation; however, co-targeting FGFR4 and PI3K was not synergistic. Protein expression data from hundreds of cancer cell lines was incorporated to adapt the model to diverse cellular contexts. This revealed that while AKT rebound was common, it was not a general phenomenon. For example, ERK reactivation occurred in certain cell types, including an FGFR4-driven HCC cell line, where there is a synergistic effect of co-targeting FGFR4 and MEK but not AKT. In summary, this study offers key insights into drug-induced network remodeling and the role of protein expression heterogeneity in targeted therapy responses. These findings underscore the utility of computational network modeling for designing cell type-selective combination therapies and enhancing precision cancer treatment.

Substance P Inhibitor Promotes Tendon Healing in a Collagenase-Induced Rat Model of Tendinopathy.

BACKGROUND: The substance P-neurokinin 1 receptor pathway has been proposed as a therapeutic target for tendinopathy. However, there is a lack of evidence regarding its practical applications. PURPOSE: To investigate the therapeutic effects of substance P inhibitor (SPI) on inflamed tenocytes in vitro and in a collagenase-induced rat model of tendinopathy in vivo. STUDY DESIGN: Controlled laboratory study. METHODS: We analyzed the mRNA levels of inflammatory (cyclooxygenase [COX]-2 and interleukin [IL]-6) and tenogenic (Mohawk and scleraxis [SCX]) markers using reverse transcription quantitative polymerase chain reaction to demonstrate the effects of SPI on lipopolysaccharide-treated (inflamed) tenocytes. A collagenase-induced rat model of tendinopathy was created by injecting 20 µL of collagenase into the Achilles tendon. A behavior test using an incapacitance apparatus was performed to detect changes in postural equilibrium. The tendon specimens were obtained, and their gross findings were examined. The tensile strength was measured, and histopathological evaluation was performed (hematoxylin and eosin, alcian blue, and immunohistochemical staining). RESULTS: The mRNA levels of COX-2, IL-6, Mohawk, and SCX differed significantly between inflamed tenocytes and those treated with SPI. SPI improved the weight burden in a rat model of tendinopathy in a behavioral test. The specimens of the SPI group showed a normal tendon-like appearance. In the biomechanical test, the tensile strength of the SPI group was significantly greater than that of the tendinopathy group. In the histopathological evaluation, the degree of collagen matrix breakdown was mild in the SPI group. In alcian blue staining, only small focal depositions of proteoglycans and glycosaminoglycans were observed in the SPI group. The SPI group showed decreased expression of IL-6 and neurokinin 1 receptor. CONCLUSION: This study suggests that SPI has therapeutic effects on tendon healing and restoration in a collagenase-induced rat model of tendinopathy. CLINICAL RELEVANCE: SPI is a promising agent for tendinopathy in humans.

Activation of Hypoxia-Inducible Factor-1α Signaling Pathway Has the Protective Effect of Intervertebral Disc Degeneration.

Intervertebral discs (IVDs) have poor nutrient diffusion, because the nucleus pulposus (NP) lacks direct vascular supply and likely generates adenosine triphosphate by anaerobic glycolysis. Regulation of glycolysis is mediated by hypoxia-inducible factor-1α (HIF-1α), a transcription factor that responds to local oxygen tension. Constitutively active HIF-1α (CA HIF-1α) was created by point mutation and determined the protective role of HIF-1α in IVD degeneration. Under fluoroscopy, rat caudal IVD segments were stabbed by a needle puncture, and pcDNA3- HIF-1α wild-type (WT) or pcDNA3-CA HIF-1α was transfected into NP cell lines. The constitutive activity of CA HIF-1α was analyzed using a luciferase assay after cell lysis. Next, IVD tissue samples were retrieved from five patients with degenerative lumbar spinal stenosis at the time of surgery, and NP cells were cultured. NP cells were transfected with CA HIF-1α, and relevant gene expression was measured. HIF-1α protein levels in the nucleus were significantly higher, and transcriptional activity was 10.3-fold higher in NP cells with CA HIF-1α than in those with HIF-1α WT. Gene transfer of CA HIF-1α into NP cells enhanced the expression of Glut-1, Glut-3, aggrecan, type II collagen, and Sox9. Moreover, CA HIF-1α reduced the apoptosis of NP cells induced by the Fas ligand. The HIF-1α and collagen 2 expression levels were notably increased in the NP cells of the CA HIF-1α transfected segments in histology and immunohistochemistry study. Collectively, these results suggest that activation of HIF-1α signaling pathway may play a protective role against IVD degeneration and could be used as a future therapeutic agent.

MiR-200c downregulates HIF-1α and inhibits migration of lung cancer cells.

BACKGROUND: Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor with a pivotal role in physiological and pathological responses to hypoxia. While HIF-1α is known to be involved in hypoxia-induced upregulation of microRNA (miRNA) expression, HIF-1α is also targeted by miRNAs. In this study, miRNAs targeting HIF-1α were identified and their effects on its expression and downstream target genes under hypoxic conditions were investigated. Cell migration under the same conditions was also assessed. METHODS: microRNAs that target HIF-1α were screened using 3'-untranslated region luciferase (3'-UTR-luciferase) reporter assays. The expression levels of HIF-1α and its downstream target genes after transfection with miRNA were assessed using quantitative RT-PCR and western blot analyses. The effect of the miRNAs on the transcriptional activity of HIF-1α was determined using hypoxia-responsive element luciferase (HRE-luciferase) assays. Cell migration under hypoxia was examined using the wound-healing assay. RESULTS: Several of the 19 screened miRNAs considerably decreased the luciferase activity. Transfection with miR-200c had substantial impact on the expression level and transcription activity of HIF-1α. The mRNA level of HIF-1α downstream genes decreased in response to miR-200c overexpression. MiR-200c inhibited cell migration in normoxia and, to a greater extent, in hypoxia. These effects were partly reversed by HIF-1α expression under hypoxic conditions. CONCLUSION: miR-200c negatively affects hypoxia-induced responses by downregulating HIF-1α, a key regulator of hypoxia. Therefore, overexpression of miR-200c might have therapeutic potential as an anticancer agent that inhibits tumor hypoxia.