BackgroundCachexia 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.MethodsNod 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.ResultsIn 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.ConclusionsOur 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.

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 over‐expression 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. FASEB J. 33, 7778–7790 (2019). http://www.fasebj.org

Colorectal cancer (CRC) is often accompanied by formation of liver metastases (LM) and skeletal muscle wasting, i.e. cachexia. Despite affecting the majority of CRC patients, cachexia remains underserved, understudied and uncured. Animal models for the study of CRC-induced cachexia, in particular models containing LM, are sparse; therefore, we aimed to characterize two new models of CRC cachexia. Male NSG mice were injected subcutaneously (HCT116) or intrasplenically (mHCT116) with human HCT116 CRC tumor cells to disseminate LM, whereas experimental controls received saline (n=5-8/group). Tumor growth was accompanied by loss of skeletal muscle mass (HCT116: −20%; mHCT116: −31%; quadriceps muscle) and strength (HCT116: −20%; mHCT116: −27%), with worsened loss of skeletal muscle mass in mHCT116 compared with HCT116 (gastrocnemius: −19%; tibialis anterior: −22%; quadriceps: −21%). Molecular analyses revealed elevated protein ubiquitination in HCT116, whereas mHCT116 also displayed elevated Murf1 and atrogin-1 expression, along with reduced mitochondrial proteins PGC1α, OPA1, mitofusin 2 and cytochrome C. Further, elevated IL6 levels were found in the blood of mHCT116 hosts, which was associated with higher phosphorylation of STAT3 in skeletal muscle. To clarify whether STAT3 was a main player in muscle wasting in this model, HCT116 cells were co-cultured with C2C12 myotubes. Marked myotube atrophy (-53%) was observed, along with elevated phospho-STAT3 levels (+149%). Conversely, inhibition of STAT3 signaling by means of a JAK/STAT3 inhibitor was sufficient to rescue myotube atrophy induced by HCT116 cells (+55%). Overall, our results indicate that the formation of LM exacerbates cachectic phenotype and associated skeletal muscle molecular alterations in HCT116 tumor hosts.

No abstract

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 (À 79%, P < 0.0001), bone mass (À 39%, P < 0.05), and SKM mass (quadriceps: À 22%, P < 0.001), in line with reduced muscle cross-sectional area (À 24%, P < 0.01) and plantarflexion force (À 28%, P < 0.05). Further, despite only moderately affected heart size, cardiac function was significantly impaired (ejection fraction %: À 16%, P < 0.0001; fractional shortening %: À 25%, P < 0.0001) in the mHCT116 hosts. Conversely, ACVR2B/Fc preserved fat mass (+ 238%, P < 0.001), bone mass (+ 124%, P < 0.0001), SKM mass (quadriceps: + 31%, P < 0.0001), size (cross-sectional area: + 43%, P < 0.0001) and plantarflexion force (+ 28%, P < 0.05) in tumour hosts. Cardiac function was also completely preserved in tumour hosts receiving ACVR2B/Fc (ejection fraction %: + 19%, P < 0.0001), despite no effect on heart size. RNA sequencing analysis of heart muscle revealed rescue of genes related to cardiac development and contraction in tumour hosts treated with ACVR2B/Fc. Conclusions Our metastatic CRC model recapitulates the multi-systemic derangements of cachexia by displaying loss of fat, bone, and SKM along with decreased muscle strength in mHCT116 hosts. Additionally, with evidence of severe cardiac dysfunction, our data support the development of cardiac cachexia in the occurrence of metastatic CRC. Notably, ACVR2B antagonism preserved adipose tissue, bone, and SKM, whereas muscle and cardiac functions were completely maintained upon treatment. Altogether, our observations implicate ACVR2B signalling in the development of multi-organ perturbations in metastatic CRC and further dictate that ACVR2B represents a promising therapeutic target to preserve body composition and functionality in cancer cachexia.

