Abstract 4904: GLUT4 exhibits a non-canonical role of regulating lung cancer metastasis
Authors: Wei Changyong , Achreja Abhinav , Konen Jessica , Sica Gabriel , Gilbert-Ross Melissa , Nagrath Deepak , Marcus Adam , Shanmugam Mala 
Published: July 2017

Abstract
Lung cancer continues to be fatal, in part due to the inability to prevent and treat metastases. Highly metastatic cancers exhibit enhanced glucose uptake to sustain proliferation and importantly, tumor invasion. Among the SLC2A family of facilitative glucose transporters, GLUT1 is largely attributed to be responsible for increased glucose uptake of cancer cells. GLUT1 is however responsible for glucose transport across the blood-brain barrier, expressed in many normal cell types and therefore a less desirable therapeutic target. We previously reported that multiple myeloma cells rely on overexpression and constitutive plasma membrane localization of insulin-responsive glucose transporter, GLUT4. In this study we investigated a role for GLUT4 in lung cancer. To interrogate contributions of GLUT1 and GLUT4 in proliferation, invasion and migration we generated H1299 and A549 GLUT 1 or GLUT4 knockdowns. Knockdown (KD) of GLUT4 did not inhibit proliferation but suppressed migration and invasion assessed through scratch and Boyden chamber assays, respectively. On the contrary, knockdown of GLUT1 reduced proliferation of these lines. Treatment of H1299 and A549 with our newly developed GLUT4-selective inhibitors also reduced invasion, phenocopying the effects detected with GLUT4 KD. GLUT4 inhibition also reduced H1299 invasion in a spheroid invasion model. We utilized H1299 cells to isolate highly invasive less proliferative “leader cells” and less invasive but highly proliferative “follower cells”. Interestingly, examination of these two cell types exhibited a differential expression pattern of GLUT1/GLUT4. Leader cells have elevated expression of GLUT4 and decreased GLUT1. On the contrary, follower cells have high GLUT1 and low GLUT4 expression. Leader cells are more sensitive to GLUT4 inhibitors indicating they are more dependent on GLUT4 than follower cells. In addition, leader cells are more sensitive to mitochondrial complex I inhibitors compared to follower cells, suggesting they rely more on oxidative phosphorylation. A differential reliance on glycolysis/OXPHOS was further supported by evaluation of glucose uptake/oxygen consumption. Isotope tracer and bioenergetics analyses further support altered nutrient dependencies of leader and follower cells. Lastly, we found that GLUT4 is expressed in patient lung adenocarcinoma specimens including more aggressive micropapillary lung adenocarcinoma. Examination of collective invasion packs in human adenocarcinoma demonstrated patchy GLUT1 expression suggestive of a subset of more proliferative “follower” cells. These results suggest that in a lung cancer population a subset of more invasive cells are reliant on GLUT4 with reduced GLUT1 expression while more proliferative cells rely on high GLUT1 expression, making GLUT4 a promising candidate for targeting metastasis in lung cancer.
Citation Format: Changyong Wei, Abhinav Achreja, Jessica Konen, Gabriel Sica, Melissa Gilbert-Ross, Deepak Nagrath, Adam Marcus, Mala Shanmugam. GLUT4 exhibits a non-canonical role of regulating lung cancer metastasis [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 4904. doi:10.1158/1538-7445.AM2017-4904