PAK1 belongs to a family of serine-threonine kinases and contributes to cellular pathways like NFκB, MAPK, PI3K/AKT and Wnt/ β-catenin all of which are involved in intestinal homeostasis. Overexpression of PAK1 is linked to IBD as well as colitis-associated cancer (CAC) and similar was observed in IL-10 KO mice, a model of colitis and CAC. Here we tested the effects of PAK1 deletion on intestinal inflammation and carcinogenesis in IL-10 KO mice. IL-10/PAK1 double knockout mice (DKO) were generated and development of colitis and CAC was analyzed. Large intestines were measured and prepared for histology or RNA isolation. Swiss rolls were stained with H&E and PAS. Co-immunoprecipitation and immunofluorescence were performed using intestinal organoids, SW480 and normal human colon epithelial cells (HCEC-1CT). When compared to IL-10 KO mice, DKOs showed longer colons and prolonged crypts, despite having higher inflammation and numbers of dysplasia. Crypt hyper-proliferation was associated with Notch1 activation and diminished crypt differentiation, indicated by a reduction of goblet cells. Gene expression analysis indicated upregulation of the Notch1 target HES1 and the stem cell receptor LGR5 in DKO mice. Interestingly, the stem cell marker OLFM4 was present in colonic tissue. Increased β-catenin mRNA and cytoplasmic accumulation indicated an aberrant Wnt-signaling. A co-localization and direct interaction of Notch1 and PAK1 was found in colon epithelial cells. Notch1 activation abrogated this effect whereas silencing of PAK1 led to Notch1 activation. PAK1 contributes to the regulation of crypt homeostasis under inflammatory conditions by controlling Notch1. This identifies a novel PAK1-Notch1 axis in intestinal pathophysiology of IBD and CAC.

Hypothesis: Anti-diabetic drugs modulate p-21 activated kinase (PAK) signaling. Introduction: Type 2 diabetes mellitus (T2DM) is a chronic inflammatory disease associated with increased cancer risk. PAK signaling is implicated in cellular homeostasis when regulated, and cancer when unrestrained. Recent reports provided a role for PAK signaling in glucose homeostasis, but the role of PAKs in the pathogenesis of T2DM is unknown. Here, we performed a mini-meta-analysis to explore if anti-diabetic drugs modify PAK signaling pathways, and provide insight regarding modulation of these pathways, to potentially reduce diabetes-associated cancer risk. Methods: PAK interacting partners in T2DM were identified using the online STRING database. Correlation studies were performed via systematic literature review to understand the effect of anti-diabetic drugs on PAK signaling. A mini-meta-analysis correlated multiple clinical studies and revealed the overall clinical response rate and percentage of adverse events in piogliazone (n = 53) and metformin (n = 91) treated patients with PAK-associated diseases. Results: A total of 30 PAK interacting partners were identified (10: reduced beta-cell mass; 10: beta-cell dysfunction; 10: obesity-insulin resistance), which were highly associated with Wnt, and G-protein signaling. The anti-diabetic drug metformin activated signaling pathways upstream; whereas pioglitazone inhibited pathways downstream of PAK. Overall, clinical response upon pioglitazone treatment was 53%. Seventy-nine percent of pioglitazone and 75% of metformin treated patients had adverse events. Pioglitazone reduced molecular-PAK biomarkers of proliferation (Ki67 and CyclinD1), and metformin had the opposite effect. Conclusions: PAK signaling in T2DM likely involves Wnt and G-protein signaling, which may be altered by the anti-diabetic drugs metformin and pioglitazone. Apart from the therapeutic limitations of adverse events, pioglitazone may be promising in chemoprevention. However long-term multi-centered studies, which initiate pioglitazone treatment early will be required to fully assess the full potential of these drugs.

Postoperative patients are susceptible to alterations in electrolyte homeostasis. Although electrolytes are replaced in critically ill patients, stable asymptomatic non-intensive care unit (ICU) patients often receive treatment of abnormal electrolytes. We hypothesize there is no proven benefit in asymptomatic patients. In 2016, using the electronic medical records and pharmacy database at a university academic medical center, we conducted a retrospective cost analysis of the frequency and cost of electrolyte analysis (basic metabolic panel [BMP], ionized calcium [Ca], magnesium [Mg], and phosphorus [P]) and replacement (potassium chloride [KCl], Mg, oral/iv Ca, oral/iv P) in perioperative patients. Patients without an oral diet order, with creatinine more than 1.4, age less than 16 years, admitted to the ICU, or with length of stay of more than 1 week were excluded. Nursing costs were calculated as a fraction of hourly wages per laboratory order or electrolyte replacement. One hundred thirteen patients met our criteria over 11 months. Mean length of stay was 4 days; mean age was 54 years; and creatinine was 0.67 ± 0.3. Electrolyte analysis laboratory orders (n = 1,045) totaled $6,978, and BMP was most frequently ordered accounting for 36% of laboratory costs. In total, 683 doses of electrolytes cost the pharmacy $1,780. Magnesium was most frequently replaced, followed by KCl, P, and Ca. Nursing cost associated with electrolyte analysis/replacement was $7,782. There is little evidence to support electrolyte analysis and replacement in stable asymptomatic noncritically ill patients, but their prevalence and cost ($146/case) in this study were substantial. Basic metabolic panels, pharmacy charges for potassium, and nursing staff costs accounted for the most significant portion of the total cost. Considering these data, further research should determine whether these practices are warranted.

Hypothesis: Anti-diabetic drugs modulate p-21 activated kinase (PAK) signaling Introduction: Type 2 diabetes mellitus (T2DM) is a chronic inflammatory disease associated with increased cancer risk. PAK signaling is implicated in cellular homeostasis when regulated, and cancer when unrestrained. Recent reports provided a role for PAK signaling in glucose homeostasis, but the role of PAKs in the pathogenesis of T2DM is unknown. Here we explored whether PAK signaling should be targeted via chemoprevention to reduce diabetes-associated cancer risk. Methods: PAK interacting partners in T2DM were identified using online STRING database. Systematic literature review provided the effect of anti-diabetic drugs on PAK signaling. Review of clinical studies revealed the overall clinical response rate and percentage of adverse events in piogliazone (n=53) and metformin (n=91) treated patients with PAK-dependent diseases. Results: A total of 30 PAK interacting partners were identified (10: reduced beta-cell mass; 10: beta-cell dysfunction; 10: obesity-insulin resistance) which were highly associated with Wnt, and G-protein signaling. Anti-diabetic drug metformin activated signaling pathways upstream; whereas pioglitazone inhibited pathways downstream of PAK. Overall clinical response upon pioglitazone treatment was 53%. 79% of pioglitazone and 75% of metformin treated patients had adverse events. Pioglitazone reduced molecular-PAK biomarkers of proliferation (Ki67 and CyclinD1), and metformin had the opposite effect. Conclusions: PAK signaling in T2DM involves Wnt and G-protein signaling which is altered by anti-diabetic drugs metformin and pioglitazone. Apart from the therapeutic limitations of adverse events, pioglitazone is promising in chemoprevention, however long-term multi-centered studies, which initiate pioglitazone treatment early will be required to fully assess the full potential of these drugs.