Calcineurin inhibitor (CNI)-associated skin cancers: New insights on exploring mechanisms by which CNIs downregulate DNA repair machinery

Disrupting TSLP-TSLP receptor interactions via putative small molecule inhibitors yields a novel and efficient treatment option for atopic diseases

Thymic stromal lymphopoietin (TSLP) is a key player in atopic diseases, which has sparked great interest in therapeutically targeting TSLP. Yet, no small-molecule TSLP inhibitors exist due to the challenges of disrupting the protein-protein interaction between TSLP and its receptor. Here, we report the development of small-molecule TSLP receptor inhibitors using virtual screening and docking of >1,000,000 compounds followed by iterative chemical synthesis. BP79 emerged as our lead compound that effectively abrogates TSLP-triggered cytokines at low micromolar concentrations. For in-depth analysis, we developed a human atopic disease drug discovery platform using multi-organ chips. Here, topical application of BP79 onto atopic skin models that were co-cultivated with lung models and Th2 cells effectively suppressed immune cell infiltration and IL-13, IL-4, TSLP, and periostin secretion, while upregulating skin barrier proteins. RNA-Seq analysis corroborate these findings and indicate protective downstream effects on the lungs. To the best of our knowledge, this represents the first report of a potent putative small molecule TSLPR inhibitor which has the potential to expand the therapeutic and preventive options in atopic diseases.

Effect of education on sun-safe behaviour in kidney transplant recipients

BACKGROUND

Organ transplant recipients (OTR) are more likely to develop skin cancer than the general population. One of the main components of the exposome that triggers the development of skin tumours is solar ultraviolet (UV) radiation. To reduce the incidence of harmful consequences of sun exposure, sun protection education is needed for patients taking long-term immunosuppressive drugs.

METHODS

In a previous study, we assessed the sun-safe behaviour of 221 OTR using a questionnaire before and after transplantation and personally educated the patients about proper sun protection. After the education, there were no further reminder presentations. Presently, the sun protection and sun seeking habits of the available 176 of these patients were questioned to assess the long-term effect of the previous sun protection education.

RESULTS

Two-four years after the education, more patients wore hats and protected their skin with long-sleeved clothing than before the education. In terms of sun seeking habits, both occupational and recreational sun exposure decreased significantly. Significantly fewer people went on holiday after transplantation, but those who went on holiday spent significantly less time in the sun.

CONCLUSION

The long-term positive effects of education can be seen both in the patients' sun protection and in their sun seeking habits. However, the long-term goal is to maintain these results and thereby reduce the likelihood of skin tumours and consequently the associated tumour death.

Evaluating the safety profile of calcineurin inhibitors: cancer risk in patients with systemic lupus erythematosus from the LUNA registry-a historical cohort study

BACKGROUND

Previous studies have shown conflicting evidence regarding the incidence of cancer in patients with systemic lupus erythematosus (SLE) compared with that in healthy individuals. Calcineurin inhibitors (CNIs) such as cyclosporine and tacrolimus have been widely used to treat SLE; however, their effects on cancer risk remain unclear. We aimed to investigate the incidence of cancer in patients with SLE and determine the potential association between CNI use and cancer risk.

METHODS

The standardized incidence ratio (SIR) of cancer among patients with lupus in the Lupus Registry of Nationwide Institutions (LUNA) was calculated based on the age-standardized incidence rate of cancer reported by Japan's Ministry of Health, Labour and Welfare. We also examined the association between CNI exposure and cancer risk, while considering potential confounding factors. The analysis accounted for confounding variables such as age, sex, smoking history, maximum glucocorticoid dose, treatment history with cyclophosphamide, ongoing hydroxychloroquine, Systemic Lupus International Collaboration Clinics/American College of Rheumatology Damage Index (SDI) value (excluding cancer occurrence), comorbidity of diabetes mellitus, and smoking history.

RESULTS

The study included 704 patients with SLE (625 females; 88.8%) with a median age of 44 years [interquartile range (IQR) = 34-55] years. The median past maximum glucocorticoid dose was 40 mg/day [IQR = 30-60 mg/day], and the SDI at registration was 1 [IQR = 0-2]. Among the patients, 246 (35.1%) had smoking histories, and 38 (5.4%) experienced cancer complications. Gynecological malignancies accounted for 63.2% of all cancers. The SIR of cancer in the LUNA cohort was 1.08 (95% confidence interval [CI] = 0.74-1.43). No statistically significant risks of cancer were found in relation to CNI treatment history; the odds ratio using multiple logistic regression was 1.12 (95% CI = 0.42-3.00), the risk ratio using standardization was 1.18 (95% CI = 0.47-2.16), and the risk ratio using inverse probability weighting was 1.8 (95% CI = 0.41-4.66).

