A Novel NHE1-Centered Signaling Cassette Drives Epidermal Growth Factor Receptor–Dependent Pancreatic Tumor Metastasis and Is a Target for Combination Therapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. Its aggressiveness is driven by an intense fibrotic desmoplastic reaction in which the increasingly collagen I-rich extracellular matrix (ECM) and several cell types, including cancer stem cells (CSCs), create a tumor-supportive environment. However, how ECM composition regulates CSC dynamics and their relationship with the principle parenchymal tumor population to promote early invasive growth is not yet characterized. For this, we utilized a platform of 3D organotypic cultures composed of laminin-rich Matrigel, representative of an early tumor, plus increasing concentrations of collagen I to simulate malignant stroma progression. As ECM collagen I increases, CSCs progress from a rapidly growing, vascular phenotype to a slower growing, avascular phase, while maintaining their endothelial-like gene signatures. This transition is supported autocrinically by the CSCs and paracrinically by the parenchymal cells via their ECM-dependent secretomes. Indeed, when growing on an early tumor ECM, the CSCs are dedicated toward the preparation of a vascular niche by (a) activating their growth program, (b) secreting high levels of proangiogenic factors which stimulate both angiogenesis and vasculogenic mimicry, and (c) overexpressing VEGFR-2, which is activated by VEGF secreted by both the CSC and parenchymal cells. On Matrigel, the more differentiated parenchymal tumor cell population had reduced growth but a high invasive capacity. This concerted high local invasion of parenchymal cells into the CSC-derived vascular network suggests that a symbiotic relationship between the parenchymal cells and the CSCs underlies the initiation and maintenance of early PDAC infiltration and metastasis.

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“…high-invadopodia-driven invasive capacity (Fig. 2D,E) that is stimulated by EGF [32], which is highly secreted by the CSCs (Fig. 4A).…”

Section: Discussionmentioning

confidence: 99%

Extracellular matrix composition modulates PDAC parenchymal and stem cell plasticity and behavior through the secretome

et al. 2018

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“…1 a ) and an extensive local tumour growth ( n = 4, tumour take = 100%) already within 4 weeks after implantation was observed. In fixed tissue, tumour cells were visualized by staining for epidermal growth factor receptor (EGFR), a receptor that is over‐expressed in PDAC 31. PancTu‐1 Luc cells formed poorly differentiated, highly EGFR‐expressing tumours (Supporting Information Fig.…”

Section: Resultsmentioning

confidence: 99%

Targeting of the P2X7 receptor in pancreatic cancer and stellate cells

Giannuzzo

Saccomano

Napp

et al. 2016

Intl Journal of Cancer

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The ATP‐gated receptor P2X7 (P2X7R) is involved in regulation of cell survival and has been of interest in cancer field. Pancreatic ductal adenocarcinoma (PDAC) is a deadly cancer and new markers and therapeutic targets are needed. PDAC is characterized by a complex tumour microenvironment, which includes cancer and pancreatic stellate cells (PSCs), and potentially high nucleotide/side turnover. Our aim was to determine P2X7R expression and function in human pancreatic cancer cells in vitro as well as to perform in vivo efficacy study applying P2X7R inhibitor in an orthotopic xenograft mouse model of PDAC. In the in vitro studies we show that human PDAC cells with luciferase gene (PancTu‐1 Luc cells) express high levels of P2X7R protein. Allosteric P2X7R antagonist AZ10606120 inhibited cell proliferation in basal conditions, indicating that P2X7R was tonically active. Extracellular ATP and BzATP, to which the P2X7R is more sensitive, further affected cell survival and confirmed complex functionality of P2X7R. PancTu‐1 Luc migration and invasion was reduced by AZ10606120, and it was stimulated by PSCs, but not by PSCs from P2X7‐/‐ animals. PancTu‐1 Luc cells were orthotopically transplanted into nude mice and tumour growth was followed noninvasively by bioluminescence imaging. AZ10606120‐treated mice showed reduced bioluminescence compared to saline‐treated mice. Immunohistochemical analysis confirmed P2X7R expression in cancer and PSC cells, and in metaplastic/neoplastic acinar and duct structures. PSCs number/activity and collagen deposition was reduced in AZ10606120‐treated tumours.

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“…17 Thus, NHE1 plays an important role for mammary tumor cell growth, in congruence with its important role in several other types of solid tumors including pancreatic 38 and colon 39 cancer. 17 Thus, NHE1 plays an important role for mammary tumor cell growth, in congruence with its important role in several other types of solid tumors including pancreatic 38 and colon 39 cancer.…”

Section: Discussionmentioning

confidence: 99%

The net acid extruders NHE1, NBCn1 and MCT4 promote mammary tumor growth through distinct but overlapping mechanisms

Andersen

Samsøe-Petersen

Oernbo

et al. 2018

Intl Journal of Cancer

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High metabolic and proliferative rates in cancer cells lead to production of large amounts of H and CO , and as a result, net acid extruding transporters are essential for the function and survival of cancer cells. We assessed protein expression of the Na /H exchanger NHE1, the Na - HCO3- cotransporter NBCn1, and the lactate-H cotransporters MCT1 and -4 by immunohistochemical analysis of a large cohort of breast cancer samples. We found robust expression of these transporters in 20, 10, 4 and 11% of samples, respectively. NHE1 and NBCn1 expression both correlated positively with progesterone receptor status, NHE1 correlated negatively and NBCn1 positively with HER2 status, whereas MCT4 expression correlated with lymph node status. Stable shRNA-mediated knockdown (KD) of either NHE1 or NBCn1 in the MDA-MB-231 triple-negative breast cancer (TNBC) cell line significantly reduced steady-state intracellular pH (pH ) and capacity for pH recovery after an acid load. Importantly, KD of any of the three transporters reduced in vivo primary tumor growth of MDA-MB-231 xenografts. However, whereas KD of NBCn1 or MCT4 increased tumor-free survival and decreased in vitro proliferation rate and colony growth in soft agar, KD of NHE1 did not have these effects. Moreover, only MCT4 KD reduced Akt kinase activity, PARP and CD147 expression and cell motility. This work reveals that different types of net acid extruding transporters, NHE1, NBCn1 and MCT4, are frequently expressed in patient mammary tumor tissue and demonstrates for the first time that they promote growth of TNBC human mammary tumors in vivo via distinct but overlapping mechanisms.

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A Novel NHE1-Centered Signaling Cassette Drives Epidermal Growth Factor Receptor–Dependent Pancreatic Tumor Metastasis and Is a Target for Combination Therapy

Cited by 82 publications

References 45 publications

Extracellular matrix composition modulates PDAC parenchymal and stem cell plasticity and behavior through the secretome

Extracellular matrix composition modulates PDAC parenchymal and stem cell plasticity and behavior through the secretome

Targeting of the P2X7 receptor in pancreatic cancer and stellate cells

The net acid extruders NHE1, NBCn1 and MCT4 promote mammary tumor growth through distinct but overlapping mechanisms

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