Hormonally Regulated Myogenic miR-486 Influences Sex-specific Differences in Cancer-induced Skeletal Muscle Defects

Mutant RAS-driven Secretome Causes Skeletal Muscle Defects in Breast Cancer

Cancer-induced skeletal muscle defects differ in severity between individuals with the same cancer type. Cancer subtype-specific genomic aberrations are suggested to mediate these differences, but experimental validation studies are very limited. We utilized three different breast cancer patient-derived xenograft (PDX) models to correlate cancer subtype with skeletal muscle defects. PDXs were derived from brain metastasis of triple-negative breast cancer (TNBC), estrogen receptor-positive/progesterone receptor-positive (ER+/PR+) primary breast cancer from a BRCA2-mutation carrier, and pleural effusion from an ER+/PR- breast cancer. While impaired skeletal muscle function as measured through rotarod performance and reduced levels of circulating and/or skeletal muscle miR-486 were common across all three PDXs, only TNBC-derived PDX activated phospho-p38 in skeletal muscle. To further extend these results, we generated transformed variants of human primary breast epithelial cells from healthy donors using HRASG12V or PIK3CAH1047R mutant oncogenes. Mutations in RAS oncogene or its modulators are found in approximately 37% of metastatic breast cancers, which is often associated with skeletal muscle defects. Although cells transformed with both oncogenes generated adenocarcinomas in NSG mice, only HRASG12V-derived tumors caused skeletal muscle defects affecting rotarod performance, skeletal muscle contraction force, and miR-486, Pax7, pAKT, and p53 levels in skeletal muscle. Circulating levels of the chemokine CXCL1 were elevated only in animals with tumors containing HRASG12V mutation. Because RAS pathway aberrations are found in 19% of cancers, evaluating skeletal muscle defects in the context of genomic aberrations in cancers, particularly RAS pathway mutations, may accelerate development of therapeutic modalities to overcome cancer-induced systemic effects.

SIGNIFICANCE

Mutant RAS- and PIK3CA-driven breast cancers distinctly affect the function of skeletal muscle. Therefore, research and therapeutic targeting of cancer-induced systemic effects need to take aberrant cancer genome into consideration.

Matrix metalloproteinase‑1 and microRNA‑486‑5p in urinary exosomes can be used to detect early lung cancer: A preliminary report

The present study describes a novel molecular-genetic method suitable for lung cancer (LC) screening in the work-place and at community health centers. Using urinary-isolated exosomes from 35 patients with LC and 40 healthy volunteers, the expression ratio of MMP-1/CD63, and the relative expression levels of both microRNA (miRNA)-21 and miRNA-486-5p were measured. MMP-1/CD63 expression ratio was significantly higher in patients with LC than in the healthy controls {1.342 [95% confidence interval (CI): 0.890-1.974] vs. 0.600 (0.490-0.900); P<0.0001}. The relative expression of miRNA-486-5p in male healthy controls was significantly different from that in female healthy controls, whereas there was no significant difference in miRNA-21. Receiver operating characteristic curve (ROC) analysis of MMP-1/CD63 showed 92.5% sensitivity and 54.3% specificity, whereas miRNA-486-5p showed 85% sensitivity and 70.8% specificity for men, and 70.0% sensitivity and 72.7% specificity for women. The logistic regression model used to evaluate the association of LC with the combination of MMP-1/CD63 and miRNA-486-5p revealed that the area under the ROC curve was 0.954 (95% CI: 0.908-1.000), and the model had 89% sensitivity and 88% specificity after adjusting for age, sex and smoking status. These data suggested that the combined analysis of MMP-1/CD63 and miRNA-486-5p in urinary exosomes may be used to detect patients with early-stage LC in the work-place and at community health centers, although confirmational studies are warranted.

