Encapsulated multicellular tumor spheroids as a novel in vitro model to study small size tumors

Abstract

Presently multicellular tumor spheroids (MTS) are being widely used in various aspects of tumor biology, including studies in biology and photodynamic therapy. The cellular organization of spheroids allows the recreation of in vivo small tumors much better than all common two-dimensional in vitro models. The cell encapsulation method could be proposed as a novel technique to quickly and easily prepare a large number of spheroids with narrow size distribution within a desirable diameter range. Moreover, the proposed technique for spheroid generation using encapsulated growing tumor cells could provide entirely new avenues to develop a novel spheroid co-culture model (for instance, the in vitro co-cultvation of tumor cells and monocytes, or epithelial cells, or fibroblasts etc). The current research was aimed at developing a simple and reliable method to encapsulate tumor cells and to cultivate them in vitro. In order to generate spheroids, MCF-7 cells were encapsulated and cultivated in 200 ml T-flasks in a 5% CO2 atmosphere at 37?C for 4-5 weeks. The cell proliferation was easily observed using a light microscope. The cells grew in aggregates increasing in size with time. The cell growth resulted in the formation of large cell clusters (spheroids) which filled the whole microcapsule volume in 4-5 weeks.Visecelijski sferoidi tumora (VST) se danas koriste u izucavanju tumora, za razna ispitivanja u biologiji i fotodinamickoj terapiji. U sferoidima se celije mogu organizovati gotovo identicno kao u malim tumorima in vivo, pa je ovo mnogo pogodniji model tumora nego postojeci dvodimenzioni in vitro modeli. Opisani metod inkapsulacije celija moze se predloziti kao nova tehnika za jednostavnu i brzu pripremu velikog broja sferoida sa prilicno ravnomernom distribucijom zeljenog opsega precnika. Pored toga, predlozena tehnika za pravljenje sferoida na bazi rastucih tumorskih celija pruza mogucnosti za razvoj novog sferoidnog modela kulture tkiva (na pr. za in vitro kultivaciju tumorskih celija i monocita, ili celija epitela, ili fibroplasta itd) Cilj ovog istrazivanja je bio razvoj jednostavnog i pouzdanog metoda za inkapsulaciju tumorskih celija i za njihovu in vitro kultivaciju. Da bi se napravili sferoidi, MCF-7 celije su inkapsulirane i kultivisane u T-posudama za gajenje u atmosferi sa 5% CO2 na 37?C u toku 4-5 nedelja. Proliferacija celija je pracena koriscenjem svetlosnog mikroskopa. Celije su rasle u agregatima koji su se uvecavali tokom vremena, sto je rezultiralo formiranjem velikih nakupina (sferoida) koji su za 4-5 nedelja ispunili celokupnu zapreminu mikrokapsule.