Krüppel-like factor 7 influences translation and pathways involved in ribosomal biogenesis in breast cancer.

BACKGROUND: Ribosomal biogenesis and ribosomal proteins have attracted attention in the context of tumor biology in recent years. Instead of being mere translational machineries, ribosomes might play an active role in tumor initiation and progression. Despite its importance, regulation of ribosomal biogenesis is still not completely understood. METHODS: Using Gene Set Enrichment Analysis of RNA sequencing and proteomical mass spectrometry data in breast cancer cells expressing Krüppel-like factor 7 (KLF7), we identified processes altered by this transcription factor. In silico analyses of a cohort of breast cancer patients in The Cancer Genome Atlas confirmed our finding. We further verified the role of KLF7 the identified ribosomal processes in in vitro assays of mammary carcinoma cell lines and analyses of breast cancer patients' tissue slices. RESULTS: We identified the transcription factor Krüppel-like factor 7 (KLF7) as a regulator of ribosomal biogenesis and translation in breast cancer cells and tissue. Highly significant overlapping processes related to ribosomal biogenesis were identified in proteomics and transcriptomics data and confirmed in patients' breast cancer RNA Seq data. Further, nucleoli, the sites of ribosomal biogenesis, were morphologically altered and quantitatively increased in KLF7-expressing cells. Pre-rRNA processing was identified as one potential process affected by KLF7. In addition, an increase in global translation independent from proliferation and transcription was observed upon exogenous KLF7 expression in vitro. Importantly, in a cohort of breast cancer patients, KLF7-expression levels correlated with aggressiveness of the intrinsic breast cancer subtype and tumor grading. Moreover, KLF7 correlated with nucleolar characteristics in human breast tumor tissue, indicating a role for KLF7 in ribosomal biogenesis. CONCLUSION: In mammary carcinoma, KLF7 is involved in ribosomal biogenesis. Alterations of ribosomal biogenesis has far reaching quantitative and qualitative implications for the proteome of the cancer cells. This might influence the aggressiveness of cancer cells.

Long-Term Diabetes Improvement After Duodenal Exclusion in Zucker Diabetic Fatty Rats Is Associated with Prevention of Strain-Specific Pancreatic Remodeling and Increased Beta Cell Proliferation.

BACKGROUND: Response to metabolic surgery is heterogeneous and the metabolic states that underpin weight loss and metabolic improvement are still unclear. In this study, we investigate parameters of post-bariatric fasting glucoregulation and leverage artificial intelligence-assisted whole-slide image analyses to characterize associated immunohistologic features of the pancreas. MATERIALS AND METHODS: We performed either loop duodeno-jejunostomy (DJOS) with exclusion of 1/3 of total intestinal length, loop duodeno-ileostomy with exclusion of 2/3 of total intestinal length (DiOS), or a sham operation on 8-week-old male obese ZDF rats. Six months post-operative, we measured blood metabolites and hormones. Subsequently, pancreatic and intestinal tissue was removed, formalin fixed, and paraffin embedded. Immunohistologic (IHC) analyses included proliferating cell nuclear antigen (PCNA) to visualize the proliferation fraction and pancreatic and duodenal homeobox 1 (PDX 1) as a measure of pancreatic cell differentiation. For IHC quantification, all slides were digitalized and analyzed using QuPath. All analyzed slides were reviewed by two independent pathologists for correctness. RESULTS: DJOS and DiOS were associated with preserved fasting insulin production compared to sham. Histopathologic evaluation showed significantly higher numbers of beta cells and specifically of clustered cell organization in DJOS and DiOS compared to sham. Cell proliferation (PCNA) was significantly elevated in DJOS and DiOS compared to sham. CONCLUSION: In this interventional model of bariatric surgery in severe genetic diabetes, we demonstrate post-operative histologic and immunohistologic features of the pancreas associated with improved fasting glucose homeostasis.

Surgeon vs Pathologist for Prediction of Pancreatic Fistula: Results from the Randomized Multicenter RECOPANC Study.

BACKGROUND: Surgically assessed pancreatic texture has been identified as the strongest predictor of postoperative pancreatic fistula. However, texture is a subjective parameter with no proven reliability or validity. Therefore, a more objective parameter is needed. In this study, we evaluated the fibrosis level at the pancreatic neck resection margin and correlated fibrosis and all clinico-pathologic parameters collected over the course of the Pancreatogastrostomy vs Pancreatojejunostomy for RECOnstruction (RECOPANC) study. STUDY DESIGN: The RECOPANC trial was a multicenter randomized prospective trial of patients undergoing pancreatoduodenectomy. There were 261 hematoxylin and eosin-stained slides allocated for histopathologic analyses. Pancreatic fibrosis was scored from 0 to III (no fibrosis up to severe fibrosis) by 2 blinded independent pathologists. All variables possibly associated with POPF were entered into a generalized linear model for multivariable analysis. RESULTS: The fibrosis grade and pancreatic texture were scored in all 261 patients. In POPF B/C (postoperative pancreatic fistula grade B or C) patients, 71% had a soft pancreas, and fibrosis grades were distributed as follows: 48% with score 0, 28% with score I, 20% with score II, and 7% with score III, respectively. Fibrosis grading showed substantial inter-rater reliability (kappa = 0.74) and correlated positively with hard pancreatic texture (p < 0.05). In univariable analysis, area under the curve (AUC) for POPF B/C prediction was higher for fibrosis grade than for pancreatic texture (0.71 vs 0.59). In multivariate analysis, the following predictors were selected: sex, surgeon volume, pancreatic texture, and fibrosis grade. However, the addition of pancreatic texture only led to an incremental improvement (AUC 0.794 vs 0.819). CONCLUSIONS: Histologically evaluated pancreatic fibrosis is an easily applicable and highly reproducible POPF predictor and superior to surgically evaluated pancreatic texture. Future studies might use fibrosis grade for risk stratification in pancreatoduodenectomy.