It Takes Two to Tango! Protein-Protein Interactions behind cAMP-Mediated CFTR Regulation

Over the last fifteen years, with the approval of the first molecular treatments, a breakthrough era has begun for patients with cystic fibrosis (CF), the rare genetic disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). These molecules, known as CFTR modulators, have led to unprecedented improvements in the lung function and quality of life of most CF patients. However, the efficacy of these drugs is still suboptimal, and the clinical response is highly variable even among individuals bearing the same mutation. Furthermore, not all patients carrying rare CFTR mutations are eligible for CFTR modulator therapies, indicating the need for alternative and/or add-on therapeutic approaches. Because the second messenger 3',5'-cyclic adenosine monophosphate (cAMP) represents the primary trigger for CFTR activation and a major regulator of different steps of the life cycle of the channel, there is growing interest in devising ways to fine-tune the cAMP signaling pathway for therapeutic purposes. This review article summarizes current knowledge regarding the role of cAMP signalosomes, i.e., multiprotein complexes bringing together key enzymes of the cAMP pathway, in the regulation of CFTR function, and discusses how modulating this signaling cascade could be leveraged for therapeutic intervention in CF.

A PI3Kγ mimetic peptide triggers CFTR gating, bronchodilation, and reduced inflammation in obstructive airway diseases

Cyclic adenosine 3',5'-monophosphate (cAMP)-elevating agents, such as β₂-adrenergic receptor (β₂-AR) agonists and phosphodiesterase (PDE) inhibitors, remain a mainstay in the treatment of obstructive respiratory diseases, conditions characterized by airway constriction, inflammation, and mucus hypersecretion. However, their clinical use is limited by unwanted side effects because of unrestricted cAMP elevation in the airways and in distant organs. Here, we identified the A-kinase anchoring protein phosphoinositide 3-kinase γ (PI3Kγ) as a critical regulator of a discrete cAMP signaling microdomain activated by β₂-ARs in airway structural and inflammatory cells. Displacement of the PI3Kγ-anchored pool of protein kinase A (PKA) by an inhaled, cell-permeable, PI3Kγ mimetic peptide (PI3Kγ MP) inhibited a pool of subcortical PDE4B and PDE4D and safely increased cAMP in the lungs, leading to airway smooth muscle relaxation and reduced neutrophil infiltration in a murine model of asthma. In human bronchial epithelial cells, PI3Kγ MP induced unexpected cAMP and PKA elevations restricted to the vicinity of the cystic fibrosis transmembrane conductance regulator (CFTR), the ion channel controlling mucus hydration that is mutated in cystic fibrosis (CF). PI3Kγ MP promoted the phosphorylation of wild-type CFTR on serine-737, triggering channel gating, and rescued the function of F508del-CFTR, the most prevalent CF mutant, by enhancing the effects of existing CFTR modulators. These results unveil PI3Kγ as the regulator of a β₂-AR/cAMP microdomain central to smooth muscle contraction, immune cell activation, and epithelial fluid secretion in the airways, suggesting the use of a PI3Kγ MP for compartment-restricted, therapeutic cAMP elevation in chronic obstructive respiratory diseases.

A National Multicenter Study on overall survival in elderly metastatic castrate-resistant prostate cancer patients treated with Radium-223

BACKGROUND

Radium-223 prolongs overall survival (OS) and delays time to the first symptomatic skeletal events in patients with symptomatic metastatic castration-resistant prostate cancer (mCRPC). There is a lack of evidence on the safety and efficacy of Radium-223 treatment in the very elderly population.

AIMS

Aim of this multicentre study is to analyze mCRPC patients treated with Radium-223 in terms of OS and to assess whether there are differences between young and elderly, as well as to verify efficacy and safety in patients ≥ 75 years of age.

METHODS

430 mCRPC patients of six Italian Centres were analyzed in this multicenter retrospective study. At baseline and after each cycle were collected clinical and diagnostic patients' parameters. The whole cohort was divided into two groups based on the age of the patients (< 75 years old and ≥ 75 years old).

