AMPK is elevated in human cachectic muscle and prevents cancer-induced metabolic dysfunction in mice

Raun, S. H.; Ali, M. S.; Han, X.; Henriquez-Olguin, C.; Pham, T. C. P.; Knudsen, J. R.; Willemsen, A. C. H.; Larsen, S.; Jensen, T. E.; Langen, R.; Sylow, L.

doi:10.1101/2022.06.07.495096

bioRxiv · 10.1101/2022.06.07.495096

AMPK is elevated in human cachectic muscle and prevents cancer-induced metabolic dysfunction in mice

Raun, S. H.·Ali, M. S.·Han, X.·Henriquez-Olguin, C.·Pham, T. C. P.·Knudsen, J. R.·Willemsen, A. C. H.·Larsen, S.·Jensen, T. E.·Langen, R.·Sylow, L.

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Abstract

BackgroundMetabolic dysfunction and cancer cachexia are associated with poor cancer prognosis, yet the molecular mechanisms causing cancer-induced metabolic dysfunction and cachexia remain to be defined. A key link between metabolic- and muscle mass-regulation is adenosine monophosphate-activated protein kinase (AMPK). As AMPK could be a potential treatment, it is important to determine the function for AMPK in cancer-associated metabolic dysfunction and cachexia. Here we determined the function of AMPK in cancer-associated metabolic dysfunction, insulin resistance, and cachexia. MethodsIn vastus lateralis muscle biopsies from pre-cachectic and cachectic patients with Non-Small-Cell Lung Carcinoma (NSCLC), AMPK signaling and expression were examined by immunoblotting. To investigate the role of muscle AMPK, male mice overexpressing a dominant-negative AMPK2 (kinase-dead) specifically in striated muscle (mAMPK-KD) were inoculated with Lewis Lung Carcinoma (LLC) cells. In a subsequent cohort, male LLC-tumor-bearing mice were treated with/without 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) to activate AMPK for 13 days. Littermate mice were used as control. Metabolic phenotyping of mice was performed via indirect calorimetry, body composition analyses, glucose- and insulin tolerance tests, tissue-specific 2-deoxy- glucose (2-DG) uptake, and immunoblotting. ResultsIn muscle from patients with NSCLC, we found increased expression of AMPK subunits 1, 2, {beta}2, {gamma}1, and {gamma}3; ranging from +27% to +79% compared to healthy control subjects. AMPK subunit expression correlated with indices of cachexia, including cross sectional area and weight loss. Tumor-bearing mAMPK-KD mice presented increased fat loss as well as glucose and insulin intolerance. LLC in mAMPK-KD mice displayed lower insulin-stimulated 2-DG uptake in skeletal muscle (quadriceps; -35%, soleus; -49%, EDL; -48%) and the heart (-29%) compared to non-tumor-bearing mice. In skeletal muscle, mAMPK-KD abrogated the tumor-induced increase in phosphorylation of TBC1D4thr642. Additionally, protein expression of TBC1D4 (+26%), pyruvate dehydrogenase (PDH, +94%), and PDH-kinases (PDKs, +45% to +100%), and glycogen synthase (+48%) were increased in skeletal muscle of tumor-bearing mice in an AMPK-dependent manner. Lastly, chronic AICAR treatment elevated hexokinase-II protein expression and normalized phosphorylation of p70S6Kthr389 (mTORC1 substrate) and ACCser212 (AMPK substrate) and rescued the cancer-induced insulin intolerance. ConclusionsUpregulated protein expression of AMPK subunits observed in skeletal muscle of (pre)cachectic patients with non-small-cell lung carcinoma. This seemed protective inferred by AMPK-deficient tumor-bearing mice being highly prone to developing metabolic dysfunction, which included the AMPK-dependent regulation of several proteins involved in glucose metabolism. These observations highlight the potential for targeting AMPK to counter cancer-associated metabolic dysfunction and cachexia. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=141 SRC="FIGDIR/small/495096v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@7ff169org.highwire.dtl.DTLVardef@1c249aeorg.highwire.dtl.DTLVardef@736350org.highwire.dtl.DTLVardef@17d2be2_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Raun, S. H., Ali, M. S., Han, X., Henriquez-Olguin, C., Pham, T. C. P., Knudsen, J. R., Willemsen, A. C. H., Larsen, S., Jensen, T. E., Langen, R., Sylow, L.. 2022-06-07. AMPK is elevated in human cachectic muscle and prevents cancer-induced metabolic dysfunction in mice. https://doi.org/10.1101/2022.06.07.495096

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