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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.

This file Includes 2 figures and one table as follow: 1: Supplementary figure S1 showing relative IL-22 mRNA expression (S1A), mutant K-ras protein expression (S1B), representative T regulatory cell flow cytometry plot (S1C), and total CD4 and CD8 flow cytometry plots (S1D) 2: Supplementary figure S2 showing pSTAT3 immunohistochemistry (S2A) and T cell related transcription factor mRNA expression (S2B) 3: Supplementary Table S1: List of Q-PCR primers and sequences

Purpose: Radiation is used extensively to treat localized cancer, but improved understanding of its effects on the immune system has increased interest in its potential systemic (abscopal) effects, particularly in combination with checkpoint inhibitors such as anti-PD1. The majority of patients either do not respond or develop resistance to monotherapy over time. Here, we investigated the efficacy of OX40 (CD134) stimulation as an alternative immunotherapeutic approach in combination with radiotherapy (XRT) in a murine model of anti–PD1-resistant lung tumors.Experimental Design: We established a bilateral tumor model in 129Sv/Ev mice using an anti–PD1-resistant lung tumor cell line. Primary tumors were treated with intratumoral injection of an OX40 agonist antibody, given as adjuvant therapy after XRT (36 Gy in three 12-Gy fractions), whereas secondary tumors were left untreated to investigate abscopal outcomes.Results: The combination of XRT followed by OX40 stimulation effectively inhibited local and systemic antitumor growth, limited lung metastases, and improved survival rates. This treatment regimen augmented CD4+ and CD8+ T-cell expansion. XRT induced the expression of OX40 on T cells in tumors and spleens and increased the percentages of splenic CD103+ dendritic cells.Conclusions: Our data extend the benefits of radiation to systemic disease control, especially when combined with anti-OX40 agonist to promote immunologically mediated abscopal effects. Moreover, this study provides a rational treatment approach and sequence to overcome anti–PD1-resistant poorly immunogenic tumors. Clin Cancer Res; 24(22); 5735–43. ©2018 AACR.

CD8+ CD103+ TRM cells express high levels of PD1. Flow cytometric analysis for TILs on day 29 from the triple therapy group (RT + α-PD1 + α-MerTK). Cells were gated on CD45 population then on CD4 and CD8, followed by CD8 and CD103 to check for PD1 expression in the final gate.

Purpose:Radiotherapy (RT) traditionally has been used for local tumor control in the treatment of cancer. The recent discovery that radiotherapy can have anticancer effects on the immune system has led to recognition of its ability to sensitize the tumor microenvironment to immunotherapy. However, radiation can also prompt adverse immunosuppressive effects that block aspects of systemic response at other tumor sites. Our hypothesis was that inhibition of the MER proto-oncogene tyrosine kinase (MerTK) in combination with anti-programmed cell death-1 (α-PD1) checkpoint blockade will enhance immune-mediated responses to radiotherapy.Experimental Design:We tested the efficacy of this triple therapy (Radiation + α-PD1 + α-MerTK mAbs) in 129Sv/Ev mice with bilateral lung adenocarcinoma xenografts. Primary tumors were treated with stereotactic radiotherapy (36 Gy in 3 12-Gy fractions), and tumors were monitored for response.Results:The triple therapy significantly delayed abscopal tumor growth, improved survival rates, and reduced numbers of lung metastases. We further found that the triple therapy increased the activated CD8+ and NK cells populations measured by granzyme B expression with upregulation of CD8+CD103+ tissue-resident memory cells (TRM) within the abscopal tumor microenvironment relative to radiation only.Conclusions:The addition of α-PD1 + α-MerTK mAbs to radiotherapy could alter the cell death to be more immunogenic and generate adaptive immune response via increasing the retention of TRM cells in the tumor islets of the abscopal tumors which was proven to play a major role in survival of non-small cell lung cancer patients.

Table 1. List of Q-RT-PCR primers. Supplementary methods and supplementary figure legends.

Supplementary Figure 2. (A) Heatmap representing IL-6/STAT3 pathway genes expression status. (B-C) Mass spectrometric quantification of IL-6 and STAT3 in lung cancer cell lines. (D) Siltuximab and Tocilizumab decreased STAT3 activation in NSCLC cell lines.

Supplementary Figure 5. Relative expression of Arg1 mRNA normalized by Cd45 expression in lungs of CC-LR mice.

Supplementary Figure 3. Increased levels of IL-6 in bronchoalveolar lavage fluid (BALF) of CC-LR mice during tumor progression.

Supplementary Figure 1. Gating method for FACS analysis and sorting.

Supplementary Figure 6. Increased levels of IL-6 in bronchoalveolar lavage fluid (BALF) of CC-LR mice after NTHi exposure.

Supplementary Figure 4. Lung lesion distribution in lungs of CC-LR mice.

Supplementary Figure 7. Relative expression of Scgb1 (CCSP) mRNA in lungs of CC-LR mice.

Bioactive molecule library screening may empirically identify effective combination therapies, but molecular mechanisms underlying favorable drug–drug interactions often remain unclear, precluding further rational design. In the absence of an accepted systems theory to interrogate synergistic responses, we introduce Omics-Based Interaction Framework (OBIF) to reveal molecular drivers of synergy through integration of statistical and biological interactions in synergistic biological responses. OBIF performs full factorial analysis of feature expression data from single versus dual exposures to identify molecular clusters that reveal synergy-mediating pathways, functions and regulators. As a practical demonstration, OBIF analyzed transcriptomic and proteomic data of a dyad of immunostimulatory molecules that induces synergistic protection against influenza A and revealed unanticipated NF-κB/AP-1 cooperation that is required for antiviral protection. To demonstrate generalizability, OBIF analyzed data from a diverse array of Omics platforms and experimental conditions, successfully identifying the molecular clusters driving their synergistic responses. Hence, unlike existing synergy quantification and prediction methods, OBIF is a phenotype-driven systems model that supports multiplatform interrogation of synergy mechanisms.

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.