RESULTS

47% of the patients were < 75 years old and 53% were ≥ 75 years old. The primary outcome, OS, does not show significant differences between the two subgroups if other basal parameters are considered. Considering clinical covariates in univariate models (p < 0.05) several clinical aspects have an impact on OS, except for age (p = 0.072). Age continues to have no significant impact on the OS (p = 0.274) even in multivariate models in the two groups. The toxic effects are similar in the two groups.

CONCLUSIONS

Radium-223 prolongs survival in both younger and older patients at the same baseline condition and is a good option in the symptomatic mCRPC setting compared to other agents.

Sequencing radium 223 and other life-prolonging agents in castration-resistant prostate cancer patients

Background: Radium 223 (RA223) is currently administered as part of a therapeutic sequence with the other life-prolonging agents (LPAs) for metastatic castration-resistant prostate cancer (mCRPC). Patients & methods: We retrospectively reviewed the clinical records of patients who had received at least three LPAs including RA223. Results: Median overall survival (OS) from the start of first-line treatment was 39.8 months, with the patients who completed all six planned courses of RA223 having a longer OS than those who did not (53.2 vs 29.5 months; p < 0.0001). Conclusions: Our study confirms the activity of RA223 regardless of the treatment line in which it is administered and suggests that patient selection plays a central role in maximizing this activity.

Therapeutic peptides for the treatment of cystic fibrosis: Challenges and perspectives

Cystic fibrosis (CF) is the most common amongst rare genetic diseases, affecting more than 70.000 people worldwide. CF is characterized by a dysfunctional chloride channel, termed cystic fibrosis conductance regulator (CFTR), which leads to the production of a thick and viscous mucus layer that clogs the lungs of CF patients and traps pathogens, leading to chronic infections and inflammation and, ultimately, lung damage. In recent years, the use of peptides for the treatment of respiratory diseases, including CF, has gained growing interest. Therapeutic peptides for CF include antimicrobial peptides, inhibitors of proteases, and modulators of ion channels, among others. Peptides display unique features that make them appealing candidates for clinical translation, like specificity of action, high efficacy, and low toxicity. Nevertheless, the intrinsic properties of peptides, together with the need of delivering these compounds locally, e.g. by inhalation, raise a number of concerns in the development of peptide therapeutics for CF lung disease. In this review, we discuss the challenges related to the use of peptides for the treatment of CF lung disease through inhalation, which include retention within mucus, proteolysis, immunogenicity and aggregation. Strategies for overcoming major shortcomings of peptide therapeutics will be presented, together with recent developments in peptide design and optimization, including computational analysis and high-throughput screening.

Mechanisms of Anthracycline-Induced Cardiotoxicity: Is Mitochondrial Dysfunction the Answer?

Cardiac side effects are a major drawback of anticancer therapies, often requiring the use of low and less effective doses or even discontinuation of the drug. Among all the drugs known to cause severe cardiotoxicity are anthracyclines that, though being the oldest chemotherapeutic drugs, are still a mainstay in the treatment of solid and hematological tumors. The recent expansion of the field of Cardio-Oncology, a branch of cardiology dealing with prevention or treatment of heart complications due to cancer treatment, has greatly improved our knowledge of the molecular mechanisms behind anthracycline-induced cardiotoxicity (AIC). Despite excessive generation of reactive oxygen species was originally believed to be the main cause of AIC, recent evidence points to the involvement of a plethora of different mechanisms that, interestingly, mainly converge on deregulation of mitochondrial function. In this review, we will describe how anthracyclines affect cardiac mitochondria and how these organelles contribute to AIC. Furthermore, we will discuss how drugs specifically targeting mitochondrial dysfunction and/or mitochondria-targeted drugs could be therapeutically exploited to treat AIC.

Inhaled Biologicals for the Treatment of Cystic Fibrosis

Background:

Cystic Fibrosis (CF), one of the most frequent genetic diseases, is characterized by the production of viscous mucus in several organs. In the lungs, mucus clogs the airways and traps bacteria, leading to recurrent/resistant infections and lung damage. For cystic fibrosis patients, respiratory failure is still lethal in early adulthood since available treatments display incomplete efficacy.

Objective:

The objective of this review is to extend the current knowledge in the field of available treat-ments for cystic fibrosis. A special focus has been given to inhaled peptide-based drugs.

