Increased Motility and Invasiveness in Tumor Cells That Survive 10 Gy Irradiation

Abstract

ABSTRACT. Radiotherapy is an important noninvasive treatment for many types of cancer. However, it has been reported that the proliferative, invasive, and metastatic capacities of tumor cells can be increased in the repopulated tumors that survive radiotherapy. We have previously established a radiation-surviving cell model for the human non-small cell lung cancer cell line H1299 by harvesting relic cells 14 days after irradiation (IR cells). Here, we report that cell invasion, cell migration, and cell adhesion are enhanced in these surviving cancer cells. The mRNA expression levels of matrix metalloproteinases (MMPs), including mmp1, mmp2, and mmp9, were upregulated in IR cells compared with parental cells. A gelatin zymogram, wound healing assay, and invasion assay showed increased MMP activity, cell motility, and invasiveness in IR cells, respectively. Moreover, IR cells adhered more tightly to collagen-coated dishes than parental cells. Consistently, paxillin, phosphorylated FAK, integrin β1, and vinculin were strongly localized at focal adhesions in IR cells, as visualized by immunofluorescence. In this report, we identify molecules responsible for the malignant properties of tumor cells that survive irradiation. These molecules may be important therapeutic targets for the control of repopulated tumors after radiotherapy.

Integrin β1-dependent invasive migration of irradiation-tolerant human lung adenocarcinoma cells in 3D collagen matrix

“…Mouse fibrosarcoma QRsP cells exhibit an enhanced invasive activity after survival through 10 Gy irradiation [14]. Moreover, in human non-small lung cancer H1299 cells, invasiveness is enhanced after 10 Gy irradiation [3]. Increase in invasive activity after irradiation might be a common phenomenon in cancer cells making it difficult to use radiotherapy as a single modality treatment for the complete cure of many malignant cancers.…”

“…However, it has been reported that local tumor irradiation can lead to enhancement of metastases [1]. Recent studies indicate that tumors surviving irradiation acquire high metastatic ability in vivo [2], and the irradiation-tolerant cancer cells enhance cellular physiological activities, such as invasion, migration, and adhesion in vitro [3]. These results suggest that irradiation of tumors could induce malignant transformation and result in poor prognosis, although the detailed mechanism is not well understood.…”

An improved method for western blotting when extracting proteins from mammalian cells cultured on a collagen gel under serum-free conditions

“…In previous studies, conventional cell lysis methods, which do not involve TCA fixation and collagenase treatment, were often used for WB (Engler et al 2006;Tsutsumi et al 2009;Wu et al 2009). In these studies, the cells were cultured on polyacrylamide gels, plastic plates, or dishes.…”

“…Thus, by means of the collagenase treatment, we were able to dissolve the collagen gel and remove it from cell lysates. In previous studies, researchers often lysed the cells without TCA and collagenase treatment for WB (Wang et al 2003;Engler et al 2006;Tsutsumi et al 2009;Wu et al 2009). We refer to this approach as ''the conventional method'' in this study.…”

Histamine and Breast Cancer: A New Role for a Well Known Amine

“…After surgical removal of primary breast tumors, malignant cells may still remain and radiotherapy is an efficient modality to reduce the risk of local recurrence. However, proliferative, invasive, and metastatic capacities can be increased in the surviving tumor cells of irradiated breast and other neoplasias (Baluna et al, 2006;Tsukamoto et al, 2007;Tsutsumi et al, 2009). To improve the efficacy of radiotherapy, this phenomenon must be further studied to elaborate therapeutic modalities to prevent radiation enhancement of cancer cell invasion.…”