Purpose: Radiotherapy (RT) traditionally has been used for local tumor control in the treatment of cancer. The recent discovery that radiotherapy can have anticancer effects on the immune system has led to recognition of its ability to sensitize the tumor microenvironment to immunotherapy. However, radiation can also prompt adverse immunosuppressive effects that block aspects of systemic response at other tumor sites. Our hypothesis was that inhibition of the MER proto-oncogene tyrosine kinase (MerTK) in combination with anti-programmed cell death-1 (α-PD1) checkpoint blockade will enhance immune-mediated responses to radiotherapy. Experimental Design: We tested the efficacy of this triple therapy (Radiation + α-PD1 + α-MerTK mAbs) in 129Sv/Ev mice with bilateral lung adenocarcinoma xenografts. Primary tumors were treated with stereotactic radiotherapy (36 Gy in 3 12-Gy fractions), and tumors were monitored for response. Results: The triple therapy significantly delayed abscopal tumor growth, improved survival rates, and reduced numbers of lung metastases. We further found that the triple therapy increased the activated CD8+ and NK cells populations measured by granzyme B expression with upregulation of CD8+CD103+ tissue-resident memory cells (TRM) within the abscopal tumor microenvironment relative to radiation only. Conclusions: The addition of α-PD1 + α-MerTK mAbs to radiotherapy could alter the cell death to be more immunogenic and generate adaptive immune response via increasing the retention of TRM cells in the tumor islets of the abscopal tumors which was proven to play a major role in survival of non-small cell lung cancer patients.

Purpose The limitation of hypofractionated radiation efficacy is due partly to the immunosuppressive tumor microenvironment. Indoleamine 2,3-dioxygenase 1 (IDO1) is an important regulator of tumor immune suppression. We evaluated the effects of IDO1 in hypofractionated radiation using a Lewis lung carcinoma (LLC) mouse model and tested whether IDO1 inhibition could sensitize those tumors to hypofractionated radiation. Methods and Materials Bilateral LLC tumors were established in C57BL/6 mice. Primary tumors were treated with 3 fractions of either 12 Gy or 6 Gy, and the IDO1 inhibitor INCB023843 was given starting on the first day of radiation. Plasma tryptophan and kynurenine levels were quantified by liquid chromatography and tandem mass spectrometry. Tumor-infiltrating immune cells were isolated from the tumors, stained, and quantified by flow cytometry. Results The combination of INCB023843 and three 12-Gy fractions led to better tumor control and survival than radiation alone; INCB023843 plus three 6-Gy fractions had no benefit. IDO1 expression by tumor-infiltrating immune cells was increased by three 12-Gy doses and inhibited by the addition of INCB023843. Nearly all IDO1+ immune cells were also F4/80+. Percentages of IDO1+F4/80+ immune cells were drastically increased by three 12-Gy fractions and by three 6-Gy fractions, but only INCB023843 combined with three 12-Gy fractions reduced those percentages. IDO1+F4/80+ immune cells were further found to be CD11b+, Gr1-intermediate-expressing, CD206–, and CD11c– (ie, myeloid-derived suppressor cells). Three 12-Gy fractions also increased the percentages of tumor-infiltrating T regulatory cells and CD8+ T cells, but adding INCB023843 did not affect those percentages. Conclusions In addition to its immune activation effects, hypofractionated radiation induced “rebound immune suppression” in the tumor microenvironment by activating and recruiting IDO1-expressing myeloid-derived suppressor cells in a dose-dependent manner. Adding an IDO1 inhibitor to hypofractionated radiation reduced the percentages of these cells, overcame the immune suppression, and sensitized LLC tumors to hypofractionated radiation.

Immunotherapies revolutionized cancer treatment by harnessing the immune system to target cancer cells. However, most patients are resistant to immunotherapies and the mechanisms underlying this resistant is still poorly understood. Here, we report that overexpression of BMP7, a member of the TGFB superfamily, represents a mechanism for resistance to anti-PD1 therapy in preclinical models and in patients with disease progression while on immunotherapies. BMP7 secreted by tumor cells acts on macrophages and CD4+ T cells in the tumor microenvironment, inhibiting MAPK14 expression and impairing pro-inflammatory responses. Knockdown of BMP7 or its neutralization via follistatin in combination with anti-PD1 re-sensitizes resistant tumors to immunotherapies. Thus, we identify the BMP7 signaling pathway as a potential immunotherapeutic target in cancer., The mechanisms underlying resistance to immunotherapy are still poorly understood. Here, the authors show that BMP7, a molecule part of the TGF-beta superfamily, suppresses proinflammatory antitumor responses and may represent a target for overcoming resistance to PD1 inhibitors.

Bioactive molecule library screening strategies may empirically identify effective combination therapies. However, without a systems theory to interrogate synergistic responses, the molecular mechanisms underlying favorable drug-drug interactions remain unclear, precluding rational design of combination therapies. Here, we introduce Omics-Based Interaction Framework (OBIF) to reveal molecular drivers of synergy through integration of statistical and biological interactions in supra-additive biological responses. OBIF performs full factorial analysis of feature expression data from single vs. dual factor exposures to identify molecular clusters that reveal synergy-mediating pathways, functions and regulators. As a practical demonstration, OBIF analyzed a therapeutic dyad of immunostimulatory small molecules that induces synergistic protection against influenza A pneumonia. OBIF analysis of transcriptomic and proteomic data identified biologically relevant, unanticipated cooperation between RelA and cJun that we subsequently confirmed to be required for the synergistic antiviral protection. To demonstrate generalizability, OBIF was applied to data from a diverse array of Omics platforms and experimental conditions, successfully identifying the molecular clusters driving their synergistic responses. Hence, OBIF is a phenotype-driven systems model that supports multiplatform exploration of synergy mechanisms.

Lung adenocarcinomas (LUADs) with mutations in the K-ras oncogene display dismal prognosis. Proinflammatory and immunomodulatory events that drive development of K-ras mutant LUAD are poorly understood. Here, we develop a lung epithelial specific K-ras mutant/Stat3 conditional knockout (LR/Stat3Δ/Δ) mouse model. Epithelial Stat3 deletion results in intriguing sex-associated discrepancies; K-ras mutant tumors are decreased in female LR/Stat3Δ/Δ mice whereas tumor burdens are increased in males. RNA-sequencing and tumor microenvironment (TME) analysis demonstrate increased anti-tumor immune responses following Stat3 deletion in females and, conversely, elevated pro-tumor immune pathways in males. While IL-6 blockade in male LR/Stat3Δ/Δ mice reduces lung tumorigenesis, inhibition of estrogen receptor signaling in female mice augments K-ras mutant oncogenesis and reprograms lung TME toward a pro-tumor phenotype. Our data underscore a critical sex-specific role for epithelial Stat3 signaling in K-ras mutant LUAD, thus paving the way for developing personalized (e.g. sex-based) immunotherapeutic strategies for this fatal disease., Proinflammatory and immunomodulatory events that drive development of K-ras mutant lung adenocarcinoma (LUAD) are poorly understood. Here they develop a lung epithelial specific K-ras mutant/Stat3 conditional knockout mouse model and show a sex-specific role for epithelial Stat3 signaling in K-ras-mutant LUAD.

