Multicellular
tumor spheroid (MTS) represents a three-dimensional structural form of
tumors in laboratory conditions, and it has the characteristics of avascular
micrometastases or intervascular spaces of big
tumors. Recent studies indicate that extracellular matrix (ECM)
proteins play a critical role in
tumor metastasis, therefore normal and
cancer cells require an ECM for survival, proliferation and differentiation.
Doxorubicin and
Docetaxel are widely used in the
therapy of
breast cancer, as well as in in vivo and in vitro studies. In this study, we examined the effect of apoptosis and proliferation of cells on the human
breast cancer cell line, MCF-7, by using p53, bcl-2 and Ki67 gene expression, and the tendency to
metastasis with
extracellular matrix proteins,
laminin and
type IV collagen after
chemotherapy in the spheroid model. The apoptotic cell death in situ was detected by TUNEL method. TUNEL-positive cells and positive immunoreactivities of
laminin,
type IV collagen, p53 and, bcl-2 were detected in the control group. There was no
laminin and
type IV collagen immunoreactivities in spheroids of
drug groups. While TUNEL-positive cells and p53 immunoreactivity were detected in
Docetaxel,
Doxorubicin and
Docetaxel/
Doxorubicin groups, p53 immunoreactivity was not observed in the
Docetaxel group. There was no bcl-2 immunoreactivity in either
drug group. In addition, we did not detect Ki67 immunoreactivity in both control and
drug treatment groups. However, the absence of Ki67
protein in MCF-7 breast multicellular
tumor spheroids is possibly related to the cells in G0 or S phase. These chemotherapeutic agents may affect the presence of ECM
proteins in this in vitro model of
micrometastasis of spheroids. These findings suggest that the possible mechanism of cell death in
Doxorubicin and
Docetaxel/
Doxorubicin treatment groups is related to apoptosis through the p53 pathway. However, we considered the possibility that there is another control mechanism for the
Docetaxel group.