A human skeletal muscle stem/myotube model reveals multiple signaling targets of cancer secretome in skeletal muscle

Skeletal muscle dysfunction or reprogramming due to the effects of the cancer secretome is observed in multiple malignancies. Although mouse models are routinely used to study skeletal muscle defects in cancer, because of species specificity of certain cytokines/chemokines in the secretome, a human model system is required. Here, we establish simplified multiple skeletal muscle stem cell lines (hMuSCs), which can be differentiated into myotubes. Using single nuclei ATAC-seq (snATAC-seq) and RNA-seq (snRNA-seq), we document chromatin accessibility and transcriptomic changes associated with the transition of hMuSCs to myotubes. Cancer secretome accelerated stem to myotube differentiation, altered the alternative splicing machinery and increased inflammatory, glucocorticoid receptor, and wound healing pathways in hMuSCs. Additionally, cancer secretome reduced metabolic and survival pathway associated miR-486, AKT, and p53 signaling in hMuSCs. hMuSCs underwent myotube differentiation when engrafted into NSG mice and thus providing a humanized in vivo skeletal muscle model system to study cancer cachexia.

Preoperative low absolute and relative handgrip strength as predictors of postoperative short-term outcomes: a prospective study based on patients aged 60 years and older with gastric cancer

PURPOSE

This study aimed to determine the association of absolute and relative HGS indicators with postoperative short-term outcomes in older patients with gastric cancer.

METHODS

The prospective, single-center, observational study involved 230 patients (age ≥ 60 years) who underwent radical gastrectomy. Absolute HGS was directly obtained from results measured by a hand dynamometer, while relative HGS was calculated as the value of absolute HGS divided by body mass index (BMI), appendicular skeletal muscle mass index (ASMI) and age, respectively. Low absolute HGS was defined according to the criterion in AWGS 2019 consensus and the first gender-specific quartile. Low relative handgrip strength was defined if it was below the first gender-specific quartile of the distribution. Postoperative outcomes included total complications, malnutrition and length of hospital stay. Univariate and multivariate regression models were performed to investigate and compare the predictive values of different HGS indicators.

RESULTS

For the five HGS indicators, multivariate analyses showed that low absolute HGS (AWGS consensus), low HGS/BMI and HGS/age were independent risk factors for both postoperative total complications (absolute HGS(AWGS consensus): OR  2.03, 95%CI:1.05-3.93; HGS/BMI: OR  2.12, 95%CI 1.05-4.28; HGS/age: OR  2.79, 95%CI 1.40-5.54) and malnutrition (absolute HGS(AWGS consensus): OR   2.01, 95%CI 1.10-3.67; HGS/BMI: OR  2.28, 95%CI 1.20-4.33; HGS/age: OR   2.70, 95%CI 1.42-5.14). Low absolute HGS (quartile) was an independent risk factor for malnutrition (OR   1.96, 95%CI 1.04-3.71). Moreover, Low HGS/age was associated with lengthened postoperative hospital stay (OR  2.07, 95%CI 1.12-3.85).

CONCLUSIONS

Except HGS/ASMI, both absolute and relative HGS indicators were associated with postoperative short-term outcomes. Particularly, HGS/age revealed relatively better predictive value for the studied outcomes.

Skeletal muscle-specific overexpression of miR-486 limits mammary tumor-induced skeletal muscle functional limitations

miR-486 is a myogenic microRNA, and its reduced skeletal muscle expression is observed in muscular dystrophy. Transgenic overexpression of miR-486 using muscle creatine kinase promoter (MCK-miR-486) partially rescues muscular dystrophy phenotype. We had previously demonstrated reduced circulating and skeletal muscle miR-486 levels with accompanying skeletal muscle defects in mammary tumor models. To determine whether skeletal muscle miR-486 is functionally similar in dystrophies and cancer, we performed functional limitations and biochemical studies of skeletal muscles of MMTV-Neu mice that mimic HER2+ breast cancer and MMTV-PyMT mice that mimic luminal subtype B breast cancer and these mice crossed to MCK-miR-486 mice. miR-486 significantly prevented tumor-induced reduction in muscle contraction force, grip strength, and rotarod performance in MMTV-Neu mice. In this model, miR-486 reversed cancer-induced skeletal muscle changes, including loss of p53, phospho-AKT, and phospho-laminin alpha 2 (LAMA2) and gain of hnRNPA0 and SRSF10 phosphorylation. LAMA2 is a part of the dystrophin-associated glycoprotein complex, and its loss of function causes congenital muscular dystrophy. Complementing these beneficial effects on muscle, miR-486 indirectly reduced tumor growth and improved survival, which is likely due to systemic effects of miR-486 on production of pro-inflammatory cytokines such as IL-6. Thus, similar to dystrophy, miR-486 has the potential to reverse skeletal muscle defects and cancer burden.