Priya Suboj

Obesity-induced inflammation and desmoplasia promote pancreatic cancer progression and resistance to chemotherapy

UNLABELLED It remains unclear how obesity worsens treatment outcomes in patients with pancreatic ductal adenocarcinoma (PDAC). In normal pancreas, obesity promotes inflammation and fibrosis. We found in mouse models of PDAC that obesity also promotes desmoplasia associated with accelerated tumor growth and impaired delivery/efficacy of chemotherapeutics through reduced perfusion. Genetic and pharmacologic inhibition of angiotensin-II type-1 receptor reverses obesity-augmented desmoplasia and tumor growth and improves response to chemotherapy. Augmented activation of pancreatic stellate cells (PSC) in obesity is induced by tumor-associated neutrophils (TAN) recruited by adipocyte-secreted IL1β. PSCs further secrete IL1β, and inactivation of PSCs reduces IL1β expression and TAN recruitment. Furthermore, depletion of TANs, IL1β inhibition, or inactivation of PSCs prevents obesity-accelerated tumor growth. In patients with pancreatic cancer, we confirmed that obesity is associated with increased desmoplasia and reduced response to chemotherapy. We conclude that cross-talk between adipocytes, TANs, and PSCs exacerbates desmoplasia and promotes tumor progression in obesity. SIGNIFICANCE Considering the current obesity pandemic, unraveling the mechanisms underlying obesity-induced cancer progression is an urgent need. We found that the aggravation of desmoplasia is a key mechanism of obesity-promoted PDAC progression. Importantly, we discovered that clinically available antifibrotic/inflammatory agents can improve the treatment response of PDAC in obese hosts. Cancer Discov; 6(8); 852-69. ©2016 AACR.See related commentary by Bronte and Tortora, p. 821This article is highlighted in the In This Issue feature, p. 803.

Aloe emodin inhibits colon cancer cell migration/angiogenesis by downregulating MMP-2/9, RhoB and VEGF via reduced DNA binding activity of NF-κB.

Aloe emodin (AE), a natural anthraquinone, is reported to have antiproliferative activity in various cancer cell lines. In this study we analyzed molecular mechanisms involved in the antimigratory and antiangiogenic activity of this hydroxy anthraquinone in colon cancer cell, WiDr. Our results show that a relatively non toxic concentration of AE suppressed the phorbol-12-myristyl-13-acetate (PMA) induced migration and invasion of tumor cells. On analysis for the molecules involved in the migration/invasion, we found AE downregulated mRNA expression and promoter/gelatinolytic activity of Matrix Metalloproteinase (MMP)-2/9, as well as the RhoB expression at gene and protein level. It was also a strong inhibitor of Vascular Endothelial Growth Factor (VEGF) expression, promoter activity and endothelial cell migration/invasion and in vitro angiogenesis. AE suppressed the nuclear translocation and DNA binding of NF-κB, which is an important transcription factor for controlling MMP-2/9 and VEGF gene expression. Taken together these data indicate that AE target multiple molecules responsible for cellular invasion, migration and angiogenesis. Inhibitory effect on angiogenic and metastatic regulatory processes make AE a sensible candidate as a specific blocker of tumor associated events.

Insidious role of nitric oxide in migration/invasion of colon cancer cells by upregulating MMP-2/9 via activation of cGMP-PKG-ERK signaling pathways.

Nitric oxide (NO), an uncharged free radical is implicated in various physiological and pathological processes. The present study is an investigation on the effect of NO on proliferation, apoptosis and migration of colon cancer cells. Colon adenocarcinoma cells, WiDr, were used for the in vitro experiments. Tissues from colon adenocarcinoma, adjacent normal and inflammatory tissue and lymph node with metastasis were evaluated for iNOS, MMP-2/9 and Fra-1/Fra-2. NO increases the proliferation of cancer cells and simultaneously prevents apoptosis. Expression of MMP-2/9, RhoB and Rac-1 was enhanced by NO in a time dependent manner. Further, NO increased phosphorylation of ERK1/2 and induced nuclear translocation of Fra-1 and Fra-2. Electrophoretic mobility shift analysis and use of deletion mutant promoter constructs identified role of AP-1 in NO-mediated regulation of MMP-2/9. iNOS, MMP-2/9, Fra-1 and Fra-2 in normal and colon adenocarcinoma tissues were analyzed and it was found that increased expression of these proteins in cancer when compared to normal provides support to our in vitro findings. The study showed that the NO-cGMP-PKG promotes MMP-2/9 expression by activating ERK-1/2 and AP-1. This study reveals the insidious role of NO in imparting tumor aggressiveness.

