AIM:To investigate the effect of Sonic Hedgehog ( Shh) signaling blockade on the growth of hema-tocarcinoma cells and underlying mechanisms.METHODS: The expression of Shh signaling molecules in hematocarci-noma cell lines BEL-7402, Huh7 and HepG2 was detected by RT-PCR.The cell viability was detected by MTT assay.The cell cycle and apoptosis were analyzed by flow cytometry.The expression of apoptosis-related proteins was determined by Western blot.RESULTS:Shh signaling molecules were all expressed in BEL-7402, Huh7 and HepG2 cells.The mRNA expression of Patched ( Ptch) , Gli1 and Gli2 was down-regulated by anti-Shh antibody.Blockade of Shh signaling pathway inhibited the proliferation of hepatocarcinoma cells with increasing cells in G0/G1 phase and induced the apoptosis of hepa-tocarcinoma cells.Treatment with anti-Shh antibody down-regulated the protein expression of pro-caspase-3, pro-caspase-8 and pro-caspase-9, while up-regulated the protein levels of cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9 in BEL-7402 cells.CONCLUSION:Blockade of Shh signaling pathway inhibits the growth of hepatocarcinoma at different levels by cell cycle arrest and inducing apoptosis of hematocarcinoma cells.

The secondary structure is a fundamental feature of both non-coding RNAs (ncRNAs) and messenger RNAs (mRNAs). However, our understanding of the secondary structures of mRNAs, especially those of the coding regions, remains elusive, likely due to translation and the lack of RNA-binding proteins that sustain the consensus structure like those binding to ncRNAs. Indeed, mRNAs have recently been found to adopt diverse alternative structures, but the overall functional significance remains untested. We hereby approach this problem by estimating the folding specificity, i.e., the probability that a fragment of an mRNA folds back to the same partner once refolded. We show that the folding specificity of mRNAs is lower than that of ncRNAs and exhibits moderate evolutionary conservation. Notably, we find that specific rather than alternative folding is likely evolutionarily adaptive since specific folding is frequently associated with func-tionally important genes or sites within a gene. Additional analysis in combination with ribosome density suggests the ability to modulate ribosome movement as one potential functional advantage provided by specific folding. Our findings reveal a novel facet of the RNA structurome with important functional and evolutionary implications and indicate a potential method for distinguishing the mRNA secondary structures maintained by natural selection from molecular noise.