Occurrence Of Radioresistance Research Articles

Exosomal transfer of tumor-associated macrophage-derived hsa_circ_0001610 reduces radiosensitivity in endometrial cancer

The occurrence of radioresistance is a clinical obstacle to endometrial cancer (EC) treatment and induces tumor relapse. In this study, we found that tumor-associated macrophages (TAMs) enriched in EC specimens were determined to present an M2-like phenotype. In vitro, the coculture of M2-polarized macrophages significantly downregulated the radiosensitivity of EC cells by releasing exosomes. Hsa_circ_0001610 was found to be abundant in exosomes derived from M2-polarized macrophages (EXOs), and hsa_circ_0001610 knockdown eliminated the reduction effect of EXOs on the radiosensitivity of EC cells. The following mechanism research revealed that hsa_circ_0001610 functioned as the competing endogenous RNA of miR-139-5p, thereby upregulating cyclin B1 expression, which is a vital pusher of radioresistance in several types of cancer by regulating the cell cycle. Hsa_circ_0001610 overexpression reduced the radiosensitivity of EC cells, which was then reversed by miR-139-5p overexpression. In vivo, the promotion effect of EXOs on xenograft tumor growth in nude mice treated with irradiation was further reinforced after hsa_circ_0001610 overexpression. In conclusion, TAM-derived exosomes transferred hsa_circ_0001610 to EC cells, and the overexpressed hsa_circ_0001610 in EC cells released cyclin B1 expression through adsorbing miR-139-5p, thereby weakening the radiosensitivity of EC cells.

The Role of Cyclin D1 and VEGF in Radiotherapy Response of Advance Stage Undifferentiated Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma has a high incidence and mortality rate in Southeast Asia and Indonesia. Radioresistance is a major obstacle to successful treatment of nasopharyngeal carcinoma. DNA repair in the cell cycle and angiogenesis factors affects the response of tumor cells to radiotherapy. Cyclin D1 that functions in the cell cycle process and VEGF as an angiogenesis factor are considered to play a role in the occurrence of radioresistance. The objective of this study is to find the association between immunoexpression of Cyclin D1 and VEGF with radiotherapy response in undifferentiated nasopharyngeal carcinoma. This study used a retrospective case control analysis design, secondary data from medical records of patients diagnosed as undifferentiated nasopharyngeal carcinoma who received complete radiotherapy at the Radiation Oncology Department Dr Hasan Sadikin Bandung were taken. There were 44 samples divided into radiosensitive (22 samples) and radioresistant (22 samples) groups. Immunohistochemical examination of Cyclin D1 and VEGF was performed on paraffin blocks of patients' biopsy. Data analysis using Chi-Square test (p ≤0.05) , OR 95% CI. Cyclin D1 expressed strongly in 86.4% of the radioresistant group and 59.1% in the radiosensitive group (p<0.05) and the OR 4,385 (0.993-19.356), VEGF was strongly expressed in 77.3% of the radioresistant group and 54.5% in the radiosensitive group (p>0.05). As conclusion, there were significant association between Cyclin D1 with radiotherapy respons in undifferentiated nasopharyngeal carcinoma. The stronger immunoexpression of Cyclin D1, the higher likelihood of radioresistancy. VEGF immunoexpression showed no significant association with radiotherapy response.

The Role of Cyclin D1 and VEGF in Radiotherapy Response of Advance Stage Undifferentiated Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma has a high incidence and mortality rate in Southeast Asia and Indonesia. Radioresistance is a major obstacle to successful treatment of nasopharyngeal carcinoma. DNA repair in the cell cycle and angiogenesis factors affects the response of tumor cells to radiotherapy. Cyclin D1 that functions in the cell cycle process and VEGF as an angiogenesis factor are considered to play a role in the occurrence of radioresistance. The objective of this study is to find the association between immunoexpression of Cyclin D1 and VEGF with radiotherapy response in undifferentiated nasopharyngeal carcinoma. This study used a retrospective case control analysis design, secondary data from medical records of patients diagnosed as undifferentiated nasopharyngeal carcinoma who received complete radiotherapy at the Radiation Oncology Department, Dr. Hasan Sadikin Bandung were taken. There were 44 samples divided into radiosensitive (22 samples) and radioresistant (22 samples) groups. Immunohistochemical examination of Cyclin D1 and VEGF was performed on paraffin blocks of patients' biopsy. Data analysis using Chi-Square test (p≤0.05) , OR 95% CI. Cyclin D1 expressed strongly in 86.4% of the radioresistant group and 59.1% in the radiosensitive group (p<0.05) and the OR 4,385 (0.993-19.356), VEGF was strongly expressed in 77.3% of the radioresistant group and 54.5% in the radiosensitive group (p>0.05). As conclusion, there were significant association between Cyclin D1 with radiotherapy respons in undifferentiated nasopharyngeal carcinoma. The stronger immunoexpression of Cyclin D1, the higher likelihood of radioresistancy. VEGF immunoexpression showed no significant association with radiotherapy response.

