Matrix Metalloproteinase 14 promotes lung cancer by cleavage of Heparin-Binding EGF-like Growth Factor

Molecularly targeted therapies benefit approximately 15–20% of non-small cell lung cancer (NSCLC) patients carrying specific drug-sensitive mutations. Thus, there is a clinically unmet need for the identification of novel targets for drug development. Here, we performed RNA-deep sequencing to identify altered gene expression between malignant and non-malignant lung tissue. Matrix Metalloproteinase 14 (MMP14), a membrane-bound proteinase, was significantly up-regulated in the tumor epithelial cells and intratumoral myeloid compartments in both mouse and human NSCLC. Overexpression of a soluble dominant negative MMP14 (DN-MMP14) or pharmacological inhibition of MMP14 blocked invasion of lung cancer cells through a collagen I matrix in vitro and reduced tumor incidence in an orthotopic K-Ras^G12D/+p53^−/− mouse model of lung cancer. Additionally, MMP14 activity mediated proteolytic processing and activation of Heparin-Binding EGF-like Growth Factor (HB-EGF), stimulating the EGFR signaling pathway to increase proliferation and tumor growth. This study highlights the potential for development of therapeutic strategies that target MMP14 in NSCLC with particular focus on MMP14-HB-EGF axis.

Abstract 3214: Genome-wide analysis of stroma-tumor crosstalk pathways in lung cancer: therapeutic implications

We have systematically dissected the microenvironmental hetereogeneity of lung adenocarcinomas, and provide cellular and molecular landscapes that contribute to carcinogenesis. RNA deep sequencing analysis of individually sorted stromal and tumor epithelial compartments from fresh clinical specimens and a mouse model of KrasG12D; p53-/- tumors identified cell type-specific differentially regulated genes, indicative of tumor “activated/reprogrammed” stroma. We developed a computational crosstalk discovery algorithm to model crosstalk signaling discovery based on ligand-receptor interactions and downstream signaling networks, and identified novel tumor-stroma paracrine and tumor autocrine crosstalk signaling pathways in the lung cancer microenvironment. We have explored the mechanistic basis of selected crosstalk pathways including HGF-MET, IL6-Stat3, Tsp-1-CD36, MMP14-HB-EGF in conferring lung adenocarcinoma progression and in mediating therapeutic resistance, and have used both genetic and pharmacological approaches to block these pathways. This study has the potential for development of therapeutic strategies that target tumor-stroma interactions, and may complement conventional anti-cancer treatments.

Citation Format: Hyejin Choi, Jianting Shen, Anna Durrans, Tina El Rayes, Kari Fischer, Dingcheng Gao, Steve Wong, Nasser Altorki, Vivek Mittal. Genome-wide analysis of stroma-tumor crosstalk pathways in lung cancer: therapeutic implications. [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 3214. doi:10.1158/1538-7445.AM2015-3214

Identification of Reprogrammed Myeloid Cell Transcriptomes in NSCLC

Lung cancer is the leading cause of cancer related mortality worldwide, with non-small cell lung cancer (NSCLC) as the most prevalent form. Despite advances in treatment options including minimally invasive surgery, CT-guided radiation, novel chemotherapeutic regimens, and targeted therapeutics, prognosis remains dismal. Therefore, further molecular analysis of NSCLC is necessary to identify novel molecular targets that impact prognosis and the design of new-targeted therapies. In recent years, tumor “activated/reprogrammed” stromal cells that promote carcinogenesis have emerged as potential therapeutic targets. However, the contribution of stromal cells to NSCLC is poorly understood. Here, we show increased numbers of bone marrow (BM)-derived hematopoietic cells in the tumor parenchyma of NSCLC patients compared with matched adjacent non-neoplastic lung tissue. By sorting specific cellular fractions from lung cancer patients, we compared the transcriptomes of intratumoral myeloid compartments within the tumor bed with their counterparts within adjacent non-neoplastic tissue from NSCLC patients. The RNA sequencing of specific myeloid compartments (immature monocytic myeloid cells and polymorphonuclear neutrophils) identified differentially regulated genes and mRNA isoforms, which were inconspicuous in whole tumor analysis. Genes encoding secreted factors, including osteopontin (OPN), chemokine (C-C motif) ligand 7 (CCL7) and thrombospondin 1 (TSP1) were identified, which enhanced tumorigenic properties of lung cancer cells indicative of their potential as targets for therapy. This study demonstrates that analysis of homogeneous stromal populations isolated directly from fresh clinical specimens can detect important stromal genes of therapeutic value.

