CD44 over Expression Caused Drug Resistance in Activated B Cell-like Diffuse Large B-Cell Lymphoma

CD44, a transmembrane glycocoptotein, involved in tumor cell survival, migration , invasion, metastasis and prognosis of many cancers. This study was performed to investigate the effects of CD44 over expression on the biological function and the chemotherapeutic sensitivity of ABC-DLBCL. The full length CD44 cDNA was cloned into pEASY-T vector and then transfected into activated B cell-like diffuse large B-cell lymphoma cell line OCI-ly3. QPCR and western blot confirmed that the CD44 expression was up-regulated in both mRNA and protein levels in CD44-transfected OCI-ly3 cells. The cell proliferation of OCI-ly3-CD44 cells was significantly faster than that in OCI-ly3-GFP cells and the OCI-ly3 cells (p<0.001). Annexin V-APC/PI staining results showed that the apoptosis ratio wasn't difference among three groups (p=0.676). OCI-ly3-CD44 cells showed significantly higher migration ratio than OCI-ly3-GFP cells and the OCI-ly3 cells(p=0.031). The IC50 of doxorubicin in OCI-ly3-CD44 cells (0.348±0.072uM) was higher than that in OCI-ly3-GFP (0.348±0.072uM ) and OCI-ly3cells(0.138±0.029uM ) ( P<0.001). After treatment with doxorubicin for 24h, the OCI-ly3-CD44 cells showed lower apoptotic ratio than OCI-ly3-GFP and OCI-ly3 cells ( (17.5±1.33)% VS. (41.7±9.91) %, (41.8±7.23)%), P<0.001). In conclusion, CD44 plays a key role in cell growth regulation and chemo-resistance and is a potential target to overcome drug resistance and improve prognosis in DLBCL.