p-21 Activated Kinase as a Molecular Target for Chemoprevention in Diabetes

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

Resuscitation Endpoints in Traumatic Shock: A Focused Review with Emphasis on Point-of-Care Approaches

Trauma resuscitation is a blend of art and science, with the traumatologist at the helm of a large, multidisciplinary team, making split-second decisions and overseeing various parallel processes. Despite tremendous progress over the past few decades, the “art” component continues to play a large part in the overall trauma resuscitation process, with the “science” part slowly but steadily increasing its footprint as a determinant of processes and decisions. Thus, it becomes critical for all clinicians to be able to recognize the evidence-based factors which can be most valuable in guiding trauma resuscitations. This chapter serves as an overview of the current clinical findings, resuscitative endpoints, imaging techniques, and physiologic indices that are most helpful in order to promptly recognize and treat traumatic shock as well as projecting forward to look at novel techniques and biomarkers. Though a single universal marker that accurately and consistently identifies traumatic shock has yet to be discovered, certain factors discussed, such as lactate and base deficit, have been proven to be much more reliable than others

Operative Hemostasis in Trauma and Acute Care Surgery: The Role of Biosurgical Agents

Trauma and acute care surgery (TACS) constitutes the foundation of emergency surgical services in the United States. Blunt and penetrating traumatic injuries are a leading cause of death worldwide. Non-trauma general surgical emergencies are also a major source of morbidity and mortality. Operative interventions performed within the scope of TACS often revolve around the core principles of contamination control, hemostasis, surgical repair, and subsequent functional restoration. Hemorrhage control is an integral part of emergent operative interventions, and while most instances of surgical bleeding require direct suture ligation or some other form of direct tissue intervention, some circumstances call for the use of adjunctive means of hemostasis. This is especially applicable to situations and settings where direct applications of surgical energy, suture ligation, or direct compression are not possible. Difficult-to-control bleeding can be highly lethal and operative control can be very challenging when confounded by the lethal triad of acidosis, coagulopathy and hypothermia. Topical biosurgical materials (BSM) are of great value in such scenarios, and their use across a variety of settings, from pre-hospital trauma application to emergency general surgery operations, represents an important adjunct to improve patient outcomes. Here we present the different BSMs, discuss their various uses, and provide insight on future applications and developments in this important area

PAK1 modulates a PPARγ/NF-κB cascade in intestinal inflammation

P21-activated kinases (PAKs) are multifunctional effectors of Rho GTPases with both kinase and scaffolding activity. Here, we investigated the effects of inflammation on PAK1 signaling and its role in colitis-driven carcinogenesis. PAK1 and p-PAK1 (Thr423) were assessed by immunohistochemistry, immunofluorescence, and Western blot. C57BL6/J wildtype mice were treated with a single intraperitoneal TNFα injection. Small intestinal organoids from these mice and from PAK1-KO mice were cultured with TNFα. NF-κB and PPARγ were analyzed upon PAK1 overexpression and silencing for transcriptional/translational regulation. PAK1 expression and activation was increased on the luminal intestinal epithelial surface in inflammatory bowel disease and colitis-associated cancer. PAK1 was phosphorylated upon treatment with IFNγ, IL-1β, and TNFα. In vivo, mice administered with TNFα showed increased p-PAK1 in intestinal villi, which was associated with nuclear p65 and NF-κB activation. p65 nuclear translocation downstream of TNFα was strongly inhibited in PAK1-KO small intestinal organoids. PAK1 overexpression induced a PAK1–p65 interaction as visualized by co-immunoprecipitation, nuclear translocation, and increased NF-κB transactivation, all of which were impeded by kinase-dead PAK1. Moreover, PAK1 overexpression downregulated PPARγ and mesalamine recovered PPARγ through PAK1 inhibition. On the other hand PAK1 silencing inhibited NF-κB, which was recovered using BADGE, a PPARγ antagonist. Altogether these data demonstrate that PAK1 overexpression and activation in inflammation and colitis-associated cancer promote NF-κB activity via suppression of PPARγ in intestinal epithelial cells

