Search

We investigated the impact of tumor burden on muscle wasting in metastatic (m) and xenograft (x) models of colorectal cancer (CRC). Male Nod SCID γ and CD2F1 mice were injected subcutaneously or intrasplenically with HCT116 or C26 tumor cells, respectively. CRC tumors resulted in significant muscle wasting regardless of tumor type or model, although muscle loss was exacerbated in mHCT116 hosts. The mHCT116 model decreased ribosomal (r)RNA content and rDNA transcription, whereas the mC26 model showed no loss of rRNA and the upregulation of rDNA transcription. The xHCT116 model reduced mTOR, RPS6, and 4E-BP1 phosphorylation, whereas the mHCT116 model had a similar effect on RPS6 and 4E-BP1 without altering mTOR phosphorylation. The C26 models caused a reduction in 4E-BP1 phosphorylation independent of mTOR. Muscle interleukin (IL)-6 mRNA was elevated in all models except xHCT116, and the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) mRNA was induced only in the mC26 model. IL-1β mRNA increased in all groups with greater expression in metastatic relative to the xenograft model regardless of tumor types. Our findings indicate that HCT116 tumor burden results in more drastic muscle wasting and anabolic deficits, whereas C26 tumor burden causes similar muscle wasting but exhibits a divergent proinflammatory phenotype. These results highlight potentially important divergence in the pathogenesis of muscle wasting among preclinical models of CRC and demonstrate that tumor burden plays a role in determining anabolic deficits and the expression of proinflammatory effectors of muscle wasting in a tumor-type-dependent manner.

More than 85% of patients with pancreatic ductal adenocarcinoma (PDAC) suffer from cachexia, a debilitating syndrome characterized by the loss of muscle and fat and remains an unmet medical need. While chemotherapy remains an effective treatment option, it can also induce weight and muscle loss in patients with cancer. Gemcitabine combined with nab paclitaxel (GnP) is a first line treatment option for patients with PDAC but its effect on cachexia has not been comprehensively investigated. We interrogated the effects of GnP in a murine model of pancreatic cancer cachexia. Mice were orthotopically implanted with the cachexia inducing pancreatic cell line (KPC) and were administered GnP or vehicle. The controls underwent sham surgery. We defined GnP effects on cachexia and tumor burden by evaluating muscle and cardiac mass and function, fat mass, bone morphometry, and hematology measurements. We completed RNA sequencing and deep proteome profiling in skeletal and cardiac muscle. KPC+GnP reduced tumor burden over 50% and increased survival compared to KPC. KPC vehicle group had more than 15% muscle mass loss and decreased left ventricular mass, this was not present in KPC+GnP when compared to controls. RNA Seq and deep proteomics analyses suggested that muscle and cardiac dysfunction pathways activated in KPC group were either reversed or decreased in KPC+GnP. In all, our data suggests that GnP protects against muscle and cardiac wasting in an experimental model of PDAC cachexia.

Cachexia is detrimental for patients with head and neck cancer (HNC). However, postoperative consequences of HNC cachexia remain unknown.A 2014-2019 retrospective review was performed of adults undergoing aerodigestive HNC resection with free tissue reconstruction. Propensity score matching using inverse probability of treatment weighting (IPTW) of cachectic and control groups was employed to adjust for covariate imbalances followed by binary logistic regression on postoperative outcomes.Out of 252 total patients, 135 (53.6%) had cancer cachexia. The cohort was predominantly white (94.4%) males (65.1%) aged 61.5 ± 11.5 years with stage III-IV (84.1%) malignancy of the oral cavity (66.3%). After matching cohort pre- and intra-operative covariates using IPTW, cancer cachexia remained a strong, significant predictor of serious National Surgical Quality Improvement Program (NSQIP) complications (OR [95%CI] = 3.84 [1.80-8.21]) and major Clavien-Dindo complications (OR [95%CI] = 3.00 [1.18-7.60]).Cancer cachexia is associated with worse HNC free flap reconstruction outcomes.

Tumor- and bone-derived soluble factors have been proposed to participate in the alterations of skeletal muscle size and function in cachexia. We previously showed that mice bearing ovarian cancer (OvCa) exhibit cachexia associated with marked bone loss, whereas bone-targeting agents, such as bisphosphonates, are able to preserve muscle mass in animals exposed to anticancer drugs. De-identified CT images and plasma samples from female patients affected with OvCa were used for body composition assessment and quantification of circulating cross-linked C-telopeptide type I (CTX-I) and receptor activator of NF-kB ligand (RANKL), respectively. Female mice bearing ES-2 tumors were used to characterize cancer- and RANKL-associated effects on muscle and bone. Murine C2C12 and human HSMM myotube cultures were used to determine the OvCa- and RANKL-dependent effects on myofiber size. To the extent of isolating new regulators of bone and muscle in cachexia, here we demonstrate that subjects affected with OvCa display evidence of cachexia and increased bone turnover. Similarly, mice carrying OvCa present high RANKL levels. By using in vitro and in vivo experimental models, we found that elevated circulating RANKL is sufficient to cause skeletal muscle atrophy and bone resorption, whereas bone preservation by means of antiresorptive and anti-RANKL treatments concurrently benefit muscle mass and function in cancer cachexia. Altogether, our data contribute to identifying RANKL as a novel therapeutic target for the treatment of musculoskeletal complications associated with RANKL-expressing non-metastatic cancers. © 2021 American Society for Bone and Mineral Research (ASBMR).

