Radiosensitivity Of Squamous Cell Carcinoma Research Articles

PCL22-186: A Potential Biomarker for Radiosensitivity of Squamous Cell Carcinomas in the Head and Neck

PCL22-186: A Potential Biomarker for Radiosensitivity of Squamous Cell Carcinomas in the Head and Neck

Abstract PO-071: Characterizing transcriptomic indicators of radiosensitivity in cancer and identifying sensitizing therapeutic agents

Abstract While radiation therapy is an integral method for cancer treatment, clinical choices are not currently informed by the genetic and molecular profile of a patient’s tumor. Though it has been shown that genetic features implicate variability, the exact relationship between these features and radiosensitivity is poorly understood. Our work focuses on predicting radiosensitivity of squamous cell carcinoma from molecular features. First, we employ RadioGx, a computational platform for integrative analysis of radiogenomic datasets, to identify a gene expression signature predictive of radiosensitivity. To mitigate the high-dimensionality of gene expression data, we employ pathway-level transcriptomic modeling methods to identify cellular programs associated with radiation sensitivity. Our pancancer radiosensitivity model achieves a Pearson’s correlation of 0.47 with measured radiosensitivity from a radiogenomic dataset using only high level transcriptomic features. Second, we use that gene expression signature to query the Connectivity Map via the PharmacoGx resource and identify candidate radiosensitizers - compounds that may induce the radiosensitivity signature. Further validation is necessary to evaluate the efficacy of these compounds at improving radiosensitivity in both model systems and patient contexts. These results implicate cellular processes in radiosensitivity and advance an approach for identifying radiosensitizing agents through integration of large scale datasets. Citation Format: Ian Smith, Rachel Bell, Meghan Lambie, Benjamin Haibe-Kains, Scott Bratman. Characterizing transcriptomic indicators of radiosensitivity in cancer and identifying sensitizing therapeutic agents [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-071.

Radiosensitivity Effect of Epidermal Growth Factor Receptor Nanoparticles on Head and Neck Squamous Cell Carcinoma.

The effect of antisense epidermal growth factor receptor (EGFR) nanoparticles on the radiosensitivity of squamous cell carcinoma in mice was studied. Antisense EGFR oligonucleotide nanoparticles were introduced into the SCCVII cell line, and the expression of the antisense EGFR in the SCCVII cell line was detected using western blot analysis. After radiotherapy intervention, a cell cloning test and MTT test were used to detect the radiosensitivity of the cells, and flow cytometry was used to detect the cell cycle distribution and apoptosis to establish a model of head and neck cancer in mice. Antisense EGFR nanoparticles were injected into the tumors and treated with 4 Gy radiation therapy to observe their inhibition on the growth of tumors. SCCVII cell line nanoparticles could significantly inhibit the expression of antisense EGFR proteins. The combination of antisense EGFR nanoparticles and radiotherapy could reduce the differentiation and division ability of cancer cells (P < 0.05). It could arrest cancer cells in the G1 phase and significantly increase the apoptotic rate (P <0.05). The growth of tumors in the antisense EGFR nanoparticles group was significantly delayed. Antisense EGFR nanoparticles could induce G1 phase arrest by down-regulating the expression of EGFRs, which had a radiosensitization effect.

Knockdown of RNF2 enhances the radiosensitivity of squamous cell carcinoma in lung.

A previous study has reported that knockdown of RING finger protein 2 (RNF2) increases the radiosensitivity of esophageal cancer cells both in vitro and in vivo. However, the effect of RNF2 knockdown on radiosensitivity in squamous cell carcinoma (SqCC) remains unknown. For this, NCI-H226 and SK-MES-1 cells were exposed to X-ray irradiation and then RNF2 levels were determined. RNF2 was knocked-down and stable transfectants were selected. Radiosensitivity, cell proliferation, apoptosis, cell cycle, and γ-H2AX foci formation were evaluated. Interaction among ataxia telangiectasia mutated protein (ATM), mediator of DNA damage checkpoint 1 (MDC1), and H2AX were examined. Xenograft models were used to explore the effect of RNF2 knockdown on radiosensitivity in vivo. The results showed that RNF2 expression was significantly increased by X-ray irradiation. RNF2 knockdown combined with X-ray irradiation markedly inhibited cell proliferation, caused cell cycle arrest at the G1 phase, and induced cell apoptosis. In addition, RNF2 knockdown enhanced the radiosensitivity of SqCC cells, inhibited irradiation-induced γ-H2AX foci formation, and impaired the interactions among ATM, MDC1, and H2AX. Furthermore, combination of RNF2 knockdown and X-ray irradiation suppressed tumor growth and promoted tumor cell apoptosis in vivo. RNF2 may be a new therapeutic target to enhance the radiosensitivity of SqCC cells in lung.

