In addition, antigenic peptide-containing OMLs can induce CTLs specific to the HLA-restricted epitopes of survivin 2B, which is expressed in many types of tumors, in PBMCs obtained from patients in vitro and in HLA-transgenic mice in vivo (personal communication).
Xiong L., Rao J. Self-luminescing BRET-FRET NIR nanoparticles for in vivo tumor Imaging.Nature Communication 2012, 3, 1193.
The observed tumor regression was not surprising, because matrigel is not stable for longer than 14 days in culture, and probably not in vivo either (personal communication; Collaborative Biomedical Products, Bedford, MA, USA).
Conventional 2-D cell cultures are unlike in vivo systems where cellular communication, transport of oxygen and nutrients, removal of wastes and cellular metabolism take place in a 3-D environment.
Further, the work of Impey et al. [13] showed that miR132 regulates synapse formation and function, thus raising the possibility that over-expression of miR132 affects synaptic communication in vivo.
The possibility of this kind of "combinatorial" or "intersectional" recombination, without the temporal regulation that DiCre allows however, was evocated in the case of the alpha-complementation of Cre fragments worked out a few years ago [35], but, contrary to DiCre, this system could not be shown to work in vivo (E. Casanova, personal communication).
Identification of the intercellular communication in vivo is still unresolved.
Others have tried to study the functional role of EV-mediated cell-cell communication in vivo by inhibiting multivesicular body-related EV pathways in order to render cells vesiculation deficient.
These compounds may be converted in rats to other fluorinated molecules, such as PFOA, and hence, fluorotelomer alcohol exposures result in PFOA-like in vivo effects (Berger U, personal communication; Lehmler 2004).
Interestingly, all cellular and histopathologic abnormalities observed in Skp2-deficient mice are abolished in Skp2/p27 double knockout mice, indicating that p27 is a primary substrate of Skp2 in vivo (K Nakayama, personal communication).