Indoleamine 2,3-dioxygenase 1 (IDO1), involved in the catabolism of tryptophan (Trp) to kynurenine (Kyn) is an important regulator of tumor-mediated immunosuppression implicated in resistance to anti-PD1 immunotherapy. We investigated the role of IDO1 in an anti-PD1-resistant lung cancer model (344SQ_R) compared to the parental 344SQ tumors (344SQ_P). IDO1 was overexpressed in tumor-infiltrating leukocytes, and plasma Kyn levels were increased, in 344SQ_R vs. 344SQ_P. The IDO1 inhibitor INCB023843 retarded tumor growth and reduced lung metastases in 344SQ_R. IDO1 was expressed at higher levels in F4/80+Gr1intCD11b+ myeloid-derived suppressor cells (MDSCs) that were prominent in 344SQ_R. The INCB023843 reduced IDO1 expression and percentages of these MDSCs while increasing CD8+ T cells infiltration, hence reactivating antitumor T-cell responses in 344SQ_R. Therefore, IDO1 inhibition holds promise for treating lung cancer that does not respond to anti-PD1 therapy.

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.

Several promising chemopreventive agents have for lung cancer emerged in preclinical models and in retrospective trials. These agents have been shown to modulate pathways altered in carcinogenesis and reduce markers of carcinogenesis in animal and cell culture models. Cancer-prone transgenic mice with oncogenic Kras expressed in the airway epithelium (CcspCre/+ ; KrasLSL-G12D/+ ) were raised on diets compounded with myo-inositol. These animals form lung premalignant lesions in a stereotypical fashion over the ten weeks following weaning. Mice raised on myo-inositol containing diets showed potent reduction in the number, size, and stage of lesions as compared to those raised on control diets. myo-inositol has previously been reported to inhibit phosphoinositide 3-kinase (PI3K) signaling. However, in mice raised on myo-inositol, total PI3K signaling was largely unaffected. Proteomic and cytokine analyses revealed large reduction in IL-6 related pathways, including STAT3 phosphorylation. This effect was not due to direct inhibition of IL-6 production and autocrine signaling within the tumor cell, but rather through alteration in macrophage recruitment and in phenotype switching, with an increase in antitumoral M1 macrophages.

Activating mutations of K-ras are the most common oncogenic alterations found in lung cancer. Unfortunately, attempts to target K-ras–mutant lung tumors have thus far failed, clearly indicating the need for new approaches in patients with this molecular profile. We have previously shown NF-κB activation, release of IL6, and activation of its responsive transcription factor STAT3 in K-ras–mutant lung tumors, which was further amplified by the tumor-enhancing effect of chronic obstructive pulmonary disease (COPD)-type airway inflammation. These findings suggest an essential role for this inflammatory pathway in K-ras–mutant lung tumorigenesis and its enhancement by COPD. Therefore, here we blocked IL6 using a monoclonal anti-IL6 antibody in a K-ras–mutant mouse model of lung cancer in the absence or presence of COPD-type airway inflammation. IL6 blockade significantly inhibited lung cancer promotion, tumor cell–intrinsic STAT3 activation, tumor cell proliferation, and angiogenesis markers. Moreover, IL6 inhibition reduced expression of protumor type 2 molecules (arginase 1, Fizz 1, Mgl, and IDO), number of M2-type macrophages and granulocytic myeloid-derived suppressor cells, and protumor T-regulatory/Th17 cell responses. This was accompanied by increased expression of antitumor type 1 molecule (Nos2), and antitumor Th1/CD8 T-cell responses. Our study demonstrates that IL6 blockade not only has direct intrinsic inhibitory effect on tumor cells, but also reeducates the lung microenvironment toward an antitumor phenotype by altering the relative proportion between protumor and antitumor immune cells. This information introduces IL6 as a potential druggable target for prevention and treatment of K-ras–mutant lung tumors. Cancer Res; 76(11); 3189–99. ©2016 AACR.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

BackgroundDespite some successes with checkpoint inhibitors for treating cancer, most patients remain refractory to treatment, possibly due to the inhibitory nature of the tumor stroma that impedes the function and entry of effector cells. We devised a new technique of combining immunotherapy with radiotherapy (XRT), more specifically low-dose XRT, to overcome the stroma and maximize systemic outcomes.MethodsWe bilaterally established 344SQ lung adenocarcinoma tumors in 129Sv/Ev mice. Primary and secondary tumors were irradiated with either high-dose or low-dose of XRT with systemic anti-programmed cell death protein 1 and anti-cytotoxic T-lymphocyte associated protein 4 administration. Survival and tumor growth were monitored for the various groups, and secondary tumors were phenotyped by flow cytometry for immune populations. Tumor growth factor-beta (TGF-β) cytokine levels were assessed locally after low-dose XRT, and specific immune-cell depletion experiments were conducted to identify the major contributors to the observed systemic antitumor effect.ResultsThrough our preclinical and clinical studies, we observed that when tumor burden was high, there was a necessity of combining high-dose XRT to ‘prime’ T cells at the primary tumor site, with low-dose XRT directed to secondary (metastatic) tumors to ‘modulate the stroma’. Low-dose XRT improved the antitumor outcomes of checkpoint inhibitors by favoring M1 macrophage polarization, enhancing natural killer (NK) cell infiltration, and reducing TGF-β levels. Depletion of CD4+T cells and NK cells abrogated the observed antitumor effect.ConclusionOur data extend the benefits of low-dose XRT to reprogram the tumor environment and improve the infiltration and function of effector immune cells into secondary tumors.

