Fragile Treg cells: Traitors in immune homeostasis?

Regulatory T (Treg) cells play a key role in maintaining immune tolerance and tissue homeostasis. However, in some disease microenvironments, Treg cells exhibit fragility, which manifests as preserved FoxP3 expression accompanied by inflammation and loss of immunosuppression. Fragile Treg cells are formatively, phenotypically and functionally diverse in various diseases, further complicating the role of Treg cells in the immunotherapeutic response and offering novel targets for disease treatment by modulating specific Treg subsets. In this review, we summarize findings on fragile Treg cells to provide a framework for characterizing the formation and role of fragile Treg cells in different diseases, and we discuss how this information may guide the development of more specific Treg-targeted immunotherapies.

A phase Ib/II study of galunisertib in combination with nivolumab in solid tumors and non-small cell lung cancer.

BACKGROUND: In this phase Ib/II open-label study, tumor immune suppression was targeted in patients with advanced refractory solid tumors and patients with recurrent/refractory non-small cell lung cancer (NSCLC) using galunisertib with nivolumab. METHODS: Eligible patients were ≥ 18 years old, had an Eastern Cooperative Oncology Group performance status ≤ 1, and were treatment-naive for anti-programmed cell death-1, its ligand, or transforming growth factor ß receptor 1 kinase inhibitors. Phase Ib was an open-label, dose-escalation assessment of the safety and tolerability of galunisertib with nivolumab in patients with advanced refractory solid tumors. Phase II evaluated the safety of galunisertib with nivolumab in NSCLC patients who had received prior platinum-based treatment but were immuno-oncology agent-naive. RESULTS: This trial was conducted between October 2015 and August 2020. No dose-limiting toxicities were observed in phase I. In the phase II NSCLC cohort (n = 25), patients received 150 mg twice daily galunisertib (14 days on/14 days off dosing schedule for all phases) plus nivolumab at 3 mg/kg (intravenously every 2 weeks). In this phase, the most frequent treatment-related adverse events (AEs) were pruritus (n = 9, 36%), fatigue (n = 8, 32%), and decreased appetite (n = 7, 28%). No grade 4 or 5 treatment-related AEs were observed. Six (24%) patients had confirmed partial response (PR) and 4 (16%) had stable disease; 1 additional patient had confirmed PR after initial pseudo-progression. The median duration of response was 7.43 months (95% confidence interval [CI]: 3.75, NR). Among the 7 responders, including the delayed responder, 1 had high PD-L1 expression (≥ 50%). The median progression-free survival was 5.26 months (95% CI: 1.77, 9.20) and the median overall survival was 11.99 months (95% CI: 8.15, NR). Interferon gamma response genes were induced post-treatment and cell adhesion genes were repressed, although the association of these observations with tumor response and clinical outcomes was not statistically powered due to limited samples available. CONCLUSIONS: The study met its primary endpoint as galunisertib combined with nivolumab was well tolerated. Preliminary efficacy was observed in a subset of patients in the Phase 2 NSCLC cohort. TRIAL REGISTRATION: Trial registered with ClinicalTrials.gov (NCT02423343; 22.04.2015).

Blockade of the TGF-ß pathway by galunisertib inhibits the glial-mesenchymal transition in Müller glial cells.

