Double inhibition of cAMP and mTOR signalling may potentiate the reduction of cell growth in ADPKD cells.

BACKGROUND: ADPKD is a renal pathology caused by mutations of PKD1 and PKD2 genes, which encode for polycystin-1 (PC1) and polycystin-2 (PC2), respectively. PC1 plays an important role regulating several signal transducers, including cAMP and mTOR, which are involved in abnormal cell proliferation of ADPKD cells leading to the development and expansion of kidney cysts that are a typical hallmark of this disease. Therefore, the inhibition of both pathways could potentiate the reduction of cell proliferation enhancing benefits for ADPKD patients. METHODS: The inhibition of cAMP- and mTOR-related signalling was performed by Cl-IB-MECA, an agonist of A3 receptors, and rapamycin, respectively. Protein kinase activity was evaluated by immunoblot and cell growth was analyzed by direct cell counting. RESULTS: The activation of A3AR by the specific agonist Cl-IB-MECA causes a marked reduction of CREB, mTOR, and ERK phosphorylation in kidney tissues of Pkd1 flox/-: Ksp-Cre polycystic mice and reduces cell growth in ADPKD cell lines, but not affects the kidney weight. The combined sequential treatment with rapamycin and Cl-IB-MECA in ADPKD cells potentiates the reduction of cell proliferation compared with the individual compound by the inhibition of CREB, mTOR, and ERK kinase activity. Conversely, the simultaneous application of these drugs counteracts their effect on cell growth, because the inhibition of ERK kinase activity is lost. CONCLUSION: The double treatment with rapamycin and Cl-IB-MECA may have synergistic effects on the inhibition of cell proliferation in ADPKD cells suggesting that combined therapies could improve renal function in ADPKD patients.

Evaluation of switching or simultaneous use of biologic treatment in patients with severe chronic rhinosinusitis with nasal polyps and severe asthma. Considerations in clinical decision making.

INTRODUCTION: Type 2 targeting biologics have reached the market first for asthma and since 2019 also for CRSwNP. As clear guidelines and predictors for optimal biological choice are missing, patients are sometimes required to switch biologic therapy in order to find the optimal treatment result. In this paper, we evaluate reasons for switching biologics and the treatment effects after each sequential switch. MATERIALS AND METHODS: Ninety-four patients who switched from one biologic to another for their treatment of CRSwNP and asthma were evaluated. RESULTS: Twenty patients experienced satisfactory control of CRSwNP, but insufficient control of severe asthma. Fifty-one patients experienced satisfactory control of severe asthma, but insufficient control of CRSwNP/EOM. Twenty-eight patients experienced insufficient control of both upper and lower airways. Thirteen patients had to switch because of side effects. Furthermore, two cases are described to clarify clinical decision-making. DISCUSSION: For abovementioned patients, a multidisciplinary approach is mandatory to find the best suitable biologic. It seems ineffective to switch to a second anti-IL5 treatment if the first one is not successful. Most patients that failed omalizumab and/or an anti-IL-5 treatment are well controlled on dupilumab. Therefore, we suggest to use dupilumab as first choice when switching biologic agents.