Many metabolic alterations, including the Warburg effect, occur in cancer cells that influence the tumor microenvironment, including switching to glycolysis from oxidative phosphorylation, using opportunistic modes of nutrient acquisition, and increasing lipid biosynthesis. The altered metabolic landscape of the tumor microenvironment can suppress the infiltration of immune cells and other functions of antitumor immunity through the production of immune-suppressive metabolites. Metabolic dysregulation in cancer cells further affects the expression of cell surface markers, which interferes with immune surveillance. Immune checkpoint therapies have revolutionized the standard of care for some patients with cancer, but disease in many others is resistant to immunotherapy. Specific metabolic pathways involved in immunotherapy resistance include PI3K-Akt-mTOR, hypoxia-inducible factor (HIF), adenosine, JAK/STAT, and Wnt/Beta-catenin. Depletion of essential amino acids such as glutamine and tryptophan and production of metabolites like kynurenine in the tumor microenvironment also blunt immune cell function. Targeted therapies against metabolic checkpoints could work in synergy with immune checkpoint therapy. This combined strategy could be refined by profiling patients' mutation status before treatment and identifying the optimal sequencing of therapies. This personalized combinatorial approach, which has yet to be explored, may well pave the way for overcoming resistance to immunotherapy.

Despite the potential to cure metastatic disease, immunotherapy on its own often fails outright or early on due to tumor immune evasion. To address this obstacle, we investigated combinations of anti-GITR, anti-PD1 and radiation therapy (XRT) in our previously developed anti-PD1 resistant 344SQ non-small cell lung adenocarcinoma preclinical tumor model. We hypothesized that targeting multiple mechanisms of immune evasion with this triple therapy would lead to an enhanced tumor-specific immune response and improve survival more so than any mono- or dual therapy. In a two tumor 344SQR murine model, treatment with anti-GITR, anti-PD1, and XRT led to significantly improved survival and an abscopal response, with half of the mice becoming tumor free. These mice showed durable response and increased CD4+ and CD8+ effector memory on tumor rechallenge. Regulatory T cells (Tregs) expressed the highest level of GITR at the tumor site and anti-GITR therapy drastically diminished Tregs at the tumor site. Anti-tumor effects were largely dependent on CD4+ T cells and partially dependent on CD8+ T cells. Anti-GITR IgG2a demonstrated superior efficacy to anti-GITR IgG1 in driving antitumor effects. Collectively, these results suggest that combinatorial strategies targeting multiple points of tumor immune evasion may lead to a robust and lasting antitumor response.

Purpose: Radiation is used extensively to treat localized cancer, but improved understanding of its effects on the immune system has increased interest in its potential systemic (abscopal) effects, particularly in combination with checkpoint inhibitors such as anti-PD1. The majority of patients either do not respond or develop resistance to monotherapy over time. Here, we investigated the efficacy of OX40 (CD134) stimulation as an alternative immunotherapeutic approach in combination with radiotherapy (XRT) in a murine model of anti–PD1-resistant lung tumors. Experimental Design: We established a bilateral tumor model in 129Sv/Ev mice using an anti–PD1-resistant lung tumor cell line. Primary tumors were treated with intratumoral injection of an OX40 agonist antibody, given as adjuvant therapy after XRT (36 Gy in three 12-Gy fractions), whereas secondary tumors were left untreated to investigate abscopal outcomes. Results: The combination of XRT followed by OX40 stimulation effectively inhibited local and systemic antitumor growth, limited lung metastases, and improved survival rates. This treatment regimen augmented CD4+ and CD8+ T-cell expansion. XRT induced the expression of OX40 on T cells in tumors and spleens and increased the percentages of splenic CD103+ dendritic cells. Conclusions: Our data extend the benefits of radiation to systemic disease control, especially when combined with anti-OX40 agonist to promote immunologically mediated abscopal effects. Moreover, this study provides a rational treatment approach and sequence to overcome anti–PD1-resistant poorly immunogenic tumors. Clin Cancer Res; 24(22); 5735–43. ©2018 AACR.

Chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lung, is an independent risk factor for lung cancer. Lung tissues obtained from human smokers with COPD and lung cancer demonstrate hypoxia and up-regulated hypoxia inducible factor-1 (HIF-1). HIF-1 activation is the central mechanism for controlling the cellular response to hypoxia during inflammation and tumor development. These facts suggest a link between COPD-related airway inflammation, HIF-1, and lung cancer. We have previously established a mouse model of COPD-like airway inflammation that promotes lung cancer in a K-ras mutant mouse model (CC-LR). Here we show that tumors in the CC-LR model have significantly elevated levels of HIF-1α and HIF-1 activity. To determine the tumor-promoting functions of HIF-1 in CC-LR mice, the gene Hif1a which encodes HIF-1α and is required for HIF-1 activity, was disrupted in the lung epithelium of CC-LR animals. Airway epithelial specific HIF-1α deficient mice demonstrated significant reductions in lung surface tumor numbers, tumor angiogenesis, and tumor cell proliferation in the absence or presence of COPD-like airway inflammation. In addition, when CC-LR mice were bred with transgenic animals that overexpress a constitutively active mutant form of human HIF-1α in the airway epithelium, both COPD- and adenocarcinoma-like phenotypes were observed. HIF-1α overexpressing CC-LR mice had significant emphysema, and they also showed potentiated tumorigenesis, angiogenesis, and cell proliferation accompanied by an invasive metastatic phenotype. Our gain and loss of function studies support a key role for HIF-1α in the promotion of lung cancer by COPD-like inflammation.

With more than 150,000 deaths per year in the US alone, lung cancer has the highest number of deaths for any cancer. These poor outcomes reflect a lack of treatment for the most common form of lung cancer, non-small cell lung carcinoma (NSCLC). Lung adenocarcinoma (ADC) is the most prevalent subtype of NSCLC, with the main oncogenic drivers being KRAS and epidermal growth factor receptor (EGFR). Whereas EGFR blockade has led to some success in lung ADC, effective KRAS inhibition is lacking. KRAS-mutant ADCs are characterized by high levels of gel-forming mucin expression, with the highest mucin levels corresponding to worse prognoses. Despite these well-recognized associations, little is known about roles for individual gel-forming mucins in ADC development causatively. We hypothesized that MUC5AC/Muc5ac, a mucin gene known to be commonly expressed in NSCLC, is crucial in KRAS/Kras-driven lung ADC. We found that MUC5AC was a significant determinant of poor prognosis, especially in patients with KRAS-mutant tumors. In addition, by using mice with lung ADC induced chemically with urethane or transgenically by mutant-Kras expression, we observed significantly reduced tumor development in animals lacking Muc5ac compared with controls. Collectively, these results provide strong support for MUC5AC as a potential therapeutic target for lung ADC, a disease with few effective treatments.