Clinical care and research around cancer cachexia in children is lacking. Cachexia increases treatment-related toxicity and long-term morbidity and potentially affects mortality. We highlight the urgent need for specific focus on childhood cancer cachexia and discuss potential solutions to inform cachexia therapeutics for children.

Background: Osteocytic microRNA21 (miR21) removal alters cytokine production and bone mass by modulating osteoclast and osteoblast differentiation and activity. Removing osteocytic miR21 alters bone in a sex-dependent manner in mice but produces sex-independent increases in mechanical bone strength. Because changes in bone remodeling and strength affect skeletal muscle through bone-muscle crosstalk, we investigated whether osteocytic miR21 deletion influences skeletal muscle.Methods: miR21fl/fl mice and 8kbDMP1-Cre mice were mated to obtain mice miR21-deficient mice primarily in the osteocyte (OtmiR21Δ) and littermate controls (miR21fl/fl). Four-month-old male and female mice were analyzed. Body composition was examined by DXA/Piximus and gene expression by qPCR. 2-tailed Student’s t-tests were performed to determine significant differences between groups within each sex.Results: Lean body mass was increased only in female OtmiR21Δ mice, although miR21 levels in soleus muscle were similar in miR21fl/fl (0.05±0.02) and OtmiR21Δ (0.09±0.04) mice. Female, but not male, OtmiR21Δ mice exhibited increased soleus (42%) and gastrocnemius (21%) muscle weight compared to miR21fl/fl littermates. However, muscle strength and gastrocnemius muscle fiber cross-sectional area were unaltered for either sex. C2C12 myotubes treated after 5 day-differentiation with conditioned media from 48h-cultured marrow-flushed bones of female OtmiR21Δ mice exhibit 12% higher average diameter compared to cells exposed to miR21fl/fl bone conditioned media. Yet, conditioned media from male bones had no effect on myotube size. Kinase activation in soleus muscle, measured by phospho-/total protein ratio using Multiplex analyses was also selectively changed depending on the mouse sex. Thus, female OtmiR21Δ mice have increased ERK1/2 but decreased Akt activation than miR21fl/fl controls, while male OtmiR21Δ mice had increased Akt activation, suggesting sex-dimorphic shifts in anabolic vs. catabolic signaling. Levels of FOXO3 and MuRF-1, known to be regulated by Akt, were only increased in male OtmiR21Δ mice. MUSA and Atrogin-1 mRNA levels were upregulated in female OtmiR21Δ mice, suggesting a potential shift in protein regulation. Conclusions: We present a novel aspect of bone-muscle crosstalk in which osteocyte-derived miR21 influences skeletal muscle size, but not strength, in female but not male mice, whereas intracellular signaling alterations resulting from loss of miR21 seem to alter protein dynamics in a sex-dimorphic fashion.

Colorectal cancer (CRC) is frequently accompanied by cachexia, an uncured multi-systemic wasting syndrome that affects the majority of patients, especially when the disease recurs with liver metastases (LMs). Muscle and bone loss are amongst the most detrimental symptoms of cachexia and directly cause increased morbidity and mortality. We and others have shown that CRC also promotes metabolic and genomic perturbations of the liver, and further, that formation of LMs exacerbates muscle and bone wasting. These observations, along with evidence that liver-derived factors (i.e., hepatokines) may poorly influence musculoskeletal health, suggest an endocrine role of the liver in mediating cancer-induced cachexia. In the present study, we identified the hepatokine insulin-like growth factor binding protein 1 (IGFBP1) as a novel mediator of musculoskeletal wasting in CRC. Plasma from CRC patients and preclinical mouse models of CRC (C26, MC38, HCT116, ApcMin/+) were assessed for circulating IGFBP1 levels. AML12 hepatocytes were cultured with CRC cells (C26, MC38, HCT116) to assess tumor induced hepatic IGFBP1 production, while C2C12 myotubes and osteoclast precursor cells were cultured to examine the in vitro effects of IGFBP1 on myotube atrophy and osteoclastogenesis. 8-week-old male wild-type (WT) C57BL/6J and IGFBP1-KO mice were intrasplenically injected with MC38 tumor cells (mMC38) to mimic hepatic dissemination of cancer cells, while sham-operated animals received saline. Animals were assessed for muscle force 24-hours prior to euthanasia, and skeletal muscles and bone were collected for molecular and morphological analyses. CRC patients and CRC tumor-bearing mice demonstrated markedly elevated circulating plasma IGFBP1, also supported by increased liver IGFBP1 mRNA expression in C26, MC38 and HCT116 hosts. Follow-up in vitro studies demonstrated that co-culturing CRC cells (lacking IGFBP1 expression) with AML12 hepatocytes promotes IGFBP1 production, thereby suggesting that IGFBP1 is purely host-derived. Further, treatment with recombinant IGFBP1 was sufficient to stimulate osteoclastogenesis, while also promoting atrophy of C2C12 myotubes. Conversely, use of anti-IGFBP1 neutralizing antibodies prevented osteoclastogenesis and preserved C2C12 myotube size when exposed to plasma from mice bearing CRCs. Notably, WT mMC38 bearers displayed reductions in muscle mass and strength, as well as in trabecular bone volume fraction (BV/TV) and trabecular number (Tb.N). Conversely, IGFBP1-KO tumor hosts exhibited preserved skeletal muscle and bone mass. Altogether, our data implicate IGFBP1, an exquisitely liver-derived factor, as a novel mediator of musculoskeletal deficits in CRC cachexia, and supports novel strategies to counteract host-derived factors in the treatment of cancer-associated multi-organ complications. Citation Format: Joshua R. Huot, Fabrizio Pin, Andrea Bonetto. IGFBP1 mediates musculoskeletal defects in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3490.

