OBJECTIVE: Smoothened (SMO), a key component of the hedgehog signaling pathway, represents a therapeutic target for triple negative breast cancer (TNBC), yet the chemotherapy response rate in TNBC patients is only 40-50%, underscoring the urgent need for the development of novel drugs to effectively treat this condition. The novel compound TPB15, an SMO inhibitor derived from [1,2,4] triazolo [4,3-α] pyridines, demonstrated superior anti-TNBC activity and lower toxicity compared to the first SMO inhibitor vismodegib in both in vitro and in vivo. However, the compound\'s pharmacokinetic properties remain unclear. The present work aims to develop a simple HPLC-MS/MS method to profile the pharmacokinetics and bioavailability of TPB15 in rats as a ground work for further clinical research.
METHODS: Separation was performed on an Agilent ZORBAX StableBond C18 column by gradient elution using acetonitrile and 0.1% formic acid as mobile phase at a flow rate of 0.3 mL/min. Multiple reaction monitoring(MRM) in positive mode with the transitions of m/z 454.2 → 100.0, 248.1 → 121.1 was employed to determine TPB15 and internal standard tinidazole, respectively. The specificity, intra- and inter- day precision and accuracy, extraction recovery, stability, matrix effect, dilution integrity and carryover of the method was validated. The pharmacokinetics and bioavailability  study of TPB15 were carried out on rats through intravenous injection at the dose of 5 mg/kg and oral gavage at the dose of 25 mg/kg, and the pharmacokinetics parameters were calculated by the non-compartment analysis using the pharmacokinetics software DAS 2.1.1.
RESULTS: The values of specificity, intra- and inter- day precision and accuracy, extraction recovery, stability, matrix effect, dilution integrity and carryover satisfied the acceptable limits. The lower limit of quantification of this method was 10 ng/mL with a linear range of 10-2000 ng/mL. The validated method was then applied to pharmacokinetics and bioavailability studies in rat by dosing with gavage (25 mg/kg) and intravenous injection(5 mg/kg), and the oral bioavailability of TBP15 in rat was calculated as 16.4 ± 3.5%. The pharmacokinetic parameters were calculated as following: maximum of plasma concentration (Cmax) (PO: 2787.17 ± 279.45 µg/L), Time to maximum plasma concentration (Tmax) (PO: 4.20 ± 0.90 h), the area under the concentration-time curve 0 to time (AUC0-t) (PO: 17,373.03 ± 2585.18 ng/mL·h, IV: 21,129.79 ± 3360.84 ng/mL·h), the area under the concentration-time curve 0 to infinity (AUC0-∞) (PO: 17,443.85 ± 2597.63 ng/mL·h, IV: 17,443.85 ± 2597.63 ng/mL·h), terminal elimination half-life (t1/2) (PO: 7.26 ± 2.16 h, IV: 4.78 ± 1.09 h).
CONCLUSIONS: TPB15, a promising candidate for treating TNBC, has demonstrated outstanding efficacy and safety in vitro and in vivo. This study established a simple, sensitive, and rapid HPLC-MS/MS bioanalytical method, developed and validated in accordance with FDA and EMA guidelines, for conducting pharmacokinetic and bioavailability studies of TPB15. The results revealed a favorable pharmacokinetic profile owing to its long t1/2. Nevertheless, the next phase of research should include formulation screening to enhance bioavailability, as well as clinical trials, metabolism pathway analysis, and assessment of potential drug-drug interactions.

The purpose of this study was to investigate the effects of BOC on glioblastoma cells and its underlying mechanisms. In vitro, BOC-knockdown was performed in glioma cell lines. CCK-8 and Transwell were used to assess the impact of BOC on the viability, invasion, and migration of gliobma cells. RNA-seq technology was employed to analyze the differential gene expression between BOC-knockdown glioma cells and the control group, and qRT-PCR was used to validate the expression of downstream differential genes. SMO-overexpression was performed to investigate the effects of SMO on glioma cells. A BOC-knockdown mouse subcutaneous tumor model was to verify the effects of BOC on mouse tumors. Tissue microarray technology was used to detect the expression of BOC and SMO in samples of normal human brain tissue and glioma tissue. In vitro, BOC-knockdown inhibited the viability, invasion, and migration of glioma cells, as well as downregulated the expression of downstream differential genes SMO, EGFR, HRAS, and MRAS. Conversely, SMO-overexpression upregulated the viability, invasion, and migration abilities of BOC-knockdown cells. In vivo, BOC-knockdown suppressed tumor growth in mice and downregulated the expression of downstream differential genes SMO, EGFR, HRAS, and MRAS. Tissue microarray results showed that both BOC and SMO were highly expressed in glioma tissues. BOC is aberrantly overexpressed in glioma patients and promotes glioma development. Mechanistically, BOC activates the Hedgehog (Hh) and RAS signaling pathways by upregulating the expression of SMO, EGFR, HRAS, and MRAS, thereby facilitating the Proliferation, invasion and migration of glioma cells.

