| Literature DB >> 30784173 |
Yann Cormerais1, Marina Pagnuzzi-Boncompagni1, Sandra Schrötter2, Sandy Giuliano1, Eric Tambutté3, Hitoshi Endou4, Michael F Wempe5, Gilles Pagès1,6, Jacques Pouysségur1,6, Vincent Picco1.
Abstract
Most cases of medulloblastoma (MB) occur in young children. While the overall survival rate can be relatively high, current treatments combining surgery, chemo- and radiotherapy are very destructive for patient development and quality of life. Moreover, aggressive forms and recurrences of MB cannot be controlled by classical therapies. Therefore, new therapeutic approaches yielding good efficacy and low toxicity for healthy tissues are required to improve patient outcome. Cancer cells sustain their proliferation by optimizing their nutrient uptake capacities. The L-type amino acid transporter 1 (LAT1) is an essential amino acid carrier overexpressed in aggressive human cancers that was described as a potential therapeutic target. In this study, we investigated the therapeutic potential of JPH203, a LAT1-specific pharmacological inhibitor, on two independent MB cell lines belonging to subgroups 3 (HD-MB03) and Shh (DAOY). We show that while displaying low toxicity towards normal cerebral cells, JPH203 disrupts AA homeostasis, mTORC1 activity, proliferation and survival in MB cells. Moreover, we demonstrate that a long-term treatment with JPH203 does not lead to resistance in MB cells. Therefore, this study suggests that targeting LAT1 with JPH203 is a promising therapeutic approach for MB treatment.Entities:
Keywords: ATF4; GCN2; amino acid transport; mTORC1; medulloblastoma
Mesh:
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Year: 2019 PMID: 30784173 PMCID: PMC6433660 DOI: 10.1111/jcmm.14176
Source DB: PubMed Journal: J Cell Mol Med ISSN: 1582-1838 Impact factor: 5.310
Figure 1L‐type amino acid transporter 1 (LAT1) is the main leucine Na+ independent transporter expressed in MB cell lines HD‐MB03 and DAOY and is essential for AA homeostasis and mTORC1 activity. A, Western blot analysis of the expression levels of LAT1 and its chaperone CD98 in HD‐MB03 and DAOY. Tubulin served as a loading control. The results presented are representative of at least three independent experiments. B, Transport assay using radio‐labelled leucine (14C‐LEU) in the absence or presence of 10 µmol/L of JPH203 (***P < 0.001, Student's t test). C, Activity of the two AA sensing pathways GCN2 and mTORC1 were analysed by immunoblot in the absence or presence of either 20 or 30 µmol/L of JPH203. ERK1/2 served as a loading control (the experiment presented here is representative of at least three independent experiments)
Figure 2L‐type amino acid transporter 1 (LAT1) inhibition selectively impairs growth and decreases viability of MB cells. A, Proliferation assay of HD‐MB03 and DAOY cells treated or not with 20 or 30 µmol/L of JPH203 for 72 h. Control (Ct) conditions were treated with DMSO for the same time period. B, Viability assay of HD‐MB03 and DAOY cells treated or not with 20 or 30 µmol/L of JPH203 for 72 h. Control (Ct) conditions were treated with DMSO for the same time period. C, Viability assay of murine primary astrocytes (C8‐D1A) and primary cortical neurons (PCN) treated with 30 µmol/L of JPH203 or DMSO (control, Ct) for 72 h. D, In vitro 3‐D growth assay of HD‐MB03 and DAOY cells. Spheroids generated with HD‐MB03 or DAOY cells were treated with 20 or 30 µmol/L of JPH203 or DMSO (control, Ct) for 12 d. E, Spheroid growth measurements over time. The surface area of spheroids was measured at the indicated time points and normalized by the initial size of the control (■), 20 µmol/L JPH203 (▲) and 30 µmol/L JPH203 (●) spheroids. Data points indicate mean ± SEM from at least three independent experiments (***P < 0.001; **P < 0.01; *P < 0.05; ns: P > 0.05, Student's t test)
Figure 3L‐type amino acid transporter 1 (LAT1) inhibition impairs MB cell migration. A, Scratch‐wound assay on a DAOY cell confluent layer treated or not with JPH203 at the indicated concentrations and on which a ‘mechanical’ wound was made at time 0. B, Dot plot showing quantitative determination of wound closure after 8 h in the absence or presence of the indicated concentrations of JPH203. The results are expressed as the percentage of closure of each individual wound relative to time 0. The bars represent the mean ± SEM for each experimental condition (**P < 0.01, Student's t test)
Figure 4MB cell adaptation to long‐term JPH treatment does not cause resistance. A, The expression levels of CD98 and LAT1 in HD‐MB03 and DAOY cells chronically exposed for 120 d to the indicated concentrations of JPH203 were analysed by immunoblot. Tubulin was used as a loading control. B, Proliferation assay of HD‐MB03 and DAOY cells treated with 20 or 30 µmol/L of JPH203 or DMSO (control, Ct) for 120 d. C, Viability assay of HD‐MB03 and DAOY cells treated with 20 or 30 µmol/L of JPH203 or DMSO (control, Ct) for 120 d (***P < 0.001; **P < 0.01; *P < 0.05; ns: P > 0.05, Student's t test)