Expression of IL-37 Correlates With Immune Cell Infiltrate and Fibrosis in Pediatric Autoimmune Liver Diseases.

OBJECTIVES: The activation of innate immune mechanisms is key for chronic liver injury. Interleukin-37 (IL-37) is a profound inhibitor of innate and adaptive immune responses, and its overexpression protects mice from liver inflammation and fibrosis. Here, we characterize the hepatic inflammatory infiltrate and expression of IL-37 in children with autoimmune liver diseases. METHODS: We compared the inflammatory microenvironment of the liver in a retrospective cohort of children with primary sclerosing cholangitis (PSC), autoimmune sclerosing cholangitis (ASC) and autoimmune hepatitis (AIH) by immunohistochemistry. The expression of IL-37 was quantified in liver parenchyma and portal tracts. Double immunofluorescence was used for detection of IL-37 in specific cell types and colocalization with Smad3. RESULTS: AIH is characterized by a dense lymphoplasmacytic infiltrate whereas ASC shows high numbers of granulocytes in portal tracts. IL-37 expression correlates positively with liver inflammation and fibrosis, the number of infiltrating immune cells and serum markers for hepatic inflammation. IL-37 is mainly expressed in hepatocytes, cholangiocytes and infiltrating immune cells. Double staining revealed IL-37 positivity in T helper and regulatory T cells (Treg), Kupffer (KC) and hepatic stellate cells (HSC). IL-37 colocalizes with intranuclear pSmad3L in areas of liver inflammation. CONCLUSIONS: Pediatric ASC separates from PSC and AIH by a granulocyte-rich portal infiltrate. Upregulation of IL-37 with liver injury, the expression in Treg as well as KC and HSC and the colocalization of IL-37 with pSmad3L in cholangiocytes and hepatocytes suggest a modulating role to limit hepatic inflammation and fibrosis in pediatric autoimmune liver diseases.

Clinical Evidence on the Interaction Between MLK4, KRAS and Microsatellite Instability to Determine the Prognosis of Early-Stage Colorectal Carcinoma.

BACKGROUND/AIMS: MLK4 (KIAA1804) is the second most frequently mutated kinase in microsatellite stable (MSS) colorectal carcinomas (CRC). This molecule is known to regulate different physiological cellular processes, including cell cycle, senescence and apoptosis, and mechanistic evidence has been provided that MLK4 plays a role in carcinogenesis. However, whether this kinase exerts a tumor suppressive role or an oncogenic function is still an object of debate. This study aims to elucidate the role of MLK4 in the pathogenesis of CRC by investigating human tumor specimens. METHODS: This study assessed MLK4 expression levels by immunohistochemistry in surgical tumor samples from 204 early-stage CRC patients and their correlation with various clinical-pathological features and patients' outcomes. In addition, MLK4 mRNA transcription was analysed in an independent cohort of 786 colon cancer samples. RESULTS: Loss of MLK4 staining was associated with poor overall (OS) and progression free survival (PFS) in CRC patients during a univariate analysis (OS:101 vs 164 months, p=0.0002; PFS:85 vs 125 months, p=0.0001), as well as in multivariate analysis (OS:HR=1.70; p=0.001; PFS:HR=1,61; p=0.001). This was confirmed by analysis of MLK4 mRNA in the second independent cohort. A subgroup analysis according to KRAS mutation status showed that MLK4 staining was associated with better OS and PFS in KRAS mutated cases (HR=2.77; p=0.0001 and HR=2.31; p=0.0003, respectively) and microsatellite stable tumors (HR=1.87; p=0.002 and HR=1.06; p=0.006) but not in KRAS wildtype and microsatellite unstable tumors. CONCLUSION: By providing the first report from clinical specimens on the prognostic significance of MLK4, we define an oncogenic loss-of-function of this kinase and suggest a possible role in the interaction with KRAS signaling in determining an aggressive phenotype of CRC. These findings warrant the further investigation of MLK4 in wider cohorts and various clinical settings.

Single-cell transcriptomic atlas-guided development of CAR-T cells for the treatment of acute myeloid leukemia.

