Application of carbon-ion beams or gamma-rays on primary tumors does not change the expression profiles of metastatic tumors in an in vivo murine model.

PURPOSE: To clarify how carbon-ion radiotherapy (C-ion) on primary tumors affects the characteristics of subsequently arising metastatic tumor cells. METHODS AND MATERIALS: Mouse squamous cell carcinomas, NR-S1, in synergic C3H/HeMsNrs mice were irradiated with a single dose of 5-50 Gy of C-ion (290 MeV per nucleon, 6-cm spread-out Bragg peak) or gamma-rays ((137)Cs source) as a reference beam. The volume of the primary tumors and the number of metastatic nodules in lung were studied, and histologic analysis and microarray analysis of laser-microdissected tumor cells were also performed. RESULTS: Including 5 Gy of C-ion and 8 Gy of gamma-rays, which did not inhibit the primary tumor growth, all doses used in this study inhibited lung metastasis significantly. Pathologic findings showed no difference among the metastatic tumor nodules in the nonirradiated, C-ion-irradiated, and gamma-ray-irradiated groups. Clustering analysis of expression profiles among metastatic tumors and primary tumors revealed a single cluster consisting of metastatic tumors different from their original primary tumors, indicating that the expression profiles of the metastatic tumor cells were not affected by the local application of C-ion or gamma-ray radiotherapy. CONCLUSION: We found no difference in the incidence and histology, and only small differences in expression profile, of distant metastasis between local C-ion and gamma-ray radiotherapy. The application of local radiotherapy per se or the type of radiotherapy applied did not influence the transcriptional changes caused by metastasis in tumor cells.

The proangiogenic factor ephrin-A1 is up-regulated in radioresistant murine tumor by irradiation.

While the pre-treatment status of cancer is generally correlated with outcome, little is known about microenvironmental change caused by anti-cancer treatment and how it may affect outcome. For example, treatment may lead to induction of gene expression that promotes resistance to therapy. In the present study, we attempted to find a gene that was both induced by irradiation and associated with radioresistance in tumors. Using single-color oligo-microarrays, we analyzed the gene expression profiles of two murine squamous cell carcinomas, NR-S1, which is highly radioresistant, and SCCVII, which is radiosensitive, after irradiation with 137-Cs gamma rays or carbon ions. Candidate genes were those differentially regulated between NR-S1 and SCCVII after any kind of irradiation. Four genes, Efna1 (Ephrin-A1), Sprr1a (small proline-rich protein 1A), Srgap3 (SLIT-ROBO Rho GTPase activating protein 3) and Xrra1 [RIKEN 2 days neonate thymus thymic cells (NOD) cDNA clone E430023D08 3'], were selected as candidate genes associated with radiotherapy-induced radioresistance. We focused on Efna1, which encodes a ligand for the Eph receptor tyrosine kinase known to be involved in the vascular endothelial growth factor (VEGF) pathway. We used immunohistochemical methods to detect expression of Ephrin-A1, VEGF, and the microvascular marker CD31 in radioresistant NR-S1 tumor cells. Ephrin-A1 was detected in the cytoplasm of NR-S1 tumor cells after irradiation, but not in SCCVII tumor cells. Irradiation of NR-S1 tumor cells also led to significant increases in microvascular density, and up-regulation of VEGF expression. Our results suggest that radiotherapy-induced changes in gene expression related with angiogenesis might also modulate microenvironment and influence responsiveness of tumors.

CD44 and Bak expression in IL-6 or TNF-alpha gene knockout mice after whole lung irradiation.

To understand the molecular mechanisms that underlie radiation pneumonitis, we examined whether knockout of the TNF or the IL-6 gene could give mice an inherent resistance to radiation in the acute phase of alveolar damage after thoracic irradiation. The temporal expression of inflammation (CD44) and apoptosis (Bak) markers in lung after thoracic irradiation was measured to determine the degree of alveolar damage. At 4 weeks post-irradiation (10 Gy), small inflammatory foci were observed in all mice, but there were no obvious histological differences between control (C57BL/6JSlc), TNF-alpha knockout (TNF KO), and IL-6 knockout (IL-6 KO) mice. However, immunohistochemical analysis of CD44 and Bak expression over a time course of 2 weeks highlighted significant differences between the three groups. C57BL/6JSlc and TNF KO mice had increased numbers of both CD44-positive and Bak-positive cells after irradiation, while the IL-6 KO mice showed stable levels of CD44 and Bak. In conclusion, the radioresistant status of IL-6 KO mice in the acute phase of alveolar damage after irradiation suggested an important role for IL-6 in radiation pneumonitis.

Upregulation of stress-response genes with cell cycle arrest induced by carbon ion irradiation in multiple murine tumors models.