Cachexia is an involuntary weight loss and muscle wasting that affects up to 80% of advanced cancer patients. It is an independent prognostic marker for response to treatment and overall survival and accounts for 20% of cancer-associated deaths. Skeletal muscles of cachectic patients manifest metabolic abnormalities, notably increased dependence on lipids as a source of energy at the expense of glucose. Pyruvate Dehydrogenase Kinase 4 (PDK4) is upregulated in the muscles of patients and mice with cancer cachexia. PDK4 inhibits the enzyme responsible for the conversion of pyruvate to acetyl coenzyme A which is further oxidized in the tricarboxylic acid cycle. As a result, lipids become the major substrate for oxidative metabolism at the expense of glucose. Recent reports suggested that PDK4 is responsible for metabolic dysregulation in cachexia, proposing PDK4 as a potential drug target. Here, we hypothesized that the deletion of PDK4 would protect against muscle wasting in an orthotopic model of pancreatic ductal adenocarcinoma (PDAC) by countering metabolic abnormalities driven by PDK4. Methods: 50,000 KPC (LSL-KrasG12D:LSL-Trp53R172H:Pdx1-Cre) cells were injected into the pancreas of male PDK4 knockout mice or wild-type controls. For each genotype, a sham surgery group without implantation was included. Body weight was measured at baseline and later every other day starting from day 7 after implantation. Body composition, i.e., lean and fat mass, was assessed at baseline and then once a week using EchoMRI. In-vivo muscle force production measured by the Aurora Scientific system and locomotor activity measured by Auto-Track were used as readouts of muscle function. Tissue was harvested at early and late stages of disease progression representing early and late cachexia. All measurements were normalized to initial body weight. Two-way ANOVA or Student’s t-test was used for statistical analysis as appropriate. Results: Consistent with previous results, PDAC cachexia induced an increase in the expression of PDK4 in muscle both at mRNA and protein. Expression of other members of the PDK family did not change with cachexia or genotype. Mice with KPC tumors produced less muscle force (-7%, p = 0.03), walked less distance (-30%), and had a longer resting time (17%), p < 0.05 without difference between genotypes. At euthanasia, both genotypes had similar tumor burdens (p >0.9) and exhibited similar degrees of muscle (-13 and -17%, p < 0.0001) and adipose tissue wasting (-50%, p < 0.0001). Deletion of PDK4 did not protect against induction of the muscle-specific E3 ubiquitin ligases in PDAC: FBXO32 and TRIM63 (10.7 fold and 13.6 fold on average, respectively, p < 0.01), molecular hallmarks of muscle atrophy. Overall, our work shows that the knockout of PDK4 does not protect against the development of PDAC cachexia suggesting that PDK4 might be a marker of cachexia but not necessarily a driving mechanism. Citation Format: Omnia U. Gaafer, Joseph Rupert, Joshua Huot, Daenique Jengelley, Andrea Bonetto, Leonidas Koniaris, Teresa Zimmers. PDK4 is dispensable for PDAC chachexia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 361.

To determine the role of skeletal muscle index (SMI) in the assessment of frailty and determination of discharge to post-acute care facilities (PACF) after head and neck cancer free flap reconstruction (HNCFFR).Retrospective cohort.Single-institution, academic tertiary referral center.Adult patients undergoing HNCFFR from 2014 to 2019 with preoperative abdominal computed tomography imaging were retrospectively analyzed. Patient demographics, 5-factor modified frailty index (5-mFI), body mass index (BMI), SMI at the third lumbar vertebra, oncologic history, perioperative data, and Clavien-Dindo (CD) complications were collected. Binary logistic regression was used to identify independent predictors of discharge disposition.The cohort consisted of 206 patients, 62 (30.1%) of whom were discharged to PACF. Patients discharged to PACF were of older age (65.4 vs 57.1 years,SMI and 5-mFI are independently associated with discharge to PACF after HNCFFR and should be considered in preoperative planning and assessment of frailty.

Background Advanced colorectal cancer (CRC) is often accompanied by the development of liver metastases, as well as cachexia, a multi‐organ co‐morbidity primarily affecting skeletal (SKM) and cardiac muscles. Activin receptor type 2B (ACVR2B) signalling is known to cause SKM wasting, and its inhibition restores SKM mass and prolongs survival in cancer. Using a recently generated mouse model, here we tested whether ACVR2B blockade could preserve multiple organs, including skeletal and cardiac muscle, in the presence of metastatic CRC. Methods NSG male mice (8 weeks old) were injected intrasplenically with HCT116 human CRC cells (mHCT116), while sham‐operated animals received saline (n = 5–10 per group). Sham and tumour‐bearing mice received weekly injections of ACVR2B/Fc, a synthetic peptide inhibitor of ACVR2B. Results mHCT116 hosts displayed losses in fat mass ( − 79%, P

Previous studies proposed the Triggering Receptor Expressed on Myeloid Cells 2 (TREM2), a receptor expressed in myeloid cells including microglia in brain and osteoclasts in bone, as a link between brain and bone disease. The TREM2 R47H variant is a known risk factor for Alzheimer's disease (AD), the most common form of dementia. To investigate whether altered TREM2 signaling could contribute to bone and skeletal muscle loss, independently of central nervous system defects, we used mice globally hemizygous for the TREM2 R47H variant (TREM2