Radiosensitization of Squamous Cell Carcinoma by the Alkylphospholipid Perifosine in Cell Culture and Xenografts

Combined modality treatment has improved outcome in various solid tumors. Besides classic anticancer drugs, a new generation of biological response modifiers has emerged that increases the efficacy of radiation. Here, we have investigated whether perifosine, an orally applicable, membrane-targeted alkylphospholipid, enhances the antitumor effect of radiation in vitro and in vivo. Several long-term and short-term in vitro assays (clonogenic survival, sulforhodamine B cytotoxicity, apoptosis, and cell cycle analysis) were used to assess the cytotoxic effect of perifosine in combination with radiation. In vivo, the response of human KB squamous cell carcinoma xenografts was measured after treatment with perifosine, irradiation, and the combination. Radiolabeled perifosine was used to determine drug disposition in tumor and normal tissues. At various intervals after treatment, tumor specimens were collected to document histopathologic changes. In vitro, perifosine reduced clonogenic survival, enhanced apoptosis, and increased cell cycle arrest after radiation. In vivo, radiation and perifosine alone induced a dose-dependent tumor growth delay. When combining multiple perifosine administrations with single or split doses of radiation, complete and sustained tumor regression was observed. Histopathologic analysis of tumor specimens revealed a prominent apoptotic response after combined treatment with radiation and perifosine. Radiation-enhanced tumor response was observed at clinically relevant plasma perifosine concentrations and accumulating drug disposition of >100 microg/g in tumor tissue. Perifosine enhances radiation-induced cytotoxicity, as evidenced by reduced clonogenic survival and increased apoptosis induction in vitro and by complete tumor regression in vivo. These data provide strong support for further development of this combination in clinical studies.

P53 and Ki-67 as predictive markers for radiosensitivity in squamous cell carcinoma of the oral cavity? an immunohistochemical and clinicopathologic study

Purpose: Previously published data relating the expression of p53 and Ki-67 to radiation response in head and neck cancer are conflicting. This may be due to differences in patient selection and treatment modalities. In this study of a homogenous population of patients with oral cavity cancer, Ki-67 and p53 indices were correlated with histopathologically assessed tumor regression after preoperative radiochemotherapy and longterm outcome. Methods and Materials: Eighty-eight patients with squamous cell carcinoma of the oral cavity and treated between September 1985 and November 1995 by preoperative radiochemotherapy and definitive surgery were included in this analysis. By immunohistochemistry (IHC) the pre-irradiation expression of p53 and of Ki-67 were analyzed and correlated with the histopathologically proven tumor regression, overall survival and local control. Results: The overall 2- and 5-year survival rates were 76.5% and 63%, the locoregional control rates were 84% and 79%, respectively. After preoperative radiochemotherapy 29 patients (33%) showed complete tumor regression (ypT 0 classification). Survival and local control rates were significantly higher for patients showing ypT 0 classification than ypT 1–4 classification ( p < 0.01). This effect was independent of pretreatment tumor classification in multivariate analysis. Pre-irradiation p53 status and Ki-67 index had no influence on tumor regression and clinical outcome in these patients. Conclusions: Complete tumor regression after preoperative treatment is related to an improved outcome in combined modality treatment of oral cavity cancer. The presented study could not demonstrate an influence of p53 and Ki-67 status as detected by immunohistochemical staining on survival, local control, or tumor regression after radiochemotherapy.

Changes of mutant-type p53 expression in squamous cell carcinoma of the head and neck during radiation therapy and its clinical significance: comparison of an immunohistochemical method and PCR-SSCP assay.

P53 has been reported to be one of tumor suppressor genes that play a major role in signal transduction following many kinds of stresses, including ionizing radiation. Changes in p53 expression during radiation therapy in tumor tissues have not yet been reported. We determined whether radiotherapy changes p53 expression in human squamous cell carcinomas of the head and neck, and established the possible correlations between p53 expression and the therapeutic effects of radiation therapy. 30 patients with tumors of the oral cavity, oropharynx, and maxillary sinus were examined, and all the tumors were confirmed as squamous cell carcinomas. Biopsies were performed on the cancer tissues before treatment and at doses of 4, 10, and 20 Gy of radiotherapy, and the specimens were preserved in liquid nitrogen for further examination. Samples were immunohistochemically stained using streptoavidin-biotin peroxidase method and a monoclonal antibody against p53 (Ab-3, mutant type). For all the samples p53 PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) assays were performed. 14 of the 30 patients with squamous cell carcinomas showed expression of p53 in their tumor cells before and/or at 4 Gy or 10 Gy of radiotherapy. Eleven of the 14 tumors showed high radiosensitivity. Results of the p53 PCR-SSCP assays revealed mutations of p53 in 13 of 30 patients examined, and percentages of mutated p53 DNA varied at radiation doses of 4 Gy and 10 Gy. Ten of 12 patients with mutated p53 in their tumors showed decreased percentages of mutated p53 DNA during radiotherapy. The relationship between the immunohistochemical findings and the antitumor effect of a radiation dose of 20 Gy was examined on the correspondent hematoxylin-eosin sections. In patients whose p53 expressions in tumor cells were grades + or ++ or before radiotherapy and/or at 4 Gy of radiotherapy, the tumors responded significantly well to radiation therapy but the patients responded with significantly unfavorable clinical courses. The high radiosensitivity of squamous cell carcinomas in our samples could be explained by an overexpression of mutant type p53 in the tumor cells, and these mutant type p53-positive tumor cells possibly showed radioresponsiveness.

