Regulation of nonmuscle myosin II during 3-methylcholanthrene induced dedifferentiation of C2C12 myotubes

Journal Article · Fri Aug 01 04:00:00 EDT 2014 · Experimental Cell Research

DOI:https://doi.org/10.1016/J.YEXCR.2014.05.015· OSTI ID:22416912

Dey, Sumit K.; Saha, Shekhar; Das, Provas; Das, Mahua R.

3-Methylcholanthrene (3MC) induces tumor formation at the site of injection in the hind leg of mice within 110 days. Recent reports reveal that the transformation of normal muscle cells to atypical cells is one of the causes for tumor formation, however the molecular mechanism behind this process is not well understood. Here, we show in an in vitro study that 3MC induces fragmentation of multinucleate myotubes into viable mononucleates. These mononucleates form colonies when they are seeded into soft agar, indicative of cellular transformation. Immunoblot analysis reveals that phosphorylation of myosin regulatory light chain (RLC{sub 20}) is 5.6±0.5 fold reduced in 3MC treated myotubes in comparison to vehicle treated myotubes during the fragmentation of myotubes. In contrast, levels of myogenic factors such as MyoD, Myogenin and cell cycle regulators such as Cyclin D, Cyclin E1 remain unchanged as assessed by real-time PCR array and reverse transcriptase PCR analysis, respectively. Interestingly, addition of the myosin light chain kinase inhibitor, ML-7, enhances the fragmentation, whereas phosphatase inhibitor perturbs the 3MC induced fragmentation of myotubes. These results suggest that decrease in RLC{sub 20} phosphorylation may be associated with the fragmentation step of dedifferentiation. - Highlights: • 3-Methylcholanthrene induces fragmentation of C2C12-myotubes. • Dedifferentiation can be divided into two steps – fragmentation and proliferation. • Fragmentation is associated with rearrangement of nonmuscle myosin II. • Genes associated with differentiation and proliferation are not altered during fragmentation. • Phosphorylation of myosin regulatory light chain is reduced during fragmentation.

• OSTI ID: 22416912
• Journal Information: Experimental Cell Research, Journal Name: Experimental Cell Research Journal Issue: 1 Vol. 326; ISSN 0014-4827; ISSN ECREAL
• Country of Publication: United States
• Language: English

Related Subjects

3-METHYLCHOLANTHRENE
60 APPLIED LIFE SCIENCES
AGAR
CELL CYCLE
IN VITRO
MICE
MYOSIN
NEOPLASMS
PHOSPHORYLATION
POLYMERASE CHAIN REACTION