Aging increases the risks for developing fibrocontractile membranes on the retina, which causes significant macular distortion, as in the idiopathic epiretinal membrane (iERM). Retinal Müller glial cells are components of these membranes and may play a key role in the iERM pathogenesis. The transforming growth factor-ß (TGF-ß) induces Müller cell transdifferentiation into myofibroblast, reducing glial cell markers (glutamine synthetase, GS, and glial fibrillary acidic protein, GFAP) and increasing α-smooth muscle actin (α-SMA). Our aim was to investigate the effect of the TGF-ß inhibitor galunisertib (LY2157299) on the glial-mesenchymal transition and contraction of Müller cells. MIO-M1 human Müller cells were treated with TGF-ß1 (10 ng/mL), galunisertib (5, 10 and 20 µM) and TGF-ß1+galunisertib for 24h and 48h. Galunisertib cytotoxicity was analyzed by MTT and trypan blue, and TGF-ß1 blockade by phospho-SMAD3 immunofluorescence. Caspase-3 (cell death indicator), GS, GFAP and α-SMA expression was examined by immunofluorescence, Western blotting, and qPCR analysis. Cell contractility was determined by collagen gel contraction assay with Müller cells incorporated. Galunisertib did not show cytotoxicity at the concentrations evaluated and maintained the Müller cells phenotype, ensuring the GS expression. Galunisertib inhibited the TGF-ß1 pathway by decreasing phospho-SMAD3 immunoreactivity, attenuated the α-SMA expression, and prevented the contraction of Müller cells in collagen gel. Although more studies are needed, in vitro assays suggest that galunisertib may be a potential candidate to attenuate the formation of fibrocontractile membranes and prevent retinal detachment and consequent loss of vision.

The pancreatic cancer immune tumor microenvironment is negatively remodeled by gemcitabine while TGF-ß receptor plus dual checkpoint inhibition maintains antitumor immune cells.

Pancreatic ductal adenocarcinoma (PDA) tumors have a highly immunosuppressive desmoplastic tumor microenvironment (TME) where immune checkpoint inhibition (ICI) therapy has been exceptionally ineffective. Transforming growth factor-ß (TGF-ß) receptor activation leads to cancer and immune cell proliferation and phenotype, and cytokine production leading to tumor progression and worse overall survival in PDA patients. We hypothesized that TGF-ß receptor inhibition may alter PDA progression and antitumor immunity in the TME. Here, we used a syngeneic preclinical murine model of PDA to explore the impact of TGF-ß pathway inhibitor galunisertib (GAL), dual checkpoint immunotherapy (anti-PD-L1 and CTLA-4), the chemotherapy gemcitabine (GEM), and their combinations on antitumor immune responses. Blockade of TGF-ß and ICI in immune-competent mice bearing orthotopically injected murine PDA cells significantly inhibited tumor growth and was accompanied by antitumor M1 macrophage infiltration. In contrast, GEM treatment resulted in increased PDA tumor growth, decreased antitumor M1 macrophages, and decreased cytotoxic CD8+ T cell subpopulation compared to control mice. Together, these findings demonstrate the ability of TGF-ß inhibition with GAL to prime antitumor immunity in the TME and the curative potential of combining GAL with dual ICI. These preclinical results indicate that targeted inhibition of TGF-ß may enhance the efficacy of dual immunotherapy in PDA. Optimal manipulation of the immune TME with non-ICI therapy may enhance therapeutic efficacy.

Radiosensitizing effect of galunisertib, a TGF-ß receptor I inhibitor, on head and neck squamous cell carcinoma in vitro.

BACKGROUND: Resistance to radiation therapy poses a major clinical problem for patients suffering from head and neck squamous cell carcinoma (HNSCC). Transforming growth factor ß (TGF-ß) has emerged as a potential target. This study aimed to investigate the radiosensitizing effect of galunisertib, a small molecule TGF-ß receptor kinase I inhibitor, on HNSCC cells in vitro. METHODS: Three HNSCC cell lines were treated with galunisertib alone, or in combination with radiation. Of those three cell lines, one has a known inactivating mutation of the TGF-ß pathway (Cal27), one has a TGF-ß pathway deficiency (FaDu) and one has no known alteration (SCC-25). The effect on metabolic activity was evaluated by a resazurin-based reduction assay. Cell migration was evaluated by wound-healing assay, clonogenic survival by colony formation assay and cell cycle by FACS analysis. RESULTS: Galunisertib reduced metabolic activity in FaDu, increased in SCC-25 and had no effect on CAL27. Migration was significantly reduced by galunisertib in all three cell lines and showed additive effects in combination with radiation in CAL27 and SCC-25. Colony-forming capabilities were reduced in SCC-25 by galunisertib and also showed an additive effect with adjuvant radiation treatment. Cell cycle analysis showed a reduction of cells in G1 phase in response to galunisertib treatment. CONCLUSION: Our results indicate a potential antineoplastic effect of galunisertib in HNSCC with intact TGF-ß signaling in combination with radiation.