CONCLUSIONS

The incidence of cancer in patients with SLE in the LUNA cohort did not significantly differ from that in the general population. These findings suggest that CNI treatment in this cohort did not pose a risk factor for cancer development.

Tacrolimus monitoring in hair samples of kidney transplant recipients

Background

Calcineurin inhibitors, including tacrolimus, remain a cornerstone of immunosuppressive therapy after kidney transplantation. However, the therapeutic window is narrow, and nephrotoxic side effects occur with overdose, while the risk of alloimmunization and graft rejection increases with underdose. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) allows quantification of tacrolimus in biological samples from patients. This study investigates the feasibility of quantifying tacrolimus in scalp hair from kidney transplant (KT) recipients and correlates hair tacrolimus concentrations with tacrolimus dosage and blood trough levels. The aim was to provide proof-of-principle for hair tacrolimus drug monitoring in KT recipients.

Method

Single-center prospective study between September 9, 2021 and December 4, 2021, including KT recipients under tacrolimus. Minors, patients with active skin or hair diseases, and patients with scalp hair shorter than 4 cm were excluded from participation. Scalp hair was collected from the posterior vertex of patients, cut into segments, and analyzed for tacrolimus by LC-MS/MS. Patients filled out a questionnaire on hair treatments and washing habits. In parallel, tacrolimus trough levels were measured in whole blood and correlated with hair tacrolimus concentrations.

Results

In total, 39 consenting KT recipients were included, and hair samples were collected at 53 visits. Tacrolimus was detected in 98% of hair samples from patients exposed to the drug. Tacrolimus hair levels and whole blood trough levels were correlated with a beta coefficient of 0.42 (95% CI: -0.22-1.1, p = n.s.). Age and dark hair affected hair tacrolimus measurements, while different tacrolimus formulations (immediate release vs. extended release), hair washes, and permanent coloring did not. Longitudinal measurements in a subgroup of patients indicate that long-term measurement of hair tacrolimus levels is feasible.

Conclusion

Measuring tacrolimus in hair is a potentially reliable method to monitor drug exposure in KT patients. Rapid wash-in effects and consistent concentrations over time indicate that tacrolimus is incorporated into the hair matrix, allowing temporal resolution in the analysis of recent exposure and exposure history. This method provides a simple and low-risk alternative to regular blood sampling, sparing patients from frequent hospital visits through the self-collection of hair samples.

Contemporary review of heart transplant immunology and immunosuppressive therapy

Background

Survival after heart transplantation (HT) has improved considerably since the first HT was performed in 1967 in Cape Town, South Africa. Understanding immunology behind organ rejection has paved way for advances in the assessment of pre-transplant compatibility, development of newer and more specific immunosuppressive drugs, and management of rejection.

Objectives

Unlike medical therapy for heart failure, transplant protocols vary considerably between different centers. These variations in protocols generally reflect unique population characteristics and the availability of resources. This review article aims to provide a consolidated update on contemporary cardiac transplant medicine. We also aim to highlight local practice and its difference from our international counterparts.

Methods

A literature search was performed on Pubmed and Cochrane Central Register of Controlled Trials to identify trials and review articles that discussed heart transplant immunology and protocols. The International Society for Heart and Lung Transplant (ISHLT) guidelines were also reviewed. We focused on risk factors, prevention strategies, and treatment of cardiac rejection.

Results

A total of 48 articles were selected to provide a comprehensive overview of the contemporary practice of cardiac transplant immunosuppressive therapy. Comparisons were made with local data and practice protocols to highlight key differences.

Conclusion

Heart transplant covers a small subset of cardiac patients and much of the evidence is derived from empirical observations and retrospective analysis. This accounts for the heterogeneity in care and treatment protocols. More studies are needed to select best practices from around the world to further improve outcomes.

