Hypoxia theranostics of a human prostate cancer xenograft and the resulting effects on the tumor microenvironment

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Developed a hypoxia theranostic imaging strategy to eliminate hypoxic cells.

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Hypoxic cell elimination resulted in fewer cancer associated fibroblasts (CAFs)

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Collagen 1 fiber patterns were altered with hypoxic cell elimination.

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cDNA nanoparticles with HRE driven prodrug enzyme expression can target hypoxia.

Hypoxia is frequently observed in human prostate cancer, and is associated with chemoresistance, radioresistance, metastasis, and castrate-resistance. Our purpose in these studies was to perform hypoxia theranostics by combining in vivo hypoxia imaging and hypoxic cancer cell targeting in a human prostate cancer xenograft. This was achieved by engineering PC3 human prostate cancer cells to express luciferase as well as a prodrug enzyme, yeast cytosine deaminase, under control of hypoxic response elements (HREs). Cancer cells display an adaptive response to hypoxia through the activation of several genes mediated by the binding of hypoxia inducible factors (HIFs) to HRE in the promoter region of target gene that results in their increased transcription. HIFs promote key steps in tumorigenesis, including angiogenesis, metabolism, proliferation, metastasis, and differentiation. HRE-driven luciferase expression allowed us to detect hypoxia in vivo to time the administration of the nontoxic prodrug 5-fluorocytosine that was converted by yeast cytosine deaminase, expressed under HRE regulation, to the chemotherapy agent 5-fluorouracil to target hypoxic cells. Conversion of 5-fluorocytosine to 5-fluorouracil was detected in vivo by ¹⁹F magnetic resonance spectroscopy. Morphological and immunohistochemical staining and molecular analyses were performed to characterize tumor microenvironment changes in cancer-associated fibroblasts, cell viability, collagen 1 fiber patterns, and HIF-1α. These studies expand our understanding of the effects of eliminating hypoxic cancer cells on the tumor microenvironment and in reducing stromal cell populations such as cancer-associated fibroblasts.

Abstract 3480: COX-2 alters the metabolic secretome in triple negative human breast cancer xenografts

Cyclooxygenase-2 (COX-2) is an active mediator of the inflammatory response of cells and plays an important role in the development, progression, invasion, and metastasis of cancers including breast cancer [1]. Tumor interstitial fluid (TIF), the milieu that contains the tumor secretome, is one of the least examined aspects of the TME because of the difficulty in sampling this fluid from tumors. Here, for the first time, we have sampled TIF from COX-2 overexpressing triple negative SUM-149 human breast cancer xenografts and empty vector SUM-149 xenografts.

The cloning, construction of a lentivirus vector expressing COX-2 gene, and the establishment of SUM-149 cells stably overexpressing COX-2 (SUM-COX-2) were reported by us previously[2]. A home-built TIF collection chamber was inserted subcutaneously in female SCID mice with 4-6 1-2 mm tumor pieces packed around the chamber. Once tumors were ~ 400 mm3, TIF was collected from chambers. Each chamber yielded ~50μL of TIF that was analyzed with high-resolution 1H magnetic resonance spectroscopy (MRS) at 750 MHz.

SUM-COX-2 tumors showed consistently higher COX-2 expression compared to SUM-EV tumors. COX-2 overexpression resulted in a significant increase of lactate, glutamate, acetate, and succinate, and a significant decrease of glucose, glutamine, citrate, formate, and lipids; pyruvate tended to decrease. The changes in lactate and lipids are consistent with our earlier observations where COX-2 downregulation in triple negative MDMB-231 human breast cancer cells resulted in a significant decrease of lactate and an increase of lipids and lipid droplets in intact perfused cells[3]. Here, COX-2 overexpression increased glycolysis. Depletion of pyruvate observed here in COX-2 overexpressing cells would limit production of acetyl-CoA and consequently citrate to diminish fatty acid synthesis/lipids. Increased succinate parallels the increase in glutamate/α-ketoglutarate, the upstream intermediate to succinate in the tricarboxylic acid cycle [1], and indicates increased utilization/depletion of glutamine to supplement the TCA cycle. Importantly, accumulation of succinate inhibits HIF-1α prolyl hydroxylase that stabilizes HIF-1α driven cancer promoting metabolic pathways such as enhanced glycolysis and increased ROS[4]. Moreover, increased succinate also through the succinate/succinate dehydrogenase reaction, provides necessary electrons to the electron transport chain upstream of the COX-2 reaction[5]. These data provide new insights into the role of COX-2 in the metabolic secretome and tumor metabolism, and identify metabolic pathways as potential targets for reducing the effects of COX-2 expression in cancer.

