Radiosensitivity Of Cervical Cancer Research Articles

Role and mechanism of miR-4778-3p and its targets NR2C2 and Med19 in cervical cancer radioresistance

The aim of this study was to investigate the effect of miR-4778-3p on the radiosensitivity of cervical cancer cells and to elucidate the underlying mechanism. Tissue samples were collected from eight patients with cervical cancer prior to chemoradiotherapy. MicroRNA chip analyses, RT-PCR, gene transfection, CCK8, wound healing and Transwell assays, colony-forming assay, western blot, and the Dual-Luciferase Reporter Assay System were used to evaluate the role of miR-4778-3p in cervical cancer radiosensitivity and its relationships with target molecules NR2C2 and Med19. Thirty-two differentially expressed miRNA molecules (fold-change > 2; p < 0.05) associated with cervical cancer radioresistance were identified. The expression of miR-4778-3p was significantly lower in recurrent or metastatic patients than in control subjects. In vitro studies using radioresistant HeLa and SiHa cervical cancer cell lines showed that miR-4778-3p upregulation significantly inhibited cell proliferation, invasiveness, and migration after irradiation. There was also a significant increase in apoptosis and a significant decrease in the proportion of cells at the G2/M phase. Further, miR-4778-3p upregulation led to increased expression of apoptosis-related molecules, such as Bax, Caspase-3, Caspase-8, and Caspase-9. Reporter gene assays showed that miR-4778-3p bound specifically to NR2C2 and Med19 and negatively regulated their expression. Thus, miR-4778-3p reduces the vitality, proliferation, and migration of radioresistant cervical cancer cells and may regulate the radiosensitivity of cervical cancer by targeting and regulating NR2C2 and Med19 expression.

The Radiosensitivity of Cervical Cancer and its Influence on Patterns of Failure Following Definitive Concurrent Chemotherapy and Radiation

The Radiosensitivity of Cervical Cancer and its Influence on Patterns of Failure Following Definitive Concurrent Chemotherapy and Radiation

Silencing of FTS increases radiosensitivity by blocking radiation-induced Notch1 activation and spheroid formation in cervical cancer cells

Increasing evidence(s) suggests that cancer stem cells (CSC) in tumours contribute to radio-resistance and recurrence. Notch plays an important role in the maintenance of CSC in many cancers including cervical cancer. Previously, we have reported the role of Fused Toes Homolog (FTS) in conferring radioresistance in cervical cancer cells in vitro and human subjects. The present study investigated the regulatory role of FTS in Notch signaling and maintenance of CSC upon irradiation of cervical cancer cells. The expression of Notch1, 2, 3, cleaved Notch1 and its downstream target Hes1, and spheroid formation was increased by irradiation. Silencing of FTS prevented the radiation-induced increase in the expression of Notch signaling molecules and spheroid formation. Immunoprecipitation showed FTS binds Notch1 and Hes1. Also in silico structural analysis identified putative residues responsible for the binding between FTS and Notch1. Spheroid formation and the expression of CSC markers, Nanog, Oct4A and Sox2 were greatly reduced by combining silencing of FTS and radiation. Taken together, these results suggest that FTS is involved in the regulation of irradiation-induced Notch signaling and CSC activation and can be used as a target to increase radiosensitivity in cervical cancer.

Abstract SY24-02: Improving radio-sensitivity in cervical cancer by targeting tumor metabolism

Abstract Our group has previously shown that cervical cancers that take up large quantities of glucose, as defined by pretreatment 18F-fluoro-deoxy-glucose positron emission tomography (FDG-PET) imaging, are resistant to standard-of-care treatment (cisplatin plus concurrent pelvic irradiation). In this session, we will review the clinical evidence that supports this finding, and translational studies that support a connection between aberrant PI3K/AKT signaling and increased glucose uptake in tumors. We will then detail recent preclinical evidence that supports simultaneous inhibition of glycolysis and redox metabolism as an effective and safe alternative treatment strategy for highly glycolytic, radiation-resistant cervical cancers. Ongoing efforts to identify, characterize, and validate biomarkers to guide this strategy will be discussed. Citation Format: Julie K. Schwarz. Improving radio-sensitivity in cervical cancer by targeting tumor metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr SY24-02.