Transcriptome analysis of individual stromal cell populations identifies stroma-tumor crosstalk in mouse lung cancer model

Emerging studies have begun to demonstrate that reprogrammed stromal cells play pivotal roles in tumor growth, metastasis, and resistance to therapy. However, the contribution of stromal cells to non-small-cell lung cancer (NSCLC) has remained underexplored. We used an orthotopic model of Kras-driven NSCLC to systematically dissect the contribution of specific hematopoietic stromal cells in lung cancer. RNA deep-sequencing analysis of individually sorted myeloid lineage and tumor epithelial cells revealed cell-type-specific differentially regulated genes, indicative of activated stroma. We developed a computational model for crosstalk signaling discovery based on ligand-receptor interactions and downstream signaling networks and identified known and novel tumor-stroma paracrine and tumor autocrine crosstalk-signaling pathways in NSCLC. We provide cellular and molecular insights into components of the lung cancer microenvironment that contribute to carcinogenesis. This study has the potential for development of therapeutic strategies that target tumor-stroma interactions and may complement conventional anti-cancer treatments.

Abstract 4972: Analysis of the reprogrammed bone marrow-derived stroma in lung cancer unravels potential targets for prognosis and therapy

Background: Lung cancer is the leading cause of cancer related mortality, with NSCLC the most prevalent form. Despite advances in treatment options (minimally invasive surgery, CT-guided radiation, novel chemotherapy regimens, targeted therapeutics) prognosis remains dismal. Most research to date has focused on cancer cell intrinsic mutagenesis (K-ras, p53, EGFR, EML4-ALK fusion), however recent studies have begun to recognize that cross talk between tumor epithelial cells and intratumoral stromal cells contributes to tumor progression. Unfortunately, little is known about the contribution or role of the stroma in NSCLC. Here, we present the first comprehensive analysis of specific individual stromal components of human NSCLC, which has led to the identification of stromal-specific activated pro-tumorigenic genes of prognostic and therapeutic potential.

Materials and Methods: Surgically resected Stage I/II adenocarcinoma and matched adjacent non-neoplastic lung tissue were mechanically dissociated within 1hour of resection. Cell populations marked with specific antibodies were sorted to homogeneity by flow cytometry. RNA was isolated to construct cDNA libraries, which were deep sequenced using the Illumina HiSeq 2000. Validation of differentially regulated genes was carried out by RT-PCR and immunostaining. Mouse models of K-rasG12D and p53flox/flox derived NSCLC together with a bone marrow transplantation approach were used to determine the functional role of activated genes, and a NSCLC tissue microarray was used to ascertain their prognostic value.

Results: Flow cytometry analysis revealed a 4-fold increase in the number of intratumoral hematopoietic cells, compared with adjacent non-neoplastic lung tissue. Deep RNA sequencing of two predominant myeloid specific subpopulations, CD11b+CD33+ monocytic myeloid cells and CD11b+CD33- polymorphonuclear neutrophils, revealed 783 and 938 differentially regulated genes respectively when comparing tumor vs. adjacent lung-derived cells. Many genes encoded secreted proteins such as OPN, TSP1, CCL7, and MMP12, suggesting activation of aberrant autocrine and paracrine regulatory pathways likely to support stromal-mediated tumor progression. We will present data showing the prognostic and therapeutic potential of these genes in NSCLC.

Conclusions: This study is based on an emerging paradigm that activated intratumoral stromal cells play a fundamental role in promoting tumor growth. Using a unique and novel approach of quantitative analysis of individual stromal components from freshly procured NSCLC tumor tissue, we have identified differentially regulated genes previously undiscovered in traditional whole tumor profiling approaches. The activated stromal genes constitute novel therapeutic targets against lung cancer, either alone or in combination with treatments that target cancer cells.

Citation Format: Anna Durrans, Dingcheng Gao, Ravi Gupta, Seongho Ryu, Navneet Narula, Kari R. Fischer, Hyejin Choi, Brendon M. Stiles, Abu Nasar, Ramana V. Davuluri, Nasser K. Altorki, Vivek Mittal. Analysis of the reprogrammed bone marrow-derived stroma in lung cancer unravels potential targets for prognosis and therapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4972. doi:10.1158/1538-7445.AM2013-4972

Abstract 1420: Mechanisms of stroma-derived CCL7 in promoting lung cancer

Lung cancer is a leading cause of cancer related deaths worldwide, with non-small cell lung cancer (NSCLC) being the most prevalent form. Considerable attention has been directed to cancer cell intrinsic abnormalities (K-ras, p53, EGFR, AML-ALK4 fusions etc.), but little is known about the contribution of stromal cells to NSCLC progression.