Background Sarcopenia has been implicated as a positive predictor of postsurgical complications. Its role in head and neck (H&N) free flap reconstruction has yet to be examined. Our study aimed to determine the clinical impact of sarcopenia on postoperative outcomes in patients receiving autologous free tissue reconstruction for H&N cancer (HNC). Methods A retrospective case–control study was conducted at our tertiary referral center. Patients with HNC who received oncologic resection followed by autologous free tissue reconstruction were included. Preoperative abdominal computed tomography (CT) imaging was analyzed at the third lumbar vertebra (L3) to calculate skeletal muscle cross-sectional area (CSA, cm2). Skeletal muscle index (SMI, cm2/m2) was calculated by normalizing CSA to patient height. Sarcopenia at L3 was defined as SMI ≤ 41.6 cm2/m2 for males and ≤ 32.0 cm2/m2 for females. Data analyses were performed to compare postoperative outcomes. Results Of the 168 patients who met inclusion criteria, 47 patients (28.0%) were determined to have preoperative sarcopenia. The sarcopenic group was older (63 vs. 58 years, p = 0.017), had lower body mass index (BMI; 21.2 vs. 27.2, p Conclusion Sarcopenia was found to be a predictor of postoperative complications in H&N free flap reconstruction, signifying its value as a negative prognostic factor in surgical outcomes. This study reflects level of evidence IV.

Background and Hypothesis: We and others have shown that chemotherapy promotes skeletal muscle wasting and weakness (i.e., cachexia) by disrupting mitochondrial homeostasis and causing oxidative stress. Peroxisome proliferative-activated receptor gamma coactivator 1-alpha (PGC1α) is a pivotal regulator of mitochondrial biogenesis and is involved in reducing oxidative damage in skeletal muscle. Hence, in the present study we investigated whether overexpression of skeletal muscle PGC1α (mPGC1α) was sufficient to preserve skeletal muscle mass and function in young and old mice treated with cisplatin. Experimental Design or Project Methods: Young (2-month; n = 5) and old (18-month; n = 5-8) male wild type (WT) or mPGC1α transgenic mice were treated with cisplatin (2.5mg/kg), while age-matched WT mice received vehicle for 2 weeks. Animals were assessed for muscle force and motor unit number estimation (MUNE). Skeletal muscles were weighed and processed for molecular analyses, including assessment of mitochondrial protein content. Results: Young WT mice exposed to cisplatin showed evidence of cachexia, as indicated by reduced gastrocnemius size (-16%), plantarflexion force (-8%) and MUNE (-56%), whereas mPGC1α mice were only partially protected. Interestingly, despite exacerbated cachexia in aged WT mice treated with chemotherapy, as demonstrated by markedly decreased gastrocnemius size (-22%), plantarflexion force (-18%) and MUNE (-80%) compared to untreated WT, muscle mass, strength and innervation were fully preserved in age-matched mPGC1α mice. Follow-up molecular analyses revealed that WT animals exposed to chemotherapy present loss of muscle mitochondrial proteins PGC1α, OPA1 and CytochromeC, whereas their levels in mPGC1α mice were robustly increased. Conclusion and Potential Impact: Altogether, our data suggest that PGC1α plays a pivotal role in preserving skeletal muscle mass and function, usually impaired by anticancer treatments. These findings enforce developing mitochondria-targeting therapeutics to combat the negative consequences that chemotherapy has on skeletal muscle.

Background: Pulmonary hypertension in the context of heart failure with preserved ejection fraction (PH-HFpEF) is the most common cause of PH worldwide. However, major pathways involved in the regulation of PH-HFpEF are still not well understood. We have recently reported on a role of skeletal muscle sirtuin-3 (SIRT3) in modulating PH-HFpEF. In this study, we attempted to define the processes by which skeletal muscle SIRT3 defects affect pulmonary vascular health in PH-HFpEF. Methods and Results: Skeletal muscle-specific Sirt3 knockout mice ( Sirt3 skm-/- ) exhibited drastically reduced pulmonary vascular density accompanied by pulmonary vascular proliferative remodeling and elevated pulmonary pressures. Using global mass spectrometry-based comparative secretome analysis, we found elevated secretion of lysyl oxidase homolog 2 (LOXL2) in SIRT3-deficeint skeletal muscle cells. Elevated circulation and protein expression levels of LOXL2 were also observed in plasma and skeletal muscle of Sirt3 skm-/- mice, rats with experimental PH-HFpEF (SU5416/Obese ZSF1, Ob-Su), and patients with PH-HFpEF. Interestingly, expression levels of the tumor suppressor WW domain-containing oxidoreductase (WWOX), which plays a housekeeping role in repressing cellular proliferation, were decreased in PASMCs from Sirt3 skm-/- mice. Reduced WWOX expression levels were also detected in PASMCs from Ob-Su rats and human subjects with obesity and diabetes. Treatment with LOXL2 recombinant protein resulted in reduced WWOX expression ex vivo in precision-cut lung slices (PCLS) and in vitro in PASMCs. Media conditioned by SIRT3-deficient skeletal muscle cells reduced WWOX expression in PASMCs, concomitant with increased PCNA levels and cellular proliferation. Finally, knockdown of both SIRT3 and LOXL2 in skeletal muscle cells or suppression of LOXL2 with β-aminopropionitrile (BAPN) restored WWOX and PCNA levels in PASMCs. Conclusions: These studies indicate a systemic pathogenic impact of skeletal muscle SIRT3 deficiency in remote pulmonary vascular remodeling and PH-HFpEF. These studies also reveal a new endocrine signaling axis that links skeletal muscle SIRT3 deficiency to remote WWOX regulation in the pulmonary vasculature through myokine LOXL2.