Methods:

The current review is based on recent and/or relevant literature and patents already available in various scientific databases, which include PubMed, PubMed Central, Patentscope and Science Direct. The information obtained through these diverse databases is compiled, critically interpreted and presented in the current study. An in-depth but not systematic approach to the specific research question has been adopted.

Results:

Recently, peptides have been proposed as possible pharmacologic agents for the treatment of respiratory diseases. Of note, peptides are suitable to be administered by inhalation to maximize efficacy and reduce systemic side effects. Moreover, innovative delivery carriers have been developed for drug administration through inhalation, allowing not only protection against proteolysis, but also a prolonged and controlled release.

Conclusion:

Here, we summarize newly patented peptides that have been developed in the last few years and advanced technologies for inhaled drug delivery to treat cystic fibrosis.

Radium-223 treatment in castration resistant bone metastatic prostate cancer. Should be the primary tumor always treated?

INTRODUCTION

Radium-223 (223Ra) improves symptoms and survival in patients with bone metastatic castration-resistant prostate cancer (mCRPC).

STUDY AIM

To evaluate the impact of a previous radical prostatectomy (RP) on the outcome of 223Ra therapy in mCRPC patients. The primary prostate tumor left untreated could progress during 223Ra treatment.

MATERIALS AND METHODS

mCRPC symptomatic patients treated with 223Ra were enrolled. Luteinizing Hormone-Releasing Hormone analogue was maintained. No other anticancer therapy was given. 223Ra was administered i.v. at the dose of 55 kBq/kg every 4 weeks for 6 cycles. Patients were stratified according to previous RP or not. Hematological toxicity was monitored. Statistical analysis of 223Ra discontinuations, progressions, and deaths were performed.

RESULTS

Forty-four patients were enrolled, 16 (36.4%) previously received RP, 5 (11.3%) prostate radiotherapy and 23 (52.3%) maintained the primary prostate tumor after local treatment. All patients presented only bone metastases, 24 patients (54.5%) had more than 20. Twenty-six (59.1%) patients were treated after first or second line systemic chemotherapy. Treatment interruptions occurred in 14 patients (50%) with prostate and in 4 (25%) without (P = 0.04). After a median follow-up of 18 months (6-30 months), 15 (53.6%), and 7 (43.7%) progressions (P = 0.34) and 13 and 1 (6.2%) deaths (P = 0.04) occurred in patients with and without prostate respectively.

CONCLUSION

The presence of the primary prostate tumor seems to play a detrimental role in mCRPC patients undergoing 223Ra treatment in absence of other concomitant anticancer therapy. On the other hand a previous RP might play a protective role.

Therapeutic effect of RA223 in the management of breast cancer bone metastases

Radium 223 dichloride (Ra223) is the only targeted alpha therapy able to extend survival in patients with bone metastases from prostate cancer. Mechanism of action and data currently available focused mainly on osteoblastic metastases from prostate cancer. Phase 1 and 2 trials documented a clinical efficacy also in breast cancer patients with predominately bone disease, highlighting a reduction in alkaline phosphatase and other bone biomarkers. In our institution, a patient with breast cancer affected by osteolytic metastases was treated with off-label use of Ra223. Our patient had a good treatment compliance and up to now she has not been revealed the presence of SSE or hematological complications. Our preliminary experience shows that Ra223 may play a critical role to bone metastates in patients with breast cancer.

Can radium 223 be a conservative non-surgical management of medication-related osteonecrosis of the jaw?

Osteonecrosis of the jaw (ONJ) is a rare and severe necrotic bone disease reflecting a compromise in the body's osseous healing mechanisms and unique to the craniofacial region. Radium 223 dichloride (Ra223) is the only targeted alpha therapy able to extend survival in patients with bone metastases from prostate cancer. Mechanism of action and data currently available focused mainly on osteoblastic metastases from prostate cancer. In 2018, a Caucasian 54-year-old woman presented to our institution for a breast cancer with bone metastases. Since the patient refused any treatment and taking into account the bone disease, our multidisciplinary team evaluated a supplementary strategy with radium 223. A total of six treatments were planned with a dose of 50 KBq/kg every 4 weeks according to Phase 2 data. Four days after the second cycle administration, the patient presented for examination with a self-extracted necrotic bone fragment. Oroantral communication remained in the absence of algic symptomatology or suppuration. The multidisciplinary approach between oncologists, nuclear physicians, and dental health teams is crucial throughout the treatment process to avoid unnecessary suffering in patients at risk. More prospective studies are needed; however, considering the limitation of the present case, radio 223 may play an adjuvant role in the medical treatment of cancer patients with active ONJ.