Over-expression of miR-15a-3p enhances the radiosensitivity of cervical cancer by targeting tumor protein D52.

Radioresistance is a challenge in the treatment of cervical cancer. Recent studies have reported that microRNAs (miRNAs) mediate radiotherapy resistance and play a vital role in the occurrence and development of cancer. The aim of this study was to investigate whether the expression of miR-15a-3p was correlated with radiosensitivity in cervical cancer. Quantitative real-time PCR experiment was performed to detect the expression of miR-15a-3p in cervical cancer tissues and cells lines. Then, the effect of miR-15a-3p on proliferation in cervical cancer cells radiation-induced were determined by using CCK-8, clonogenic formation and EdU assays. In addition, the TUNEL, flow cytometry analysis and western blotting assays were conducted to evaluate radiation-induced cells apoptosis. A dual-luciferase reporter assay was used to test the target. In addition, tumor xenograft experiment was conducted to test tumor growth in vivo. In this study, miR-15a-3p was downregulated in cervical cancer tissues and cells lines, however, the expression of miR-15a-3p significantly increased exposed to radiation. Moreover, over-expression of miR-15a-3p inhibited cells proliferation and enhanced cells apoptosis radiation-induced. Further, TPD52 was identified as a direct target of miR-15a-3p. Inhibition of TPD52 could suppress cells proliferation and induce cells apoptosis. Tumor xenograft experiments indicated that over-expression of miR-15a-3p could increase sensitivity to radiation therapy by targeting TPD52. In conclusion, our findings suggested that miR-15a-3p enhanced radiosensitivity in cervical cancer by targeting tumor protein D52, suggesting that miR-15a-3p may be a potential therapeutic target for cervical cancer patients.

Significance of p53 in cervical cancer and its influence on radiosensitivity

Radiotherapy is a major local treatment for cervical cancer. However, local uncontrollability due to radioresistance is still common. Therefore, the prediction of radiosensitivity is quite beneficial to develop an optimal treatment strategy for individual patients. Multiple factors could influence the radiosensitivity of cells, and p53 status is one of them. The upstream or downstream molecules of p53 could also be regulated to affect the radiosensitivity of cervical cancer. The aim of the review is to analyze the difference in p53 status between different types of cervical cancer and to discuss how p53 regulates the response to radiotherapy. Key words: p53 gene; Cervical neoplasms; Radiosensitivity; Regulate

SP-0595: Modeling the interplay among volume, vascularization and radio-sensitivity in cervical cancer exploiting 3D-Doppler data

SP-0595: Modeling the interplay among volume, vascularization and radio-sensitivity in cervical cancer exploiting 3D-Doppler data

MicroRNA-320 regulates the radiosensitivity of cervical cancer cells C33AR by targeting β-catenin.

Cervical cancer is the second most common malignancy in women worldwide and always has recurrence owing to radioresistance. MicroRNA (miRNA or miR) has been identified to relate to the sensitivity of cancer radiotherapy. Here, we investigated the potential of miRNA-320 as a biomarker for radiosensitivity by targeting β-catenin in cervical cancer. A radioresistant cervical cancer cell line, C33AR, was established, and the radioresistance of C33AR cells was confirmed by a colony-formation assay. The expression of miRNA-320 was detected by reverse transcription-quantitative polymerase chain reaction, and compared between C33A and C33AR. β-catenin, the target of miRNA-320, was determined at the protein level by western blotting after transfecting the inhibitor of miRNA-320. The expression of miRNA-320 was markedly decreased in C33AR cells, which appeared to be more radioresistant, compared with its parental cell line C33A. Target prediction suggested that miRNA-320 negatively regulated the expression of β-catenin. Knockdown of β-catenin increased C33AR radiosensitivity, which revealed that the inhibition of β-catenin could rescue the miRNA-320-mediated cell radioresistance. On the other hand, overexpressing miRNA-320 increased C33AR radiosensitivity. In conclusion, miRNA-320 regulated the radiosensitivity of C33AR cells by targeting β-catenin. This finding provides evidence that miRNA-320 may be a potential biomarker of radiosensitivity in cervical cancer.