Novel targets to overcome antiangiogenesis therapy resistance in glioblastoma multiforme: Systems biology approach and suggestion of therapy by galunisertib.

Glioblastoma multiforme (GBM) is a tumor with high microvessel density. Antiangiogenesis therapy (AAT) resistance occurs due to the complex mechanisms involved in angiogenesis, with increased chances of recurrence. The vascular endothelial growth factor (VEGF) pathway is the main pathway of angiogenesis, and anti-VEGF drugs have been ineffective in controlling it. New oncogenes in the VEGF signaling pathway may be new candidates for angiogenesis targeting. Oncogene candidates were chosen using gene expression profiles and databases. Then oncogenes were subjected to gene set enrichment analysis (GSEA) and survival analysis (SA). Molecular docking was conducted to evaluate the interaction of the oncogenes with galunisertib. NRAS, AKT1, and HSPB1 were the most effective oncogenes upregulating genes that play a role in GBM expression in the VEGF signaling pathway. The VEGF and MAPK signaling pathways were found to be effective using GSEA and Kyoto Encyclopedia Gene and Genome pathway analysis. Survival analyses revealed that patients with high HSPB1 expression had poorer overall survival rates than those with low HSPB1 expression. Galunisertib exhibits intermolecular interactions with 6DV5, 5UHV, and 3O96 (binding energy -8.0, -8.6, and -10.3 kcal/mol, respectively). The current AAT should be restrategized to suppress the numerous angiogenic elements to manage angiogenesis and combat AAT resistance in GBM. In silico analysis indicated that NRAS, AKT1, and HSPB1 genes can be the main oncogenes in the VEGF signaling pathway and galunisertib strongly interacts with these genes. Consequently, the use of galunisertib to overcome AAT in GBM in combination therapy can be assessed.

SERS Quantification of Galunisertib Delivery in Colorectal Cancer Cells by Plasmonic-Assisted Diatomite Nanoparticles.

The small molecule Galunisertib (LY2157299, LY) shows multiple anticancer activities blocking the transforming growth factor-ß1 receptor, responsible for the epithelial-to-mesenchymal transition (EMT) by which colorectal cancer (CRC) cells acquire migratory and metastatic capacities. However, frequent dosing of LY can produce highly toxic metabolites. Alternative strategies to reduce drug side effects can rely on nanoscale drug delivery systems that have led to a medical revolution in the treatment of cancer, improving drug efficacy and lowering drug toxicity. Here, a hybrid nanosystem (DNP-AuNPs-LY@Gel) made of a porous diatomite nanoparticle decorated with plasmonic gold nanoparticles, in which LY is retained by a gelatin shell, is proposed. The multifunctional capability of the nanosystem is demonstrated by investigating the efficient LY delivery, the enhanced EMT reversion in CRCs and the intracellular quantification of drug release with a sub-femtogram resolution by surface-enhanced Raman spectroscopy (SERS). The LY release trigger is the pH sensitivity of the gelatin shell to the CRC acidic microenvironment. The drug release is real-time monitored at single-cell level by analyzing the SERS signals of LY in CRC cells. The higher efficiency of LY delivered by the DNP-AuNPs-LY@Gel complex paves the way to an alternative strategy for lowering drug dosing and consequent side effects.

A concise review of bioanalytical methods of small molecule immuno-oncology drugs in cancer therapy.