Construction and analysis of miRNA-mRNA regulatory networks in the radioresistance of nasopharyngeal carcinoma.

Radiotherapy has been the major treatment strategy for nasopharyngeal carcinoma (NPC), while the occurrence of radioresistance may lead to cancer recurrence or progression. This study aimed to identify the key microRNAs (miRNAs) and their target genes in the development of NPC radioresistance. Public microarray data were searched and analyzed to screen the differentially expressed miRNAs (DEMs) and genes (DEGs) between radioresistant and radiosensitive NPC samples. MiRNA-mRNA networks were constructed. As a result, 5 DEMs and 195 DEGs were screened out. The DEGs were enriched in various signaling pathways, such as Cytokine-cytokine receptor interaction, Jak-STAT signaling pathway, and Toll-like receptor signaling pathway. Several hub genes, such as IGF2, OLA1, BBS10, MMP9, and BBS7 were identified. A regulatory miRNA-mRNA network containing 87 miRNA-mRNA pairs was constructed. Then, 14 key miRNA-mRNA pairs that contained the hub genes were further filtered out. In the networks, miR-203a-3p had the largest number of target genes. Afterwards, the candidate pairs (miR-203a-3p/BTK and miR-484/OLA1) have been verified by a qRT-PCR assay. In summary, we identified several miRNAs and hub genes via big data screening. A total of 87 miRNA-mRNA pairs (including 14 key pairs) were predicted to play a crucial role in the development of NPC radioresistance. These data provide a bioinformatics basis for further exploring the molecular mechanism of radiotherapy resistance in NPC. Future studies are needed to validate the results.

Activation of AhR with nuclear IKK\u03b1 regulates cancer stem-like properties in the occurrence of radioresistance

Most cancer patients receive radiotherapy in the course of their disease and the occurrence of radioresistance is associated with poor prognosis. The molecular pathways that drive enhanced tumorigenic potential during the development of radioresistance are poorly understood. Here, we demonstrate that aryl hydrocarbon receptor (AhR) plays a vital role in the maintenance of cancer stem-like properties. AhR promotes the cancer stem-like phenotype and drives metastasis by directly targeting the promoters of ‘stemness’ genes, such as the ATP-binding cassette sub-family G member 2 (ABCG2) gene. Moreover, the radioresistant sublines display high levels of oncometabolites including α-ketoglutarate, and treatment of cancer cells with α-ketoglutarate enhances their stem-like properties in an AhR activation-dependent manner. IKKα directly activates stemness-related genes through an interaction with AhR as a bone fide chromatin modifier. Thus, AhR is functionally linked with cancer stem-like properties, and it drives tumorigenesis in the occurrence of radioresistance.

The role of cyclin D1 and vascular endothelial growth factor (VEGF) in radiotherapy response of undifferentiated nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) has a high incidence and mortality rate in Southeast Asia included in Indonesia. Radioresistance is a major obstacle for a successful treatment of NPC. DNA repair in the cell cycle and angiogenesis factors affect the response of tumor cells to radiotherapy. Cyclin D1 that functions in the cell cycle process and vascular endothelial growth factor (VEGF) as an angiogenesis factor are considered to play a role in the occurrence of radioresistance. The objective of this study was to evaluate the association between cyclin D1 and VEGF expressions with radiotherapy response in undifferentiated NPC. This study used a retrospective case control analysis design. Secondary data from medical records of patients diagnosed as undifferentiated NPC who received a complete radiotherapy at the Department of Radiation Oncology, Dr. Hasan Sadikin General Hospital, Bandung. There were 44 samples divided into radiosensitive (22 samples) and radioresistant (22 samples) groups. Immunohistochemical examination of cyclin D1 and VEGF expressions was performed on paraffin blocks of patients’ nasopharyngeal biopsy. Data analysis used Chi-Square test with p ≤0.05. Cyclin D1 was expressed strongly in 86.4% of the radioresistant group and 59.1% in the radiosensitive group (p 0.05). In conclusion, there is significant association between cyclin D1 expression with radiotherapy response in undifferentiated NPC. However, there is no association between VEGF expression with radiotherapy response.

