GLI1/GLI2 functional interplay is required to control Hedgehog/GLI targets gene expression.

The Hedgehog-regulated transcription factors GLI1 and GLI2 play overlapping roles in development and disease; however, the mechanisms underlying their interplay remain elusive. We report for the first time that GLI1 and GLI2 physically and functionally interact in cancer cells. GLI1 and GLI2 were shown to co-immunoprecipitate in PANC1 pancreatic cancer cells and RMS13 rhabdomyosarcoma cells. Mapping analysis demonstrated that the zinc finger domains of both proteins are required for their heteromerization. RNAi knockdown of either GLI1 or GLI2 inhibited expression of many well-characterized GLI target genes (BCL2, MYCN, PTCH2, IL7 and CCND1) in PANC1 cells, whereas PTCH1 expression was only inhibited by GLI1 depletion. qPCR screening of a large set of putative canonical and non-canonical Hedgehog/GLI targets identified further genes (e.g. E2F1, BMP1, CDK2) strongly down-regulated by GLI1 and/or GLI2 depletion in PANC1 cells, and demonstrated that ANO1, AQP1 and SOCS1 are up-regulated by knockdown of either GLI1 or GLI2. Chromatin immunoprecipitation showed that GLI1 and GLI2 occupied the same regions at the BCL2, MYCN and CCND1 promoters. Furthermore, depletion of GLI1 inhibited GLI2 occupancy at these promoters, suggesting that GLI1/GLI2 interaction is required for the recruitment of GLI2 to these sites. Together, these findings indicate that GLI1 and GLI2 co-ordinately regulate the transcription of some genes, and provide mechanistic insight into the roles of GLI proteins in carcinogenesis.

Ethnic/racial differences in risk factors and clinical outcomes among patients with amyloidosis.

BACKGROUND: Cardiac amyloidosis is caused by abnormal extracellular deposition of insoluble fibrils in cardiac tissue. It can be fatal when untreated and is often underdiagnosed. Understanding the ethnic/racial differences in risk factors is critical for early diagnosis and treatment to improve clinical outcomes. METHODS: We performed a retrospective cross-sectional study utilizing the National Inpatient Sample database from 2015 to 2018 using ICD-10-CM codes. The primary variables of interest were race/ethnicity and amyloidosis subtypes, while the primary outcomes were in-hospital mortality, gastrointestinal bleeding, renal failure, and hospital length-of-stay. RESULTS: Amyloidosis was reported in 0.17% of all hospitalizations (N  =  19,678,415). Of these, 0.09% were non-Hispanic whites, 0.04% were non-Hispanic blacks, and 0.02% were Hispanic. Hospitalizations with ATTR amyloidosis subtype were frequently observed in older individuals and males with coronary artery disease, whereas AL amyloidosis subtype was associated with non-Hispanic whites, congestive heart failure, and longer hospital length of stay. Renal failure was associated with non-Hispanic blacks (adjusted relative risk [RR]  =  1.31, p < 0.001), Hispanics (RR  =  1.08, p  =  0.028) and had an increased risk of mortality. Similarly, the hospital length of stay was longer with non-Hispanic blacks (RR  =  1.19, p < 0.001) and Hispanics (RR  =  1.05, p  =  0.03) compared to non-Hispanic whites. Hispanics had a reduced risk of mortality (RR  =  0.77, p  =  0.028) compared to non-Hispanic whites and non-Hispanic blacks, and no significant difference in mortality was seen between non-Hispanic whites and non-Hispanic blacks (RR  =  1.00, p  =  0.963). CONCLUSIONS: Our findings highlight significant ethnic/racial differences in risk factors and outcomes among amyloidosis-related US hospitalizations that can possibly be used for early detection, treatment, and better clinical outcomes.