Immuno-oncology (IO) is an emerging option to treat cancer malignancies. In the last two years, IO has accounted for more than 90% of the new active drugs in various therapeutic indications of oncology drug development. Bioanalytical methods used for the quantitation of various IO small molecule drugs have been summarized in this review. The most commonly used are HPLC and LC-MS/MS methods. Determination of IO drugs from biological matrices involves drug extraction from the biological matrix, which is mostly achieved by simple protein precipitation, liquid-liquid extraction and solid-phase extraction. Subsequently, quantitation is usually achieved by LC-MS/MS, but HPLC-UV has also been employed. The bioanalytical methods reported for each drug are briefly discussed and tabulated for easy access. Our review indicates that LC-MS/MS is a versatile and reliable tool for the sensitive, rapid and robust quantitation of IO drugs.

Design of Gelatin-Capped Plasmonic-Diatomite Nanoparticles with Enhanced Galunisertib Loading Capacity for Drug Delivery Applications.

Inorganic diatomite nanoparticles (DNPs) have gained increasing interest as drug delivery systems due to their porous structure, long half-life, thermal and chemical stability. Gold nanoparticles (AuNPs) provide DNPs with intriguing optical features that can be engineered and optimized for sensing and drug delivery applications. In this work, we combine DNPs with gelatin stabilized AuNPs for the development of an optical platform for Galunisertib delivery. To improve the DNP loading capacity, the hybrid platform is capped with gelatin shells of increasing thicknesses. Here, for the first time, full optical modeling of the hybrid system is proposed to monitor both the gelatin generation, degradation, and consequent Galunisertib release by simple spectroscopic measurements. Indeed, the shell thickness is optically estimated as a function of the polymer concentration by exploiting the localized surface plasmon resonance shifts of AuNPs. We simultaneously prove the enhancement of the drug loading capacity of DNPs and that the theoretical modeling represents an efficient predictive tool to design polymer-coated nanocarriers.

P-glycoprotein (MDR1/ABCB1) controls brain accumulation and intestinal disposition of the novel TGF-ß signaling pathway inhibitor galunisertib.

Galunisertib (LY2157299), a promising small-molecule inhibitor of the transforming growth factor-beta (TGF-ß) receptor, is currently in mono- and combination therapy trials for various cancers including glioblastoma, hepatocellular carcinoma and breast cancer. Using genetically modified mouse models, we investigated the roles of the multidrug efflux transporters ABCB1 and ABCG2, the OATP1A/1B uptake transporters and the drug-metabolizing CYP3A complex in galunisertib pharmacokinetics. In vitro, galunisertib was vigorously transported by human ABCB1, and moderately by mouse Abcg2. Orally administered galunisertib (20 mg/kg) was very rapidly absorbed. Galunisertib brain-to-plasma ratios were increased by ~24-fold in Abcb1a/1b-/- and Abcb1a/1b;Abcg2-/- mice compared to wild-type mice, but not in single Abcg2-/- mice, whereas galunisertib oral availability was not markedly affected. However, recovery of galunisertib in the small intestinal lumen was strongly reduced in Abcb1a/1b-/- and Abcb1a/1b;Abcg2-/- mice. Oral coadministration of the ABCB1/ABCG2 inhibitor elacridar boosted galunisertib brain accumulation in wild-type mice to equal the levels seen in Abcb1a/1b;Abcg2-/- mice. Oatp1a/1b deficiency did not alter oral galunisertib pharmacokinetics or liver distribution. Cyp3a-/- mice showed a 1.9-fold higher plasma AUC0-1 hr than wild-type mice, but this difference disappeared over 8 hr. Also, transgenic human CYP3A4 overexpression did not significantly alter oral galunisertib pharmacokinetics. Abcb1 thus markedly restricts galunisertib brain penetration and affects its intestinal disposition, possibly through biliary excretion. Elacridar coadministration could fully inhibit both processes, without causing acute toxicity. Moreover, mouse Cyp3a, but not human CYP3A4, may eliminate galunisertib at high plasma concentrations. These insights may help to guide the further clinical development and application of galunisertib.

Phase 1b/2a study of galunisertib, a small molecule inhibitor of transforming growth factor-beta receptor I, in combination with standard temozolomide-based radiochemotherapy in patients with newly diagnosed malignant glioma.

