Objective   To investigate the functions of the ITSN1-S SH3 domains in U87 glioblastoma cell proliferation and to determine the underlying molecular mechanism.

  Methods  A recombinant lentiviral vector with an mGFP label was constructed. EH1-EH2, EH1-EH2-CC, and ITSN1-S genes were amplified using polymerase chain reaction and then cloned into recombinant lentiviral vectors. The four lentiviral plasmids were packaged using HEK 293T cells and subsequently used to infect U87 cells. Stable cells were screened using puromycin and separately labeled as vector/U87, EH1-EH2/U87, EH1-EH2-CC/U87, and ITSN1-S/U87. Western blotting was used to detect the expression of each protein. Proliferation and soft agar assays were performed to detect cell proliferation.

  Results   In the proliferation and soft agar assays, the proliferation capacity of the ITSN1-S/U87 cells was clearly enhanced compared with those of the vector/U87, EH1-EH2/U87, and EH1-EH2-CC/U87 cells (P < 0.05). Moreover, the proliferation capacity of the latter three groups showed no observable difference (P>0.05). On the 6th day, the vector/U87, EH1-EH2/U87, EH1-EH2-CC/U87, and ITSN1-S/U87 cell numbers were (29.16±1.19)×10⁴, (22.82±0.94)×10⁴, (22.17±0.90)×10⁴, and (21.93±1.15)×10⁴, respectively. On the 21st day, the number of colony formation in vector/U87, EH1-EH2/U87, EH1-EH2-CC/U87, and ITSN1-S/U87 was (6.37±0.41)×10³, (2.65±0.34)×10³, (2.23±0.31)×10³, and (2.1±0.29)×10³, respectively.

  Conclusion   ITSN1-S overexpression significantly promotes U87 cell proliferation. Specifically, the SH3 domains possibly serve vital functions in glioma cell proliferation.