Ref.

1. Wang et. al. Nat. Rev. Can. 2010

2. Krishnamachary et al. Oncot. 2017

3. Shah et al. NMR Biomed. 2012

4. Selak et al. Can Cell. 2005

5. Mills et al. Trd in Cell Bio. 2014

Citation Format: Santosh Kumar Bharti, Paul T. Winnard, Yelena Mironchik, Louis Dore-Savard, Balaji Krishnamachary, Zaver M. Bhujwalla. COX-2 alters the metabolic secretome in triple negative human breast cancer xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3480.

Abstract 2495: The metabolic secretome of cachexia inducing pancreatic ductal adenocarcinoma

Cachexia is an underexplored and yet devastating consequence of cancer that is the cause of 20% of all cancer related deaths1. Cachexia inducing tumors cause a ‘wasting away’ of the body. The condition is associated with poor treatment outcome2, fatigue, and extremely poor quality of life2,3. Because of the multi-factorial characteristics of this condition, it has been difficult to understand the mechanisms driving the impact of the tumor on body organs and the sequence of events that leads to this lethal condition. Here we have used 1H MRS to characterize the metabolic profile of tumor interstitial fluid (TIF) obtained from noncachexia (Panc1) and cachexia inducing (Pa04C) tumors to further understand the impact of the deranged metabolism of cachexia-inducing tumors on the tumor metabolic secretome.

The human pancreatic cancer cell line, Panc1, was obtained from ATCC. The human pancreatic cancer cell line, Pa04C, was provided by Dr. Maitra4. Six to 8 week old male SCID mice were inoculated in both the right and left flank with cancer cells (5×106, Panc1 N=2, Pa04C N=2). We created a collection chamber to collect TIF. The chamber was implanted together with small tumor pieces harvested from the subcutaneous flank tumors, into the subcutaneous flank space of SCID mice (Panc1 N=8 and Pa04C N=6) until the tumor encompassed the chamber (4-5 weeks). The tumor was then removed and the tumor tissue and TIF were collected. To obtain control TIF, an empty chamber was implanted in the subcutaneous flank space of healthy mice. Dual phase solvent extraction was performed on tumor tissue. The water phase was separated, freeze dried, reconstituted in D2O PBS for spectral acquisition. All 1H MR spectra were acquired on an Avance III 750 MHz (17.6T) Bruker NMR spectrometer equipped with a 5 mm broad band inverse (BBI) probe. Spectral acquisition, processing and quantification were performed using TOPSPIN 2.1 software.

Notable differences between Pa04C compared to Panc1 TIF or normal interstitial fluid were a significant decrease of polyunsaturated fatty acids (PUFA) and lipids, and formate, pyruvate, glutamine, and glucose. Lactate, glutamate, succinate, glycine and acetone significantly increased in Pa04C TIF compared to Panc1 TIF or normal interstitial fluid. These differences in TIF cannot be explained solely by the differences in the tumor metabolic profile. Our data provide new insights into changes in the metabolic secretome with induction of cachexia that may shed new light on the cachexia cascade, and identify metabolic strategies to reverse the syndrome.

References:

(1) Argiles, J. M., et al. Nature reviews. Cancer 2014, 14, 754-762.

(2) Ozola Zalite, I., et al. Pancreatology 2015, 15, 19-24.

(3) Fearon, K. C., et al. HPB (Oxford) 2010, 12, 323-324.

(4) Penet, M. F., et al. Clinical Cancer Research 2015, 21, 386-395.

Acknowledgment: This work was supported by NIH R01 CA193365, NIH P50CA013175 and NIH P30CA06973.