MiR-21 modulates radiosensitivity of cervical cancer through inhibiting autophagy via the PTEN/Akt/HIF-1α feedback loop and the Akt-mTOR signaling pathway.

MiR-21 is an important microRNA (miRNA) modulating radiosensitivity of cervical cancer cells. However, the underlying mechanism of miR-21 upregulation in radioresistant cervical cancer has not been fully understood. In addition, autophagy may either promote or alleviate radioresistance, depending on the types of cancer and tumor microenvironment. How autophagy affects radiosensitivity in cervical cancer and how miR-21 is involved in this process has not been reported. This study showed that miR-21 upregulation in radioresistant cervical cancer is related to HIF-1α overexpression. MiR-21 overexpression decreases PTEN, increases p-Akt, and subsequently increases HIF-1α expression, while miR-21 inhibition results in increased PTEN, decreased p-Akt, and then decreased HIF-1α. Therefore, we inferred that there is a HIF-1α-miR-21 positive feedback loop through the PTEN/Akt/HIF-1α pathway in cervical cancer cells. In addition, we also demonstrated that miR-21 confers decreased autophagy in cervical cancer cells after IR via the Akt-mTOR signaling pathway. Decreased autophagy is one of the potential mechanisms of increased radioresistance in cervical cancer cells. These findings expand our understanding of radioresistance development in cervical cancer.

MicroRNA-218 enhances the radiosensitivity of human cervical cancer via promoting radiation induced apoptosis.

We previously reported frequent loss of microRNA-218 (miR-218) in cervical cancer, which was associated with tumor progression and poor prognosis. As microRNAs were found invovled in the regulation of radiosensitivity in various human cancers, we therefore aim to investigate the effects of miR-218 on radiosensitivity of cervical cancer in the present study. The clonogenic survival assay demonstrated that loss of miR-218 could predict radioresistance in the primary cervical cancer cells (R2=0.6516, P<0.001). In vitro, abundant miR-218 increased the radiosensitivity in cervical cancer cells (P<0.001 for HeLa, P=0.009 for SiHa, P=0.016 for C33A and P=0.01 for CaSki). Upregulation of miR-218 significantly enhanced the radiation-induced apoptosis, which was further enhanced by the combination of miR-218 overexpression and radiation In xenograft growth assay, combination of miR-218 overexpression and radiation notably induced cellular apoptosis and suppressed tumor growth. In conclusion, we demonstrated that miR-218 resensitized cervical cancer cells to radiation via promoting cellular apoptosis. Moreover, we proved that miR-218 as a potent predictor of radiosensitivity in cervical cancer, especially for those patients with loss of miR-218.

Effects of the Proapoptotic Regulator Bcl2/Adenovirus EIB 19 kDa-Interacting Protein 3 on Radiosensitivity of Cervical Cancer

Bcl2/adenovirus EIB 19 kDa-interacting protein 3 (BNIP3) is a proapoptotic member of the Bcl-2 family. To address its potential as a therapeutic target for radiosensitization, this study investigated the effect of Bnip3 expression on radiosensitivity of cervical cancer in vitro and in vivo. In vitro: A plasmid expressing the BNIP3 gene was transfected into human cervical cancer HeLa cells using Lipofectamine(2000), and western blot and immunohistochemistry analysis were performed to evaluate the expression of BNIP3 in transfected cells. The effects on radiation-induced apoptosis were investigated using a clone formation assay and flow cytometry. In vivo: A total of 6 × 10⁶ HeLa cells were subcutaneously inoculated into the dorsal flank of nude mice, and plasmids expressing the BNIP3 gene were injected into the mice via the tail vein. Tumor volume was calculated, and immunohistochemistry was used to detect the expression of BNIP3 in tumor cells. TUNEL assays were performed to determine the apoptosis rates in tumor tissues. Transfection with the recombinant BNIP3 plasmid increased expression of the Bnip3 protein in tumor cells. This apoptosis regulator significantly decreased the viability of cells (p < 0.01) and increased the apoptosis rates (p < 0.01) both in vitro and in vivo. The antitumor effect of radiotherapy was enhanced by overexpression of BNIP3, as revealed by tumor growth curve analysis. Radiosensitization in human cervical cancer cells was observed after treatment with the recombinant BNIP3 plasmid in vitro and in vivo. Results suggested that BNIP3 may play a role in enhancement of radiotherapy efficiency, and its expression may have a synergistic effect on radiation treatments.