Purpose Galunisertib, a TGF-ß inhibitor, has demonstrated antitumor effects in preclinical and radiographic responses in some patients with malignant glioma. This Phase 1b/2a trial investigated the clinical benefit of combining galunisertib with temozolomide-based radiochemotherapy (TMZ/RTX) in patients with newly diagnosed malignant glioma (NCT01220271). Methods This is an open-label, 2-arm Phase 1b/2a study (N = 56) of galunisertib (intermittent dosing: 14 days on/14 days off per cycle of 28 days) in combination with TMZ/RTX (n = 40), versus a control arm (TMZ/RTX, n = 16). The primary objective of Phase 1b was to determine the safe and tolerable Phase 2 dose of galunisertib. The primary objective of Phase 2a was to confirm the tolerability and pharmacodynamic profile of galunisertib with TMZ/RTX, and the secondary objectives included determining the efficacy and pharmacokinetic (PK) profile of galunisertib with TMZ/RTX in patients with glioblastoma. This study also characterized the changes in the major T-cell subsets during TMZ/RTX plus galunisertib treatment. Results In the Phase 2a study, efficacy results for patients treated with galunisertib plus TMZ/RTX or TMZ/RTX were: median overall survival (18.2 vs 17.9 months), median progression-free survival (7.6 vs 11.5 months), and disease control rate (80% [32/40] vs 56% [9/16] patients) respectively. PK profile of galunisertib plus TMZ/RTX regimen was consistent with previously published PK data of galunisertib. The overall safety profile across treatment arms was comparable. Conclusion No differences in efficacy, safety or pharmacokinetic variables were observed between the two treatment arms.

A phase 1b study of transforming growth factor-beta receptor I inhibitor galunisertib in combination with sorafenib in Japanese patients with unresectable hepatocellular carcinoma.

Background Galunisertib inhibits type I transforming growth factor-beta receptor serine/threonine kinase. The primary objective of this study was to evaluate the safety and tolerability of galunisertib in combination with sorafenib in Japanese patients with unresectable hepatocellular carcinoma. Patients and methods This open-label, dose-escalation, multicenter, nonrandomized phase 1b study consisted of two dose levels of galunisertib, 160 or 300 mg/day, in combination with sorafenib 800 mg/day. Galunisertib 80 mg or 150 mg was administered orally twice daily for 14 days followed by 14 days of rest plus sorafenib 400 mg administered orally twice daily for 28 days. The dose-limiting toxicity evaluation was 28 days after the first dose. Safety measures, pharmacokinetics, and antitumor activity were assessed. Results Fourteen patients, 7 at each galunisertib dose, were enrolled and treated. Three dose-limiting toxicities were reported for 2 patients. The most common treatment-emergent adverse events (TEAEs) were hypophosphatemia (14 patients [100%]), palmar-plantar erythrodysesthesia syndrome (12 patients [85.7%]), and decreased platelet count (10 patients [71.4%]). The most common grade ≥ 3 TEAEs were hypophosphatemia (10 patients [71.4%]) and palmar-plantar erythrodysesthesia syndrome (7 patients [50.0%]). No grade 5 TEAEs were reported. The pharmacokinetic profile of galunisertib in combination with sorafenib was similar to that previously reported for galunisertib. Eleven patients had a best overall response of stable disease, and 1 patient achieved a partial response by hepatocellular carcinoma-specific modified RECIST. Conclusions These data are consistent with the known safety profile for galunisertib and sorafenib and confirm tolerability of the recommended dose of galunisertib (150 mg twice daily for 14 days) in combination with sorafenib in Japanese patients with unresectable hepatocellular carcinoma.

Novel transforming growth factor beta receptor I kinase inhibitor galunisertib (LY2157299) in advanced hepatocellular carcinoma.