Citation Format: Santosh K. Bharti, Paul T. Winnard, Louis Dore-Savard, Yelena Mironchik, Marie-France Penet, Zaver M. Bhujwalla. The metabolic secretome of cachexia inducing pancreatic ductal adenocarcinoma [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 2495. doi:10.1158/1538-7445.AM2017-2495

Delayed Progression of Lung Metastases Following Delivery of a Prodrug-activating Enzyme

BACKGROUND

Chemotherapy is an effective option to treat recurrent or metastatic cancer but its debilitating side-effects limit the dose and time of exposure. Prodrugs that can be activated locally by an activating enzyme can minimize collateral damage from chemotherapy. We previously demonstrated the efficacy of a poly-L-lysine-based theranostic nanoplex containing bacterial cytosine deaminase (bCD) that locally converted 5-fluorocytosine (5-FC) to the chemotherapeutic agent 5-fluorouracil in MDA-MB-231 primary tumor xenografts.

MATERIALS AND METHODS

Here we used a more effective variant of bCD to target metastatic red fluorescence protein expressing MDA-MB-435 cells in the lungs. We used an intravenous injection of tumor cells and monitored tumor growth in the lungs for 5 weeks by which time metastatic nodules were detected with optical imaging. The animals were then treated with the bCD-nanoplex and 5-FC.

RESULTS

We observed a significant decrease in metastatic burden with a single dose of the enzyme-nanoplex and two consecutive prodrug injections.

CONCLUSION

These results are a first step towards the longitudinal evaluation of such a strategy with multiple doses. Additionally, the enzyme can be directly coupled to imaging reporters to time prodrug administration for the detection and treatment of aggressive metastatic cancer.

Abstract 4228: Imaging and targeting of hypoxic microenvironments in prostate cancer

Cancer cells display an adaptive response to hypoxia through the activation of several genes mediated by the binding of hypoxia inducible factors (HIFs) to hypoxia response elements (HRE) in the promoter region of target gene that results in their increased transcription [1]. HIFs promote key steps in tumorigenesis, including angiogenesis, metabolism, proliferation, metastasis, and differentiation [1]. Bacterial or yeast cytosine deaminase (yCD) converts the nontoxic prodrug 5-fluorocytosine (5-FC) to the anti-cancer drug 5-fluorouracil (5-FU) that is widely used in cancer treatment [2]. Using a lentivirus approach, we established controlled expression of yCD by HRE in prostate cancer cells (PC-3). These cells also report on HIF-1α expression with regulated luciferase (Luc) expression, allowing detection of hypoxia, and the generation of 5-FU from 5-FC by yCD in the presence of hypoxia. Transduction efficiency and reporter activity in response to hypoxia was evaluated by performing luciferase assays, and bioluminescence imaging (BLI) of cells in vitro or in vivo using a Xenogen IVIS Spectrum system. Cell viability in vitro in response to hypoxia in the presence of 5-FC was assessed by MTS assay. In vivo studies were performed by inoculating 2×10⁁6 PC-3-HRE-Luc cells and PC-3-HRE-yCD+Luc cells on either flank of 5-week-old male severely combined immune deficient (SCID) mice. BLI was performed once tumors reached ∼200mm3 followed by 5-FC injection through the tail vein (200mg/kg) and intraperitoneally (250mg/kg). BLI was performed 3 days after the first 5-FC injection and continued through the treatment protocol. At the end of the treatment protocol, tumors were excised, and a part of the tumor was processed for immunohistochemistry. Bioluminescence was detected in both PC3-HRE-Luc and PC-3-HRE-yCD+Luc cells only in response to the hypoxia mimetic cobalt chloride or hypoxia (1% O2) confirming the regulation of luciferase by hypoxia and activation of CD. Expression of yCD and its ability to convert the prodrug 5-FC to 5-FU, with increased cell kill was evident under hypoxia. In vivo, engineered PC-3-HRE-yCD+Luc cells reported hypoxia, and showed significant reduction of hypoxic regions and tumor volume. Morphologically, PC-3-HRE-yCD+Luc tumors exhibited extensive necrosis. We are currently evaluating the effects of eliminating hypoxic cancer cells on distant metastasis as well as on aggressive subpopulations such as cancer stem cells in the primary tumor.

