High invasive cancer cells are thought to recruit specialised actin-rich protrusions for invasion in metastasis process. These protrusions are termed invadopodia. To study invadopodia formation, one of the first challenges faced by researchers has been to optimise the cell line passage number in order to be used for the invadopodia assay. Therefore, this study aims to investigate the effects of the passage number on invadopodia formation in MDA-MB-231 breast cancer cell line. Invadopodia assay was used to achieve the aim of the study. The results provided evidence that invadopodia formation is affected by the high passage number. The cells were also tested with dimethyloxalylglycine (DMOG) a hypoxic mimicking agent which is known to be an invadopodia inducer, the results showed that the cells in low passage number (P7) treated with DMOG increase the cells forming invadopodia, while the cells with high passage number (P35) showed that DMOG fails to stimulate the cells to form invadopodia. Furthermore, the cells with high passage number after passage 15 are starting to lose the ability to degrade the gelatin. In conclusion, this study suggests that only cells with a low passage number, less than passage 15 should be used in the study of invadopodia formation to obtain the results in the search for molecular targets and signaling at invadopodia.
Cancer metastasis is a multistep process, which results in cancer cells disseminating to other organs. The crucial metastasis step involves cancer invasion which occurs via actin-protrusion by invasive malignant cells, termed as invadopodia. In solid tumours, invadopodia formation increases as a result of hypoxia which is found to be resis- tant against chemotherapy and radiotherapy. Phytochemicals have been potentially identified as a prime source of effective conventional drugs for metastasis treatments, which target cancer cell invasion, particularly molecular components of the invadopodia formation. The Hypoxia-Inducible Factor-1α (HIF-1α) is an essential target in terms of treatment for hypoxic tumour, as well as helping to identify the mode of action for the drugs, particularly phy- tochemical compounds. The aim of this review is to highlight the current development with regards to the ability of phytochemicals in targeting cancer metastasis, as well as phytochemical compounds which are able to inhibit HIF-1α and invadopodia formation. The use of phytochemicals for targeting hypoxic cancer cells may open new prospects for reducing cancer metastasis.