Asthma is the most prevalent chronic inflammatory disease of the airways in children. The most prevalent phenotype of asthma is eosinophilic asthma, which is driven by a Th2 immune response and can be effectively managed by inhaled corticosteroid therapy. However, there are phenotypes of asthma with Th17 immune response that are insensitive to corticosteroid therapy and manifest a more severe phenotype. The treatment of this corticosteroid-insensitive asthma is currently immature and requires further attention. The objective of this study is to elucidate the regulation of the Hedgehog signaling pathway in Th17 cell differentiation in asthma. The study demonstrated that both Smo and Gli3, key components of the Hedgehog signaling pathway, were upregulated in Th17 polarization in vitro and in a Th17-dominant asthma model in vivo. Inhibiting Smo with a small molecule inhibitor or genetically knocking down Gli3 was found to suppress Th17 polarization. Smo was found to increase in Th1, Th2, Th17 and Treg polarization, while Gli3 specifically increased in Th17 polarization. ChIP-qPCR analyses indicated that Gli3 can directly interact with IL-6 in T cells, inducing STAT3 phosphorylation and promoting Th17 cell differentiation. Furthermore, the study demonstrated a correlation between elevated Gli3 expression and IL-17A and IL-6 expression in children with asthma. In conclusion, the study demonstrated that the Hedgehog signaling pathway plays an important role in the pathogenesis of asthma, as it regulates the differentiation of Th17 cells through the IL-6/STAT3 signaling. This may provide a potential therapeutic target for corticosteroid-insensitive asthma driven by Th17 cells.

OBJECTIVE: Apart from the role of the retinoblastoma gene, the genomic events associated with poor outcomes in patients with ophthalmic tumors are poorly understood.
METHODS: We retrospectively analyzed 48 patients with six types of ophthalmic tumors. We searched for high-frequency mutated genes and susceptibility genes in these patients using combined exome and transcriptome analysis.
RESULTS: We identified four clearly causative genes (TP53, PTCH1, SMO, BAP1). Susceptibility gene analysis identified hotspot genes, including RUNX1, APC, IDH2, and BRCA2, and high-frequency gene analysis identified several genes, including TP53, TTN, and MUC16. Transcriptome analysis identified 5868 differentially expressed genes, of which TOP2A and ZWINT were upregulated in all samples, while CFD, ELANE, HBA1, and HBB were downregulated. Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated that the phosphoinositide 3-kinase (PI3K)-Akt and Transcriptional misregulation in cancer signaling pathways may be involved in ophthalmic tumorigenesis.
CONCLUSIONS: TP53 is clearly involved in ophthalmic tumorigenesis, especially in basal cell carcinoma, and the PI3K-Akt signaling pathway may be an essential pathway involved in ophthalmic tumorigenesis. RUNX1, SMO, TOP2A, and ZWINT are also highly likely to be involved in ophthalmic tumorigenesis, but further functional experiments are needed to verify the mechanisms of these genes in regulating tumorigenesis.

In this issue of Cell Chemical Biology, Liu et al.1 report the identification of Q29, a synthetic diterpenoid that blocks covalent cholesterol modification of smoothened (SMO) and inhibits hedgehog signaling. Q29 is capable of suppressing tumor cell growth, both in vitro and in vivo, and overcoming resistance to SMO inhibitors.

The Hedgehog (Hh) signaling pathway is involved in T cell differentiation and development and plays a major regulatory part in different stages of T cell development. A previous study by us suggested that prenatal exposure to staphylococcal enterotoxin B (SEB) changed the percentages of T cell subpopulation in the offspring thymus. However, it is unclear whether prenatal SEB exposure impacts the Hh signaling pathway in thymic T cells. In the present study, pregnant rats at gestational day 16 were intravenously injected once with 15 μg SEB, and the thymi of both neonatal and adult offspring rats were aseptically acquired to scrutinize the effects of SEB on the Hh signaling pathway. It firstly found that prenatal SEB exposure clearly caused the increased expression of Shh and Dhh ligands of the Hh signaling pathway in thymus tissue of both neonatal and adult offspring rats, but significantly decreased the expression levels of membrane receptors of Ptch1 and Smo, transcription factor Gli1, as well as target genes of CyclinD1, C-myc, and N-myc in Hh signaling pathway of thymic T cells. These data suggest that prenatal SEB exposure inhibits the Hh signaling pathway in thymic T lymphocytes of the neonatal offspring, and this effect can be maintained in adult offspring via the imprinting effect.

