Nanostructured Non-Newtonian Drug Delivery Barrier Prevents Postoperative Intrapericardial Adhesions

With the increasing volume of cardiovascular surgeries and the rising adoption rate of new methodologies that serve as a bridge to cardiac transplantation and that require multiple surgical interventions, the formation of postoperative intrapericardial adhesions has become a challenging problem that limits future surgical procedures, causes serious complications, and increases medical costs. To prevent this pathology, we developed a nanotechnology-based self-healing drug delivery hydrogel barrier composed of silicate nanodisks and polyethylene glycol with the ability to coat the epicardial surface of the heart without friction and locally deliver dexamethasone, an anti-inflammatory drug. After the fabrication of the hydrogel, mechanical characterization and responses to shear, strain, and recovery were analyzed, confirming its shear-thinning and self-healing properties. This behavior allowed its facile injection (5.75 ± 0.15 to 22.01 ± 0.95 N) and subsequent mechanical recovery. The encapsulation of dexamethasone within the hydrogel system was confirmed by ¹H NMR, and controlled release for 5 days was observed. In vitro, limited cellular adhesion to the hydrogel surface was achieved, and its anti-inflammatory properties were confirmed, as downregulation of ICAM-1 and VCAM-1 was observed in TNF-α activated endothelial cells. In vivo, 1 week after administration of the hydrogel to a rabbit model of intrapericardial injury, superior efficacy was observed when compared to a commercial adhesion barrier, as histological and immunohistochemical examination revealed reduced adhesion formation and minimal immune infiltration of CD3+ lymphocytes and CD68+ macrophages, as well as NF-κβ downregulation. We presented a novel nanostructured drug delivery hydrogel system with unique mechanical and biological properties that act synergistically to prevent cellular infiltration while providing local immunomodulation to protect the intrapericardial space after a surgical intervention.

Interplay between estrogen and Stat3/NF-κB-driven immunomodulation in lung cancer

K-ras mutant lung adenocarcinoma (LUAD) is the most common type of lung cancer, displays abysmal prognosis and is tightly linked to tumor-promoting inflammation, which is increasingly recognized as a target for therapeutic intervention. We have recently shown a gender-specific role for epithelial Stat3 signaling in the pathogenesis of K-ras mutant LUAD. The absence of epithelial Stat3 in male K-ras mutant mice (LR/Stat3Δ/Δ mice) promoted tumorigenesis and induced a nuclear factor-kappaB (NF-κB)-driven pro-tumor immune response while reducing tumorigenesis and enhancing anti-tumor immunity in female counterparts. In the present study, we manipulated estrogen and NF-κB signaling to study the mechanisms underlying this intriguing gender-disparity. In LR/Stat3Δ/Δ females, estrogen deprivation by bilateral oophorectomy resulted in higher tumor burden, an induction of NF-κB-driven immunosuppressive response, and reduced anti-tumor cytotoxicity, whereas estrogen replacement reversed these changes. On the other hand, exogenous estrogen in males successfully inhibited tumorigenesis, attenuated NF-κB-driven immunosuppression and boosted anti-tumor immunity. Mechanistically, genetic targeting of epithelial NF-κB activity resulted in reduced tumorigenesis and enhanced the anti-tumor immune response in LR/Stat3Δ/Δ males, but not females. Our data suggest that estrogen exerts a context-specific anti-tumor effect through inhibiting NF-κB-driven tumor-promoting inflammation and provide insights into developing novel personalized therapeutic strategies for K-ras mutant LUAD.

