Management of transthyretin amyloidosis

Transthyretin amyloidosis (ATTR amyloidosis) is a disease caused by deposition of transthyretin fibrils in organs and tissues, which causes their dysfunction. The clinical heterogeneity of ATTR amyloidosis and the variable presentation of symptoms at early disease stages, historically meant treatment delays. Diagnostic tools and therapy options of ATTR amyloidosis have markedly improved in recent years. The first Swiss Amyloidosis Network (SAN) meeting (Zurich, Switzerland, January 2020) aimed to define a consensus statement regarding the diagnostic work-up and treatment for systemic amyloidosis, tailored to the Swiss healthcare system. A consortium of 45 clinicians and researchers from all Swiss regions and universities was selected by the SAN committee to represent all sub-specialty groups involved in care of patients with amyloidosis. A steering committee conducted the literature search and analysis, wrote the critical synthesis and elaborated a list of statements that were evaluated by all the participants. These recommendations will improve outcomes and quality of life for patients with ATTR amyloidosis. A global review of these guidelines is planned every 3 years with a formal meeting of all the involved experts.

Expert recommendation from the Swiss Amyloidosis Network (SAN) for systemic AL-amyloidosis

Systemic amyloidosis is a heterogeneous group of diseases associated with protein misfolding into insoluble beta-sheet rich structures that deposit extracellularly in different organs, eventually compromising their function. There are more than 30 different proteins, known to be amyloidogenic with “light chain” (AL)-amyloidosis being the most common type, followed by transthyretin (ATTR)-, and amyloid protein A (AA)-amyloidosis. Systemic amyloidosis is a rare disease with an incidence of around 10 patients in 1 million inhabitants. Recently several new therapeutic options have been developed for subgroups of amyloidosis patients, and the introduction of novel therapies for plasma cell myeloma has led to an increase in the therapeutic armamentarium for plasma cell disorders, including AL amyloidosis. Among them, proteasome inhibitors, immunomodulatory agents (-imids), and monoclonal antibodies have been successfully introduced into clinical practice. Still, high-quality data from randomised controlled trials regarding the benefit of these cost-intensive drugs in AL amyloidosis are widely lacking, and due to the rarity of the disease many physicians will not gain routine experience in the management of these frail patients. The diagnosis of AL amyloidosis relies on a close collaboration between clinicians, pathologists, imaging experts, and sometimes geneticists. Diagnosis and treatment options in this complex disorder should be discussed in dedicated multidisciplinary boards. In January 2020, the first meeting of the Swiss Amyloidosis Network took place in Zurich, Switzerland. One aim of this meeting was to establish a consensus guideline regarding the diagnostic work-up and the treatment recommendations for systemic amyloidosis tailored to the Swiss health care system. Forty-five participants from different fields in medicine discussed many aspects of amyloidosis. These are the Swiss Amyloidosis Network recommendations which focus on diagnostic work-up and treatment of AL-amyloidosis.

CYFIP1 is directly controlled by NOTCH1 and down-regulated in cutaneous squamous cell carcinoma

Squamous cell carcinoma of the skin (SCC) represents one of the most common cancers in the general population and is associated with a substantial risk of metastasis. Previous work uncovered the functional role of CYFIP1 in epithelial tumors as an invasion inhibitor. It was down-regulated in some cancers and correlated with the metastatic properties of these malignant cells. We investigated its role and expression mechanisms in SCC. We analyzed the expression of CYFIP1 in patient derived SCC, primary keratinocytes and SCC cell lines, and correlated it to the differentiation and NOTCH1 levels. We analyzed the effects of Notch1 manipulation on CYFIP1 expression and confirmed the biding of Notch1 to the CYFIP1 promoter. CYFIP1 expression was down-regulated in SCC and correlated inversely with histological differentiation of tumors. As keratinocyte differentiation depends on Notch1 signaling, we investigated the influence of Notch1 on CYFIP1 expression. CYFIP1 mRNA was highly increased in human Notch1-overexpressing keratinocytes. Further manipulation of the Notch1 pathway in keratinocytes impacted CYFIP1 levels and chromatin immunoprecipitation assay confirmed the direct binding of Notch1 to the CYFIP1 promoter. CYFIP1 may be a link between loss of differentiation and invasive potential in malignant keratinocytes of cutaneous squamous cell carcinoma.

The oncogene ATF3 is potentiated by cyclosporine A and ultraviolet light A

Cutaneous squamous cell carcinoma (SCC) represents the most important cutaneous complication following organ transplantation. It develops mostly on sun-exposed areas. A recent study showed the role of activating transcription factor 3 (ATF3) in SCC development following treatment with calcineurin inhibitors. It has been reported that ATF3, which may act as an oncogene, is under negative calcineurin/nuclear factor of activated T cells (NFAT) control and is upregulated by calcineurin inhibitors. Still, these findings do not fully explain the preferential appearance of SCC on chronically sun-damaged skin. We analyzed the influence of UV radiation on ATF3 expression and its potential role in SCC development. We found that ATF3 is a specifically induced AP1 member in SCC of transplanted patients. Its expression was strongly potentiated by combination of cyclosporine A and UVA treatment. UVA induced ATF3 expression through reactive oxygen species-mediated nuclear factor erythroid 2-related factor 2 (NRF2) activation independently of calcineurin/NFAT inhibition. Activated NRF2 directly binds to ATF3 promoter, thus inducing its expression. These results demonstrate two mechanisms that independently induce and, when combined together, potentiate the expression of ATF3, which may then force SCC development. Taking into account the previously defined role of ATF3 in the SCC development, these findings may provide an explanation and a mechanism for the frequently observed burden on SCCs on sun-exposed areas of the skin in organ transplant recipients treated by calcineurin inhibitors.