The Viability of Serval (Leptailurus serval) and Pallas Cat (Felis manul) Oocytes after Cryopreservation Using the Rapid-I Method

BACKGROUND

Vitrification by Rapid-I method could be essential for felid rescue programs to protect wild felid in the future.

OBJECTIVE

This study was aimed at adapting the Rapid I method and evaluating the viability of serval and Pallas cat oocytes compared to oocytes of the domestic cat.

MATERIALS AND METHODS

Oocytes after collection and in vitro maturation were vitrified using Cryotech medium (Cryotech, Japan) and a Rapid-I device (Vitrolife, Sweden). To evaluate viability, oocytes after warming were stained with fluorescein diacetate and ethidium bromide.

RESULTS

Survival rate in the control group (domestic cat) was 75 %. In the experimental group, 70% (serval) and 60% (pallas cat) viable oocytes were found.

CONCLUSION

The Rapid-I method can be applied successfully for the vitrification of wild felid oocytes.

mTOR, a novel target in breast cancer: the effect of CCI-779, an mTOR inhibitor, in preclinical models of breast cancer

The mammalian target of rapamycin (mTOR) is a central regulator of G1 cell cycle protein synthesis that precedes commitment to normal cellular replication. We have studied the effect of cell cycle inhibitor-779 (CCI-779), a rapamycin ester that inhibits mTOR function, on the proliferation of a panel of breast cancer cell lines. Six of eight lines studied were sensitive (IC(50)< or = 50 nM) and two lines were resistant (IC(50)>1.0 microM) to CCI-779. Sensitive lines were estrogen dependent (MCF-7, BT-474, T-47D), or lacked expression of the tumor suppressor PTEN (MDA-MB-468, BT-549), and/or overexpressed the Her-2/neu oncogene (SKBR-3, BT-474). Resistant lines (MDA-MB-435, MDA-MB-231) shared none of these properties. CCI-779 (50 nM) inhibited mTOR function in both a sensitive and a resistant line. In nu/nu mouse xenografts, CCI-779 inhibited growth of MDA-MB-468 (sensitive) but not MDA-MB-435 resistant tumors. Treatment of sensitive lines with CCI-779 resulted in a decrease in D-type cyclin and c-myc levels and an increase in p27(kip-1) levels. There was good correlation between activation of the Akt pathway and sensitivity to CCI-779. Amplification of mTOR-regulated p70S6 kinase, which is downstream of Akt, may also have conferred CCI-779 sensitivity to MCF-7 cells. Taken together, the data suggest that mTOR may be a good target for breast cancer therapy, especially in tumors with Akt activation resulting from either growth factor dependency or loss of PTEN function.