Chimeric antigen receptor T cells (CAR-T cells) have emerged as a powerful treatment option for individuals with B cell malignancies but have yet to achieve success in treating acute myeloid leukemia (AML) due to a lack of safe targets. Here we leveraged an atlas of publicly available RNA-sequencing data of over 500,000 single cells from 15 individuals with AML and tissue from 9 healthy individuals for prediction of target antigens that are expressed on malignant cells but lacking on healthy cells, including T cells. Aided by this high-resolution, single-cell expression approach, we computationally identify colony-stimulating factor 1 receptor and cluster of differentiation 86 as targets for CAR-T cell therapy in AML. Functional validation of these established CAR-T cells shows robust in vitro and in vivo efficacy in cell line- and human-derived AML models with minimal off-target toxicity toward relevant healthy human tissues. This provides a strong rationale for further clinical development.

Expression of Nectin-4 in Variant Histologies of Bladder Cancer and Its Prognostic Value-Need for Biomarker Testing in High-Risk Patients?

Variant histologies of bladder cancer (BC) often present with advanced tumor stage and the status of perioperative therapy is unclear. Thereby, squamous cell carcinoma (SCC), adenocarcinoma (ADENO), and sarcomatoid urothelial carcinoma (SARCO) are the most frequent variants. Nectin-4 has emerged as a highly interesting target in BC and might guide therapeutic application of antibody−drug conjugates (ADC). We therefore aimed to investigate expression patterns and prognostic value of Nectin-4 in variant histologies of BC. A single-center retrospective analysis was conducted of patients who underwent radical cystectomy (RC) for BC and revealed variant histologies of BC in the final specimens. Immunohistochemical staining for Nectin-4 was performed on tissue microarrays with 59 SCC, 22 ADENO, and 24 SARCO, and Nectin-4 expression was scored using the histochemical scoring system (H-score). Overall survival (OS) and progression-free survival (PFS) was calculated by Kaplan−Meier method. Median expression of Nectin-4 was 150 (range 0−250) in SCC, 140.5 (range 30−275) in ADENO, and 10 (0−185) in SARCO, with significantly lower levels for SARCO compared to SCC or ADENO (p < 0.001). For SCC, ADENO or SARCO no differences regarding OS or PFS were observed based on Nectin-4 expression levels (p > 0.05). Multivariate analysis revealed nodal stage as an independent prognostic factor for OS and PFS and metastases for PFS but not Nectin-4 expression. In conclusion, Nectin-4 was not prognostic in histological subtypes of BC in our study cohort. However, the high expression of Nectin-4 in SCC and ADENO might guide future treatment with novel Nectin-4-directed ADCs and provide this high-risk patient collective with a new promising therapeutic option. Testing Nectin-4 expression as a biomarker should be considered in trials with SARCO, where low Nectin-4 expression has been observed.

Targeting c-MYC through Interference with NAMPT and SIRT1 and Their Association to Oncogenic Drivers in Murine Serrated Intestinal Tumorigenesis.

We recently described a positive feedback loop connecting c-MYC, NAMPT, DBC1 and SIRT1 that contributes to unrestricted cancer cell proliferation. Here we determine the relevance of the loop for serrated route intestinal tumorigenesis using genetically well-defined BrafV600E and K-rasG12D mouse models. In both models we show that c-MYC and SIRT1 protein expression increased through progression from hyperplasia to invasive carcinomas and metastases. It correlated with high NAMPT expression and was directly associated to activation of the oncogenic drivers. Assessing functional and molecular consequences of pharmacological interference with factors of the loop, we found that inhibition of NAMPT resulted in apoptosis and reduced clonogenic growth in human BRAF-mutant colorectal cancer cell lines and patient-derived tumoroids. Blocking SIRT1 activity was only effective when combined with a PI3K inhibitor, whereas the latter antagonized the effects of NAMPT inhibition. Interfering with the positive feedback loop was associated with down-regulation of c-MYC and temporary de-repression of TP53, explaining the anti-proliferative and pro-apoptotic effects. In conclusion we show that the c-MYC-NAMPT-DBC1-SIRT1 positive feedback loop contributes to murine serrated tumor progression. Targeting the feedback loop exerted a unique, dual therapeutic effect of oncoprotein inhibition and tumor suppressor activation. It may therefore represent a promissing target for serrated colorectal cancer, and presumably for other cancer types with deregulated c-MYC.