Post-transplant Malignancies Show Reduced T-cell Abundance and Tertiary Lymphoid Structures as Correlates of Impaired Cancer Immunosurveillance

PURPOSE

An increased risk to develop cancer is one of the most challenging negative side effects of long-term immunosuppression in organ transplant recipients and impaired cancer immunosurveillance is assumed as underlying mechanism. This study aims to elucidate transplant-related changes in the tumor immune microenvironment (TME) of cancer.

EXPERIMENTAL DESIGN

Data from 123 organ transplant recipients (kidney, heart, lung, and liver) were compared with historic data from non-immunosuppressed patients. Digital image analysis of whole-section slides was used to assess abundance and spatial distribution of T cells and tertiary lymphoid structures (TLS) in the TME of 117 tumor samples. Expression of programmed cell death 1 ligand 1 (PD-L1) and human-leucocyte-antigen class I (HLA-I) was assessed on tissue microarrays.

RESULTS

We found a remarkably reduced immune infiltrate in the center tumor (CT) regions as well as the invasive margins (IM) of post-transplant cancers. These differences were more pronounced in the IM than in the CT and larger for CD8+ T cells than for CD3+ T cells. The Immune-score integrating results from CT and IM was also lower in transplant recipients. Density of TLS was lower in cancer samples of transplant recipients. The fraction of samples with PD-L1 expression was higher in controls whereas decreased expression of HLA-I was more common in transplant recipients.

CONCLUSIONS

Our study demonstrates the impact of immunosuppression on the TME and supports impaired cancer immunosurveillance as important cause of post-transplant cancer. Modern immunosuppressive protocols and cancer therapies should consider the distinct immune microenvironment of post-transplant malignancies.

Outcomes of Primary Mucosal Head and Neck Squamous Cell Carcinoma in Solid Organ Transplant Recipients

Introduction Patients who undergo solid organ transplants have a higher risk of developing malignancies and subsequent recurrences. Clinical outcomes in transplant recipients with primary mucosal head and neck squamous cell carcinoma (HNSCC) are not well described in the published literature. Therefore, we retrospectively studied the outcomes in this group of patients.  Methods This Institutional Review Board (IRB)-approved analysis included patients who had previously undergone solid organ transplants and subsequently were diagnosed with primary mucosal HNSCC between 2006 and 2021. Our institutional database of solid organ transplant recipients was cross-referenced with our head and neck cancer database to identify the patients included in this cohort. In addition, Kaplan-Meier analyses were performed to calculate overall and disease-free survival. Results Of 1,221 patients, 20 met the inclusion criteria. The median time from organ transplant to HNSCC diagnosis was 5.9 years (range: 0.5-18.5 years). A total of 11 (55.0%) and 9 (45.0%) patients presented with localized and locally advanced disease, respectively. Two-year overall and disease-free survivals were 59.1% and 73.5%, respectively. After initial treatment, six (30.0%) patients experienced a recurrence. All patients who developed a recurrence died within the follow-up period. The median time of death after recurrence for all six patients was 11.5 months (range: 2-22 months).  Conclusion This series highlights a high mortality rate following recurrence among patients with primary mucosal HNSCC and a solid organ transplant history. A better understanding of how solid organ transplant history adversely impacts the course of HNSCC could help properly guide treatment, follow-up, and survivorship decisions.

Calcineurin inactivation inhibits pyruvate dehydrogenase complex activity and induces the Warburg effect

Calcineurin is a calcium- and calmodulin-dependent serine/threonine protein phosphatase that connects the Ca2+-dependent signalling to multiple cellular responses. Calcineurin inhibitors (CNIs) have been widely used to suppress immune response in allograft patients. However, CNIs significantly increase cancer incidence in transplant recipients compared with the general population. Accumulating evidence suggests that CNIs may promote the malignant transformation of cancer cells in addition to its role in immunosuppression, but the underlying mechanisms remain poorly understood. Here, we show that calcineurin interacts with pyruvate dehydrogenase complex (PDC), a mitochondrial gatekeeper enzyme that connects two key metabolic pathways of cells, glycolysis and the tricarboxylic acid cycle. Mitochondrial-localized calcineurin dephosphorylates PDHA1 at Ser232, Ser293 and Ser300, and thus enhances PDC enzymatic activity, remodels cellular glycolysis and oxidative phosphorylation, and suppresses cancer cell proliferation. Hypoxia attenuates mitochondrial translocation of calcineurin to promote PDC inactivation. Moreover, CNIs promote metabolic remodelling and the Warburg effect by blocking calcineurin-mediated PDC activation in cancer cells. Our findings indicate that calcineurin is a critical regulator of mitochondrial metabolism and suggest that CNIs may promote tumorigenesis through inhibition of the calcineurin-PDC pathway.

