CO(2) pneumoperitoneum induces in vitro hypoxic response culminating in apoptosis of human neuroblastoma cells.

The ablative role of minimally invasive surgery (MIS) in neuroblastoma (NB) is still controversial due to the possible CO2 pneumoperitoneum side-effects on tumor aggressiveness. It is known that CO2 produces hypoxic condition with changes in tumor microenvironment influencing cell functions. Here we investigated whether CO2 exposure affects the transcription factor HIF-1α and the apoptotic signalling pathway in SH-SY5Y NB cells. SH-SY5Y cells were exposed to a pressure of 15 mmHg CO2 (100%) for 4 h (T0) and then moved to normal condition for 24 h (T24). In control and CO2 -exposed cells, we analyzed the mRNA levels and DNA binding activity of HIF-1α. We also evaluated the proliferative activity and cell viability as well as caspase-9/3 cleavage and nuclear fragmentation. A significant increase in HIF- 1α activation was observed in SH-SY5Y cells exposed to CO2 compared to control cells. CO2 treatment also decreased the proliferation rate and the percentage of viable cells. In addition, the expression and cleavage of caspase-9 and -3 were significantly increased in NB cells exposed to CO2. These data correlated with apoptotic feature observed in CO2 -treated NB cells. Our findings show that CO2 -induced hypoxic condition exerts cytotoxic effects on NB cells by eliciting mitochondrial apoptotic pathway and thereby improving the understanding of the possible clinical impact of CO2 pneumoperitoneum on NB behaviour.

Overview and new strategies in metastatic breast cancer (MBC) for treatment of tamoxifen-resistant patients.

The treatment with aromatase inhibitors (AIs) and fulvestrant has been demonstrated to be active in a proportion of tamoxifen-resistant breast cancer patients, obtaining, in some cases, a long-term control of tumor growth. Results from clinical trials indicate that treatment with fulvestrant might either precede or follow AIs. However, the AIs are now replacing tamoxifen as first-line advanced and adjuvant therapies, and thus, other options following tamoxifen failure are required. Fulvestrant may be effective in this setting, even if there is also evidence of a lack of cross-resistance between nonsteroidal and steroidal AIs, resulting in the potential use of steroidal AIs following nonsteroidal AI failure and vice versa. Resistance mechanisms to these therapies appear to be related to a cross talk between estrogen receptor (ER) and growth factor-signaling cascades. Novel therapeutic approaches for ER+ patients, which combine hormonal agents and signal transduction inhibitors, have been developed to overcoming resistance. Several trials are now investigating signal transduction inhibitors combined with endocrine agents. This approach might provide efficient treatments and delay the onset of antihormone resistance, thereby significantly improving patient's survival.