The c-MYC/NAMPT/SIRT1 feedback loop is activated in early classical and serrated route colorectal cancer and represents a therapeutic target.

We have recently identified a positive feedback loop in which c-MYC increases silent information regulator 1 (SIRT1) protein level and activity through transcriptional activation of nicotinamide phosphoribosyltransferase (NAMPT) and NAD+ increase. Here, we determined the relevance of the c-MYC-NAMPT-SIRT1 feedback loop, including the SIRT1 inhibitor deleted in breast cancer 1 (DBC1), for the development of conventional and serrated colorectal adenomas. Immunohistochemical analyses of 104 conventional adenomas with low- and high-grade dysplasia and of 157 serrated lesions revealed that elevated expression of c-MYC, NAMPT, and SIRT1 characterized all conventional and serrated adenomas, whereas DBC1 was not differentially regulated. Analyzing publicly available pharmacogenomic databases from 43 colorectal cancer cell lines demonstrated that responsiveness towards a NAMPT inhibitor was significantly associated with alterations in PTEN and TGFBR2, while features such as BRAF or RNF43 alterations, or microsatellite instability typical for serrated route colorectal cancer, showed increased sensitivities for inhibition of NAMPT and SIRT1. Our findings suggest an activation of the c-MYC-NAMPT-SIRT1 feedback loop that may crucially contribute to initiation and development of both routes to colorectal cancer. Targeting of NAMPT or SIRT1 may represent novel therapeutic strategies with putative higher sensitivity of the serrated route colorectal cancer subtype.

Preinvasive intraductal neoplasia in salivary adenocarcinoma, not otherwise specified.

Preinvasive intraductal neoplasia of the salivary glands has only been identified in the rare salivary-duct carcinoma, whereas, it is an established feature of carcinomas of other glands. A fortuitous observation of what appeared to be intraductal tumor in a salivary adenocarcinoma, not otherwise specified, led to the present investigation to determine whether intraductal neoplasia is a significant feature of this carcinoma. Intraductal tumor confined by normal CK14-positive, actin-negative ductal basal cells was identified in 15 of 22 cases (68%). The degree of cellular atypia and the pattern of growth of intraductal tumor was similar to that of the invasive tumor. Cases with intraductal tumor devoid of invasive tumor were not found. Intraductal tumor is identified as the pre-invasive precursor of adenocarcinoma, not otherwise specified, and apparently develops in excretory ducts. The findings support the possibility that different salivary tumors arise from different types of parenchymal cell. Possibly intraductal neoplasia is a universal feature of many types of salivary tumor, but has been overlooked because of the need to use immunohistology to demonstrate it and because it may no longer be present as such when the tumor presents as a clinical lesion.

Regeneration in chronic sialadenitis: an analysis of proliferation and apoptosis based on double immunohistochemical labelling.

The understanding of regeneration in salivary glands as a finely tuned balance of cellular proliferation, differentiation and apoptosis has been limited by the difficulty of identifying proliferating cells. This has been overcome in the present investigation by double immunohistochemical labelling for the proliferation-associated antigen Ki67 and for different cell-type-specific antigens applied to 8 specimens of normal parotids and 16 specimens of chronic parotid sialadenitis with particular reference to acini and intercalated ducts. In comparison with low baseline rates of proliferation in normal parotids, proliferative indices were significantly increased in chronic sialadenitis in mature acinar cells, intercalated ductal cells and myoepithelial cells without evidence of proliferation by an additional population of cells. In accordance with findings in glands of experimental animals, the present data do not support the previously postulated concept of regeneration of acini and intercalated ducts by a hypothetical population of uncommitted ductal stem cells. The demonstration of a profound capacity for intrinsic glandular regeneration from differentiated cells represents a biological basis for the good results obtained from conservative therapy of chronic sialadenitis and offers hope for novel therapies designed to reconstitute impaired salivary flow.

A morphogenetic concept of salivary duct regeneration and metaplasia.