Metformin Reduces Desmoplasia in Pancreatic Cancer by Reprogramming Stellate Cells and Tumor-Associated Macrophages

Background Pancreatic ductal adenocarcinoma (PDAC) is a highly desmoplastic tumor with a dismal prognosis for most patients. Fibrosis and inflammation are hallmarks of tumor desmoplasia. We have previously demonstrated that preventing the activation of pancreatic stellate cells (PSCs) and alleviating desmoplasia are beneficial strategies in treating PDAC. Metformin is a widely used glucose-lowering drug. It is also frequently prescribed to diabetic pancreatic cancer patients and has been shown to associate with a better outcome. However, the underlying mechanisms of this benefit remain unclear. Metformin has been found to modulate the activity of stellate cells in other disease settings. In this study, we examine the effect of metformin on PSC activity, fibrosis and inflammation in PDACs. Methods/Results In overweight, diabetic PDAC patients and pre-clinical mouse models, treatment with metformin reduced levels of tumor extracellular matrix (ECM) components, in particular hyaluronan (HA). In vitro, we found that metformin reduced TGF-ß signaling and the production of HA and collagen-I in cultured PSCs. Furthermore, we found that metformin alleviates tumor inflammation by reducing the expression of inflammatory cytokines including IL-1β as well as infiltration and M2 polarization of tumor-associated macrophages (TAMs) in vitro and in vivo. These effects on macrophages in vitro appear to be associated with a modulation of the AMPK/STAT3 pathway by metformin. Finally, we found in our preclinical models that the alleviation of desmoplasia by metformin was associated with a reduction in ECM remodeling, epithelial-to-mesenchymal transition (EMT) and ultimately systemic metastasis. Conclusion Metformin alleviates the fibro-inflammatory microenvironment in obese/diabetic individuals with pancreatic cancer by reprogramming PSCs and TAMs, which correlates with reduced disease progression. Metformin should be tested/explored as part of the treatment strategy in overweight diabetic PDAC patients.

Aloe Emodin Induces G2/M Cell Cycle Arrest and Apoptosis via Activation of Caspase-6 in Human Colon Cancer Cells

Aloe emodin (AE), a natural anthraquinone, is reported to have antiproliferative activity in various cancer cell lines. In this study, we analyzed the molecular mechanisms involved in the growth-inhibitory activity of this hydroxyanthraquinone in colon cancer cell, WiDr. In our observation AE inhibited cell proliferation by arresting the cell cycle at the G2/M phase and inhibiting cyclin B1. AE appreciably induced cell death specifically through the induction of apoptosis and by activating caspases 9/6. Apoptotic execution was found to be solely dependent on caspase-6 rather than caspase-3 or caspase-7. This is the first study indicating that the AE induces apoptosis specifically through the activation of caspase-6.

Obesity promotes resistance to anti-VEGF therapy in breast cancer by up-regulating IL-6 and potentially FGF-2