Potential application of the ATP cell viability assay in the measurement of intrinsic radiosensitivity in cervical cancer

Background Intrinsic radiosensitivity using the clonogenic assay and the cell surviving fraction at 2 Gy (SF 2) has been shown to be an independent prognostic factor for patient response to radiotherapy in carcinoma of the cervix. The clonogenic assay has significant shortcomings, making it unsuitable for routine clinical use. The ATP cell viability assay (ATP-CVA) has been shown to have a high tumor evaluability rate, technical simplicity, and reproducibility in chemosensitivity testing. Aims This study compares the ATP-CVA with the clonogenic assay in the in vitro radiosensitivity testing of cervical cancer cell lines. Correlation of in vitro radiosensitivity and in vivo patient response was also determined. Methods Five cervical carcinoma cell lines (SiHa, HeLa, Caski, C-33A, and C4-1) were tested using the ATP-CVA and the clonogenic assay. Survival curves were plotted and the mean SF 2 values obtained by the two different assay methods were compared using ANOVA to see if there were significant differences. Mean SF 2 values obtained from 27 cervical cancers were compared with clinical outcomes. Results The SF 2 values for the cell lines ranged from 0.28 to 0.67 when tested using the ATP-CVA. Using the clonogenic assay, the SF 2 values ranged from 0.27 to 0.70. ANOVA with Bonferroni pairwise multiple comparison showed no significant difference between the mean SF 2 values for the individual cell lines between the two assay methods. Twenty-three cervical cancer samples (85%) were evaluable for SF 2 using ATP-CVA. The mean SF 2 values of patients who had locoregional failure were significantly higher than those who achieved local control ( P < 0.01). Conclusions Testing intrinsic radiosensitivity using the surviving fraction at 2 Gy (SF 2) is comparable using the two assay methods of ATP-CVA and clonogenic assay. The ATP-CVA should be further investigated in the testing of intrinsic radiosensitivity in patients with cervical cancer.

P73 expression is associated with the cellular radiosensitivity in cervical cancer after radiotherapy.

Apoptosis is one of the causes of cell death in cervical cancer following radiotherapy. By studying the gene expression profile with cDNA apoptotic array, the p73 gene was found overexpressed in radiosensitive cervical cancers when compared with radioresistant ones. To investigate the role of the p73 gene in relation to clinical assessment of radiosensitivity in cervical cancer based on the findings of residual tumor cells in cervical biopsies after completion of radiotherapy, we studied the protein expression of p73 in 59 cervical cancers after radiotherapy and 68 normal cervices using immunohistochemistry. The expression of p73 was found to be significantly increased in cancer samples and, more importantly, in those samples sensitive to radiotherapy (P < 0.001). The overexpression of p73 actually predicted a better prognosis in cervical cancer patients (P < 0.001). To investigate the possible involvement of p73 downstream genes, the protein expressions of p21 and Bax were studied. The expression of p21, but not Bax, was found to be positively correlated with the expression of p73 (P = 0.001). Furthermore, the epigenetic regulation of p73 expression via DNA methylation was also investigated in 103 cervical cancers and 124 normals. Hypermethylation of p73 gene was observed in 38.8% of cervical cancers, and it was significantly associated with reduced or absent p73 expression (P < 0.001). Reactivation of p73 expression in two cervical cancer cell lines by demethylation treatment supported the role of methylation in the regulation of p73 expression. Our findings suggested that p73 expression was related to the radiosensitivity of cervical cancer cells and may play an important role in the regulation of cellular radiosensitivity.