Several promising chemopreventive agents have for lung cancer emerged in preclinical models and in retrospective trials. These agents have been shown to modulate pathways altered in carcinogenesis and reduce markers of carcinogenesis in animal and cell culture models. Cancer-prone transgenic mice with oncogenic Kras expressed in the airway epithelium (Ccsp(Cre/+); Kras(LSL−G12D/+)) were raised on diets compounded with myo-inositol. These animals form lung premalignant lesions in a stereotypical fashion over the ten weeks following weaning. Mice raised on myo-inositol containing diets showed potent reduction in the number, size, and stage of lesions as compared to those raised on control diets. myo-inositol has previously been reported to inhibit phosphoinositide 3-kinase (PI3K) signaling. However, in mice raised on myo-inositol, total PI3K signaling was largely unaffected. Proteomic and cytokine analyses revealed large reduction in IL-6 related pathways, including STAT3 phosphorylation. This effect was not due to direct inhibition of IL-6 production and autocrine signaling within the tumor cell, but rather through alteration in macrophage recruitment and in phenotype switching, with an increase in antitumoral M1 macrophages.

Lung cancer is the leading cause of cancer death and the second most common cancer diagnosed worldwide in both males and females. K-ras gene mutations are among the most common mutations encountered in non-small cell lung cancer (NSCLC), encompassing up to 30% of them, and are unfortunately associated with chemoresistance and poor prognosis. Recently, immunotherapy treatment of several cancers including NSCLC, particularly by targeting the co-inhibitory molecules program cell death protein 1 (PD-1) and program death-ligand 1 (PD-L1), have shown promising results given either in combination with standard chemotherapy or as neoadjuvant therapy. We have previously shown an important role for IL-6 in K-ras mutant lung tumorigenesis by reprogramming myeloid contexture in the lung tumor microenvironment (TME) and promoting tumor cell proliferation and angiogenesis through the activation of STAT3 pathway. Accordingly, we hypothesized that targeting both immunosuppressive TME and IL-6 driven pro-tumor immune response, through the use of immune checkpoint blockade (ICB), and inhibition of IL-6 would give us a synergistic/additive response and increases the tumor inhibitory effect of ICB. Briefly, starting at the age of 6 weeks, 4 cohorts of K-ras mutant mice (LSL-K-rasG12D/ CCSPCre) (CC-LR) were injected intraperitoneally with vehicle alone (PBS1x), anti-PD-1 (CD279) antibody alone (Clone: 29F.1A12- Bioxcell - BE0273-CUST) (200µg), anti-IL-6 antibody alone (Clone: MP5-20F3 - Bioxcell - BE0046-CUST) (20 mg/kg), or a combination of both. After 8 weeks of treatment, tumor burden and inflammation were studied and quantified. We found a significant (2-fold) decrease in tumor burden in the anti-PD1 alone treated group which was further reduced in the combined anti-PD-1 and anti-IL-6 treated group compared to age and sex matched vehicle treated group. There was also a significant difference in the lung macrophage infiltration in combined anti-PD1/anti-IL-6 treated group similar to what we previously observed in anti-IL-6 alone treated group. Our results suggest that immunomodulatory approaches by targeting cytokine networks like IL-6 blockade could be used to increase the efficacy of immunotherapy, i.e. PD-1 blockade, as a preventive and/or therapeutic strategy for K-ras mutant lung cancer. Citation Format: Marco A. Ramos-Castaneda, Neha Daga, Stephen Peng, Shanshan Deng, Walter Velazco, Mauricio Da Silva Caetano, Seyed Moghaddam. Effect of combined PD-1 and IL-6 blockade on K-ras mutant lung cancer [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 2712.

In an immune competent host, immune surveillance maintains the guards against abnormal cell growth, therefore establishing the need for tumors to evade immunity to grow. Tumors tend to mask themselves with an inhibitory stroma, rich with T regulatory cells, Myeloid-derived suppressor cells, Cancer associated fibroblasts, and pro-tumor M2 macrophages. Despite current advances with checkpoint inhibitors and cell-based therapies, the majority of cancer patients remain refractory to treatment due to the presence of the stroma and the inability of effector cells to penetrate. Radiotherapy (XRT) has been traditionally used to control tumors locally. More recently, we developed the RadScopal technique that combines high dose XRT (H-XRT) to release antigens and prime T-cells with low dose XRT (L-XRT) to overcome the stroma, favor the polarization of M1 macrophages, reduce TGF-β levels, and enhance NK cell infiltration. In the 129Sv/Ev murine model of bilaterally transplanted tumors, RadScopal treatment significantly improved the outcomes of anti-CTLA-4 and anti-PD1 checkpoint inhibitors and controlled the growth of primary as well as distal secondary tumors treated with L-XRT. The RadScopal efficacy was nulled when using nude mice lacking effector adaptive immunity. Moreover, specific immune-cell depletion studies highlighted the importance of CD4+ T-cells and NK cells to carry out the anti-tumor functions. Our radio-immunotherapeutic approach was operative in other models such as Lewis Lung Carcinoma, where L-XRT retarded the growth of secondary tumors. In conclusion, L-XRT significantly augmented checkpoint blockers with potential future application to cell therapies (CAR-T and TCR) to extend the benefits to more patients.

Given the unprecedentedly rapid progression of clinical immuno-oncology, evaluation of currently ongoing and upcoming clinical trials is essential to address potential deficiencies for future trial design. This observational study examined trends in the current landscape of clinical trials investigating immunotherapy with radiotherapy (iRT). The National Institute of Health's clinicaltrials.gov database was queried for trials including radiation and one of the six currently US FDA approved immunotherapy drugs: ipilimumab, nivolumab, pembrolizumab, durvalumab, atezolizumab and avelumab. This study highlights that the construction of prospective iRT trials is rapidly escalating. This study provides a framework to not only understand ongoing multidisciplinary trials, but also for prudent iRT trial design in the future.