Hematologic toxicity of radium-223 in elderly patients with metastatic Castration Resistant Prostate Cancer: a real-life experience

Background

Treatment with radium-223 has been shown to increase survival and to delay skeletal events related to bone metastases of patients with metastatic Castration Resistant Prostate Cancer (mCRPC). This treatment has also proved to be well tolerated, and hematological toxicity, in particular anemia, represents the most represented adverse event.

Materials and methods

We evaluated the hematologic toxicity of Ra-223 treatment in a real-life experience of 38 patients from two Italian cancer centers, with bone metastases from mCRPC. The main endpoint of the study was the evaluation of the efficacy and tolerability of treatment with radium-223, with greater reference to hematological toxicity (especially anemia) as the cause of interruption of treatment, specifically in the elderly patient.

Results

From August 2016 to October 2017, a total of 38 consecutive nonselected patients, 20 of them aged >75 years, with mCRPC symptomatic bone metastases, were enrolled for radium-223 at standard doses. Hematologic adverse events were recorded more frequently (72.4% with AE), and 36.8% had anemia. The most frequent cause of treatment discontinuation due to AEs was anemia [8/10 patients (80%)], followed by thrombocytopenia (2 patients) and neutropenia (1 patient). Hematologic AEs were more represented in elderly patients with greater disease burden and previously treated with docetaxel.

Conclusions

Anemia is the most represented AE related to radium-223 treatment in elderly patients with greater disease burden and previously treated with docetaxel, besides representing the main reason for interruption of treatment. Correct patient selection, appropriate timing, and adequate supportive care are elements that could facilitate successful treatment with radium-223, preventing premature interruption of the same. The results of this experience support the opportunity to propose treatment with radium-223 mostly in patients in the earliest stages.

Cause of radium 223 treatment discontinuation in elderly mCRPC patients

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Background: Prostate cancer is the most common cancer among adult men. Bones are the main metastatic site of prostate cancer. Radium-223 is indicated to treat metastatic castrate-resistant prostate cancer ( mCRPC) with symptomatic skeletal metastases. We evaluate the tolerability of Ra223 treatment in real life setting. Methods: We reported the cases of 38 consecutive non-selected patients with mCRPC symptomatic bone metastases treated in two Italian hospital cancer center from August 2016 to October 2017. The cause of Ra 223 treatment discontinuation in elderly prostate cancer patients were evaluated. Results: due bones metastases, 38 patients were treated with Radium-223; 20 were ≥75 years old (range 75-85 yrs). Patients characteristics and main toxicity are reported (Table). Regarding the elderly patients, hematologic toxicity were the most common adverse events reported. Anemia G2-G3 was observed in 10 pts (50%), thrombocytopoenia G3 in 2 patients (10%) and neutropenia G3 in 4 patients (20%); 12/20 patients interrupted the treatment, of which 10 were ECOG PS2. The number of patients who discontinued the drug because of hematologic adverse events was higher than ALSYMPCA clinical trial. Fatigue G1-G2 incidence was 32%. Unexpectedly we did not record any cases of gastrointestinal toxicity (diarrhea, nausea or constipation). Conclusions: In patients ≥75 years old, anemia G2-G3 was more frequent than data reported in literature, while diarrhea is not found. The data of this experience suggest that elderly vulnerable patients are more exposed to hematologic toxicity that may compromise the outcome of the treatment. For these patients surveillance for early supportive care is relevant. Characteristics of patients with ≥75y. [Table: see text]

Therapeutic Targeting of PDEs and PI3K in Heart Failure with Preserved Ejection Fraction (HFpEF)

PURPOSE OF REVIEW

Heart Failure with preserved Ejection Fraction (HFpEF) is a prevalent disease with considerable individual and societal burden. HFpEF patients often suffer from multiple pathological conditions thatcomplicate management and adversely affect outcome, including pulmonary hypertension and chronic obstructive pulmonary disease (COPD). To date, no treatment proved to be fully effective in reducing morbidity and mortality in HFpEF, possibly due to an incomplete understanding of the underlying molecular mechanisms.