Targeting IL-6 and potentially FGF-2 overcomes resistance to anti-VEGF therapy in breast cancer. Tailored treatment for cancer in obesity Antiangiogenic therapy with inhibitors of the vascular endothelial growth factor (VEGF) has not proven effective in patients with many tumor types, including breast cancer. Meanwhile, obesity is a well-known risk factor in many cancer types, and once again, this includes breast cancer. Now, Incio et al. link these two observations, having discovered a mechanism by which obesity promotes resistance to VEGF inhibitor therapy through increased interleukin-6 and possibly also fibroblast growth factor 2 in the tumor microenvironment. The authors target these pathways in mouse models of cancer with and without obesity and demonstrate that the deleterious effects of obesity on VEGF inhibition can be overcome through the appropriate combination therapy. Anti–vascular endothelial growth factor (VEGF) therapy has failed to improve survival in patients with breast cancer (BC). Potential mechanisms of resistance to anti-VEGF therapy include the up-regulation of alternative angiogenic and proinflammatory factors. Obesity is associated with hypoxic adipose tissues, including those in the breast, resulting in increased production of some of the aforementioned factors. Hence, we hypothesized that obesity could contribute to anti-VEGF therapy’s lack of efficacy. We found that BC patients with obesity harbored increased systemic concentrations of interleukin-6 (IL-6) and/or fibroblast growth factor 2 (FGF-2), and their tumor vasculature was less sensitive to anti-VEGF treatment. Mouse models revealed that obesity impairs the effects of anti-VEGF on angiogenesis, tumor growth, and metastasis. In one murine BC model, obesity was associated with increased IL-6 production from adipocytes and myeloid cells within tumors. IL-6 blockade abrogated the obesity-induced resistance to anti-VEGF therapy in primary and metastatic sites by directly affecting tumor cell proliferation, normalizing tumor vasculature, alleviating hypoxia, and reducing immunosuppression. Similarly, in a second mouse model, where obesity was associated with increased FGF-2, normalization of FGF-2 expression by metformin or specific FGF receptor inhibition decreased vessel density and restored tumor sensitivity to anti-VEGF therapy in obese mice. Collectively, our data indicate that obesity fuels BC resistance to anti-VEGF therapy via the production of inflammatory and angiogenic factors.

Abstract LB-203: Obesity promotes resistance to anti-VEGF therapy in breast cancer via pro-inflammatory and angiogenic pathways

Background: Most breast cancer (BC) patients are overweight or obese at the time of diagnosis. Obesity is associated with increased risk, recurrence, and worse prognosis of BC. It has been shown that obesity associates with worse outcome in metastatic kidney or colon cancer treated with bevacizumab. If and how excess body weight contributes to the failure of anti-VEGF therapy in BC is unknown. Results: Here we found that diet-induced obesity promoted resistance to anti-VEGF therapy in two syngeneic mouse breast cancer models. The effects of anti-VEGF therapy on tumor growth and metastasis, VEGF downstream signaling pathways and vessel density were significantly attenuated in obese mice. Under obesity condition, intra-tumor adipocytes increased. These adipocyte-rich regions in breast cancers were hypoxic and overexpress IL-6 or FGF-2 by adipocytes, fibroblasts, and myeloid cells. In IL-6 overexpressing obese breast cancer model (E0771), neutralization of IL-6, either genetically or pharmacologically, abrogated the obesity-induced resistance to anti-VEGF therapy seen in both primary and metastasis sites. This occurred due to a reversion of the obesity-augmented STAT3 signaling and cell proliferation, of hypoxia via vessel normalization, and of immunosuppression. In another breast cancer model (MCaIV), which overexpress FGF-2 under obesity, anti-FGF receptor antibody restored tumor sensitivity to anti-VEGF treatment in obesity. Conclusion: Our findings indicate that obesity promotes resistance to anti-VEGF therapy in breast cancer via the production of pro-inflammatory and angiogenic factors that circumvent the loss of VEGF signaling. Citation Format: Joao Incio, Daniel McManus, Priya Suboj, Nuh Rahbari, Shan M. Chin, Suboj Babycutty, Trupti Vardan-Kaur, Yuhui Huang, Keehoon Jung, Dan Duda, Raquel Soares, Dai Fukumura, Rakesh K. Jain. Obesity promotes resistance to anti-VEGF therapy in breast cancer via pro-inflammatory and angiogenic pathways. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-203. doi:10.1158/1538-7445.AM2015-LB-203

Abstract 898: Obesity-induced inflammation and desmoplasia promote pancreatic cancer progression and resistance to chemotherapy