Aberrant activation of the Hedgehog (Hh) signaling pathway plays important roles in oncogenesis and therapeutic resistance in several types of cancer. The clinical application of FDA-approved Hh-targeted smoothened inhibitors (SMOi) is hindered by the emergence of primary or acquired drug resistance. Epigenetic and transcriptional-targeted therapies represent a promising direction for developing improved anti-Hh therapies. In this study, we integrated epigenetic/transcriptional-targeted small-molecule library screening with CRISPR/Cas9 knockout library screening and identified CDK9 and CDK12, two transcription elongation regulators, as therapeutic targets for antagonizing aberrant Hh activation and overcoming SMOi resistance. Inhibition of CDK9 or CDK12 potently suppressed Hh signaling and tumor growth in various SMOi responsive or resistant Hh-driven tumor models. Systemic epigenomic profiling elucidated the Hh-driven super-enhancer (SE) landscape and identified IRS1, encoding a critical component and cytoplasmic adaptor protein of the insulin-like growth factor (IGF) pathway, as an oncogenic Hh-driven SE target gene and effective therapeutic target in Hh-driven tumor models. Collectively, this study identifies SE-driven transcriptional dependencies that represent promising therapeutic vulnerabilities for suppressing the Hh pathway and overcoming SMOi resistance. As CDK9 and IRS inhibitors have already entered human clinical trials for cancer treatment, these findings provide comprehensive preclinical support for developing trials for Hh-driven cancers. Significance: Dissecting transcriptional dependencies driven by super-enhancers uncovers therapeutic targets in Hedgehog-driven cancers and identifies strategies for overcoming resistance to smoothened inhibitors.

The smoothened (Smo) receptor facilitates hedgehog signaling between kidney fibroblasts and tubules during acute kidney injury (AKI). Tubule-derived hedgehog is protective in AKI, but the role of fibroblast-selective Smo is unclear. Here, we report that Smo-specific ablation in fibroblasts reduced tubular cell apoptosis and inflammation, enhanced perivascular mesenchymal cell activities, and preserved kidney function after AKI. Global proteomics of these kidneys identified extracellular matrix proteins, and nidogen-1 glycoprotein in particular, as key response markers to AKI. Intriguingly, Smo was bound to nidogen-1 in cells, suggesting that loss of Smo could affect nidogen-1 accessibility. Phosphoproteomics revealed that the \'AKI protector\' Wnt signaling pathway was activated in these kidneys. Mechanistically, nidogen-1 interacted with integrin β1 to induce Wnt in tubules to mitigate AKI. Altogether, our results support that fibroblast-selective Smo dictates AKI fate through cell-matrix interactions, including nidogen-1, and offers a robust resource and path to further dissect AKI pathogenesis.

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease globally. Currently, there are no effective drugs for the treatment of DN. Although several studies have reported the therapeutic potential of mesenchymal stem cells, the underlying mechanisms remain largely unknown. Here, we report that both human umbilical cord MSCs (UC-MSCs) and UC-MSC-derived exosomes (UC-MSC-exo) attenuate kidney damage, and inhibit epithelial-mesenchymal transition (EMT) and renal fibrosis in streptozotocin-induced DN rats. Strikingly, the Hedgehog receptor, smoothened (SMO), was significantly upregulated in the kidney tissues of DN patients and rats, and positively correlated with EMT and renal fibrosis. UC-MSC and UC-MSC-exo treatment resulted in decrease of SMO expression. In vitro co-culture experiments revealed that UC-MSC-exo reduced EMT of tubular epithelial cells through inhibiting Hedgehog/SMO pathway. Collectively, UC-MSCs inhibit EMT and renal fibrosis by delivering exosomes and targeting Hedgehog/SMO signaling, suggesting that UC-MSCs and their exosomes are novel anti-fibrotic therapeutics for treating DN.

Hedgehog (Hh) signaling is crucial in cardiovascular development and maintenance. However, the biological role of Patched1 (Ptch1), an inhibitory receptor of the Hh signaling pathway, remains elusive. In this study, a Ptch1 ortholog was characterized in Nile tilapia (Oreochromis niloticus), and its function was investigated through CRISPR/Cas9 gene knockout. When one-cell embryos were injected with CRISPR/Cas9 targeting ptch1, the mutation efficiency exceeded 70%. During 0-3 days post fertilization (dpf), no significant differences were observed between the ptch1 mutant group and the control group; at 4 dpf (0 day after hatching), about 10% of the larvae showed an angiogenesis defect and absence of blood flow; from 5 dpf, most larvae exhibited an elongated heart, large pericardial cavity, and blood leakage and coagulation, ultimately dying during the 6-8 dpf period due to the lack of blood circulation. Consistently, multiple differentially expressed genes related to angiogenesis, blood coagulation, and heart development were enriched in the ptch1 mutants. Furthermore, Smoothened (Smo) antagonist (cyclopamine) treatment of the ptch1 mutants greatly rescued the cardiovascular disorders. Collectively, our study suggests that Ptch1 is required for cardiovascular development and vascular integrity via Smo signaling, and excessive Hh signaling is detrimental to cardiovascular development.