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Sorafenib induces cachexia by impeding transcriptional signaling of the SET1/MLL complex on muscle-specific genes

ABSTRACT: Adverse effects of chemotherapies can outweigh the benefits in cancer patients. Various chemotherapeutics are linked to muscle wasting or cachexia, drastically reducing the survival rate of cancer patients. Insights into the molecular basis of chemotherapy-induced cachexia is an unmet need to improve treatment strategies. Here, we demonstrated that Sorafenib- tyrosine kinase inhibitor class of chemotherapeutic agents- induced cachexia. Sorafenib-treated muscle cells show sarcomere disarray, impaired sarcoplasmic reticulum-mediated calcium handling, loss of contractile ability, and reduced mitochondrial oxidative respiratory capacity. To identify the molecular mechanisms underlying Sorafenib-induced cachexia, we performed whole-genome transcriptome profiling or RNA sequencing of muscle cells in response to Sorafenib treatment, compared to DMSO-treated (control) cells. We identified a total of 3030 genes that were downregulated and 2128 genes that were upregulated in Sorafenib-treated cells, as compared to the control. Gene ontology analyses revealed that Sorafenib led to transcriptional downregulation of genes coding for proteins of the sarcomere, sarcoplasmic reticulum, and proteins responsible for muscle contraction, sarcomere organization, and calcium ion handling. Additionally, genes associated with mitochondrial oxidative phosphorylation or electron transport chain were significantly downregulated. In summary, Sorafenib deregulates the transcriptional processes of protein-coding genes associated with sarcomere assembly, calcium ion homeostasis, and mitochondrial oxidative respiration, ultimately leading to impaired muscle function.

ORGANISM(S): Mus musculus

PROVIDER: GSE273444 | GEO | 2024/08/12

REPOSITORIES: GEO

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Project description:Background. Pancreatic Ductal AdenoCarcinoma (PDAC), the most frequent pancreatic cancer, is a deadly cancer since often diagnosed late and resistant to current therapies. A high proportion of PDAC patients are affected by cachexia induced by the tumor. This cachexia, characterized by loss of muscle mass and strength, contributes to patient frailty and poor therapeutic response. We showed that mitochondrial metabolism is reprogrammed in PDAC tumor cell and constitutes a vulnerability, opening novel therapeutic avenues. The objective of the present work was to investigate the molecular mechanisms underlying mitochondrial remodeling in PDAC cachectic skeletal muscle. Methods. Our study focused on the gastrocnemius muscle of genetically-engineered mice developing spontaneously a PDAC associated with cachexia (KIC GEMM). We compared KIC mice developing a pancreatic tumor in 9-10 weeks to control littermates. We did an integrative study combining in vivo functional analyses by non-invasive Magnetic Resonance, and ex-vivo histology, Seahorse, RNA-sequencing, and proteomic mass spectrometry and western blotting analyses. Results. The cachectic KIC PDAC mice show a severe sarcopenia with loss of muscle mass and strength associated with a diminution in muscle fiber’s size and induction of protein degradation processes. Mitochondria in PDAC atrophic muscles show decreased respiratory capacities and structural alterations (“hyperfused” mitochondria), associated with deregulation of oxidative phosphorylation and mitochondrial dynamics pathways at the molecular level. Increased expression of multiple reactive oxygen species (ROS) defense genes suggests oxidative stress prone to affect mitochondrial macromolecules and homeostasis. Interestingly, multiple genes and proteins involved in DNA metabolism pathways, such as DNA damage, degradation of DNA, nucleotide synthesis, and folate pathway were found altered in sarcopenic mitochondria. While the number of mitochondria was not changed, the mitochondrial mass was decreased by a factor of 2 and the mitochondrial DNA by a factor of 3, suggesting a defect in mitochondrial genome homeostasis. Conclusions. We unveiled that mitochondrial alterations in skeletal muscle play a central role in PDAC-induced cachexia. Muscle atrophy is associated with strong mitochondrial metabolic defects that are not limited to carbohydrates and protein, but concern also lipids, ROS and nucleic acids. Our data provide a frame to guide towards the most relevant molecular markers that would be affected at the start of tumor development and could be targets in the clinic to limit PDAC-induced cachexia at early stages of the pathology.

Project description:Tyrosine kinase inhibitors (TKIs), as a class of small-molecule drugs that exert anti-tumor effects by inhibiting tyrosine kinase-catalyzed phosphorylation, have been used in the treatment of various cancers. Sorafenib, as a multi-targeted TKI drug, is the first-line treatment for advanced renal cell carcinoma and unresectable hepatocellular carcinoma. However, sorafenib has repeatedly been reported to cause cardiac events in patients without a history of heart diseases during clinical use, indicating that it has cardiotoxicity. Alternative splicing of cardiac contraction-related genes happens during heart development and cardiac diseases, and is critical for heart function. However, whether alternative splicing plays a role in drug-induced cardiotoxicity remains unexplored. RBM20 is an important cardiac-specific splicing factor, mutations of which cause dilated cardiomyopathy or other cardiac dysfunctions. Rbm20 also mediates alternative splicing of genes essential for heart contraction, which is often negatively affected in drug-induced cardiotoxicity. Existing studies do not fully explain the mechanism of sorafenib cardiotoxicity, and none of the relationship between cardiotoxicity of sorafenib and alternative splicing mediated by tissue-specific splicing factors, such as Rbm20, have been reported. In order to explore whether cardiac-specific alternative splicing plays a role in sorafenib-induced cardiotoxicity, we establish both cell and animal models of cardiotoxicity, and obtain the following results: (1) By constructing a rat animal model administered with sorafenib, we find that sorafenib causes abnormal cardiac function in rats, and the genes that undergo alternative splicing in rat hearts are related to cytoskeleton of actin; (2) Alternatively spliced genes induced by sorafenib in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are enriched in sarcomere, actin filament, calcium transient regulation, mitochondria, all of which are critical for cardiac contraction. These genes are associated with dilated cardiomyopathy, hypertrophic cardiomyopathy and other cardiomyopathy; (3) Sorafenib induces a decrease in the expression of cardiac-specific splicing factor RBM20; (3) Many genes whose splicing are altered by sorafenib overlap with Rbm20 targets, indicating that sorafenib may affect alternative splicing through Rbm20; (4) Sorafenib induces pathogenic alternative splicing of FHOD3, which is a RBM20 target gene and participates in myocardial sarcomere formation. Sorafenib also affects alternative splicing of SLC25A3, which encodes a phosphate transporter on the mitochondrial inner membrane and regulates ATP synthesis; (5) Enhancing the expression of RBM20 rescues the cardiotoxicity of sorafenib by reducing apoptosis and increasing ATP levels, which is mediated by reversing the alternative splicing of FHOD3 and SLC25A3 induced by sorafenib. This paper uncovers that sorafenib reduces the expression of RBM20 to cause pathogenic alternative splicing of genes related to myocardial sarcomere and energy mechanism, resulting in abnormal myocardial function. Increasing the expression of RBM20 reverses the alternative splicing of FHOD3 and SLC25A3 associated with cardiac sarcomeres and mitochondria respectively, rescuing the cardiotoxicity of sorafenib.

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Sorafenib induces cachexia by impeding transcriptional signaling of the SET1/MLL complex on muscle-specific genes

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