We have undertaken a comprehensive analysis to determine the contribution and biological function of the stromal cells in NSCLC. We show increased recruitment of BM hematopoietic cells in the tumor beds compared to matched adjacent non-neoplastic lung tissue in NSCLC patients. Genome-wide transcriptome analysis on specific cell populations from fresh samples of NSCLC patients identified differentially regulated genes and mRNA isoforms in NSCLC stromal cells. Genes that were successfully validated by independent RT-PCR on sorted stromal cells and tumor cells were used for further analysis. Many genes encoded secreted proteins, suggesting the activation of aberrant autocrine and paracrine regulatory loops likely to support stroma-mediated tumor progression.

Among these genes, CCL7 was upregulated in myeloid progenitor cells and was selected for further investigation. Immunostaining of lung tumor and adjacent non-neoplastic tissue of patients shows highest expression of CCL7 in BM-derived cells (CD45+ cells) in the tumor.

Cross species analysis showed that, consistent with the observation in human tissue, CCL7 was differentially regulated in BM derived cells in a mouse model of NSCLC generated in KrasG12D and p53-/- transgenic mice. We have genetically ablated CCL7 in the BM cells using lentiviral shRNA and BMT approaches and will discuss consequences of this ablation in CCL7-mediated crosstalk between tumor cells and stromal cells that regulate NSCLC progression.

Citation Format: Hyejin Choi, Anna Durrans, Dingcheng Gao, Seongho Ryu, Nasser Altorki, Vivek Mittal. Mechanisms of stroma-derived CCL7 in promoting lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1420. doi:10.1158/1538-7445.AM2013-1420

A role for Egfl7 during endothelial organization in the embryoid body model system

Epidermal growth factor-like domain 7, Egfl7, is a largely endothelial restricted gene which is thought to have a role during the differentiation of embryonic stem cells (ESCs) along the endothelial lineage. While it has been shown that Egfl7 knock-down in zebrafish impairs endothelial cord formation, the role of the gene in mammals has been unresolved. Interpretation of mouse knockout studies has been complicated by the fact that deletion of miR-126, an intronic microRNA located within Egfl7, results in vascular defects. Here we use an siRNA knock-down approach to target specific regions of Egfl7 without affecting miR-126 expression. Egfl7 was knocked down in mouse ESCs and the effect on vascular development was assessed using the in vitro embryoid body (EB) model after either 7 or 14 days of differentiation. Knock-down of Egfl7 resulted in the formation of abnormal sheet-like CD31+ structures that were abundant within EBs after 7 days of differentiation. Only up to 60% of these sheets co-expressed basement membrane and endothelial cell junction markers. Similar CD31+ sheets were also seen as outgrowths from 7 day EBs into collagen gels. A partial remodelling occurred by 14 days of differentiation when fewer CD31+ sheets were seen both within EBs, and as outgrowths from EBs. Formation of these sheets was due, at least in part, to increased proliferation specifically of CD31+ cells. Cell death within EBs was unaffected by Egfl7 knock-down. In conclusion, our work shows that knock-down of Egfl7 causes defects in early vascular cord formation, and results in the development of CD31+ sheet-like structures. This suggests that Egfl7 is vital for the formation of endothelial cell cords, and that the gene has an important role during both vasculogenesis and angiogenesis in mammalian cells.

Modulation of the NO pathway during short or prolonged blood reperfusion following ischaemia in a heterotopic rat heart transplantation model

Ischemia-reperfusion injury plays a major role in graft dysfunction following transplantation. Extensive research has demonstrated that nitric oxide (NO) plays a fundamental role to protect the heart against this injury. Consequently, we quantified NO synthase (NOS) isoform protein levels in a rat heart transplant model during short and prolonged reperfusion following ischemia. Experiments were performed using a modified Lewis to Lewis heterotopic abdominal heart transplantation with a total ischemic time of 3 hours followed by 1 or 24 hours of blood reperfusion (n = 12). Heart function, as represented by the rate pressure product, increased from 7912 +/- 489 to 27067 +/- 9982 mm Hg/min (mean +/- SEM, short vs prolonged reperfusion, P = .0027). NOS isoform protein levels determined using Western blotting of freeze-clamped hearts were compared to baseline values. eNOS protein levels were significantly lower during short reperfusion compared to the basal value (P = .0077) or to prolonged reperfusion (P = .004), returning to the basal value after 24 hours of reflow. iNOS protein was not detected in the basal condition or after 1 hour of reflow, but was present after 24 hours of reflow (P = .0001 vs basal value and 1-hour reflow). nNOS protein was 69% lower after 1 hour of reflow compared with the baseline value (P = .0001), it was not restored after 24 hours of reflow (P = .002). These results suggest involvement of the NO pathway in ischemia-reperfusion injury with distinctive roles of NOS isoforms during short and prolonged reperfusion following ischemia.