Abstract 2356: Estrogen medicates sex specific function of epithelial STAT3 in K-ras mutant lung tumorigenesis by reprogramming lung tumor microenvironment

Activating mutations of K-ras are one of the most common molecular alterations associated with lung cancer but have not yielded to therapeutic attack so far. We have recently shown a sex-specific role for epithelial Stat3 signaling in the pathogenesis of K-ras mutant lung cancer. We specifically found that deletion of STAT3 in K-ras mutant lung epithelial cells (LR/STAT3Δ/Δ mice) significantly reduced lung tumor burden in female mice which was associated with an enhanced anti-tumor immune response but, surprisingly, caused a dramatic enhancement of lung tumorigenesis and induction of a NF-κB driven pro-tumor immune response in male mice. To further dissect the mechanism of STAT3 dependent sex disparity in the pathogenies of K-ras mutant lung cancer, we performed loss- and gain- of function studies to manipulate estrogen signaling in both female and male mice. In LR/Stat3Δ/Δ males, implantation of estrogen pellet led to significantly reduced lung tumor burden and decreased neutrophils in the lung. This was accompanied by decreased Il6, and Cxcl1 expression explaining reduced neutrophil numbers. We also detected reduced expression of immunosuppressive markers; Arg1, Nos2, Tgfb, Il10, indicating to an attenuated immunosuppressive pro-tumor microenvironment. On the other hand, bilateral oophorectomy in female LR/Stat3Δ/Δ mice led to higher tumor burden, higher lung neutrophil counts, and increased Il6, and Cxcl1 expression. We also found decreased expression of Gzmb, and Ifng, and increased expression of T regulatory markers Foxp3 and Il10, suggesting an attenuated cytotoxic immune response but a stronger immune-inhibitory response. Hormonal replacement therapy by implanting estrogen pellet in oophorectomized LR/Stat3Δ/Δ females rescued the tumor-promoting effect of estrogen depletion characterized by reduced tumor number and neutrophil infiltration, decreased expression of Il6, Cxcl1, Foxp3 and Il10, and increased Gzmb and Ifng expression. Taken together, our study suggests that there is a differential regulation of NF-κB activation in K-ras mutant lung epithelium within sex, and estrogen plays a protective role (anti-tumor) by suppressing the activation of NF-κB pathway and reformatting the lung tumor microenvironment toward an anti-tumor phenotype. Our finding could lead to development of personalized (e.g. sex-based) immunotherapeutic and/or preventive modalities for K-ras mutant lung cancer.

Citation Format: Shanshan Deng, Marco Ramos-Castaneda, Walter Velasco Torrez, Oscar Noble, Neha Daga, Mauricio Caetano, Seyed Javad Moghaddam. Estrogen medicates sex specific function of epithelial STAT3 in K-ras mutant lung tumorigenesis by reprogramming lung tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2356.

IL22 Promotes Kras-Mutant Lung Cancer by Induction of a Protumor Immune Response and Protection of Stemness Properties

Somatic KRAS mutations are the most common oncogenic variants in lung cancer and are associated with poor prognosis. Using a Kras-induced lung cancer mouse model, CC-LR, we previously showed a role for inflammation in lung tumorigenesis through activation of the NF-κB pathway, along with induction of interleukin 6 (IL6) and an IL17-producing CD4+ T-helper cell response. IL22 is an effector molecule secreted by CD4+ and γδ T cells that we previously found to be expressed in CC-LR mice. IL22 mostly signals through the STAT3 pathway and is thought to act exclusively on nonhematopoietic cells with basal IL22 receptor (IL22R) expression on epithelial cells. Here, we found that higher expression of IL22R1 in patients with KRAS-mutant lung adenocarcinoma was an independent indicator of poor recurrence-free survival. We then showed that genetic ablation of Il22 in CC-LR mice (CC-LR/IL22KO mice) caused a significant reduction in tumor number and size. This was accompanied by significantly lower tumor cell proliferation, angiogenesis, and STAT3 activation. Il22 ablation was also associated with significant reduction in lung-infiltrating inflammatory cells and expression of protumor inflammatory cytokines. Conversely, this was accompanied with increased antitumor Th1 and cytotoxic CD8+ T-cell responses, while suppressing the protumor immunosuppressive T regulatory cell response. In CC-LR/IL22KO mice, we found significantly reduced expression of core stemness genes and the number of prototypical SPC+CCSP+ stem cells. Thus, we conclude that IL22 promotes Kras-mutant lung tumorigenesis by driving a protumor inflammatory microenvironment with proliferative, angiogenic, and stemness contextual cues in epithelial/tumor cells. Cancer Immunol Res; 6(7); 788-97. ©2018 AACR.