Modulation of P2X4/P2X7/Pannexin-1 sensitivity to extracellular ATP via Ivermectin induces a non-apoptotic and inflammatory form of cancer cell death

Abstract

Overexpression of P2X7 receptors correlates with tumor growth and metastasis. Yet, release of ATP is associated with immunogenic cancer cell death as well as inflammatory responses caused by necrotic cell death at sites of trauma or ischemia-reperfusion injury. Using an FDA-approved anti-parasitic agent Ivermectin as a prototype agent to allosterically modulate P2X4 receptors, we can switch the balance between the dual pro-survival and cytotoxic functions of purinergic signaling in breast cancer cells. This is mediated through augmented opening of the P2X4/P2X7-gated Pannexin-1 channels that drives a mixed apoptotic and necrotic mode of cell death associated with activation of caspase-1 and is consistent with pyroptosis. We show that cancer cell death is dependent on ATP release and death signals downstream of P2X7 receptors that can be reversed by inhibition of NADPH oxidases-generated ROS, Ca2+/Calmodulin-dependent protein kinase II (CaMKII) or mitochondrial permeability transition pore (MPTP). Ivermectin induces autophagy and release of ATP and HMGB1, key mediators of inflammation. Potentiated P2X4/P2X7 signaling can be further linked to the ATP rich tumor microenvironment providing a mechanistic explanation for the tumor selectivity of purinergic receptors modulation and its potential to be used as a platform for integrated cancer immunotherapy.

Temporally Programmed CD8α + DC Activation Enhances Combination Cancer Immunotherapy

“…For further generalization, we tested our combination immunotherapies in two alternate syngeneic tumor models, administering IFNα with FcIL2 + 7.16.4, an anti-Her2 murine IgG2a antibody, to BALB/c mice bearing established DD-Her2/neu breast tumors (Draganov et al, 2015) or with 3F8, an anti-GD2 murine IgG3 antibody, to C57BL/6 mice bearing established RM9 prostate tumors (Zhu et al, 2015). Staggering IFNα treatment after FcIL2 + antitumor antibody provided superior tumor control than giving all three components simultaneously (Figures 4E, 4F, S5E, and S5F).…”

Injectable, Tough Alginate Cryogels as Cancer Vaccines

“…HER2/neu-overexpressing DD breast cancer cell line, CT26, and HER2/neu-overexpressing CT26 colon cancer cell lines were obtained from Professor Glenn Dranoff’s laboratory, Dana-Farber Cancer Institute, Boston, Massachusetts. [38–39] BALB/cJ and C57BL/6J mice were purchased from the Jackson Laboratory (Bar Harbor, ME). APC-conjugated H-2Kb-SIINFEKL tetramer was obtained from the NIH tetramer core facility.…”

Pannexin‐1 mediated ATP release in adipocytes is sensitive to glucose and insulin and modulates lipolysis and macrophage migration

“…61 About 0.5 μg RNA per reaction was used in OneStep RT-PCR Kit (Qiagen) with amplification parameters as follows: one cycle at 50°C for 30 minutes and one cycle at 95°C for 15 min utes followed by 37 cycles at 94°C for 1 minutes, 50.4°C for 1 minutes, 72°C for 1 minutes, and finally, one cycle at 72°C | 15 of 18 TOZZI eT al for 10 minutes. Primers used were as follows: P2X7 (128 bp), 5´-TGG ATG ACA AGA ACA CGG ATG-3´ (forward), 5´-CAG GAT GTC AAA ACG GAT GC-3´ (reverse).…”