BACKGROUND AND AIMS: We assessed the activity of galunisertib, a small molecule inhibitor of the transforming growth factor beta (TGF-ß1) receptor I, in second-line patients with hepatocellular carcinoma (HCC) in two cohorts of baseline serum alpha fetoprotein (AFP). METHODS: Patients with advanced HCC who progressed on or were ineligible to receive sorafenib, Child-Pugh A/B7 and ECOG PS ≤1 were enrolled into Part A (AFP ≥ 1.5× ULN) or Part B (AFP < 1.5× ULN). Patients were treated with 80 or 150 mg galunisertib BID for 14 days per 28-day cycle. Endpoints were time-to-progression (TTP) and changes in circulating AFP and TGF-ß1 levels, as well as safety, pharmacokinetics, progression-free survival and overall survival (OS). RESULTS: Patients (n = 149) were enrolled with median age 65 years. Median TTP was 2.7 months (95% CI: 1.5-2.9) in Part A (n = 109) and 4.2 months (95% CI: 1.7-5.5) in Part B (n = 40). Median OS was 7.3 months (95% CI: 4.9-10.5) in Part A and 16.8 months (95% CI: 10.5-24.4) in Part B. OS was longer in AFP responders (>20% decrease from baseline, Part A) compared to non-responders (21.5 months vs 6.8 months). OS was longer in TGF-ß1 responders (>20% decrease from baseline, all patients) compared to non-responders. The most common Grade 3/4 treatment-related adverse events were neutropenia (n = 4) and fatigue, anaemia, increased bilirubin, hypoalbuminemia and embolism (each, n = 2). CONCLUSIONS: Galunisertib treatment had a manageable safety profile in patients with HCC. Lower baseline AFP and a response in AFP or TGF-ß1 levels (vs no response) correlated with longer survival. TRIAL REGISTRATION NUMBER: NCT01246986 at ClinicalTrials.gov.

Disposition and metabolism of [14C]-galunisertib, a TGF-ßRI kinase/ALK5 inhibitor, following oral administration in healthy subjects and mechanistic prediction of the effect of itraconazole on galunisertib pharmacokinetics.

1. The disposition and metabolism of galunisertib (LY2157299 monohydrate, a TGF-ßRI Kinase/ALK5 Inhibitor) was characterized following a single oral dose of 150 mg of [14C]-galunisertib (100 µCi) to six healthy human subjects. 2. The galunisertib plasma half-life was 8.6 h, while the 14C half-life was 10.0 h. Galunisertib was abundant in circulation (40.3% of the 14C AUC024 h), with 7 additional metabolites detected in plasma. Two metabolites LSN3199597 (M5, mono-oxidation), and M4 (glucuronide of M3) were the most abundant circulating metabolites (10.7 and 9.0% of the 14C AUC024 h respectively). The pharmacological activity of LSN3199597 was tested and found to be significantly less potent than galunisertib. 3. The dose was recovered in feces (64.5%) and in urine (36.8%). Galunisertib was cleared primarily by metabolism, based on low recovery of parent in excreta (13.0% of dose). Due to the slow in vitro metabolism of galunisertib in suspended hepatocytes, a long term hepatocyte system was used to model the human excretion profile. 4. Expressed cytochromes P450 and hepatocytes indicated clearance was primarily CYP3A4-mediated. Mechanistic static modeling that incorporated small non-CYP-mediated metabolic clearance and renal clearance components predicted an AUC ratio of 4.7 for the effect of itraconazole, a strong CYP3A4 inhibitor, on galunisertib.

Galunisertib modifies the liver fibrotic composition in the Abcb4Ko mouse model.