PURPOSE OF REVIEW: While the function of osteocytes under physiologic conditions is well defined, their role and involvement in cancer disease remains relatively unexplored, especially in a context of non-bone metastatic cancer. This review will focus on describing the more advanced knowledge regarding the interactions between osteocytes and cancer. RECENT FINDINGS: We will discuss the involvement of osteocytes in the onset and progression of osteosarcoma, with the common bone cancers, as well as the interaction that is established between osteocytes and multiple myeloma. Mechanisms responsible for cancer dissemination to bone, as frequently occurs with advanced breast and prostate cancers will be reviewed. While a role for osteocytes in the stimulation and proliferation of cancer cells has been reported, protective effects of osteocytes against bone colonization have been described as well, thus increasing ambiguity regarding the role of osteocytes in cancer progression and dissemination. Lastly, supporting the idea that skeletal defects can occur also in the absence of direct cancer dissemination or osteolytic lesions directly adjacent to the bone, our recent findings will be presented showing that in the absence of bone metastases, the bone microenvironment and, particularly, osteocytes, can manifest a clear and dramatic response to the distant, non-metastatic tumor. SUMMARY: Our observations support new studies to clarify whether treatments designed to preserve the osteocytes can be combined with traditional anticancer therapies, even when bone is not directly affected by tumor growth.

Cachexia is frequently accompanied by severe metabolic derangements, although the mechanisms responsible for this debilitating condition remain unclear. Pyruvate dehydrogenase kinase (PDK)4, a critical regulator of cellular energetic metabolism, was found elevated in experimental models of cancer, starvation, diabetes, and sepsis. Here we aimed to investigate the link between PDK4 and the changes in muscle size in cancer cachexia. High PDK4 and abnormal energetic metabolism were found in the skeletal muscle of colon-26 tumor hosts, as well as in mice fed a diet enriched in Pirinixic acid, previously shown to increase PDK4 levels. Viral-mediated PDK4 overexpression in myotube cultures was sufficient to promote myofiber shrinkage, consistent with enhanced protein catabolism and mitochondrial abnormalities. On the contrary, blockade of PDK4 was sufficient to restore myotube size in C2C12 cultures exposed to tumor media. Our data support, for the first time, a direct role for PDK4 in promoting cancer-associated muscle metabolic alterations and skeletal muscle atrophy.-Pin, F., Novinger, L. J., Huot, J. R., Harris, R. A., Couch, M. E., O'Connell, T. M., Bonetto, A. PDK4 drives metabolic alterations and muscle atrophy in cancer cachexia.

Background Cancer cachexia is a metabolic disorder involving perturbed energy balance and altered mitochondrial function. Chemotherapy is a primary treatment option for many types of cancer, but there is substantial evidence that some chemotherapeutic agents can also lead to the development and progression of cachexia. In this study, we apply a comprehensive and systems level metabolomics approach to characterize the metabolic perturbations in murine models of cancer‐induced and chemotherapy‐induced cachexia. Knowledge of the unique pathways through which cancer and chemotherapy drive cachexia is necessary in order to develop effective treatments. Methods The murine Colon26 (C26) adenocarcinoma xenograft model was used to study the metabolic derangements associated with cancer‐induced cachexia. In vivo administration of Folfiri (5‐fluorouracil, irinotecan, and leucovorin) was used to model chemotherapy‐induced cachexia. Comprehensive metabolic profiling was carried out using both nuclear magnetic resonance‐based and mass spectrometry‐based platforms. Analyses included plasma, muscle, and liver tissue to provide a systems level profiling. Results The study involved four groups of CD2F1 male mice (n = 4–5), including vehicle treated (V), C26 tumour hosts (CC), Folfiri treated (F), and C26 tumour hosts treated with Folfiri (CCF). Significant weight loss including skeletal muscle was observed for each of the experimental groups with the tumour hosts showing the most dramatic change (−3.74 g vs. initial body weight in the CC group). Skeletal muscle loss was evident in all experimental groups compared with V, with the CCF combination resulting in the most severe depletion of quadriceps mass (−38% vs. V; P

Colorectal cancer (CRC) is a leading cause of cancer-related death, and the prevalence of CRC in young adults is on the rise, making this a largescale clinical concern. Advanced CRC patients often present with liver metastases (LM) and an increased incidence of cachexia, i.e., musculoskeletal wasting. Despite its high incidence in CRC patients, cachexia remains an unresolved issue, and animal models for the study of CRC cachexia, in particular, metastatic CRC cachexia, remain limited, therefore, we aimed to establish a new model of metastatic CRC cachexia. C57BL/6 male mice (8 weeks old) were subcutaneously (MC38) or intrasplenically injected (mMC38) with MC38 murine CRC cells to disseminate LM, while experimental controls received saline (n = 5–8/group). The growth of subcutaneous MC38 tumors was accompanied by a reduction in skeletal muscle mass (−16%, quadriceps muscle), plantarflexion force (−22%) and extensor digitorum longus (EDL) contractility (−20%) compared to experimental controls. Meanwhile, the formation of MC38 LM (mMC38) led to heighted reductions in skeletal muscle mass (−30%, quadriceps), plantarflexion force (−28%) and EDL contractility (−35%) compared to sham-operated controls, suggesting exacerbated cachexia associated with LM. Moreover, both MC38 and mMC38 tumor hosts demonstrated a marked loss of bone indicated by reductions in trabecular (Tb.BV/TV: −49% in MC38, and −46% in mMC38) and cortical (C.BV/TV: −12% in MC38, and −8% in mMC38) bone. Cell culture experiments revealed that MC38 tumor-derived factors directly promote myotube wasting (−18%) and STAT3 phosphorylation (+5-fold), while the pharmacologic blockade of STAT3 signaling was sufficient to preserve myotube atrophy in the presence of MC38 cells (+21%). Overall, these results reinforce the notion that the formation of LM heightens cachexia in an experimental model of CRC.