Breast cancer frequently metastasizes to the skeleton resulting in bone degradation due to osteoclast activation. Metastases also downregulate differentiation and the bone-rebuilding function of osteoblasts. Moreover, cancer cells trigger osteoblast inflammatory stress responses. Pro-inflammatory mediators such as interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), expressed by osteoblasts (MC3T3-E1) stimulated with human breast cancer cell (MDA-MB-231) conditioned medium, are pivotal to osteoclast activation and metastasis. Given that these genes are regulated by nuclear factor-kappaB (NF-kappaB), a redox-sensitive transcription factor, we hypothesized that selenium (Se) could abrogate the inflammatory response to metastatic breast cancer cells by modulating NF-kappaB. Caffeic acid phenethyl ester and parthenolide inhibited NF-kappaB activation, as seen by gel shift assays and immunoblotting for p65 in nuclear fractions, as well as decreased production of IL-6 and MCP-1. Supplementation of MC3T3-E1 with methylseleninic acid (MSA) (0.5 microM to 4 microM) reduced the activation of NF-kappaB leading to a decrease in IL-6, MCP-1, COX-2 and iNOS in response to MDA-MB-231 conditioned medium. Addition of MSA to osteoblasts for as little as 15 min suppressed activation of NF-kappaB suggesting that short-lived active metabolites might be involved. However, brief exposure to MSA also brought about an increase in selenoprotein glutathione peroxidase 1. In summary, our data indicate that the osteoblast response to metastatic breast cancer cells is regulated by NF-kappaB activation, which can be effectively suppressed by MSA either through short-lived active metabolites and/or selenoproteins. Thus, Se supplementation may prevent the osteoblast inflammatory response or dampen the vicious cycle established when breast cancer cells, osteoblasts and osteoclasts interact.

The purpose of this study was to determine the clonal relationship between B cells within a breast cancer and the B cells in the tumor-draining lymph node (TDLN). We also determined the binding capacity of antibodies derived from these sources to autologous cancer and autologous noncancer breast tissue. Antibody clonality of B cells derived from tumor and lymph node was determined by analyzing heavy and light chain immunoglobulin sequences. The number of shared clonal groups observed between tumor and lymph node antibodies was significant for both heavy (p = 0.004) and light chain (p = 0.012) populations. Panning with phage-displayed single-chain variable fragment libraries derived from the tumor and lymph node B cells resulted in multiple antibodies that bound autologous tumor. Sequence analysis of enriched antibodies recovered after the third round of panning the tumor and TDLN libraries against autologous tumor lysates had a genetic relationship. These results indicate that B cells infiltrating a patient's breast cancer and B cells present in the tumor-draining lymph node are clonally and functionally related.

Objective 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). Study Design Retrospective cohort. Setting Single-institution, academic tertiary referral center. Methods 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. Results 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, P < .0001) and had a lower SMI (38.8 vs 46.8 cm2/m2, P < .0001), higher 5-mFI (≥3; 25.8% vs 4.2%, P < .0001), and greater incidence of stage IV (80.6% vs 64.1%, P = .0211) aerodigestive cancer (80.6% vs 66.7%, P = .0462). Patients discharged to PACF experienced more blood transfusions (74.2% vs 35.4%, P < .0001), major postoperative complications (CD ≥3, 40.3% vs 12.9%, P < .0001), and delirium (33.9% vs 4.2%, P < .0001). After adjusting for pre- and postoperative factors, multivariate binary logistic regression identified age ( P = .0255), 5-mFI ( P < .0042), SMI ( P = .0199), stage IV cancer ( P = .0250), aerodigestive tumor ( P = .0366), delirium ( P < .0001), and perioperative blood transfusion ( P = .0144) as independent predictors of discharge to PACF. Conclusions SMI and 5-mFI are independently associated with discharge to PACF after HNCFFR and should be considered in preoperative planning and assessment of frailty.