Expression profiling of radiation-induced genes in radiodermatitis of hairless mice

Tumor Cell Invasion Induced by Radiation in Balb/C Mouse is Prevented by the Cox-2 Inhibitor NS-398

Radiation stimulates the expression of inflammatory mediators known to increase cancer cell invasion. Therefore, it is important to determine whether anti-inflammatory drugs can prevent this adverse effect of radiation. Since cyclooxygenase-2 (COX-2) is a central player in the inflammatory response, we performed studies to determine whether the COX-2 inhibitor NS-398 can reduce the radiation enhancement of cancer cell invasion. Thighs of Balb/c mice treated with NS-398 were irradiated with either daily fractions of 7.5 Gy for five consecutive days or a single 30 Gy dose prior to subcutaneous injection of nonirradiated MC7-L1 mammary cancer cells. Five weeks later, tumor invasion, blood vessel permeability and interstitial volumes were assessed using magnetic resonance imaging (MRI). Matrix metalloproteinase-2 (MMP-2) was measured in tissues by zymography at 21 days postirradiation. Cancer cell invasion in the mouse thighs was increased by 12-fold after fractionated irradiations (5 × 7.5 Gy) and by 17-fold after a single 30 Gy dose of radiation. This stimulation of cancer cell invasion was accompanied by a significant increase in the interstitial volume and a higher level of the protease MMP-2. NS-398 treatment largely prevented the stimulation of cancer cell invasion, which was associated with a reduction in interstitial volume in the irradiated thighs and a complete suppression of MMP-2 stimulation. In conclusion, this animal model using MC7-L1 cells demonstrates that radiation-induced cancer cell invasion can be largely prevented with the COX-2 inhibitor NS-398.

Genetic susceptibility to cutaneous radiation injury

The use of ionizing radiation is critical to cancer treatment and fluoroscopic procedures. However, despite efforts to minimize total radiation dose, many patients experience toxic cutaneous side-effects of ionizing radiation, ranging from mild erythema to subcutaneous fibrosis, telangiectasia formation, and ulceration. Extent of injury is highly variable among patients. Studying the genetic determinants of radiation injury can help develop protocols to reduce radiation toxicity, as well as drive research into effective modulators of the genes and gene products associated with radiation injury. Many studies in the past two decades have identified single-nucleotide polymorphisms that may be associated with susceptibility to cutaneous radiation injury, such as those in genes related to the following cellular responses to ionizing radiation: inflammation, DNA repair, oxidation and stress response, and cell-cycle and apoptosis. This review summarizes the current literature on potential major genes and polymorphisms, in the previously described damage response pathways, that are involved in susceptibility to cutaneous radiation injury. Potential pitfalls of current research and further avenues of discovery will be explored.

Characterization and biological activity of the ribosomal protein L10a of the white shrimp: Fenneropenaeus merguiensis De Man during vitellogenesis

The molecular events in the ovaries of Fenneropenaeus merguiensis De Man during vitellogenesis were investigated. The ribosomal protein L10a (RPL10a) was characterized and cloned. It consisted of 669 bp and the deduced polypeptide had 217 amino acids (GeneBank/EBI accession number FJ623402). The calculated molecular mass and pI were 25.7 kDa and 10.06, respectively. An immunohistochemical technique showed that RPL10a was located in the cytoplasm and nucleus of developing oocytes and follicle cells. Treatment of undeveloped ovarian explant cultures with recombinant histidine (His)-RPL10a stimulated the expression of translationally controlled tumor protein (TCTP), heat shock protein 70 (HSP70), and shrimp ovarian peritrophin (SOP) genes, previously shown to be involved in ovarian maturation. The transcripts of all three genes in the ovarian explants showed their highest expression after 4 h incubation with the His-RPL10a at 37 degrees C. The TCTP and HSP70 transcripts declined after 12 h, while the transcript of SOP remained high until 24 h. The His-RPL10a did not stimulate the expression of the TCTP, SOP, and HSP70 genes in shrimp muscle tissue. The information on the molecular behavior of the RPL10a in this study may, in the future, lead to new methods to stimulate ovarian development in shrimp.

Anti-apoptotic role of S100A8 in X-ray irradiated keratinocytes

BACKGROUND

Ionizing radiation is used to treat a lot of cancers, however, it also produced unwanted side effect on normal tissues, such as radiodermatitis. We previously established an animal model for radiodermatitis, and identified many of radiation-induced genes by cDNA microarray. Of the candidates, we chose S100A8 gene for a further study.

OBJECTIVE

The aim of this study is to investigate the functional role of S100A8 in X-ray irradiated keratinocytes.

METHODS

RT-PCR and immunohistochemistry were performed to demonstrate the S100A8 induction by X-ray irradiation. HaCaT keratinocytes were transduced with the recombinant adenovirus expressing GFP-S100A8, and then effects on cell cycle and apoptosis were analyzed using flow cytometry and Western blot.

RESULTS

X-ray irradiation markedly induced S100A8 expression in the hyperplastic epidermis of mouse. Overexpression of S100A8 by adenoviral transduction led to the enhancement of cell proliferation in the absence and/or presence of X-ray irradiation, as compared with Ad/GFP control group. Furthermore, overexpression of S100A8 significantly protected the X-ray-induced apoptosis.

CONCLUSION

These results suggest that S100A8 have an anti-apoptotic role in X-ray irradiated keratinocytes.