Objectives: Mantle cell lymphoma (MCL) is a distinct subtype of B-cell lymphoma; the complete response rate for standard therapies in use today is 85 – 90%. NVP-BEZ235 inhibits the PI3K/Akt/mTOR signaling axis at the level of both PI3K and mTOR. In this study, we analyzed the inhibitory effects of NVP-BEZ235 on mantle cell lines and its effects in combination with enzastaurin, everolimus and perifosine.

Methods: The effects of NVP-BEZ235 on cell proliferation and apoptosis were evaluated using MTT assay and flow cytometry analysis. The cell cycle analysis was performed applying BrdU incorporation. Western blot analysis was utilized for phosphorylation status evaluation of protein kinases. The interaction between NVP-BEZ235 and enzastaurin, everolimus and perifosine was examined by Chou-Talalay method.

Results: NVP-BEZ235 induced significant increase of apoptosis, both via intrinsic and extrinsic pathways. We found that NVP-BEZ235 inhibited mantle cells growth by induction of G1 arrest. NVP-BEZ235 exerts its antitumor activity even when mantle cells were in contact with bone marrow microenvironment. Enzastaurin, everolimus and perifosine enhanced the cytotoxicity triggered by NVP-BEZ235.

Conclusions: The above results encourage clinical development of NVP-BEZ235 in combination and the possible inclusion of patients with mantle lymphoma in Phase I/II clinical trials.