Muscle wasting in cancer is associated with deficits in protein synthesis, yet, the mechanisms underlying this anabolic impairment remain poorly understood. The capacity for protein synthesis is mainly determined by the abundance of muscle ribosomes, which is in turn regulated by transcription of the ribosomal (r)RNA genes (rDNA). In this study, we investigated whether muscle loss in a preclinical model of ovarian cancer is associated with a reduction in ribosomal capacity and was a consequence of impaired rDNA transcription. Tumor bearing resulted in a significant loss in gastrocnemius muscle weight and protein synthesis capacity, and was consistent with a significant reduction in rDNA transcription and ribosomal capacity. Despite the induction of the ribophagy receptor NUFIP1 mRNA and the loss of NUFIP1 protein, in vitro studies revealed that while inhibition of autophagy rescued NUFIP1, it did not prevent the loss of rRNA. Electrophoretic analysis of rRNA fragmentation from both in vivo and in vitro models showed no evidence of endonucleolytic cleavage, suggesting that rRNA degradation may not play a major role in modulating muscle ribosome abundance. Our results indicate that in this model of ovarian cancer-induced cachexia, the ability of skeletal muscle to synthesize protein is compromised by a reduction in rDNA transcription and consequently a lower ribosomal capacity. Thus, impaired ribosomal production appears to play a key role in the anabolic deficits associated with muscle wasting in cancer cachexia.

Background and Hypothesis: Head and neck cancer (HNC) is frequently associated with cachexia, characterized by involuntary weight loss, sarcopenia, and malnutrition. In HNC patients, dysphagia and anorexia from obstructive aerodigestive tumors propagates cachexia even further. However, the impact of pathologic features and burden of HNC on cachexia has yet to be investigated. We therefore hypothesize that larger, more aggressive tumors impose greater cachexia severity in HNC patients. Methods: A single-institution, retrospective study of adult patients undergoing surgical resection of head and neck carcinoma from 2014-2017 was performed. Patients without 30-day preoperative abdominal CT imaging for skeletal muscle index (SMI, cm2/m2) measurements were excluded. Patient demographics, comorbidities, nutrition data, and cancer pathology reports were collected. Cachexia was defined as unintentional weight loss >5% over 6 months or >2% with BMI

Objective To determine if sarcopenia is a predictor of blood transfusion requirements in head and neck cancer free flap reconstruction (HNCFFR). Methods A single‐institution, retrospective review was performed of HNCFFR patients with preoperative abdominal imaging from 2014 to 2019. Demographics, comorbidities (modified Charlson Comorbidity Index [mCCI]), skeletal muscle index (cm2/m2), oncologic history, intraoperative data, and 30‐day postoperative complications (Clavien‐Dindo score [CD]) were collected. Binary logistic regression was performed to determine predictors of transfusion. Results Eighty (33.5%), 66 (27.6%), and 110 (46.0%) of n = 239 total patients received an intraoperative, postoperative, or any perioperative blood transfusion, respectively. Sixty‐two (25.9%) patients had sarcopenia. Patients receiving intraoperative transfusions had older age (P = .035), more frequent alcoholism (P = .028) and sarcopenia (P, Head and neck cancer free flap reconstruction patients are at particularly high risk of requiring perioperative blood transfusions, which imposes additional risks and consequences. Sarcopenia, which was determined by measuring skeletal muscle mass using preoperative CT imaging, is highly prevalent in this patient population and has been associated with worse perioperative outcomes. In this retrospective cohort study, we determined that sarcopenia was and independent risk factor for blood transfusion after accounting for comorbidities, operative factors, and complications in head and neck cancer free flap reconstruction patients.

Most patients with pancreatic adenocarcinoma (PDAC) suffer unintentional weight loss, or cachexia. Interleukin-6 causes cachexia in mice and associates with mortality in PDAC. Here we show that tumor cell-derived IL-6 mediates crosstalk between tumor and peripheral tissues to promote cachexia. Tumor-cell IL-6 elicits expression of IL-6 in fat and IL-6 and IL-6 receptor (IL6R) in muscle, concomitantly raising both in blood. Inflammation-induced adipose lipolysis elevates circulating fatty acids, which cooperate with IL-6 to induce skeletal muscle dysmetabolism and wasting. Thus, PDAC induces crosstalk among tumor, fat and muscle via a feed-forward, IL-6 signaling loop. Tumor talks to muscle and fat through IL-6, and muscle to fat via IL6R trans-signaling, and fat to muscle through lipids and fatty acids. Disruption of this crosstalk by depletion of tumor-derived IL-6 halved fat wasting and abolished muscle loss, supporting IL-6, IL-6R and lipids as causal nodes for tissue crosstalk in PDAC cachexia.SignificancePDAC-associated cachexia significantly increases patient morbidity and mortality. This study identifies muscle and fat crosstalk via IL6R trans-signaling in concert with muscle steatosis as a main driver of PDAC-associated cachexia.