Activating mutations of K-ras are the most common oncogenic alterations found in lung cancer, and are heavily associated with tobacco exposure and poor prognosis. Using a conditional lung cancer mouse model (CC-LR), we showed that K-ras mutant lung tumors have inflammatory characteristics with activation of NF-kB pathway, release of IL-6 and activation of its downstream target, STAT3. We further demonstrated that IL-6 blockade results in significant tumor reduction as well as decreased pSTAT3 expression, tumor cell proliferation, angiogenesis and a reduction in tumor-associated immunosuppressive myeloid populations concomitant with induction of an anti-tumor phenotype. These indicate essential autocrine and paracrine roles for IL-6/STAT3 pathway in promotion of K-ras mutant lung cancer, largely via perpetuating inflammation introducing it as a vulnerability factor for this type of tumors. Here we generated a lung epithelial specific K-ras mutant/STAT3 conditional knockout mouse (LR/STAT3Δ/Δ) to further study the role of epithelial STAT3 activity in K-ras mutant lung cancer. We found that in female mice, lack of epithelial STAT3 inhibited lung cancer, and significantly decreased the lung inflammatory cell population, particularly macrophages, whereas in male mice, STAT3-deficiency surprisingly promoted lung cancer and significantly increased lung neutrophil population. To understand genome-wide mechanisms underlying this intriguing gender disparity, we performed RNA-sequencing of whole lungs from male and female LR/STAT3Δ/Δ and control CC-LR mice. Using a mixed effects model, we found 339 transcripts that were significantly modulated differently between LR/STAT3Δ/Δ and control CC-LR mice in males relative to females. Pathways and gene network analyses of the transcripts demonstrated that lungs of male LR/STAT3Δ/Δ mice exhibited markedly reduced Th1 immune T-cell signatures. We corroborated these findings and found significant phenotypic changes in the lung tumor microenvironment (TME) with males exhibiting increased pro-tumor inflammatory markers. Markedly, we found opposing IL-6 expression patterns with LR/STAT3Δ/Δ females expressing low IL-6 while LR/STAT3Δ/Δ males expressed high levels of IL-6. We then blocked IL-6 in male LR/STAT3Δ/Δ mice, which resulted in a significantly reduced lung tumorigenesis, and reformatted lung TME towards an anti-tumor phenotype with a Th1/CD8+ T cell signature. By contrast, estrogen receptor (ER) signaling blockade by tamoxifen in female LR/STAT3Δ/Δ mice promoted lung cancer, and reprogrammed lung TME toward a pro-tumor phenotype with an increase in Th17/Treg cell signature. Taken together, we conclude that epithelial STAT3 signaling has an important gender-specific role with autocrine and paracrine effects in K-ras induced lung tumorigenesis, which might be mediated by the interplay between ER signaling, and NF-κB mediated cytokine network. Citation Format: Mauricio S. Caetano, Hieu Van, Emmanuel Bugarin, Amber Cumpian, Christina L. McDowell, Huiyuan Zhang, Scott E. Evans, Stephanie Watowich, Humam Kadara, Seyed J. Moghaddam. Gender specific function of epithelial IL-6-STAT3 pathway in K-ras mutant lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3974. doi:10.1158/1538-7445.AM2017-3974

Worldwide, lung cancer is the leading cause of cancer mortality, and cigarette smoking (CS) is its principal cause. However, several studies have found that smokers with chronic obstructive pulmonary disease (COPD), an inflammatory disease of the lung, have an increased risk of lung cancer (3 to 10-fold) compared to smokers with comparable cigarette exposure but without COPD. Importantly, among smokers with COPD, even following withdrawal of cigarette smoke, inflammation persists and lung function continues to deteriorate as does the increased risk of lung cancer. These facts suggest a strong link between COPD-related lung inflammation and lung cancer, however, the precise mechanistic link is not known. Mucociliary dysfunction and mucin hyperproduction are important features of COPD with inflammation being the major trigger. Interestingly, lung cancer with mucin overexpression has higher malignancy potential and poor prognosis, which around 76% having mutations in K-ras oncogene, the most frequent oncogenic mutation in lung adenocarcinoma. Taken these together, we hypothesized that mucins contribute to promotion of K-ras mutant lung cancer by inflammation. Here we first investigated whether Muc5ac, predominant airway mucin that plays a primary role in inflammatory lung diseases, is predictive of clinical outcome in KRAS-mutant human lung adenocarcinomas. We determined Muc5ac mRNA expression by array analysis of 150 lung adenocarcinomas from patients that did not received neoadjuvant therapy and we found that, Muc5ac mRNA level was a significant predictor of poor disease-free survival in KRAS-mutant lung adenocarcinomas. We have further found increased mucin and high expression of Muc5ac in lung tumor tissues of the mice with airway specific expression of a mutant form of K-ras (CC-LR mice). Then, we crossed previously developed Muc5ac knockout (KO) mice to CC-LR mice in order to develop a K-ras mutant lung cancer mouse model with lack of Muc5ac (CC-LR/Muc5ac KO mice). This resulted in a significant tumor reduction by ~54% (2.2-fold) in lung of CC-LR/Muc5ac KO mice compared to age and sex matched control CC-LR mice. Lung inflammation was evaluated by analysis of bronchoalveolar lavage fluid and revealed a significant reduction (3-fold) in number of macrophages, and levels of IL-6 and IL-17 in CC-LR/Muc5ac KO mice compared to CC-LR control mice. Immunohistopathological analysis of lung sections confirmed lower inflammation, decreased tumor number and size, less adenomatous lesions, and reduced tumor cell proliferation and angiogenesis in CC-LR mice with lack of Muc5ac compared to control CC-LR mice. Our experimental results suggest that Muc5ac has an essential role in promotion of K-ras mutant lung cancer through autocrine cell intrinsic and paracrine immune cell mediated mechanisms. Citation Format: Misha Umer, Amber M. Cumpian, Nasim Khosravi, Zoulikha Azzegagh, Maede Mohebnasab, Mauricio S. Caetano, Edwin J. Ostrin, Ignacio I. Wistuba, Burton Dickey, Humam Kadara, Christopher M. Evans, Seyed J. Moghaddam. Muc5ac plays an essential role in promotion of k-ras mutant lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3714. doi:10.1158/1538-7445.AM2017-3714

The transcriptional regulator STAT3 curbs pro-inflammatory cytokine production mediated by NF-κB signalling in innate immune cells, yet the mechanism by which this occurs has been unclear. Here we identify STAT3 as a pivotal negative regulator of Ubc13, an E2 ubiquitin-conjugating enzyme that facilitates TRAF6 K63-linked ubiquitination and NF-κB activation. Ubc13 accumulates intracellularly in the absence of STAT3. Depletion of Ubc13 in Stat3-deficient macrophages subdues excessive RANKL- or LPS-dependent gene expression, indicating that Ubc13 overexpression mediates enhanced transcriptional responses in the absence of STAT3. In RANKL-activated macrophages, STAT3 is stimulated by autocrine IL-6 and inhibits accrual of Ets-1, Set1 methyltransferase and trimethylation of histone H3 lysine 4 (H3K4me3) at the Ube2n (Ubc13) promoter. These results delineate a mechanism by which STAT3 operates as a transcriptional repressor on Ube2n, thus modulating NF-κB activity by regulation of Ubc13 abundance. Our data suggest that this pathway plays important roles in bone homeostasis and restraint of inflammation.