Transforming growth factor (TGF)-ß stimulates extracellular matrix (ECM) deposition during development of liver fibrosis and cirrhosis, the most important risk factor for the onset of hepatocellular carcinoma. In liver cancer, TGF-ß is responsible for a more aggressive and invasive phenotype, orchestrating remodeling of the tumor microenvironment and triggering epithelial-mesenchymal transition of cancer cells. This is the scientific rationale for targeting the TGF-ß pathway via a small molecule, galunisertib (intracellular inhibitor of ALK5) in clinical trials to treat liver cancer patients at an advanced disease stage. In this study, the hypothesis that galunisertib modifies the tissue microenvironment via inhibition of the TGF-ß pathway is tested in an experimental preclinical model. At the age of 6 months, Abcb4ko mice-a well-established model for chronic liver disease development and progression-are treated twice daily with galunisertib (150 mg/kg) via oral gavage for 14 consecutive days. Two days after the last treatment, blood plasma and livers are harvested for further assessment, including fibrosis scoring and ECM components. The reduction of Smad2 phosphorylation in both parenchymal and non-parenchymal liver cells following galunisertib administration confirms the treatment effectiveness. Damage-related galunisertib does not change cell proliferation, macrophage numbers and leucocyte recruitment. Furthermore, no clear impact on the amount of fibrosis is evident, as documented by PicroSirius red and Gomori-trichome scoring. On the other hand, several fibrogenic genes, e.g., collagens (Col1α1 and Col1α2), Tgf-ß1 and Timp1, mRNA levels are significantly downregulated by galunisertib administration when compared to controls. Most interestingly, ECM/stromal components, fibronectin and laminin-332, as well as the carcinogenic ß-catenin pathway, are remarkably reduced by galunisertib-treated Abcb5ko mice. In conclusion, TGF-ß inhibition by galunisertib interferes, to some extent, with chronic liver progression, not by reducing the stage of liver fibrosis as measured by different scoring systems, but rather by modulating the biochemical composition of the deposited ECM, likely affecting the fate of non-parenchymal cells.

Targeting TGF-ß Signaling in Kidney Fibrosis.

Renal fibrosis is the final common pathway of numerous progressive kidney diseases, and transforming growth factor-ß (TGF-ß) has an important role in tissue fibrosis by up-regulating matrix protein synthesis, inhibiting matrix degradation, and altering cell-cell interaction. Many strategies targeting TGF-ß, including inhibition of production, activation, binding to the receptor, and intracellular signaling, have been developed. Some of them were examined in clinical studies against kidney fibrosis, and some are applied to other fibrotic diseases or cancer. Here, I review the approaches targeting TGF-ß signaling in kidney fibrosis.

TGF-ß and the Tissue Microenvironment: Relevance in Fibrosis and Cancer.

Transforming growth factor-β (TGF-β) is a cytokine essential for the induction of the fibrotic response and for the activation of the cancer stroma. Strong evidence suggests that a strong cross-talk exists among TGF-β and the tissue extracellular matrix components. TGF-β is stored in the matrix as part of a large latent complex bound to the latent TGF-β binding protein (LTBP) and matrix binding of latent TGF-β complexes, which is required for an adequate TGF-β function. Once TGF-β is activated, it regulates extracellular matrix remodelling and promotes a fibroblast to myofibroblast transition, which is essential in fibrotic processes. This cytokine also acts on other cell types present in the fibrotic and tumour microenvironment, such as epithelial, endothelial cells or macrophages and it contributes to the cancer-associated fibroblast (CAF) phenotype. Furthermore, TGF-β exerts anti-tumour activity by inhibiting the host tumour immunosurveillance. Aim of this review is to update how TGF-β and the tissue microenvironment cooperate to promote the pleiotropic actions that regulate cell responses of different cell types, essential for the development of fibrosis and tumour progression. We discuss recent evidences suggesting the use of TGF-β chemical inhibitors as a new line of defence against fibrotic disorders or cancer.

Biomarker and Histopathology Evaluation of Patients with Recurrent Glioblastoma Treated with Galunisertib, Lomustine, or the Combination of Galunisertib and Lomustine.

