A pyrazolopyridine as a novel AhR signaling activator with anti-breast cancer properties in vitro and in vivo.

Breast cancer is one of the main causes of malignancy-related deaths globally and has a significant impact on women's quality of life. Despite significant therapeutic advances, there is a medical need for targeted therapies in breast cancer. Aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor mediates responses to environment stimuli, is emerging as a unique pleiotropic target. Herein, a combined molecular simulation and in vitro investigations identified 3-(3-fluorophenyl)-1H-pyrazolo[3,4-b]pyridine (3FPP) as a novel AhR ligand in T47D and MDA-MB-231 breast cancer cells. Its agonistic effects induced formation of the AhR-AhR nuclear translocator (Arnt) heterodimer and prompted its binding to the penta-nucleotide sequence, called xenobiotic-responsive element (XRE) motif. Moreover, 3FPP augmented the promoter-driven luciferase activities and expression of AhR-regulated genes encoding cytochrome P450 1A1 (CYP1A1) and microRNA (miR)-212/132 cluster. It reduced cell viability, migration, and invasion of both cell lines through AhR signaling. These anticancer properties were concomitant with reduced levels of B-cell lymphoma 2 (BCL-2), SRY-related HMG-box4 (SOX4), snail family zinc finger 2 (SNAI2), and cadherin 2 (CDH2). In vivo, 3FPP suppressed tumor growth and activated AhR signaling in an orthotopic mouse model. In conclusion, our results introduce the fused pyrazolopyridine 3FPP as a novel AhR agonist with AhR-specific anti-breast cancer potential in vitro and in vivo.

Aryl Hydrocarbon Receptor as an Anticancer Target: An Overview of Ten Years Odyssey.

Aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor belonging to the basic helix-loop-helix (bHLH)/per-Arnt-sim (PAS) superfamily, is traditionally known to mediate xenobiotic metabolism. It is activated by structurally diverse agonistic ligands and regulates complicated transcriptional processes through its canonical and non-canonical pathways in normal and malignant cells. Different classes of AhR ligands have been evaluated as anticancer agents in different cancer cells and exhibit efficiency, which has thrust AhR into the limelight as a promising molecular target. There is strong evidence demonstrating the anticancer potential of exogenous AhR agonists including synthetic, pharmaceutical, and natural compounds. In contrast, several reports have indicated inhibition of AhR activity by antagonistic ligands as a potential therapeutic strategy. Interestingly, similar AhR ligands exert variable anticancer or cancer-promoting potential in a cell- and tissue-specific mode of action. Recently, ligand-mediated modulation of AhR signaling pathways and the associated tumor microenvironment is emerging as a potential approach for developing cancer immunotherapeutic drugs. This article reviews advances of AhR in cancer research covering publication from 2012 to early 2023. It summarizes the therapeutic potential of various AhR ligands with an emphasis on exogenous ligands. It also sheds light on recent immunotherapeutic strategies involving AhR.

Activation of aryl hydrocarbon receptor signaling by gallic acid suppresses progression of human breast cancer in vitro and in vivo.

BACKGROUND: Despite the significant advances in diagnosis and treatment, breast cancer remains the most common malignancy and the second cause of death in women. Increasingly, preclinical evidence has suggested aryl hydrocarbon receptor (Ahr), a ligand activated transcription factor, a promising therapeutic target in breast cancer. PURPOSE: This study aims at screening a number of phenolic compounds to identify an Ahr ligand with suppressive effects on human breast cancer. METHODS: Potential interactions between Ahr and phenolic compounds were predicted in silico, and physical interaction was examined by ligand competitive binding in vitro. The MDA-MB-231 and T47D breast cancer cell lines were used to examine the expression of Ahr downstream genes and progression of breast cancer cells in vitro. Binding of Ahr/Ahr nuclear transporter (Arnt) complex to the xenobiotic-responsive element (XRE)-box was examined by DNA-protein interaction (DPI)-ELISA, promoter activity was assessed using luciferase reporter system, and RNA interreference was carried out using electroporation. The real-time PCR and/or immunoblotting were used to quantify gene expressions. Tumor growth in vivo was assessed using a murine orthotopic model. RESULTS: A combined computational modeling and in vitro approaches identified gallic acid (GA) as an Ahr ligand with agonistic properties. It induced binding of Ahr/Arnt to the XRE-box, enhanced the promoter activity and expression of Ahr downstream genes including cytochrome P450 1A1 (CYP1A1), and SRY-related HMG-box4 (SOX4)-targeting miR-212/132 cluster and miR-335 in both MDA-MB-231 and T47D cells. GA increased apoptosis while decreased proliferation, migration and invasion capacities of breast cancer cells in an Ahr-dependent fashion. Furthermore, it reduced the levels of B-cell lymphoma 2 (BCL-2), cyclooxygenase-2 (COX-2) and SOX4, while selectively increased that of tumor protein 53 (P53), in an Ahr-dependent and -independent fashions. In an in vivo orthotopic model, GA activated Ahr signaling and reduced the growth of breast cancer cells. CONCLUSION: We identified GA as an Ahr phenolic ligand, and provided evidence on the role of Ahr in mediating its anti-breast cancer effects, indicating that GA, and possibly other phenolic compounds, have important therapeutic implications in human breast cancer through activation of Ahr signaling.