References: [1] Philip, B., et al., Carcinogenesis, 2013. 34(8):1699-707.,[2] Longley DB, et al., Nat Rev Cancer, 2003. 3: 330-38.

Acknowledgements: This work was supported by NIH R01CA136576 and P50 CA103175. We thank Mr. Gary Cromwell for technical assistance

Citation Format: Balaji Krishnamachary, Louis Dore-Savard, Santosh Kumar Bharti, Flonne Wildes, Yelena Mironchik, Margaret E. Black, Zaver M. Bhujwalla. Imaging and targeting of hypoxic microenvironments in prostate cancer. [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 4228.

Abstract 3370: Metabolic profiling of the tumor interstitial fluid using 1H MRS: contribution of breast cancer subtypes and VEGF overexpression

One of the least examined, and yet critically important factors of the tumor microenvironment (TME) is the tumor interstitial fluid (TIF) that contains the tumor secretome. This fluid surrounds cancer and stromal cells and contains various cytokines, and nutritional and molecular factors that shape the outcome of nearly all aspects of tumor angiogenesis, growth, metastasis, and response to treatment. As mining of targets to treat cancer expands into the TME, the TIF represents an important source of identifying new targets in cancer treatment. Angiogenesis, one of the major hallmarks of cancer, is essential for cancers to establish vasculature for growth and hematogenous metastasis. To further understand the TIF and plasma metabolite content in breast cancer, and the role of VEGF in modifying metabolite concentrations in the TME, here we used 1H MRS to characterize metabolites in TIF collected from the triple negative MDA-MB-231 and the ER-positive MCF-7 human breast cancer xenografts with and without VEGF overexpression implanted in SCID mice. We created a collection chamber to collect IF from the tumors. The chamber was implanted with small tumor pieces in the subcutaneous space until the tumor encompassed the chamber (4 to 12 weeks depending on cell types). The tumor was then excised and the TIF and blood plasma were collected from euthanized mice. We also collected normal subcutaneous IF (SCIF) using the same chamber in healthy mice. 1H spectra showed several differences in metabolites in TIF compared to SCIF, between MDA-MB-231 and MCF-7 TIF, and with VEGF overexpression. We observed a consumption of amino acids in the TME with decreases ranging from 17% (glycine) to 77% (methionine) compared to normal SCIF. Lipids, especially polyunsaturated fatty acids, were markedly increased by VEGF overexpression in both MCF-7 and MDA-MB-231 TIF compared to the wild type TIF. Choline metabolism was also modified by VEGF overexpression and we measured increases of 69% and 20% in free choline in MDA-MB-231_VEGF and MCF-7_VEGF respectively, compared to their wild type counterpart. A stable glucose concentration was associated with a decrease in lactate (30%) and pyruvate (44%) in MDA-MB-231 tumors while an opposite pattern was observed in MDA-MB-231_VEGF TIF with decreased glucose (55%) and increased lactate (109%). Ketonic metabolism was also modified in those tumors. Beta-hydroxybutyrate and acetoacetate were higher (81% and 46% increase vs SCIF, respectively) in MDA-MB-231 TIF while acetone was increased in both VEGF-overexpressing TIF compared to the wild type (+48% for MDA-MB-231_VEGF and +44% for MCF-7_VEGF). The TIF represents an importance source of information to understand mechanisms that drive aggressiveness, and identify new targets for diagnosis and therapy of cancer.

Citation Format: Louis Dore-Savard, Santosh K. Bharti, Aleksander S. Popel, Zaver M. Bhujwalla. Metabolic profiling of the tumor interstitial fluid using 1H MRS: contribution of breast cancer subtypes and VEGF overexpression. [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 3370.

