MMP-2 gene mediates doxorubicin-induced phosphorylation of Src
at Tyr-416
Mohammad et al. (2021) showed that increases in Src
phosphorylation at Tyr-416, representing active Src, occurs when cancer
cells are treated with sublethal concentrations of doxorubicin
(23). The increase in
phosphorylated Src at Tyr-416 serves as an indicator of Src activation,
which plays an important role in cytoskeletal reorganization and cell
migration (12,27). We
sought to investigate Src activation induced by sublethal concentrations
of doxorubicin in both WT and MMP-2-KO cells. As a result, the WT and
MMP-2 KO cells were treated with 0.4 µM doxorubicin for 24 hours and
pSrc at Tyr-416 was measured (Figure 3a). Western blots show Src
phosphorylation at Tyr-416 was indeed significantly increased when WT
cells were treated with a sublethal concentration of doxorubicin. On the
other hand, increased Src phosphorylation at Tyr-416 was disrupted in
MMP-2 KO cells when treated with the same doxorubicin concentration
(Figure 3b).
Previous research also revealed that increases in Src phosphorylation at
Tyr-527 are observed in cases when Src is inhibited by specific upstream
kinases (28). To
determine whether Src at Tyr-527 was phosphorylated in the WT or MMP-2
KO cells, the levels in both untreated and 0.4 µM doxorubicin treated
cells were examined (Figure 3a, b). Western blots and corresponding
quantifications show non-significant change in phosphorylation of Src at
Tyr-527 among the WT and MMP-2 KO, either untreated or treated with
doxorubicin (Figure 3a, b). Therefore, the results suggest the
disruption of Src phosphorylation at Tyr-416 in MMP-2 KO cells is not as
a result of increased phosphorylation at Tyr-527 residue. However, our
results indicate that MMP-2 gene is an upstream mediator of a signaling
pathway that regulates doxorubicin-induced activation and
phosphorylation of Src at Tyr-416 in osteosarcoma cells.