Targeting T-type channels in cancer: What is on and what is off?

Over the past 20 years, various studies have demonstrated a pivotal role of T-type calcium channels (TTCCs) in tumor progression. Cytotoxic effects of TTCC pharmacological blockers have been reported in vitro and in preclinical models. However, their roles in cancer physiology are only beginning to be understood. In this review, we discuss evidence for the signaling pathways and cellular processes stemming from TTCC activity, mainly inferred by inverse reasoning from pharmacological blocks and, only in a few studies, by gene silencing or channel activation. A thorough analysis indicates that drug-induced cytotoxicity is partially an off-target effect. Dissection of on/off-target activity is paramount to elucidate the physiological roles of TTCCs, and to deliver efficacious therapies suited to different cancer types and stages.

Oh, the Mutations You'll Acquire! A Systematic Overview of Cutaneous Squamous Cell Carcinoma

Nearly two million cases of cutaneous squamous cell carcinoma (cSCC) are diagnosed every year in the United States alone. cSCC is notable for both its prevalence and its propensity for invasion and metastasis. For many patients, surgery is curative. However, patients experiencing immunosuppression or recurrent, advanced, and metastatic disease still face limited therapeutic options and significant mortality. cSCC forms after decades of sun exposure and possesses the highest known mutation rate of all cancers. This mutational burden complicates efforts to identify the primary factors driving cSCC initiation and progression, which in turn hinders the development of targeted therapeutics. In this review, we summarize the mutations and alterations that have been observed in patients’ cSCC tumors, affecting signaling pathways, transcriptional regulators, and the microenvironment. We also highlight novel therapeutic opportunities in development and clinical trials.

Calcineurin A-α suppression drives nuclear factor-κB-mediated NADPH oxidase-2 upregulation

Calcineurin inhibitors (CNIs) are vital immunosuppressive therapies in the management of inflammatory conditions. A long-term consequence is nephrotoxicity. In the kidneys, the primary, catalytic calcineurin (CnA) isoforms are CnAα and CnAβ. Although the renal phenotype of CnAα-/- mice substantially mirrors CNI-induced nephrotoxicity, the mechanisms downstream of CnAα are poorly understood. Since NADPH oxidase-2 (Nox2)-derived oxidative damage has been implicated in CNI-induced nephrotoxicity, we hypothesized that CnAα inhibition drives Nox2 upregulation and promotes oxidative stress. To test the hypothesis, Nox2 regulation was investigated in kidneys from CnAα-/-, CnAβ-/-, and wild-type (WT) littermate mice. To identify the downstream mediator of CnAα, nuclear factor of activated T cells (NFAT) and NF-κB regulation was examined. To test if Nox2 is transcriptionally regulated via a NF-κB pathway, CnAα-/- and WT renal fibroblasts were treated with the NF-κB inhibitor caffeic acid phenethyl ester. Our findings showed that cyclosporine A treatment induced Nox2 upregulation and oxidative stress. Furthermore, Nox2 upregulation and elevated ROS generation occurred only in CnAα-/- mice. In these mice, NF-κB but not NFAT activity was increased. In CnAα-/- renal fibroblasts, NF-κB inhibition prevented Nox2 upregulation and reactive oxygen species (ROS) generation. In conclusion, these findings indicate that 1) CnAα loss stimulates Nox2 upregulation, 2) NF-κB is a novel CnAα-regulated transcription factor, and 3) NF-κB mediates CnAα-induced Nox2 and ROS regulation. Our results demonstrate that CnAα plays a key role in Nox2 and ROS generation. Furthermore, these novel findings provide evidence of divergent CnA isoform signaling pathways. Finally, this study advocates for CnAα-sparing CNIs, ultimately circumventing the CNI nephrotoxicity.NEW & NOTEWORTHY A long-term consequence of calcineurin inhibitors (CNIs) is oxidative damage and nephrotoxicity. This study indicates that NF-κB is a novel calcineurin-regulated transcription factor that is activated with calcineurin inhibition, thereby driving oxidative damage in CNI nephropathy. These findings provide additional evidence of divergent calcineurin signaling pathways and suggest that selective CNIs could improve the long-term outcomes of patients by mitigating renal side effects.