Abstract 4172: Differential angiogenesis-related cytokines release in tumor interstitial fluid and plasma in ER-positive and triple-negative breast cancers overexpressing VEGF

Interstitial fluid (IF) is a key component of the tumor microenvironment (TME) that has been largely overshadowed by proteomic and genomic analysis of the cancer cell and stromal compartments of the TME. Early studies of tumor IF by Gullino and colleagues showed elevated protein and lactic acid levels and the absence of glucose. Modern analytical methods allow for comprehensive characterization of IF proteins to better understand the TME. We modified Gullino's model and created a collection chamber adapted to collect IF from mouse tumors. We used ER-positive MCF-7 and triple negative MDA-MB-231 breast cancer cells in SCID mice. Additionally, we created VEGF-overexpressing cells from each cell line to evaluate the effect of VEGF overexpression on angiogenic cytokines in tumor IF. The chamber was implanted with small tumor pieces in the subcutaneous space until the tumor encompassed the chamber (4 to 12 weeks depending on cell types). The tumor was then removed and the tumor IF (approximate volume 40μl) and blood plasma were collected. IF and plasma samples were analyzed using a multiple cytokine immunoassay (Proteome Profiler Human Angiogenesis Kit, R & D Systems Inc., Minneapolis MN). Among the 55 human angiogenesis-related cytokines tested, only 4 were detected in MCF-7 tumors IF, and 24 were detected in MDA-MB-231 IF sample. As anticipated, high VEGF levels were detected in MCF-7 overexpressing cells. Additionally, we observed a tendency to an elevated level of TIMP metallopeptidase inhibitor 1 (TIMP-1). All 4 cytokines detected in MCF-7 IF were also detected in MDA-MB-231 IF. VEGF overexpression had minimal effect on the tested cytokines. However, decreased levels of angiogenin and endostatin were observed. In plasma of tumor-bearing mice, 5 cytokines were detected. For instance, Serpin E1 (PAI-1) and TIMP-1 were detected in the plasma of both MCF-7 and MDA-MB-231, at lower levels than in IF. However, urokinase plasminogen activator was present only in mice with triple negative MDA-MB-231 tumors. We anticipate that a better understanding of the TME, via the characterization of the IF, will help identify new targets for diagnosis and therapy of cancer. We intend to examine correlations between the present data and human databanks to confirm the relevance of our model systems.

Citation Format: Louis Dore-Savard, Esak Lee, Aleksander S. Popel, Zaver M. Bhujwalla. Differential angiogenesis-related cytokines release in tumor interstitial fluid and plasma in ER-positive and triple-negative breast cancers overexpressing VEGF. [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 4172. doi:10.1158/1538-7445.AM2015-4172

Abstract 5364: Delayed progression of lung metastases in a triple-negative breast cancer model following delivery of cytosine deaminase that converts chemotherapeutic prodrug 5-fluorocytosine to 5-fluorouracil

Triple negative breast cancer (TNBC) is aggressive, has a very poor prognosis with a high rate of reoccurrence and is refractory to standard chemo- and radiotherapy. Still, chemotherapy is an effective option to treat recurrent or metastatic cancers if the debilitating side effects limiting the dose and time of exposure can be diminished. The use of pro-drugs that can be activated locally by a prodrug enzyme can minimize collateral damage since the presence of the enzyme in the tumor and clearance from normal tissue can be verified noninvasively with imaging, which allows for optimal timing of prodrug administration (1). We previously demonstrated the efficacy of the prodrug 5-fluorocytosine (5-FC) in primary triple negative MDA-MB-231 xenografts following administration of a poly-L-lysine based theranostic nanoplex containing bacterial cytosine deaminase (bCD) that converts 5-FC to the chemotherapeutic agent 5-fluorouracil. The size of the bCD-nanoplex of ∼ 300 kD allowed its delivery into the tumor interstitium through leaky tumor vasculature but not through normal vasculature (1). Here we used a more effective variant of bCD (2) to target metastatic MDA-MB-231 cells. We injected 2 × 106 td-tomato fluorescent protein expressing MDA-MB-231 cells intravenously and monitored metastases formation in the lungs for 5 weeks by which time metastatic nodules were detected. We then treated the animals with the bCD-nanoplex (300 mg/kg i.v.). Twenty-four hours later, we injected a first dose of 5-FC (200 mg/kg i.v. and 250 mg/kg i.p.), repeated at 72 hours. The animals were followed for 2 weeks with weekly optical imaging at the end of which mice were euthanized and the lungs excised. We histologically evaluated metastatic burden (area occupied by metastatic cells/total lung area) in mice treated with bCD-nanoplex + 5-FC (n = 5) and in mice injected with the bCD-nanoplex only (n = 6). We observed a 32% decrease in metastatic burden in the pro-drug treated group vs the control group (14.8% + 1.5% in treated mice vs 22.0% + 2.6% in control mice, p = 0.03). These results are a first step towards the longitudinal evaluation of such a strategy with multiple doses. Additionally, the nanoplex can be coupled to multimodal imaging reporters (1) to time prodrug administration and improve the detection and treatment of triple negative, hormone refractory metastatic cancers.