OBJECTIVE: To elucidate the in vivo biological effects induced by carbon-ion irradiation using comprehensive expression analysis. RESULTS: In all tumors, the level of expression of several tens of genes, including Ccl3, Ccng1, Cd80, Cdkn1a, Cxcl2, IL7r, Lrdd, Mgmt, Mmp8 and Polk, was significantly altered 6 h and day 1 following C-ion irradiation. At day 3, several hundred genes, many of which are also classified as stress-response or cell-communication genes, including Tnfrsf5, Ikbke and Icam1, were upregulated following C-ion irradiation. The expression level of the majority of these genes was similar following gamma-ray treatment, although the change was not as extensive and intertumor variance was apparent. Several genes, including Ikbke, Serpina3n and Saa3, responded differentially following C-ion irradiation than after gamma-ray irradiation. Pathological investigation and immunohistochemical analysis of Cdkn1a revealed cell cycle arrest with mitotic catastrophe in tumors irradiated by C-ions. MATERIALS AND METHODS: We examined gene expression changes after carbon-ion (C-ion) irradiation (290 MeV/m, SOBP 6 cm middle, 50 kev/microm) with a single dose of 30 Gy in four mouse tumors (NR-S1, SCCVII, NFSa and #8520) transplanted into the hind legs of C3H/HeNrs mice, using 44K single-color oligo-microarrays at six hours (h), one day and three days after irradiation. Gamma rays of 30 Gy and 50 Gy were used as a reference beam. Identification of C-ion-responsive genes was based on a false discovery rate of <5% using the Wilcoxon test (p < 0.001) and the Benjamini-Hochberg correction. CONCLUSIONS: This study revealed significant C-ion induced upregulation of stress-responsive and cell-communication genes common to different tumor types. These findings provide evidence for the efficacy of this modality for the treatment of local tumors.

Chemoradiation-induced expression of fibroblast growth factor-2 and laminin in patients with cervical cancer.

OBJECTIVE: To investigate the protein expression change of FGF2 in cervical cancers during chemoradiotherapy, as indicated in our previous study using microarray analysis. In addition, we sought to examine the predictive value of such changes in expression for disease failure after chemoradiotherapy. PATIENTS AND METHODS: Biopsy specimens were obtained from 35 patients with cervical cancers before (pretreatment) and 1 week after initiation (midtreatment) of chemoradiotherapy (CRT) (9 Gy and 40 mg/m(2) of cisplatin). Immunohistochemical studies (IHS) were performed to detect FGF2, laminin and CD44 expression using an automated streptavidin-biotin immunoperoxidase staining system. Positive area proportion (%) of FGF2 and CD44 were analyzed using an image analysis system and laminin staining pattern was scored by continuity of the basement membrane immunopositivity. Patients were defined as good (n = 18) or poor responders (n = 10) based on their two-year disease-free survival. RESULTS: Protein expression of FGF2 in midtreatment samples (mid) was significantly higher than in pretreatment samples (pre). Discontinuity of laminin staining pattern in mid was significantly higher than in pre. Protein expression of CD44 was not significantly different between mid and pre. The ratio change (mid versus pre) of FGF2 expression in poor responders was significantly lower than that in good responders (p < 0.05). The number of cases with discontinuity of laminin staining pattern at pre was significantly increased in the poor responders (p < 0.05). Ratio changes of FGF2 or CD44 expression in mid correlated with laminin staining pattern in pre. CONCLUSIONS: Using biopsy specimens from pretreatment and midtreatment cervical cancers, we revealed significant changes in FGF2 protein expression during fractionated radiotherapy with cisplatin. We also found that FGF2 ratio change and laminin discontinuity staining pattern at pretreatment were significantly associated with prognosis. These molecular features might help us to identify patients at high risk of disease failure after CRT.

The radiation-induced cell-death signaling pathway is activated by concurrent use of cisplatin in sequential biopsy specimens from patients with cervical cancer.

OBJECTIVE: To identify changes in gene expression related to the concurrent use of platinum compounds with radiotherapy, in the treatment of cervical cancer. PATIENTS AND METHODS: Biopsy specimens were obtained from 39 patients with squamous cell carcinoma of the uterine cervix, before and during fractionated radiotherapy. Twenty patients were treated with radiotherapy (RT) alone, while 19 received the same radiotherapy plus concomitant chemotherapy with cisplatin (CRT). Changes in gene expression induced by treatment were investigated using single-color oligo-microarrays consisting of 44K human sequences. Paraffin-embedded samples were used to examine apoptosis and the expression of protein by treatment-responsive genes. Changes in mRNA expression were assessed for these genes by real-time reverse transcriptase-polymerase chain reaction. Aberrant genomic change (detected using microarray-based comparative genomic hybridization), human papillomavirus infection, and p53 status were also evaluated. RESULTS: The expression of CDKN1A, BAX, TNFSF8, and RRM2B was consistently upregulated by CRT (9 Gy with a single administration of cisplatin). Similar expression changes were induced by RT (9 Gy) alone, although the variability between tumors was greater. Apoptotic cells were significantly increased in both groups. CRT significantly increased the numbers of cases with diffusely distributed CDKN1A-positive cells. Genetic losses at 2q33-ter and gains of 3q26-ter were detected in the samples with high frequency; 60% were positive for human papillomavirus DNA; and three tumors had deletions/mutations of the p53 gene. There was no difference in the incidence of these genomic changes between the groups, and no association was found with the changes in expression of CDKN1A, BAX, TNFSF8 or RRM2B. CONCLUSIONS: Using biopsy samples from pretreatment and midtreatment cervical tumors, we identified therapy-induced genes related to the cell death signaling pathway. CRT produced a homogenous pattern of changes in expression of known radiation-responsive genes.