RECENT FINDINGS

The emerging view proposes chronic systemic inflammation, leading to endothelial dysfunction and interstitial fibrosis, as a prominent cause of HFpEF, rather than a mere co-existent disease. In the last decade, efforts from pharmaceutical companies attempted to target pharmacologically enzymes which play key roles in systemic and lung inflammation, such as the cyclic nucleotide-degrading enzymes phosphodiesterases (PDEs) and phosphoinositide-3 phosphate kinases (PI3Ks), especially to limit COPD. In this review, we will summarize major successes and drawbacks of hitting these enzymes to tackle inflammation in HFpEF-associated co-morbidities, with a major focus on the results of completed and ongoing clinical trials. Finally, we will discuss the potential of repurposing and/or developing new PDE and PI3K inhibitors for HFpEF therapy.

The Clinical Efficacy of Radium-223 for Bone Metastasis in Patients with Castration-Resistant Prostate Cancer: An Italian Clinical Experience

BACKGROUND/AIM

Prostate cancer frequently causes bone metastases and skeletal events that impair quality of life (QoL) and survival. The alpha emitter radium-223 is a new drug that improves treatment in men with castration-resistant prostate cancer (CRPC) and bone metastases. Our aim was to evaluate the effectiveness of radium-223.

SUBJECTS AND METHODS

In this retrospective study we enrolled 48 subjects. Pain reduction, alkaline phosphatase (ALP), time to first symptomatic skeletal event, and QoL were the variables we evaluated.

RESULTS

Radium-223 was well tolerated, with a manageable toxicity profile and a modest objective response rate. A considerable difference in serum ALP levels before and after treatment was observed, with a significant correlation between pain relief and QoL, which showed a value of R2 to 0.44 with a slope of 1.50 (p = 0.0021).

CONCLUSIONS

Radium-223 showed a clinical benefit, with a reduction in pain symptoms in 58% of patients. Radium-223 was shown to be an effective and well-tolerated therapeutic option in patients with metastatic CRPC progressing after docetaxel plus prednisone treatment.

Expiratory CT scan in patients with normal inspiratory CT scan: a finding of obliterative bronchiolitis and other causes of bronchiolar obstruction

Expiratory CT scan is usually obtained as supplement to normal inspiratory CT scan to recognize air-trapping, which is expression of small airways obstruction. In some patients the air-trapping may be the only sign of an early-stage small airways disease in an otherwise normal lung. The purpose of this article is to illustrate pathologic conditions, namely obliterative bronchiolitis, in which expiratory CT scan can be abnormal despite normal inspiratory CT examination, and to highlight indications for this technique in patients with clinical and functional suspect of bronchiolar obstruction.

Expiratory CT scan in patients with normal inspiratory CT scan: a finding of obliterative bronchiolitis and other causes of bronchiolar obstruction

Expiratory CT scan is usually obtained as supplement to normal inspiratory CT scan to recognize air-trapping, which is expression of small airways obstruction. In some patients the air-trapping may be the only sign of an early-stage small airways disease in an otherwise normal lung.

The purpose of this article is to illustrate pathologic conditions, namely obliterative bronchiolitis, in which expiratory CT scan can be abnormal despite normal inspiratory CT examination, and to highlight indications for this technique in patients with clinical and functional suspect of bronchiolar obstruction.

Bone stress injuries of the leg in athletes

Bone stress injuries, whose incidence is increasing among competitive and recreational athletes, represent a pathophysiological continuum along which a bone responds to a changing mechanical environment. Frank stress fracture is the endpoint of this process, resulting from the accumulation of microinjuries due to repeated abnormal stresses. The legs are largely the most frequently affected bone district. The aim of this paper is to review the imaging findings of the whole spectrum of stress-induced bone lesions of the leg in athletes. We emphasise the role of computed tomography and magnetic resonance imaging, which allow recognition of early alterations.