Introduction: With the current epidemic of obesity, the majority of pancreatic cancer patients are overweight or obese at diagnosis. Importantly, obesity worsens treatment outcomes in pancreatic cancer patients. Therefore, understanding the mechanisms that underlie the poorer prognosis of obese cancer patients is of paramount importance. Obesity causes inflammation and fibrosis in the normal pancreas due to the accumulation of dysfunctional hypertrophic adipocytes. Importantly, desmoplasia—a fibro-inflammatory microenvironment—is a hallmark of pancreatic ductal adenocarcinoma (PDAC), and we have shown that activation of pancreatic stellate cells (PSCs) via angiotensin-II type 1 receptor (AT1) pathway is a major contribution to tumor desmoplasia. Whether obesity affects inflammation, PSCs and desmoplasia in PDACs, and interferes with delivery and response of chemotherapeutics is currently unknown. Experimental Design: Using mouse models of PDAC—multiple syngeneic models of PDAC: PAN02, AK4.4, KPC, iKRAS in diet-induced and genetic obese mouse models—we determined the effects of obesity on desmoplasia and inflammation, tumor growth and delivery and response to chemotherapy. We further evaluated whether the obesity-induced effects were mediated by AT1 signaling as well as via immune cell recruitment, and dissected the crosstalk between PSCs, cancer-associated adipocytes (CAAs), and tumor-associated neutrophils (TANs). In addition, we determined if an anti-diabetic drug metformin could counter these effects in vivo, and further dissected the mechanism of action in vitro. Results: We found that obesity aggravates desmoplasia in PDACs in multiple mouse models. In addition, tumors in obese mice presented with elevated levels of activated PSCs and fibrosis, as well as inflammatory cytokines and TANs. These alterations in the tumor microenvironment in obesity associated with accelerated tumor growth, reduced tumor blood perfusion and increased hypoxia, and impaired delivery and efficacy of chemotherapeutics. Genetic ablation and pharmacological inhibition (losartan) of AT1 signaling reversed obesity-augmented desmoplasia and tumor growth, and improved the response to chemotherapy to the level observed in lean mice. We further discovered the underlying mechanisms: 1) obesity increases intra-tumor adipocytes and IL-1s secretion by these cells; 2) increased IL-1s induces TAN recruitment; 3) recruited TANs activate PSCs; and 4) activated PSCs enhance desmoplasia. Conversely, activated PSCs also secrete IL-1s that recruits further TANs. Hence, inactivation of PSCs through AT1 blockade resulted in not only decreased fibrosis but also reduced IL-1s level and TAN recruitment. Furthermore, reduction of either TANs, IL-1s, or PSC activation reduced tumor growth in obese mice. These findings suggest that crosstalk between adipocytes, immune cells, and PSCs exacerbates desmoplasia and promotes tumor progression during obesity. Of clinical relevance, we found that metformin not only normalizes the abnormal systemic metabolism, but also alleviates the fibro-inflammatory microenvironment in pancreatic cancer in obesity/diabetes. This occurred via direct reprogramming of PSCs and immune cells by metformin. Importantly, the strategies described above were not effective in the normal weight setting. Conclusion: Here we successfully demonstrated that targeting desmoplasia, including immunomodulation with anti-IL-1s, or treatment with generic drugs such as losartan and metformin are potential strategies to potentiate treatments in PDAC patients with excess weight. With a better understanding of the mechanisms by which obesity promotes tumor progression and therapy resistance, we will be able to improve the current standard of care in pancreatic cancer. Citation Format: Joao Incio, Hao Liu, Priya Suboj, Shan Min, Ivy Chen, Mei Ng, Hadi Nia, Jelena Grahovac, Shannon Kao, Suboj Babykutty, Yuhui Huang, Keehoon Jung, Nuh Rahbari, Xiaoxing Han, Vikash Chauhan, John Martin, Julia Kahn, Peigen Huang, Vikram Deshpande, James Michaelson, Cristina Ferrone, Raquel Soares, Yves Boucher, Dai Fukumura, Rakesh Jain. Obesity-induced inflammation and desmoplasia promote pancreatic cancer progression and resistance to chemotherapy. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A45.