Department of Biochemistry and Molecular Biology, College of Basic Medicine, Key Laboratory of Medical Biotechnology of Hebei Province, Hebei Medical University, Shijiazhuang 050017, PR China.
Pathol Res Pract. 2013 Apr;209(4):237-43. doi: 10.1016/j.prp.2013.02.007. Epub 2013 Mar 13.
Colorectal cancer (CRC) is a common malignancy with a high incidence and mortality rate. Recent studies have pointed to deregulation of autophagy as a novel pathogenesis of human malignancy. SM22 is considered as a tumor suppressor. The aim of the present study was to evaluate the correlation of the SM22 expression level with the autophagy activity and the clinical characteristics in human CRC tissues. The expressions of SM22 and p62, a biomarker of autophagy activity, in paired tumor and adjacent non-tumor tissues from 43 patients with colorectal cancer were detected by western blot and immunohistochemical staining, respectively. The results showed that the SM22 level decreased significantly in 81.4% CRC tissues, while the expression of p62 increased in 79.1% cases. There was a negative correlation between p62 and SM22 expressions in colorectal cancer tissues (p=0.004). Similarly, the negative correlation between SM22 and p62 was verified in human CRC cell lines. The data suggest that the autophagy activity decreased in human CRC, which was associated with reduction in SM22 expression. However, the expression of SM22 was not associated with the gender, tumor site and Duke's stage of the patients. In conclusion, our findings suggest that the disruption of SM22 may be involved in tumorigenesis in CRC. The autophagic activity may be suppressed in human CRC, and SM22 may act as a positive regulator in the processes of autophagy.
结直肠癌（CRC）是一种常见的恶性肿瘤，发病率和死亡率都很高。最近的研究表明，自噬的失调是人类恶性肿瘤的一种新的发病机制。SM22 被认为是一种肿瘤抑制因子。本研究旨在评估 SM22 表达水平与人类 CRC 组织中自噬活性和临床特征的相关性。通过 Western blot 和免疫组织化学染色分别检测了 43 例结直肠癌患者配对肿瘤和相邻非肿瘤组织中 SM22 和自噬活性标志物 p62 的表达。结果表明，81.4%的 CRC 组织中 SM22 水平显著降低，而 79.1%的病例中 p62 的表达增加。CRC 组织中 p62 和 SM22 的表达呈负相关（p=0.004）。同样，在人 CRC 细胞系中也验证了 SM22 和 p62 之间的负相关。数据表明，人类 CRC 中的自噬活性降低，这与 SM22 表达减少有关。然而，SM22 的表达与患者的性别、肿瘤部位和 Duke 分期无关。总之，我们的研究结果表明，SM22 的破坏可能参与了结直肠癌的发生。自噬活性可能在人类 CRC 中受到抑制，SM22 可能在自噬过程中作为正调节剂发挥作用。
