Search

Background NSAIDs exhibit protective properties towards some cancers, especially colon cancer. Yet, it is not clear how they play their protective role. PGE2 is generally shown as the only target of the NSAIDs anticancerous activity. However, PGE2 known targets become more and more manifold, considering both the molecular pathways involved and the target cells in the tumour. The role of PGE2 in tumour progression thus appears complex and multipurpose. Methods To gain understanding into the role of PGE2 in colon cancer, we focused on the activity of PGE2 in apoptosis in colon cancer cell lines. Results We observed that an increase in intracellular PGE2 induced an apoptotic cell death, which was dependent on the expression of the proapoptotic protein Bax. This increase was induced by increasing PGE2 intracellular concentration, either by PGE2 microinjection or by the pharmacological inhibition of PGE2 exportation and enzymatic degradation. Conclusions We present here a new sight onto PGE2 in colon cancer cells opening the way to a new prospective therapeutic strategy in cancer, alternative to NSAIDs.

BackgroundCD40L was found to reduce doxorubicin-induced apoptosis in non Hodgkin's lymphoma cell lines through caspase-3 dependent mechanism. Whether this represents a general mechanism for other tumor types is unknown.MethodsThe resistance induced by CD40L against apoptosis induced by a panel of cytotoxic chemotherapeutic drugs in non Hodgkin's lymphoma and breast carcinoma cell lines was investigated.ResultsDoxorubicin, cisplatyl, etoposide, vinblastin and paclitaxel increased apoptosis in a dose-dependent manner in breast carcinoma as well as in non Hodgkin's lymphoma cell lines. Co-culture with irradiated L cells expressing CD40L significantly reduced the percentage of apoptotic cells in breast carcinoma and non Hodgkin's lymphoma cell lines treated with these drugs. In breast carcinoma cell lines, these 5 drugs induced an inconsistent increase of caspase-3/7 activity, while in non Hodgkin's lymphoma cell lines all 5 drugs increased caspase-3/7 activity up to 28-fold above baseline. Co-culture with CD40L L cells reduced (-39% to -89%) the activation of caspase-3/7 induced by these agents in all 5 non Hodgkin's lymphoma cell lines, but in none of the 2 breast carcinoma cell lines. Co culture with CD40L L cells also blocked the apoptosis induced by exogenous ceramides in breast carcinoma and non Hodgkin's lymphoma cell lines through a caspase-3-like, 8-like and 9-like dependent pathways.ConclusionThese results indicate that CD40L expressed on adjacent non tumoral cells induces multidrug resistance to cytotoxic agents and ceramides in both breast carcinoma and non Hodgkin's lymphoma cell lines, albeit through a caspase independent and dependent pathway respectively.