Lung cancer development is associated with extensive pulmonary inflammation. In addition, the linkage between chronic obstructive pulmonary disease (COPD) and lung cancer has been demonstrated in population-based studies. IL-17-producing CD4 helper T cells (Th17 cells) play a critical role in promoting chronic tissue inflammation. Although Th17 cells are found in human COPD and lung cancer, their role is not understood. We have thus used a mouse model of lung cancer, in which an oncogenic form of K-ras (K-ras(G12D)), frequently found in human lung cancer, is restrictedly expressed in lung epithelial cells [via Clara cell secretory protein (CCSP(cre))]. In this model, Th17 and Treg but not Th1 cells were found enriched at the tumor tissues. When CCSP(cre)/K-ras(G12D) mice were weekly challenged with a lysate of nontypeable Haemophilus influenza (NTHi), which induces COPD-type inflammation and accelerates the tumor growth, they showed greatly enhanced Th17 cell infiltration in the lung tissues. Lack of IL-17, but not IL-17F, resulted in a significant reduction in lung tumor numbers in CCSP(cre)/K-ras(G12D) mice and also those treated with NTHi. Absence of IL-17 not only resulted in reduction of tumor cell proliferation and angiogenesis, but also decreased the expression of proinflammatory mediators and reduced recruitment of myeloid cells. Depletion of Gr-1(+)CD11b(+) myeloid cells in CCSP(cre)/K-ras(G12D) mice suppressed tumor growth in lung, indicating Gr-1(+)CD11b(+) myeloid cells recruited by IL-17 play a protumor role. Taken together, our data demonstrate a critical role for Th17 cell-mediated inflammation in lung tumorigenesis and suggest a novel way for prevention and treatment of this disease.

Background Tumor cells produce various cytokines and chemokines that attract leukocytes. Leukocytes can amplify parenchymal innate immune responses, and have been shown to contribute to tumor promotion. Neutrophils are among the first cells to arrive at sites of inflammation, and the increased number of tumor-associated neutrophils is linked to poorer outcome in patients with lung cancer. Results We have previously shown that COPD-like airway inflammation promotes lung cancer in a K-ras mutant mouse model of lung cancer (CC-LR). This was associated with severe lung neutrophilic influx due to the increased level of neutrophil chemoattractant, KC. To further study the role of neutrophils in lung tumorigenesis, we depleted neutrophils in CC-LR mice using an anti-neutrophil antibody. This resulted in a significant reduction in lung tumor number. We further selectively inhibited the main receptor for neutrophil chemo-attractant KC, CXCR2. Similarly, this resulted in suppression of neutrophil recruitment into the lung of CC-LR mice followed by significant tumor reduction. Neutrophil elastase (NE) is a potent elastolytic enzyme produced by neutrophils at the site of inflammation. We crossed the CC-LR mice with NE knock-out mice, and found that lack of NE significantly inhibits lung cancer development. These were associated with significant reduction in tumor cell proliferation and angiogenesis. Conclusion We conclude that lung cancer promotion by inflammation is partly mediated by activation of the IL-8/CXCR2 pathway and subsequent recruitment of neutrophils and release of neutrophil elastase. This provides a baseline for future clinical trials using the IL-8/CXCR2 pathway or NE inhibitors in patients with lung cancer.

Tumor necrosis factor (TNF) is known as an important regulator of tumor microenvironment and inflammation. TNF levels are markedly elevated in the bronchoalveolar lavage fluid (BALF) of patients with chronic obstructive pulmonary disease (COPD), which is an independent risk factor for lung cancer. We have previously shown that COPD-like airway inflammation promotes lung cancer in a K-ras mutant mouse model (CC-LR mouse). This was associated with a significant increase of neutrophils in BALF, accompanied by a marked increase in TNF level, suggesting a link between COPD, TNF, and lung cancer promotion. Therefore, we first overexpressed TNF in the airway epithelium of CC-LR mice, which promoted lung cancer by ∼2-fold. This was associated with increased numbers of Ki67 and CD31 positive cells in lung tumors of CC-LR/TNF-Tg mice. We also found a robust increase in NF-κB activation, and numbers of neutrophils and myeloid-derived suppressor cells (MDSCs) in lung. Accordingly, we depleted MDSCs in CC-LR/TNF-Tg mice, which lead to significant tumor suppression emphasizing on the role of TNF-induced MDSCs in K-ras induced lung tumorigenesis. Finally, we targeted TNF expression by crossing CC-LR mice with TNF knock-out mice (CC-LR/TNF-KO), which resulted in a significant decrease in lung tumor burden in the absence or presence of COPD-like airway inflammation. Interestingly, there were less MDSCs and lower Ki67 and CD31 expression in the lung of the CC-LR/TNF-KO mice. We conclude that TNF links COPD to lung cancer promotion by induction of an immunosuppressive MDSC response, and subsequent amplification of proliferation and angiogenesis in tumors.