References. 1. Li et al., Clin Can Res., 2008; 2. Fuchita et al., Can Res., 2009.

This work was supported by NIH R01CA138515 and P50 CA103175.

Citation Format: Louis Dore-Savard, Zhihang Chen, Paul T. Winnard, Balaji Krishnamachary, Marie-France Penet, Venu Raman, Margaret E. Black, Zaver Bhujwalla. Delayed progression of lung metastases in a triple-negative breast cancer model following delivery of cytosine deaminase that converts chemotherapeutic prodrug 5-fluorocytosine to 5-fluorouracil. [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 5364. doi:10.1158/1538-7445.AM2015-5364

Abstract 3001: Angiogenesis-related cytokine secretion pattern in tumor interstitial fluid and its relationship with VEGF expression and metastatic profile

The tumor microenvironment (TME) contributes significantly to the phenotypic characteristics of cancer. Unraveling the roles of the TME in cancer growth and treatment, as well as mining the TME for treatment strategies is increasingly occupying center-stage. One of the least examined, and yet critically important factors in the TME is the tumor interstitial fluid (IF). This fluid surrounds cancer and stromal cells within the tumor, and contains various cytokines, and nutritional and molecular factors that shape the outcome of nearly all aspects of tumor growth, metastasis, and response to treatment. Here we have characterized IF from human breast cancer xenografts in SCID mice. The IF was obtained from the tumor using a small custom-built diffusion chamber (outer diameter 6.2 mm, inner volume approx. 40 µl) implanted in the subcutaneous space. The chamber was surrounded by 4-6 tumor pieces that were allowed to grow for 4-6 weeks that resulted in the chamber being incorporated within the tumor. Three different human breast carcinoma cell lines were used to analyze tumor IF content: invasive, highly metastatic MDA-MB-231 cells, less invasive MCF-7 cells and MCF-7 cells engineered to overexpress vascular endothelial growth factor (VEGF). After IF, plasma and tumor collection, IF samples were analyzed using a multiple cytokine assay (Proteome Profiler Human Angiogenesis Kit, R & D Systems Inc., Minneapolis MN). With this kit, 55 human angiogenesis-related cytokines were investigated for relative secretion levels. Our results identified differences in cytokine content in tumors derived from these cells. Out of the 55 cytokines tested, 24 were detected in the IF. Of these, more than 80% (20) were detected in MDA-MB-231 tumors only. Additionally, MDA-MB-231 derived tumor IF showed increased levels of TIMP metallopeptidase inhibitor 1 (TIMP-1), urokinase plasminogen activator (uPA) and Serpin E1 compared to MCF-7 cells. As expected, high VEGF levels were detected in the IF of tumors derived from VEGF-overexpressing MCF-7 cells compared to wild type cells. VEGF overexpression also influenced the levels of TIMP-1, Serpin E1 and uPA in the IF. Variations in IF cytokine content of cancers with different metastatic and angiogenic abilities provide further understanding of the TME. Measurement of cytokine content is only the first step towards the correlation of tumor IF cytokine levels with tumor vascular properties and anti-angiogenic treatments. A better understanding of the TME through characterization of the IF may identify new targets for cancer treatment and allow for optimization of therapeutic strategies.

Supported by NIH R01CA138264 and R01CA136576.

Citation Format: Louis Dore-Savard, Esak Lee, Aleksander S. Popel, Zaver M. Bhujwalla. Angiogenesis-related cytokine secretion pattern in tumor interstitial fluid and its relationship with VEGF expression and metastatic profile. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3001. doi:10.1158/1538-7445.AM2014-3001