ACCELERATE and European Medicine Agency Paediatric Strategy Forum for medicinal product development for mature B-cell malignancies in children.

Paediatric Strategy Forums have been created by the multistakeholder organisation, ACCELERATE, and the European Medicines Agency to facilitate dialogue between all relevant stakeholders and suggest strategies in critical areas of paediatric oncology drug development. As there are many medicines being developed for B-cell malignancies in adults but comparatively few in children with these malignancies, a Paediatric Strategy Forum was held to discuss the best approach to develop these products for children. It was concluded that as current frontline therapy is highly successful, despite associated acute toxicity, de-escalation of this or substitution of presently used drugs with new medicines can only be undertaken when there is an effective salvage regimen, which is currently not available. Therefore priority should be given to developing treatment for patients with relapsed and refractory mature B-cell lymphomas. The consensus of the clinicians attending the meeting was that CAR T-cells, T-cell engagers and antibody drug conjugates (excluding those with a vinca alkaloid-like drug) presently have the greatest probability of providing benefit in relapse in view of their mechanism of action. However, as producing autologous CAR T-cells currently takes at least 4 weeks, they are not products which could be quickly employed initially at relapse in rapidly progressing mature B-cell malignancies but only for the consolidation phase of the treatment. Global, industry-supported, academic-sponsored studies testing compounds from different pharmaceutical companies simultaneously should be considered in rare populations, and it was proposed that an international working group be formed to develop an overarching clinical trials strategy for these disease groups. Future Forums are planned for other relevant paediatric oncologic diseases with a high unmet medical need and relevant molecular targets.

Phase I, double-blind, randomized, placebo-controlled, dose-escalation study of NI-0401 (a fully human anti-CD3 monoclonal antibody) in patients with moderate to severe active Crohn's disease.

BACKGROUND: NI-0401 is a fully human monoclonal antibody, which binds to the CD3 subunit of the T-cell receptor, causing modulation of T-cell activity. We investigated the safety and the ability to modulate the TCR-CD3 complex of NI-0401 in patients with active Crohn's disease (CD). METHODS: A double-blind, placebo-controlled, randomized, multicenter, dose-escalating trial was conducted in CD patients age 18-70 years, a Crohn's Disease Activity Index (CDAI) of 220-450, and detectable levels of C-reactive protein. The primary outcome was safety and the ability of NI-0401 to modulate the TCR-CD3 complex on T cells. Efficacy parameters included the proportion of patients achieving remission (CDAI <150), clinical response (CDAI fall ≥100), and change from baseline in the CD Endoscopy Index of Severity (CDEIS). RESULTS: Forty patients received placebo (n = 7) or NI-0401 (n = 33) 0.05-10 mg daily for 5 days. NI-0401 doses ≤1 mg were well tolerated. Infusion reactions occurred at doses ≥2 mg. The extent and duration of TCR-CD3 modulation increased with dose. No differences between groups were observed in the proportions of patients achieving clinical remission or response. The mean CDEIS at week 6 differed significantly between the 1-mg and placebo group. CONCLUSIONS: NI-0401 was tolerated at doses ≤1 mg with manageable side effects. NI-0401 induced a dose-dependent modulation of the TCR-CD3 complex. No significant improvement of CDAI was observed but 1 mg NI-0401 demonstrated an improvement in CDEIS.

Extended valganciclovir prophylaxis in D+/R- kidney transplant recipients is associated with long-term reduction in cytomegalovirus disease: two-year results of the IMPACT study.

BACKGROUND: Whether the early reduction in cytomegalovirus (CMV) disease seen at 1 year with prolongation of antiviral prophylaxis (up to 200 days) persists in the long term is unknown. METHODS: This international, randomized, prospective, double-blind study, compared 318 CMV D+/R- kidney transplant recipients receiving valganciclovir (900 mg) once daily for up to 200 days vs. 100 days. Long-term outcomes including CMV disease, acute rejection, graft loss, patient survival, and seroconversion were assessed. RESULTS: At 2 years posttransplant, CMV disease occurred in significantly less patients in the 200- vs. the 100-day group: 21.3% vs. 38.7%, respectively (P<0.001). Between year 1 and 2, there were only 10 new cases of CMV disease; 7 in the 200-day group and 3 in the 100-day group. Patient survival was 100% in the 200-day group and 97% in the 100-day group (p=not significant). Biopsy-proven acute rejection and graft loss rates were comparable in both groups (11.6% vs. 17.2%, P=0.16, and 1.9% vs. 4.3%, P=0.22, in the 200-day vs. 100-day groups, respectively). Seroconversion was delayed in the 200-day group but was similar to the 100-day group by 2 years posttransplant (IgM or IgG seroconversion; 55.5% in the 200-day group vs. 62.0% in the 100-day group at 2-years; P=0.26). Assessment of seroconversion at the end of prophylaxis was of limited utility for predicting late-onset CMV disease. CONCLUSION: Extending valganciclovir prophylaxis from 100 to 200 days is associated with a sustained reduction in CMV disease up to 2 years posttransplant.