Galunisertib, a Transforming growth factor-ßRI (TGF-ßRI) kinase inhibitor, blocks TGF-ß-mediated tumor growth in glioblastoma. In a three-arm study of galunisertib (300 mg/day) monotherapy (intermittent dosing; each cycle =14 days on/14 days off), lomustine monotherapy, and galunisertib plus lomustine therapy, baseline tumor tissue was evaluated to identify markers associated with tumor stage (e.g., histopathology, Ki67, glial fibrillary acidic protein) and TGF-ß-related signaling (e.g., pSMAD2). Other pharmacodynamic assessments included chemokine, cytokine, and T cell subsets alterations. 158 patients were randomized to galunisertib plus lomustine (n = 79), galunisertib (n = 39) and placebo+lomustine (n = 40). In 127 of these patients, tissue was adequate for central pathology review and biomarker work. Isocitrate dehydrogenase (IDH1) negative glioblastoma patients with baseline pSMAD2⁺ in cytoplasm had median overall survival (OS) 9.5 months vs. 6.9 months for patients with no tumor pSMAD2 expression (p = 0.4574). Eight patients were IDH1 R132H⁺ and had a median OS of 10.4 months compared to 6.9 months for patients with negative IDH1 R132H (p = 0.5452). IDH1 status was associated with numerically higher plasma macrophage-derived chemokine (MDC/CCL22), higher whole blood FOXP3, and reduced tumor CD3⁺ T cell counts. Compared to the baseline, treatment with galunisertib monotherapy preserved CD4⁺ T cell counts, eosinophils, lymphocytes, and the CD4/CD8 ratio. The T-regulatory cell compartment was associated with better OS with MDC/CCL22 as a prominent prognostic marker.

The rationale for targeting TGF-ß in chronic liver diseases.

BACKGROUND: Transforming growth factor (TGF)-ß is a pluripotent cytokine that displays several tissue-specific biological activities. In the liver, TGF-ß is considered a fundamental molecule, controlling organ size and growth by limiting hepatocyte proliferation. It is involved in fibrogenesis and, therefore, in worsening liver damage, as well as in triggering the development of hepatocellular carcinoma (HCC). TGF-ß is known to act as an oncosuppressor and also as a tumour promoter in HCC, but its role is still unclear. DESIGN: In this review, we discuss the potential role of TGF-ß in regulating the tumoural progression of HCC, and therefore the rationale for targeting this molecule in patients with HCC. RESULTS: A considerable amount of experimental preclinical evidence suggests that TGF-ß is a promising druggable target in patients with HCC. To support this hypothesis, a phase II clinical trial is currently ongoing using a TGF-ß pathway inhibitor, and results will soon be available. CONCLUSIONS: The identification of new TGF-ß related biomarkers will help to select those patients most likely to benefit from therapy aimed at inhibiting the TGF-ß pathway. New formulations that may provide a more controlled and sustained delivery of the drug will improve the therapeutic success of such treatments.

Galunisertib downregulates mutant type I collagen expression and promotes MSCs osteogenesis in pediatric osteogenesis imperfecta.

Qualitative alterations in type I collagen due to pathogenic variants in the COL1A1 or COL1A2 genes, result in moderate and severe Osteogenesis Imperfecta (OI), a rare disease characterized by bone fragility. The TGF-ß signaling pathway is overactive in OI patients and certain OI mouse models, and inhibition of TGF-ß through anti-TGF-ß monoclonal antibody therapy in phase I clinical trials in OI adults is rendering encouraging results. However, the impact of TGF-ß inhibition on osteogenic differentiation of mesenchymal stem cells from OI patients (OI-MSCs) is unknown. The following study demonstrates that pediatric skeletal OI-MSCs have imbalanced osteogenesis favoring the osteogenic commitment. Galunisertib, a small molecule inhibitor (SMI) that targets the TGF-ß receptor I (TßRI), favored the final osteogenic maturation of OI-MSCs. Mechanistically, galunisertib downregulated type I collagen expression in OI-MSCs, with greater impact on mutant type I collagen, and concomitantly, modulated the expression of unfolded protein response (UPR) and autophagy markers. In vivo, galunisertib improved trabecular bone parameters only in female oim/oim mice. These results further suggest that type I collagen is a tunable target within the bone ECM that deserves investigation and that the SMI, galunisertib, is a promising new candidate for the anti-TGF-ß targeting for the treatment of OI.