Ekpenyong, A. E. | Search bioRxiv

bioRxiv2020

Radiotherapy and chemotherapy alter migration of brain cancer cells before cell death

Although radiotherapy and most cancer drugs target the proliferation of cancer cells, it is metastasis, the complex process by which cancer cells spread from the primary tumor to other tissues and organs of the body where they form new tumors, that leads to over 90% of all cancer deaths. Thus, there is an urgent need for anti-metastasis strategies alongside chemotherapy and radiotherapy. An important step in the metastatic cascade is migration. It is the first step in metastasis via local invasion. Here we address the question whether ionizing radiation and/or chemotherapy might inadvertently promote metastasis and/or invasiveness by enhancing cell migration. We used a standard laboratory irradiator, Faxitron CellRad, to irradiate both non-cancer (HCN2 neurons) and cancer cells (T98G glioblastoma) with 2 Gy, 10 Gy and 20 Gy of X-rays. Paclitaxel (5 M) was used for chemotherapy. We then measured the attachment and migration of the cells using an electric cell substrate impedance sensing device. Both the irradiated HCN2 cells and T98G cells showed significantly (p < 0.01) enhanced migration compared to non-irradiated cells, within the first 20 to 40 hours following irradiation with 20 Gy. Our results suggest that cell migration should be a therapeutic target in anti-metastasis/anti-invasion strategies for improved radiotherapy and chemotherapy outcomes.

cancer biology↗

bioRxiv2019

Microgravity modulates effects of chemotherapeutic drugs on cancer cell migration

Microgravity or the condition of apparent weightlessness causes bone, muscular and immune system dysfunctions in astronauts following spaceflights. These organ and system-level dysfunctions correlate with changes induced at the single cell level both by simulated microgravity on earth as well as microgravity conditions in outer space (as in the international space station). Reported changes in single bone cells, muscle cells and white blood cells include structural/morphological abnormalities, changes in gene expression, protein expression, metabolic pathways and signaling pathways, suggesting that cells mount some response or adjustment to microgravity. However, the implications of such adjustments on many cellular functions and responses are not clear largely because the primary mechanism of gravity sensing in animal cells is unknown. Here we used a rotary cell culture system developed by NASA, to subject leukemic and erythroleukemic cancer cells to microgravity for 48 hours and then quantified their innate immune-response to common anti-cancer drugs using biophysical parameters and our recently developed quantum-dots-based fluorescence spectroscopy. We found that leukemic cancer cells treated with daunorubicin show increased chemotactic migration (p < 0.01) following simulated microgravity (g) compared to normal gravity on earth (1g). However, cells treated with doxorubicin showed enhanced migration both in 1g and following g. Our results show that microgravity modulates cancer cell response to chemotherapy in a drug-dependent manner. These results suggest using simulated microgravity as an immunomodulatory tool for the development of new immunotherapies for both space and terrestrial medicine.

biophysics↗