Abstract 4757: Radioresistance is linked with stem-like properties via activation of aryl hydrocarbon receptor

Abstract Most cancer patients receive radiotherapy in the course of their disease and the occurrence of radioresistance is associated with a poor prognosis for cancer patients. The molecular pathways that drive the enhanced tumorigenic potential during the development of radioresistance are poorly understood. Here, we demonstrate that the aryl hydrocarbon receptor (AhR) plays a vital and previously unrecognized role in the maintenance of stem-like cells that are isolated from radioresistant epithelial lung cancer and nasopharyngeal carcinoma. AhR promotes the stem-like phenotype and drives metastasis by directly targeting the promoters of ‘stemness’ genes, such as the ATP-binding cassette sub-family G member 2 (ABCG2) gene. Cancer cell populations enriched for ABCG2 expression (CD338+) show an elevated ‘stemness’ signature and are more prone to cancer progression in vitro and in vivo. Ubiquitin C-terminal hydrolase-L3 (UCHL3), a deubiquitinating enzyme, may counteract AhR, while IKKα, a bone fide chromatin modifier, may directly activate stemness related genes. The radioresistant cancer cell sublines are associated with a hybrid state in epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET), and elevated tumor associated macrophages and proinflammatory factors. Moreover, the radioresistant sublines display high levels of oncometabolites, including α-ketoglutarate, and treatment of cancer cells with α-ketoglutarate enhances their stem-like properties through activation of the AhR. Thus AhR is functionally linked with radioresistance in lung cancer and nasopharyngeal carcinoma, and it drives tumorigenesis by an epithelial and mesenchymal composition, tumor associated macrophages and oncometabolites. Note: This abstract was not presented at the meeting. Citation Format: SHuang Liu, Bin Yan, Yongguang Tao. Radioresistance is linked with stem-like properties via activation of aryl hydrocarbon receptor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4757. doi:10.1158/1538-7445.AM2017-4757

Research progress of mechanism of tumor radioresistance

Tumor radioresistance is the leading cause of clinical radiotherapy failure and disease progression.Researches show that the occurrence of radioresistance is related to the cell cycle arrest,relevant gene change,tumor microenvironment change,autophagy,tumor stem cells and other factors.Studying the mechanism of radioresistance and looking for an effective method to avoid it is the key to improve the effect of radiotherapy,which can provide the probability of the prognosis of radiosensitivity. Key words: Neoplasms; Therapy; Radiotherapy

Abstract 4398: MicroRNA-203 enhances radiosensitivity of human malignant glioma cells

Abstract Glioblastoma multiform (GBM) is the most common, lethal and aggressive type of primary brain tumor. Despite the improvement of surgical and chemo/radiotherapeutic techniques, the prognosis for GBM is still poor, with median survival of 9-12 months. The occurrence of radio-resistance is one of the major obstacles to treat the GBM. Aberrant expression of miRNAs has been demonstrated to be involved in the initiation, progression, and metastasis of cancers. miRNA expression profiling studies revealed that a number of miRNA were dysregulated in GBM. Here, we investigated the potential role of miR-203, which is one of the downregulated miRNAs, in the modulation of radio-sensitivity in GBM. Transiently overexpressed miR-203 sensitized U251 malignant glioma cells to radiation concurrent with the downregulation of AKT activity. Overexpression of miR-203 prolonged radiation-induced γH2AX foci formation and downregulation of DNA-dependent protein kinases, suppressed invasion, migration potential and vasculogenic mimicry formation. In contrast, antisense-mediated inhibition of miR-203 expression results in decreased radio-sensitivity and features of Epithelial-Mesenchymal Transition (EMT). Taken together, our findings suggest that the miR-203 could be a useful target for overcoming the radio-resistance of GBM. Citation Format: Yeohyeon Hwang, David J. Lee, Eun Jung Choi, Bong Jun Cho, In-Ah Kim. MicroRNA-203 enhances radiosensitivity of human malignant glioma cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4398. doi:10.1158/1538-7445.AM2014-4398