Advanced colorectal cancer (CRC) is often accompanied by development of liver metastases (LMs) and skeletal muscle wasting (i.e., cachexia). Despite plaguing the majority of CRC patients, cachexia remains unresolved. By using mice injected with Colon-26 mouse tumors, either subcutaneously (s.c.; C26) or intrasplenically to mimic hepatic dissemination of cancer cells (mC26), here we aimed to further characterize functional, molecular, and metabolic effects on skeletal muscle and examine whether LMs exacerbate CRC-induced cachexia. C26-derived LMs were associated with progressive loss of body weight, as well as with significant reductions in skeletal muscle size and strength, in line with reduced phosphorylation of markers of protein anabolism and enhanced protein catabolism. mC26 hosts showed prevalence of fibers with glycolytic metabolism and enhanced lipid accumulation, consistent with abnormalities of mitochondrial homeostasis and energy metabolism. In a comparison with mice bearing s.c. C26, cachexia appeared exacerbated in the mC26 hosts, as also supported by differentially expressed pathways within skeletal muscle. Overall, our model recapitulates the cachectic phenotype of metastatic CRC and reveals that formation of LMs resulting from CRC exacerbate cancer-induced skeletal muscle wasting by promoting differential gene expression signatures.

Objective:Pulmonary hypertension (PH) due to left heart disease (group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most common cause of PH worldwide; however, at present, there is no proven effective therapy available for its treatment. PH-HFpEF is associated with insulin resistance and features of metabolic syndrome. The stable prostacyclin analog, treprostinil, is an effective and widely used Food and Drug Administration-approved drug for the treatment of pulmonary arterial hypertension. While the effect of treprostinil on metabolic syndrome is unknown, a recent study suggests that the prostacyclin analog beraprost can improve glucose intolerance and insulin sensitivity. We sought to evaluate the effectiveness of treprostinil in the treatment of metabolic syndrome-associated PH-HFpEF.Approach and Results:Treprostinil treatment was given to mice with mild metabolic syndrome-associated PH-HFpEF induced by high-fat diet and to SU5416/obese ZSF1 rats, a model created by the treatment of rats with a more profound metabolic syndrome due to double leptin receptor defect (obese ZSF1) with a vascular endothelial growth factor receptor blocker SU5416. In high-fat diet-exposed mice, chronic treatment with treprostinil reduced hyperglycemia and pulmonary hypertension. In SU5416/Obese ZSF1 rats, treprostinil improved hyperglycemia with similar efficacy to that of metformin (a first-line drug for type 2 diabetes mellitus); the glucose-lowering effect of treprostinil was further potentiated by the combined treatment with metformin. Early treatment with treprostinil in SU5416/Obese ZSF1 rats lowered pulmonary pressures, and a late treatment with treprostinil together with metformin improved pulmonary artery acceleration time to ejection time ratio and tricuspid annular plane systolic excursion with AMPK (AMP-activated protein kinase) activation in skeletal muscle and the right ventricle.Conclusions:Our data suggest a potential use of treprostinil as an early treatment for mild metabolic syndrome-associated PH-HFpEF and that combined treatment with treprostinil and metformin may improve hyperglycemia and cardiac function in a more severe disease.

Purpose of review Cancer patients undergoing chemotherapy often experience very debilitating side effects, including unintentional weight loss, nausea, and vomiting. Changes in body composition, specifically lean body mass (LBM), are known to have important implications for anticancer drug toxicity and cancer prognosis. Currently, chemotherapy dosing is based on calculation of body surface area, although this approximation does not take into consideration the variability in lean and adipose tissue mass. Recent findings Patients with depletion of muscle mass present higher chemotherapy-related toxicity, whereas patients with larger amounts of LBM show fewer toxicities and better outcomes. Commonly used chemotherapy regimens promote changes in body composition, primarily by affecting skeletal muscle, as well as fat and bone mass. Experimental evidence has shown that pro-atrophy mechanisms, abnormal mitochondrial metabolism, and reduced protein anabolism are primarily implicated in muscle depletion. Muscle-targeted pro-anabolic strategies have proven successful in preserving lean tissue in the occurrence of cancer or following chemotherapy. Summary Muscle wasting often occurs as a consequence of anticancer treatments and is indicative of worse outcomes and poor quality of life in cancer patients. Accurate assessment of body composition and preservation of muscle mass may reduce chemotherapy toxicity and improve the overall survival.

