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. 2024 May;37(5):e5102.
doi: 10.1002/nbm.5102. Epub 2024 Jan 23.

Transmembrane pH gradient imaging in rodent glioma models

Sandeep Kumar Mishra  1 , Jessica Gois Santana  2 , Jelena Mihailovic  1 , Fahmeed Hyder  1   2 , Daniel Coman  1   2
Affiliations

Transmembrane pH gradient imaging in rodent glioma models

Sandeep Kumar Mishra et al. NMR Biomed. 2024 May.

Abstract

A unique feature of the tumor microenvironment is extracellular acidosis in relation to intracellular milieu. Metabolic reprogramming in tumors results in overproduction of H+ ions (and lactate), which are extruded from the cells to support tumor survival and progression. As a result, the transmembrane pH gradient (ΔpH), representing the difference between intracellular pH (pHi) and extracellular pH (pHe), is posited to be larger in tumors compared with normal tissue. Controlling the transmembrane pH difference has promise as a potential therapeutic target in cancer as it plays an important role in regulating drug delivery into cells. The current study shows successful development of an MRI/MRSI-based technique that provides ΔpH imaging at submillimeter resolution. We applied this technique to image ΔpH in rat brains with RG2 and U87 gliomas, as well as in mouse brains with GL261 gliomas. pHi was measured with Amine and Amide Concentration-Independent Detection (AACID), while pHe was measured with Biosensor Imaging of Redundant Deviation in Shifts (BIRDS). The results indicate that pHi was slightly higher in tumors (7.40-7.43 in rats, 7.39-7.47 in mice) compared with normal brain (7.30-7.38 in rats, 7.32-7.36 in mice), while pHe was significantly lower in tumors (6.62-6.76 in rats, 6.74-6.84 in mice) compared with normal tissue (7.17-7.22 in rats, 7.20-7.21 in mice). As a result, ΔpH was higher in tumors (0.64-0.81 in rats, 0.62-0.65 in mice) compared with normal brain (0.13-0.16 in rats, 0.13-0.16 in mice). This work establishes an MRI/MRSI-based platform for ΔpH imaging at submillimeter resolution in gliomas.

Keywords: AACID; BIRDS; MRI; MRSI; extracellular pH; glioma; intracellular pH; transmembrane pH.

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Conflict of interest statement

CONFLICT OF INTEREST STATEMENT

Fahmeed Hyder is the founder of Innovacyclics LLC. All other authors declare no conflicts of interest.

References

    1. Gatenby RA and Gillies RJ, Why do cancers have high aerobic glycolysis? Nat Rev Cancer, 2004. 4(11): p. 891–9. - PubMed
    1. Warburg O, On respiratory impairment in cancer cells. Science, 1956. 124(3215): p. 269–70. - PubMed
    1. Webb BA, et al., Dysregulated pH: a perfect storm for cancer progression. Nat Rev Cancer, 2011. 11(9): p. 671–7. - PubMed
    1. Hyder F and Khan MH, Dysregulated proton and sodium gradients highlight cancer invasion and proliferation. Transl Oncol, 2022. 16: p. 101310. - PMC - PubMed
    1. Park SJ, et al., An overview of MCT1 and MCT4 in GBM: small molecule transporters with large implications. Am J Cancer Res, 2018. 8(10): p. 1967–1976. - PMC - PubMed

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