Radiobiological characteristics of cancer stem cells from esophageal cancer cell lines

To study the cancer stem cell populations in esophageal cancer cell lines KYSE150 and TE1 and identify whether resulting stem-like cell spheres display radiation resistance characteristics. Serum-free medium (SFM) suspension was used to culture the esophageal cancer stem cell lines and enrich the esophageal stem-like cell spheres. RT-PCR assay was used to detect the stem cell gene expression in the sphere cells. Radiosensitivity of the sphere cells and parental cells were evaluated by clone formation assay. Different cells after irradiation at different doses were tested to evaluate the changes of sphere formation, and cell cycle and CD44(+)CD271(+) expression of the sphere cells were also analyzed by flow cytometry before and after irradiation. Cancer stem-like cell spheres were generated from KYSE150 and TE1 cells and enriched by culture in serum-free medium, and the number of spheres was increasing alone with the increase of cell passages. The numbers of spheres formed from the 1st, 2nd and 3rd generations of KYSE150 cells were 25 ± 2, 37 ± 2 and 47 ± 3, respectively. The numbers of spheres formed from the 1st, 2nd and 3rd generations of TE1 cells were 15 ± 3, 24 ± 3 and 36 ± 4, respectively. Certain doses of radiation increased the sphere formation rate. The average survival fraction (SF2) of the suspension-cultured KYSE150 stem-like cell spheres after 2 Gy irradiation were 0.81 ± 0.03 and 0.69 ± 0.04, while that of TE1 parental cells were 0.87 ± 0.01 and 0.80 ± 0.03 (P < 0.05 for all). In the esophageal parental KYSE150 and TE1 cells, arrest at G2 phase was induced after irradiation. After the same dose of irradiation, the inhibition of proliferation of the cancer stem cells was lower than that of the parent cells (P < 0.05). After 0, 4 and 8 Gy irradiation, the CD44(+)CD271(+) cell percentage of KYSE150 parental cells were (1.08 ± 0.03)%, (1.29 ± 0.07)% and (1.11 ± 0.09)%; the CD44(+)CD271(+) cell percentage of TE1 parental cells were (1.16 ± 0.11)%, (0.97 ± 0.08)% and (1.45 ± 0.35)% (P > 0.05 for all). After 0, 4 and 8 Gy irradiation, the percentage of CD44(+)CD271(+) cells of KYSE150 stem cell-like spheres were (35.83 ± 1.23)%, (44.90 ± 1.67)% and (57.77 ± 1.88)%, and that of TE1 stem cell-like spheres were (16.07 ± 0.91)%, (22.67 ± 1.12)% and (33.27 ± 1.07)%. Compared the 4 Gy and 8 Gy irradiated KYSE150 and TE1 stem-like cell spheres with the 0 Gy irradiated spheres, the differences were statistically significant (P < 0.05 for all). The cancer stem cells in KYSE150 and TE1 spheres are more radio-resistant than their parental cells. It may suggest that cancer stem cell populations in the esophageal cancer cells are related to the mechanism of occurrence of radioresistance.

Radioresistance of human glioma spheroids and expression of HSP70, p53 and EGFr.

BackgroundRadiation therapy is routinely prescribed for high-grade malignant gliomas. However, the efficacy of this therapeutic modality is often limited by the occurrence of radioresistance, reflected as a diminished susceptibility of the irradiated cells to undergo cell death. Thus, cells have evolved an elegant system in response to ionizing radiation induced DNA damage, where p53, Hsp70 and/or EGFr may play an important role in the process. In the present study, we investigated whether the content of p53, Hsp70 and EGFr are associated to glioblastoma (GBM) cell radioresistance.MethodsSpheroids from U-87MG and MO59J cell lines as well as spheroids derived from primary culture of tumor tissue of one GBM patient (UGBM1) were irradiated (5, 10 and 20 Gy), their relative radioresistance were established and the p53, Hsp70 and EGFr contents were immunohistochemically determined. Moreover, we investigated whether EGFr-phospho-Akt and EGFr-MEK-ERK pathways can induce GBM radioresistance using inhibitors of activation of ERK (PD098059) and Akt (wortmannin).ResultsAt 5 Gy irradiation UGBM1 and U-87MG spheroids showed growth inhibition whereas the MO59J spheroid was relatively radioresistant. Overall, no significant changes in p53 and Hsp70 expression were found following 5 Gy irradiation treatment in all spheroids studied. The only difference observed in Hsp70 content was the periphery distribution in MO59J spheroids. However, 5 Gy treatment induced a significant increase on the EGFr levels in MO59J spheroids. Furthermore, treatment with inhibitors of activation of ERK (PD098059) and Akt (wortmannin) leads to radiosensitization of MO59J spheroids.ConclusionsThese results indicate that the PI3K-Akt and MEK-ERK pathways triggered by EGFr confer GBM radioresistance.