BACKGROUND Cachexia frequently occurs in women with advanced ovarian cancer (OC), along with enhanced inflammation. Despite being responsible for one third of all cancer deaths, cachexia is generally under-studied in OC due to a limited number of pre-clinical animal models. We aimed to address this gap by characterizing the cachectic phenotype in a mouse model of OC. METHODS Nod SCID gamma mice (n = 6-10) were injected intraperitoneally with 1 × 107 ES-2 human OC cells to mimic disseminated abdominal disease. Muscle size and strength, as well as bone morphometry, were assessed. Tumour-derived effects on muscle fibres were investigated in C2C12 myotube cultures. IL-6 levels were detected in serum and ascites from tumour hosts, as well as in tumour sections. RESULTS In about 2 weeks, ES-2 cells developed abdominal tumours infiltrating omentum, mesentery, and adjacent organs. The ES-2 tumours caused severe cachexia with marked loss of body weight (-12%, P < 0.01) and ascites accumulation in the peritoneal cavity (4.7 ± 1.5 mL). Skeletal muscles appeared markedly smaller in the tumour-bearing mice (approximately -35%, P < 0.001). Muscle loss was accompanied by fibre atrophy, consistent with reduced muscle cross-sectional area (-34%, P < 0.01) and muscle weakness (-50%, P < 0.001). Body composition assessment by dual-energy X-ray absorptiometry revealed decreased bone mineral density (-8%, P < 0.01) and bone mineral content (-19%, P < 0.01), also consistent with reduced trabecular bone in both femurs and vertebrae, as suggested by micro-CT imaging of bone morphometry. In the ES-2 mouse model, cachexia was also associated with high tumour-derived IL-6 levels in plasma and ascites (26.3 and 279.6 pg/mL, respectively) and with elevated phospho-STAT3 (+274%, P < 0.001), reduced phospho-AKT (-44%, P < 0.001) and decreased mitochondrial proteins, as well as with increased protein ubiquitination (+42%, P < 0.001) and expression of ubiquitin ligases in the skeletal muscle of tumour hosts. Similarly, ES-2 conditioned medium directly induced fibre atrophy in C2C12 mouse myotubes (-16%, P < 0.001), consistent with elevated phospho-STAT3 (+1.4-fold, P < 0.001) and altered mitochondrial homoeostasis and metabolism, while inhibition of the IL-6/STAT3 signalling by means of INCB018424 was sufficient to restore the myotubes size. CONCLUSIONS Our results suggest that the development of ES-2 OC promotes muscle atrophy in both in vivo and in vitro conditions, accompanied by loss of bone mass, enhanced muscle protein catabolism, abnormal mitochondrial homoeostasis, and elevated IL-6 levels. Therefore, this represents an appropriate model for the study of OC cachexia. Our model will aid in identifying molecular mediators that could be effectively targeted in order to improve muscle wasting associated with OC.

Approximately 80% of patients with pancreatic ductal adenocarcinoma (PDAC) suffer cachexia, involuntary loss of fat and muscle due to inflammation and dysmetabolism that increases treatment toxicity, reduces treatment response and promotes mortality. Most research has focused on muscle and adipose individually while neglecting tissue crosstalk. Recently, we reported that IL6 trans-signaling from muscle to fat in PDAC cachexia augments adipose lipolysis, leading to increased muscle lipid accumulation (myosteatosis) and promoting activation of lipid sensitive signaling pathways and metabolic substrate shifts in muscle. The lipid sensitive protein kinase C theta (PKC-θ) modulates myopathic phenotypes including muscular dystrophy, atrophy, and insulin resistance. PKC-θ is activated by diacylglycerol, which binds to PKC-θ promoting its translocation to the plasma membrane, phosphorylation, and activation. Activated PKC-θ modulates pathways with known roles in muscle atrophy including inhibition of insulin signaling, activation of NF-κB, and increased shedding of the IL-6R. We used in vitro and in vivo models to study the role of PKC-θ in PDAC cachexia. Here 50,000 tumor cells of a line derived from the KPC (LSL-KrasG12D:LSL-Trp53R172H:Pdx1-Cre) genetically engineered model of PDAC were implanted in the pancreases of male C57BL/6J mice. Tissues were collected when mice displayed severe cachexia (~25% muscle loss). Phospho-Thr538-PKC-θ was increased 1.8-fold (p=0.002) in muscle of mice with KPC cachexia and phosphorylation of PKC-θ substrates was correspondingly increased (p=0.048). Plasma from KPC-tumor bearing mice was used to treat C2C12 myotubes, with or without the PKC inhibitor Sotrastaurin. After 48 hours, KPC plasma caused a significant decrease in average myotube diameter compared to no tumor plasma (18%, p=0.002), whereas addition of 500nM Sotrastaurin prevented KPC plasma-induced myotube atrophy. KPC tumor growth was not different between wildtype mice and mice with germline deletion of the PKC-θ gene, Prkcq. However, Prkcq null tumor-bearing mice demonstrated greater in vivo muscle force production (p Citation Format: Joseph E. Rupert, Joshua R. Huot, Ashok Narasimhan, Daenique H. Jengelley, Andrea Bonetto, Teresa A. Zimmers. PKC-theta modulates myosteatosis, muscle function, atrophy, and survival in murine pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 969.

Chemotherapy promotes the development of cachexia, a debilitating condition characterized by muscle and fat loss. ACVR2B/Fc, an inhibitor of the Activin Receptor 2B signaling, has been shown to preserve muscle mass and prolong survival in tumor hosts, and to increase bone mass in models of osteogenesis imperfecta and muscular dystrophy. We compared the effects of ACVR2B/Fc on muscle and bone mass in mice exposed to Folfiri. In addition to impairing muscle mass and function, Folfiri had severe negative effects on bone, as shown by reduced trabecular bone volume fraction (BV/TV), thickness (Tb.Th), number (Tb.N), connectivity density (Conn.Dn), and by increased separation (Tb.Sp) in trabecular bone of the femur and vertebra. ACVR2B/Fc prevented the loss of muscle mass and strength, and the loss of trabecular bone in femurs and vertebrae following Folfiri administration. Neither Folfiri nor ACVR2B/Fc had effects on femoral cortical bone, as shown by unchanged cortical bone volume fraction (Ct.BV/TV), thickness (Ct.Th) and porosity. Our results suggest that Folfiri is responsible for concomitant muscle and bone degeneration, and that ACVR2B/Fc prevents these derangements. Future studies are required to determine if the same protective effects are observed in combination with other anticancer regimens or in the presence of cancer.