TY - UNPB
T1 - AMPK is elevated in human cachectic muscle and prevents cancer-induced metabolic dysfunction in mice
AU - Raun, Steffen Henning
AU - Ali, Mona Sadek
AU - Han, Xiuqing
AU - Henríquez-Olguín, Carlos
AU - Pham, Tang Cam Phung
AU - Knudsen, Jonas Roland
AU - Willemsen, Anna C H
AU - Larsen, Steen
AU - Jensen, Thomas Elbenhardt
AU - Langen, Ramon
AU - Sylow, Lykke
N1 - bioRxiv preprint posted June 7, 2022.
PY - 2022/6/7
Y1 - 2022/6/7
N2 - Background: Metabolic 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. Methods: In 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 AMPKα2 (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. Results: In muscle from patients with NSCLC, we found increased expression of AMPK subunits α1, α2, β2, γ1, and γ3; 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. Conclusions: Upregulated 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.
AB - Background: Metabolic 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. Methods: In 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 AMPKα2 (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. Results: In muscle from patients with NSCLC, we found increased expression of AMPK subunits α1, α2, β2, γ1, and γ3; 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. Conclusions: Upregulated 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.
KW - Faculty of Science
KW - AMP-activated protein kinase (AMPK)
KW - Cancer cachexia
KW - Skeletal muscle
KW - Glucose metabolism
KW - Insulin resistance
U2 - 10.1101/2022.06.07.495096
DO - 10.1101/2022.06.07.495096
M3 - Preprint
BT - AMPK is elevated in human cachectic muscle and prevents cancer-induced metabolic dysfunction in mice
PB - bioRxiv
ER -