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. 2014 Mar 24;9(3):e92244. doi: 10.1371/journal.pone.0092244

Figure 3. MDA-MB-468 and SK-BR-3 breast cancer cells do not retain free, enzymatically active matriptase on the cell.

Figure 3

A and D: MDA-MB-468 and SK-BR-3 human breast cancer cells were induced to activate matriptase (or not) by pH 6 (or control) buffer-exposure. Cell lysates prepared from the cells were subjected to immunodepletion to remove activated matriptase. Lysates from non-activation control cells (N), acid-activated cells (A), the M69 depleted lysates (D), and the eluted fraction (E) were analyzed for total matriptase species by immunoblot using the matriptase mAb M24. B and E. MDA-MB-468 (B) and SK-BR-3 (E) were treated with pH 6.0 buffer to induce matriptase activation. After neutralization, mixture of the cells and the buffer (Combine), the pelleted cells after centrifugation (Cell), and the buffer supernatant (shed fraction) alone (Shed) were analyzed for tryptic activity. C and F. MDA-MB-468 and SK-BR-3 cell lysates, prepared post induction of matriptase activation were immunodepleted using the mAb M69. The cell lysates (A–L) and the immunodepleted fractions (A–D) were analyzed for tryptic activity.