BackgroundMicro‐RNAs (miRNAs) are a class of small, non‐protein coding RNAs that posttranscriptionally regulate gene expression through the degradation or translational inhibition of their target complimentary messenger RNAs (mRNAs). Developing evidence indicates the importance of miRNAs in the myogenic program and their influence on disorders affecting muscle growth and metabolism.PurposeThe purpose of this study was to determine whether miR23a regulates myotube formation in skeletal muscle under lipid‐induced atrophic conditions.MethodsC2C12 myoblasts were transfected with a mimic complex to increase levels of miR23a or vehicle at seeding, then induced to differentiate into myotubes. Cells were treated with palmitic acid (0.1mM) at day 0 and day 2 of differentiation. Cells were collected at day 4 of differentiation. Real‐time PCR was used to investigate changes in miRNA expression and myosin heavy chain staining was performed to determine differences in myotube formation.ResultsCells that received mimic had increases in miR‐23a levels. Palmitic acid‐induced reductions in myotube formation were abrogated with overexpression of miR‐23a.ConclusionsThese data suggest that miR23a may exist in a regulatory pathway that alters muscle growth in the presences of saturated fatty acid. Future work is ongoing to understand the mechanisms by which miR23a may regulate skeletal muscle growth under lipid‐induced atrophic conditions.Support or Funding InformationFaculty Research GrantThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

BackgroundMicroRNAs (miRs) are non‐protein coding RNAs that interact with messenger RNAs (mRNAs) to post transcriptionally regulate protein translation. The miRs important in regulating skeletal muscle insulin resistance are not fully identified.PurposeThe purpose of this study was to determine the role of miR‐26a on lipid induced insulin resistance in skeletal muscle cells.MethodsC2C12 mouse skeletal muscle cells were treated to increase levels of miR‐26a (mimic) using commercially available kits (Qiagen). C2C12 mouse myoblasts were grown to full confluence, serum starved for 3 hours then treated with 0.5 mM palmitic acid (PA) to induce insulin resistance. Cells received PA for 24 hours followed by a 100 nM insulin treatment for 15 minutes. Real‐time PCR was used to examine levels of miR‐26a, and Western blotting was utilized to investigate insulin sensitive protein expression.ResultsCells receiving mimic had increases in miR‐26a levels and cells receiving palmitic acid had decreased responsiveness to insulin. Overexpressing miR‐26a levels in C2C12 muscle cells improved responsiveness to insulin in the presence of palmitic acid.ConclusionsHere we show that increasing miR‐26a levels in vitro can improve insulin responsiveness in mouse skeletal muscle cells with lipid induced insulin resistance. The mechanisms of how miR‐26a is operating in skeletal muscle need to be further explored.Support or Funding InformationFaculty Research GrantThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

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Lung cancer, the second most common cancer, is one of the largest causes of cancer‐related mortalities worldwide. Non‐Small Cell Lung Carcinoma (NSCLC) comprises 80–85% of all new lung cancer diagnoses, suggesting a great need to continue finding measures to combat this mounting disease. Metformin induces an anti‐proliferative effect in many other cancers, including breast, prostate and obesity‐activated thyroid cancer. The purpose of this study was to determine how Metformin treatment influences NSCLC cell viability in vitro. NSCLC cells were grown for 24 hours and serum‐starved overnight with serum‐free media to induce quiescence. Cells were treated with equal volumes of fresh growth media followed by Metformin treatment with a range of concentrations from 5mm to 15mM. NSCLC cell viability was assessed every 24 hours for 3 days via an MTT assay using 3‐(4,5‐Dimethyltiazol‐2‐yl)‐2,5‐Diphenyltetrazolium Bromide. Proliferating NSCLC treated with Metformin showed significantly reduced cell viability (p=0.0109), after 48 hours of treatment, irrespective of Metformin concentration. The results of this study indicate that Metformin is effective at decreasing NSCLC viability. Experiments are ongoing to investigate alterations in cell cycle regulators and metabolic signaling pathways. Support or Funding Information Targeted Research Internal Seed Program

Lung cancer is the second most common cancer and one of the largest causes of cancer‐related mortality worldwide. 80–85% of all new lung cancer diagnoses are Non‐Small Cell Lung Carcinoma (NSCLC), suggesting a great need to continue elucidating the metabolic mechanisms surrounding this prevalent disease. Due to the oncogenic environment surrounding NSCLC growth, factors released into the environment could have a direct impact on other tissues. In particular, skeletal muscle, a leading insulin‐sensitive and metabolically active tissue, is subject to wasting in many cancer patients. The purpose of this study was to determine how NSCLC conditioned media affects C2C12 skeletal muscle cells proliferation and metabolism. C2C12 mouse skeletal muscle cells were grown for 24 hours and serum‐starved overnight with serum‐free media to induce quiescence. Cells were treated with equal volumes of either fresh growth media or conditioned media from proliferating NSCLC cells. C2C12 myoblast proliferation was assessed every 24 hours for 3 days via an MTT assay using 3‐(4,5‐Dimethyltiazol‐2‐yl)‐2,5‐Diphenyltetrazolium Bromide. Proliferating C2C12 myoblasts treated with fresh growth media or conditioned media from NSCLC cells showed significant proliferation (p=0.0016) over 72 hours. Treatment with NSCLC conditioned media did not induce any significant increases in myoblast proliferation when compared to control C2C12 cells. In conclusion, these data suggest that C2C12 myoblasts did not respond adversely to NSCLC conditioned media. Experiments are ongoing to investigate alterations in metabolic and myogenic signaling pathways, as well as extended time courses. Support or Funding Information This work was supported by the Targeted Research Internal Seed Program, JSM. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.