Expression of Ku80 in cervical cancer correlates with response to radiotherapy and survival.

To reveal the genes relevant for prediction of cervical cancer after radiotherapy, we previously carried out cDNA microarray experiments on primary cervical cancer comparing patients with a complete response (CR) and those with no change (NC). Some of these genes had already been associated with the radiation response, such as x-ray repair cross-complementing 5 (XRCC5), which was found more in radioresistant tumors than in radiosensitive ones. The aim of this study was to confirm the possible roles of XRCC5 mRNA levels by a real-time polymerase chain reaction method in 20 cervical cancers, and Ku80 protein, which is the gene product of XRCC5, using a histopathologic method of formalin-fixed sections of tumor biopsies in determining tumor response to radiotherapy and survival in 89 patients with cervical cancer. The levels of XRCC5 mRNA were 10(4.82) +/- 10(0.2) copies/microg total RNA in tumor tissues in the CR group (mean +/- standard deviation) and 10(4.95) +/- 10(0.32) copies/microg total RNA in those in the NC group. The levels of XRCC5 mRNA were not significantly different between the CR and NC groups. Histopathologic methods revealed 29.2% (26 of 89) of the patients to be Ku80-negative, with Ku80-positive findings in 70.8% (63 of 89). Of the Ku80-negative patients, 19 had CR, 3 had a partial response (PR), and 4 had NC. Of the Ku80-positive patients, 25 had CR, 22 had PR, and 16 had NC. Ku80-negative tumors showed significantly better responses than Ku80-positive ones, comparing CR and PR/NC responses (p = 0.01). In addition, overall survival was significantly better in the Ku80-negative patients as compared with those who were Ku80-positive (p = 0.04). The results of this study suggest that a low expression of Ku80 protein leads to radiosensitivity in cervical cancer and that Ku80 might play a role in treatment outcome.

Radiosensitivity of Cervical Cancer

Methods for evaluating radiosensitivity of cervical carcinoma are described and experience in their application reported. Attempts made to predict biologic malignancy and degree of radiosensitivity from examination of pretreatment cervical biopsies showed that there is some correlation between histologic differentiation and malignancy of squamous carcinoma of the cervix. However, the available data are not sufficiently clear to establish correlation between histologic grade and either radiocurability or radiosensitivity. Histologic grading of cervical biopsies is of little or no value in predicting the prognosis of a patient with carcinoma of the cervix treated radiologically A previously reported correlation between the chromosomal population of cervical squamous carcinoma cells and radiosensitivity offers a new avenue of investigation which can be accomplished in the pretreatment stage. In most cases there was a correlation between higher ploidy (more than 60 chromosomes) of malignant cells and their radioresistant character, and between lower ploidy (less than 60 chromosomes) and radiosensitive behavior. Cervical biopsies obtained during the course of radiation therapy were examined in an attempt to correlate the histologic changes with the ultimate effect of radiation on the tumor and the survival of the patient. The presence or absence of tumor cells in vaginal smears during the monthmore » immediately following completion of radiation therapy was correlated with clinical outcome in 108 cases followed 2-4 1/2 yr. A cytological radiation response (RR) is more frequent in postmenopausal than in premenopausal women and increases with advancing age and supervoltage radiation. Gross characteristics of the tumor, stage of the lesion, and general health of the patient had no significant effect upon the frequency of or degree of RR. These data suggest that the cytological method of predicting RR is of limited value in those cases of very early or late cancer, the RR frequently being the converse of the expected and actual clinical outcome. The histological prognosis correlates well with the clinical outcome and is, generally, more reliable than cytological studies. Results of cytochemical technique were essentially the same as those with the histological technlque. The evaluation of biopsy specimens by the cytochemical method was, however, more difficult than with either of the other two techriques. The value of histological and cytochemical techniques combined appears greater than either technique alone, especially in predicting an unfavorable response. (TCO)« less