Oncogenic K-ras mutations found in ∼ 30% of all non-small cell lung cancers are associated with chemoresistance and poor prognosis. Using a K-ras induced lung cancer mouse model, CC-LR, we previously showed that K-ras mutant lung tumors have intrinsic inflammatory characteristics with activation of NF-kB pathway, release of inflammatory cytokines IL-6, and activation of the IL-6 responsive transcription factor STAT3. We have further shown that IL-6/STAT3 pathway, and IL-17 producing CD4 helper T cells (Th17 cells) through their main cytokine, IL-17A, play critical roles in promotion of lung cancer in this model. IL-22 is another effecter molecule secreted by Th17 cells which is highly expressed in our K-ras mutant mouse model. IL-22 is a unique cytokine, which seems to act exclusively on nonhematopoietic cells, with basal IL-22R expression in the epithelial cells and fibroblast, and mostly signals through STAT3 pathway. Here we found that genetic ablation of IL-22 in CC-LR mice (CC-LR/IL22-KO mice), causes significant reduction in lung surface tumor numbers by ∼54% (2.1-fold). Histopathological analysis of lung sections confirmed a reduction in number and size of tumors in CC-LR/IL22-KO mice, which was associated with significantly lower tumor cell proliferation, angiogenesis and STAT3 activation. IL-22 ablation also reduced the numbers of inflammatory cells in bronchoalveolar lavage fluid, and decreased the expression of pro-tumor inflammatory cytokines such as IL-6, IL-17 and TNFα. This was associated with increased expression of anti-tumor Th1 cells -specific transcription factor (Tbet) and their activation markers, IFNγ, and GZB, and decreased expression of pro-tumor Th17- (RORγ) and T regulatory (FOXP3+) specific transcription factors. Recent studies have shown an association between IL-22 and stem-cell like properties in colon cancer. In lung cancer, cell populations expressing NANOG, SOX2, Oct4 and/or aldehyde dehydrogenase activity are enriched with stemness properties. Interestingly, in CC-LR/IL22-KO mice we found significant reduction in expression of these stemness genes. Thus, we conclude that IL-22 promotes K-ras mutant lung tumorigenesis by inducing a pro-tumor inflammatory microenvironment with proliferative and angiogenic properties as well as protecting stemness characteristic in epithelial/tumor cells. Therefore, we propose pharmacological targeting of IL-22 as a potential therapeutic strategy in combination with conventional cytotoxic therapy, immune check point blockade, or other targeted therapies (e.g. MEK inhibition) for lung cancer patients with K-ras mutation. Citation Format: Nasim Khosravi, Amber M. Cumpian, Soudabeh Daliri, Cynthia De La Garza, Mauricio S. Caetano, Seyed Javad Moghaddam. Impact of Interleukin-22 on K-ras mutant lung tumor microenvironment and stemness properties. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4398.

The development of bleomycin-induced pulmonary fibrosis (BLEO-PF) has been associated with differences in genetic background and oxidative stress status. The authors’ aim was to investigate the crosstalk between the redox profile, lung histology, and respiratory function in BLEO-PF in C57BL/6, DBA/2, and BALB/c mice. BLEO-PF was induced with a single intratracheal dose of bleomycin (0.1 U/mouse). Twenty-one days after bleomycin administration, the mortality rate was over 50% in C57BL/6 and 20% in DBA/2 mice, and BLEO-PF was not observed in BALB/c. There was an increase in lung static elastance ( p < .001), viscoelastic/inhomogeneous pressure ( p < .05), total pressure drop after flow interruption ( p < .01), and ΔE ( p < .05) in C57BL/6 mice. The septa volume increased in C57BL/6 ( p < .05) and DBA/2 ( p < .001). The levels of IFN-γ were reduced in C57BL/6 mice ( p < .01). OH-proline levels were increased in C57BL/6 and DBA/2 mice ( p < .05). SOD activity and expression were reduced in C57BL/6 and DBA/2 mice ( p < .001 and p < .001, respectively), whereas catalase was reduced in all strains 21 days following bleomycin administration compared with the saline groups (C57BL/6: p < .05; DBA/2: p < .01; BALB/c: p < .01). GPx activity and GPx1/2 expression decreased in C57BL/6 ( p < .001). The authors conclude that BLEO-PF resistance may also be related to the activity and expression of SOD in BALB/c mice.

Background PCA3 is a non-coding RNA (ncRNA) that is highly expressed in prostate cancer (PCa) cells, but its functional role is unknown. To investigate its putative function in PCa biology, we used gene expression knockdown by small interference RNA, and also analyzed its involvement in androgen receptor (AR) signaling. Methods LNCaP and PC3 cells were used as in vitro models for these functional assays, and three different siRNA sequences were specifically designed to target PCA3 exon 4. Transfected cells were analyzed by real-time qRT-PCR and cell growth, viability, and apoptosis assays. Associations between PCA3 and the androgen-receptor (AR) signaling pathway were investigated by treating LNCaP cells with 100 nM dihydrotestosterone (DHT) and with its antagonist (flutamide), and analyzing the expression of some AR-modulated genes (TMPRSS2, NDRG1, GREB1, PSA, AR, FGF8, CdK1, CdK2 and PMEPA1). PCA3 expression levels were investigated in different cell compartments by using differential centrifugation and qRT-PCR. Results LNCaP siPCA3-transfected cells significantly inhibited cell growth and viability, and increased the proportion of cells in the sub G0/G1 phase of the cell cycle and the percentage of pyknotic nuclei, compared to those transfected with scramble siRNA (siSCr)-transfected cells. DHT-treated LNCaP cells induced a significant upregulation of PCA3 expression, which was reversed by flutamide. In siPCA3/LNCaP-transfected cells, the expression of AR target genes was downregulated compared to siSCr-transfected cells. The siPCA3 transfection also counteracted DHT stimulatory effects on the AR signaling cascade, significantly downregulating expression of the AR target gene. Analysis of PCA3 expression in different cell compartments provided evidence that the main functional roles of PCA3 occur in the nuclei and microsomal cell fractions. Conclusions Our findings suggest that the ncRNA PCA3 is involved in the control of PCa cell survival, in part through modulating AR signaling, which may raise new possibilities of using PCA3 knockdown as an additional therapeutic strategy for PCa control.

The aim of the present study was to investigate the involvement of oxidative stress in acute lung injury (ALI) induced by lipopolysaccharide (LPS) and its effects upon cell structure, function and inflammation. In total, 108 male C57BL/6 mice were divided into seven groups: CTR Group (50 µL of saline) administered intratracheally (i.t.), LPS 6 h (10 µg of LPS - i.t.), LPS 12 h (10 µg of LPS - i.t.), LPS 24 h (10 µg of LPS - i.t.), LPS 48 h (10 µg of LPS - i.t.), LPS 24 h (10 µg - i.t.) + NAC 40 mg/kg (gavage) and 24 h LPS (10 µg - i.t.) + NAC 100 mg/kg (gavage). The antioxidant treatment protected the lungs from stress in the first 12 h, but significant oxidative stress induction was observed at the 24-hour time point, and, after 48 h, there was no protection exerted by the antioxidant treatment. NAC (N-acetylcysteine) reversed the elastance parameters, and ΔP1 and ΔP2 compared with 24 h LPS alone. NAC reduced the number of inflammatory cells in histology analysis when compared with the 24 h LPS alone-treated group. NAC also inhibited the transcription of NFκB, IL-6, TNF-α and COX2 usually induced by LPS. Our results suggest that oxidative stress plays an important role in structural, functional and inflammatory responses in the ALI model.