p-21 Activated Kinase as a Molecular Target for Chemoprevention in Diabetes

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

The role of p-21 activated kinase in colitis driven colorectal carcinogenesis

Einleitung: P-21 aktivierten Kinase (PAK1) aktiviert die Rho-GTPase Rac1/Cdc42, welche an der Zellhomöostase intestinaler Epithelzellen beteiligt ist. Zusätzlich fungiert PAK1 als Gerüstprotein sowie auch als Kinase an Zellmembranen, Zytoplasma und im Zellkern. Eine Aktivierung von PAK1 führt zu zytoskeletalen Umbauten und zu Aktivierung von Signalkaskaden, die für die epitheliale Zellmigration entlang der intestinalen Villi benötigt werden. Somit reguliert dieses Protein auch die Proliferation der Darmkrypten. Beispiele hierfür sind der MAPK, PI3K/AKT, Wnt/[beta]-catenin und NF-[kappa]B Signalweg. Interessanterweise blockiert der entzündungshemmende Arzneistoff 5-Aminosalicylsäure (5-ASA) vieler dieser Signalwege und wir konnten zeigen, dass PAK1 eines von 5-ASAs therapeutischen Zielen ist. Methoden und Ergebnisse: Mittels einer Immunhistochemie (IHC) von PAK1 in Gewebe von gesunden Kontrollen, Chronisch entzündlicher Darmerkrankung und Kolitis assoziiertem Krebs (CAC) konnte gezeigt werden, dass PAK1 in entzündetem intestinalen und tumorösen Gewebe überexprimiert und aktiviert wird. Eine transiente WT-PAK1 Überexpression induzierte Proliferation und Zellüberleben in normalen Kolonepithelzellen. Zusätzlich konnte gezeigt werden, dass pro-inflammatorische Zytokine wie IL-1b, IFN[gamma] und TNF-[alpha] eine Phosphorylierung von PAK1 induzierten. Besonders TNF-[alpha] stellte sich als ein potenter Aktivator von PAK1 heraus und führte zu co-Lokalisation der NF-[kappa]B Untereinheit p65 sowohl in das Zytoplasma wie auch in den Kern. Eine PAK1 Aktivierung führte zu einer Herunterregulierung von PPAR[gamma] und einer transkriptionalen Aktvierung von p65. Desweiteren konnte mittels einer IHC von p-PAK1 gezeigt werden, dass bei der Colitis Ulcerosa die PAK1 Aktivierung vor allem in den luminal gelegenen Epithelzellen stattfindet. Sowohl die intraperitoneale Injektion von TNF-[alpha] bei Mäusen, wie auch die TNF-[alpha] Behandlung von Kolonepithelzellen und Dünndarmorganoide triggerten eine PAK1 Aktivierung und eine Translokation von p65 in den Kern. Dieser Effekt konnte in Dünndarmorganoiden, welche aus PAK1-/- Mäusen isoliert wurden oder ein in-vitro knock down von PAK1 mittels siRNAs erfahren hatten, aufgehoben werden. In einem AOM/DSS Mausmodel für den CAC führte sowohl eine Deletion von PAK1 sowie auch eine 5-ASA Behandlung zu einer reduzierten Aktivierung des PAK1-AKT-[beta]-catenin und m-TOR Signalweges. Interessanterweise war die Anzahl invasiver Tumore in den PAK-/- - Mäusen erhöht. Schlussfolgerung: Die oben angeführte Datenlage spricht dafür, dass (1) PAK1 überexprimiert ist bei einer chronischen Entzündung des Darmes und bei CAC; (2) PAK1 zur Aktivierung der PI3K/AKT, Wnt/[beta]-catenin, mTOR and NF-[kappa]B Signalübertragungswege beiträgt; (3) PAK1 den NF-[kappa]B Signalweg über Stabilisierung und Translokation von p65 und Regulierung von PPAR[gamma] moduliert; (4) PAK1 die Tumorgenese im CAC fördert; (5) 5-ASA der Überexpression von PAK1 und den damit einhergehenden Effekten auf die Zellproliferation und Apoptose entgegenwirkt.Introduction: P-21 activated kinase 1 (PAK1) is an effector of the Rho-GTPases Rac1/Cdc42, which is involved in intestinal epithelial cell homeostasis. PAK1 has both kinase and scaffold function and fulfills its roles at the membrane, cytoplasm and in the nucleus. Activation of PAK1 induces cytoskeletal rearrangements and signaling cascades required for epithelial cell migration and survival along the intestinal villus axis in addition to regulating proliferation throughout the crypts. Such pathways which are activated by PAK1 include the mitogen activated protein kinases (MAPK), phosphoinositide 3-kinases (PI3K/AKT), nuclear factor kappa B (NF-[kappa]B), and Wnt/[beta]-catenin. Interestingly, the anti-inflammatory drug 5-ASA modulates most of these pathways, and we previously identified that PAK1 is one of 5-ASA's targets. Methods & Results: Immunohistochemistry (IHC) of PAK1 from healthy controls, inflammatory bowel disease (IBD), and colitis associated cancer (CAC) patient samples revealed PAK1 was overexpressed and activated in intestinal inflammation and malignancy. Transient WT-PAK1 overexpression increased proliferation and survival in normal colonic epithelial cells, and 5-ASA blocked the effect of PAK1 overexpression. Pro-inflammatory cytokines IL-1[beta], IFN[gamma], and TNF[alpha] induced PAK1 phosphorylation. TNF[alpha] was a potent activator of PAK1 which induced co-localization of the NF-[kappa]B subunit p65 in the cytoplasm and nucleus. PAK1 activation led to downregulation of PPAR[gamma] and transcriptional activation of p65. IHC of p-PAK1 revealed PAK1 activation in UC was localized to the luminal epithelial surface. Intra-peritoneal injection of TNF[alpha] in mice, or treatment of colonic epithelial cells or small intestinal organoids with TNF[alpha] triggered PAK1 activation and nuclear translocation of p65. This was impaired in small intestinal organoids isolated from PAK1-/- mice or in vitro knock down of PAK1 with siRNA in colonic epithelial cells. In an AOM/DSS mouse model of CAC, both PAK1 deletion and 5-ASA treatment reduced PAK1-AKT-[beta]-catenin and m-TOR signaling. Surprisingly, tumor invasiveness was increased in PAK1-/- mice. Conclusions: Overall these data indicate that (1) PAK1 is overexpressed in chronic gut inflammation and in CAC (2) PAK1 contributes to PI3K/AKT, Wnt/[beta]-catenin, mTOR and NF-kB cell survival pathways (3) PAK1 modulates NF-kB pathway through p65 stability and nuclear localization and modulation of PPAR[gamma] (4) PAK1 promotes tumorigenesis in CAC (5) 5-ASA counteracts PAK1 overexpression and its effect on cell proliferation and apoptosis.submitted by Kyle DammannAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in dt. SpracheWien, Med. Univ., Diss., 2015OeBB(VLID)171620