The exact mechanisms of physiological regeneration and of metaplastic processes of the salivary duct have not been definitely established, although regeneration from a putative uncommitted stem cell population has long been favored. In the present study, double immunohistochemical labeling for Ki 67 and alpha-actin or different cytokeratin subtypes, respectively, made possible an exact localization and quantification of cellular proliferation in the regular salivary duct and in different types of metaplasia. Our data demonstrate a baseline proliferative capacity in all five cell types of the salivary duct. Luminal secretory cells of the acinus and intercalated duct regenerate independently from myoepithelial or basal cells. In contrast, the renewal of oxyphilic cells in the striated and excretory duct is maintained by proliferation and differentiation of basal cells. The great majority of metaplasias develops from uncommitted, Bcl-2 positive basal cells of striated/excretory ducts which possess an enormous capacity for pluridirectional morphogenetic differentiation. Despite this important role of basal cells, our findings demonstrate that all cell types principally have to be considered as potential progenitor cells for salivary gland tumors. The improved insight into regenerative and metaplastic processes of the salivary duct may contribute to a better understanding of the complex formal carcinogenesis.

Differential diagnosis of salivary acinic cell carcinoma and adenocarcinoma (NOS). A comparison of (immuno-)histochemical markers.

A correct histologic differential diagnosis between salivary acinic cell carcinoma (ACC) and adenocarcinoma not otherwise specified (AC-NOS) is highly relevant because of the strikingly different biologic behavior and related therapeutical strategies. The distinction between both tumor types can be difficult because of an enormous variation in histologic appearance, with either type showing partially overlapping morphologic features. Owing to a lack of approved markers, the expression of PAS-staining, alpha-Amylase, alpha-1 Anti-trypsin, cytokeratin (CK)-subtypes 7/18 and Ki-67 was evaluated in 16 cases of ACC and 16 cases of AC-NOS. CK 7 is identified as the most reliable marker with strong positivity in AC-NOS, and complete or preponderant negativity in ACC. The characteristic membranous staining pattern of CK 18 in ACC, in contrast to a diffuse cytoplasmic pattern in AC-NOS, proved to be an additional valuable criterion. PAS and alpha-Amylase are only of little value when ACC is diagnosed, as many cases are only faintly positive or completely negative. The proliferation index (Ki-67) proved to be significantly higher in AC-NOS; however, the diagnostic usefulness is limited by a relevant overlap. In conclusion, we recommend CK 7 and 18 as the most valuable markers in cases with difficult differential diagnosis between ACC and AC-NOS.

EGFR, HER-2/neu, cyclin D1, p21 and p53 in correlation to cell proliferation and steroid hormone receptor status in ductal carcinoma in situ of the breast.

Abnormalities in G1/S transition in cell cultures have been attributed to alterations in ErbB (erythroblastic leukaemia viral [v-erb-b] oncogene homologue, avian) signalling, cyclin D1 overexpression or disturbance of the p21(WAF1) (p21)-mediated cell cycle arrest induced by p53. To investigate the significance of these mechanisms on an early stage of human breast tumour growth, we studied the expression of EGFR (ErbB1), HER-2/neu (ErbB2), cyclin D1, p21 and p53 as well as oestrogen (ER) and progesterone receptor (PgR) in paraffin sections of 45 ductal carcinoma in situ (DCIS) by immunohistochemistry. Cell proliferation was assessed by immunohistochemical quantification of Ki-67. Five cases with cyclin D1 overexpression were analysed by FISH for CCND1 amplification. Increased proliferative activity was observed in 46% of DCIS. It was correlated with the expression of EGFR and HER-2/neu (p < 0.05), but neither with cyclin D1 and p21 overexpression nor with p53 accumulation. ErbB positive status was associated with p21 overexpression (p < 0.05). In addition we found a correlation between the overexpression of p21 and cyclin D1 restricted to ErbB-positive cases (p = 0.013). ErbB-negative tumours with increased proliferative activity were ER and cyclin D1 positive. No CCND1 amplification was detected in the analysed cases. In conclusion, our data support that EGFR and HER-2/neu play an important role in cell cycle control in DCIS. p21 appears to be a potential mediator of ErbB signalling. We propose that cyclin D1 could be indirectly induced by ErbB signalling through p21. Besides, ER-mediated upregulation of cyclin D1 seems to be a possible mechanism of maintaining cell proliferation in DCIS in case of EGFR- and HER-2/neu-negativity.