Differential expression profiling of gene response to ionizing radiation in two endometrial cancer cell lines with distinct radiosensitivities

Although radiotherapy is routinely administered to high-risk endometrial carcinoma and offer a significant disease-free survival advantage, the therapeutic effect is sometimes limited by the occurrence of radioresistance. To determine the patterns of gene expression responsible for the radioresistance and to search for potential target genes for radiotherapy, we selected two cell lines with distinct radiosensitivities using colony-formation assay from four endometrial cancer cell lines. The cell cycle distribution showed higher fractions of G2/M phase cells in the radiosensitive cell line KLE after radiation compared with the radioresistant cell line ISK. Apoptosis assessment also showed significant elevation in the percentage of early apoptosis cells in KLE cells. Subsequently, gene expression changes after X-ray exposure were analyzed by using oligonucleotide microarrays. We identified, respectively, in ISK and KLE, 227 and 354 genes that exhibited > or =2-fold difference. However, only 53 genes showing differences more than double the median expression value between the two groups were defined as radiosensitivity (or radioresistance)-related genes. Among these, genes associated with DNA-repair, apoptosis, growth factor, signal transduction, cell cycle and cell adhesion were predominant. The validity of the expression level of 10 randomly selected genes was confirmed by real-time PCR and/or Western blotting. In conclusion, the differential gene expression changes that occur after radiation in the two cell lines will provide insight into molecular mechanisms of radioresistance in endometrial carcinoma, and also the means to find potential targets to achieve further gains in therapeutic benefit.

Radioresistance is associated to increased Hsp70 content in human glioblastoma cell lines

Radiation therapy is routinely prescribed for high-grade malignant gliomas. However, the efficacy of this therapeutic modality is often limited by the occurrence of radioresistance, reflected as a diminished susceptibility of the irradiated cells to undergo apoptosis. Heat-shock proteins (Hsps) synthesis can be increased by cellular insults, such as radiation-induced damage. Inducible Hsp70 has been suggested to have multiple roles in cytoprotection against apoptosis. Accordingly, high levels of Hsp70 prevent stress-induced apoptosis. In the present study, we investigated whether the content of Hsp70 is associated to glioblastoma cell radioresistance. To this end, the U-87MG, U-251MG and MO59J human glioblastoma cell lines were irradiated at 2, 5 and 10 Gy and their relative radioresistance and Hsp70 were determined. Following 5 Gy irradiation, in MO59J and U-251MG a significant decrease in colony formation was found, whereas the U-87MG was relatively radioresistant. Three hours after the irradiation (at 5 Gy) Hsp70 contents increased 110% in the U-87 MG cells, but did not significantly change in the U-251MG and MO59J cells. Thus, our results suggest that Hsp70 protection against radiation-induced apoptosis might underlie glioblastoma radioresistance.

Protein kinase C zeta nuclear translocation mediates the occurrence of radioresistance in friend erythroleukemia cells.

Friend erythroleukemia cells require high doses (15 Gy) of ionizing radiation to display a reduced rate of proliferation and an increased number of dead cells. Since ionizing radiation can activate several signaling pathways at the plasma membrane which can lead to the nuclear translocation of a number of proteins, we looked at the intranuclear signaling system activated by Protein Kinases C, being this family of enzymes involved in the regulation of cell growth and death. Our results show an early and dose-dependent increased activity of zeta and epsilon isoforms, although PKC zeta is the only isoform significantly active and translocated into the nuclear compartment upon low (1.5 Gy) and high (15 Gy) radiation doses. These observations are concomitant and consistent with an increase in the anti-apoptotic protein Bcl-2 level upon both radiation doses. Our results point at the involvement of the PKC pathway in the survival response to ionizing radiation of this peculiar cell line, offering PKC zeta for consideration as a possible target of pharmacological treatments aimed at amplifying the effect of such a genotoxic agent.