Potential indicators of radiosensitivity in squamous cell carcinoma of the head and neck

Recently, attention has focused on the potential of oncogenes, tumour suppressor genes, and assessment of cell proliferation as biological response indicators in human cancer. In this study, immunocytochemical analysis was used to evaluate the usefulness of Ki67, epidermal growth factor receptor (EGFr), and the protein products of c-Myc and Bcl-2 as indicators of radiosensitivity in primary cultures of head and neck tumours. Primary cultures established from tumours taken at surgery were divided into two groups; the control group remained untreated, and the treatment group received a single dose of 2 Gy. The cultures were incubated for 14 days, after which time they were fixed and examined immunocytochemically. The response to treatment of the cultures was measured as the percentage of growth inhibition (%GI) in the treated cultures relative to the untreated controls. Expression of Ki67 measured after a single dose of 2 Gy significantly differentiated the radioresistant and radiosensitive groups (P = 0.045); high percentages of Ki67+ cells correlated with radioresistance. A significant difference was found between the expression of EGFr in the resistant and sensitive groups, as measured in control cultures and after a dose of 2 Gy (P = 0.002 and P = 0.03, respectively); high levels of expression of EGFr correlated with radioresistance. The level of expression c-Myc+ cells, as measured in control cultures, significantly distinguished the radiosensitive group from the radioresistant group (P = 0.05). These results indicate a potential role for these proteins as indicators of radioresistance. Radiat. Oncol. Invest. 5:180–186, 1997. © 1997 Wiley-Liss, Inc.

Potential indicators of radiosensitivity in squamous cell carcinoma of the head and neck.

Recently, attention has focused on the potential of oncogenes, tumour suppressor genes, and assessment of cell proliferation as biological response indicators in human cancer. In this study, immunocytochemical analysis was used to evaluate the usefulness of Ki67, epidermal growth factor receptor (EGFr), and the protein products of c-Myc and Bcl-2 as indicators of radiosensitivity in primary cultures of head and neck tumours. Primary cultures established from tumours taken at surgery were divided into two groups; the control group remained untreated, and the treatment group received a single dose of 2 Gy. The cultures were incubated for 14 days, after which time they were fixed and examined immunocytochemically. The response to treatment of the cultures was measured as the percentage of growth inhibition (%GI) in the treated cultures relative to the untreated controls. Expression of Ki67 measured after a single dose of 2 Gy significantly differentiated the radioresistant and radiosensitive groups (P = 0.045); high percentages of Ki67+ cells correlated with radioresistance. A significant difference was found between the expression of EGFr in the resistant and sensitive groups, as measured in control cultures and after a dose of 2 Gy (P = 0.002 and P = 0.03, respectively); high levels of expression of EGFr correlated with radioresistance. The level of expression c-Myc+ cells, as measured in control cultures, significantly distinguished the radiosensitive group from the radioresistant group (P = 0.05). These results indicate a potential role for these proteins as indicators of radioresistance.

Intrinsic radiosensitivity of head and neck carcinomas as predictive test for clinical tumor control: Comparative analysis and critical assessment of technical reliability

AbstractUsing a cell adhesion matrix monolayer culture system, we assayed the intrinsic radiosensitivity of 108 biopsies or surgical specimens of head and neck, colo‐rectum, or cervix uteri carcinomas. After irradiating single cell suspensions with increasing doses (0–4 Gy), surviving fractions at 2 Gy (SF‐2), initial slope α were estimated after a linear quadratic fitting of the curves. For cultures from biopsies or surgical specimens of head and neck carcinomas, the overall success rate was 65%. The pattern of the causes of failure for mass cultures was similar in other institutions investigating intrinsic radiosensitivity of squamous cell carcinomas. Within the same anatomic site and histological type, rumors were characterized by a wide range of in vitro radiosensitivity. In a series of 28 patients with head and neck cancers, the mean and standard deviation values of SF‐2 were 0.30 ± 0.34. Likewise, α coefficients had an average of 0.61 ± 0.96 Gy−1. Cultures from colo‐rectal cancers seem to have a higher mean level of intrinsic radioresistance (mean SF‐2 = 0.49) than that of cells from head and neck tumors. Papanicolaou (PAP) staining and immuno‐chemistry studies using monoclonal antibodies showed that stromal expression was a major problem for techniques using pre‐coated plates. Nevertheless, the pattern of cumulative distribution of SF‐2 values is not significantly different for cultures characterized by fibroblast overgrowth. In conclusion, notwithstanding variations in fibroblast growth, the comparative analysis of data published so far on intrinsic radiosensitivity shows that similar distributions of individual survival parameter values are yielded in the laboratories involved in this research field. Nevertheless, further studies on culture characterization, using monoclonal antibodies and flow cytometry, should be carried out to quantify better the impact of fibroblast contamination on culture response to irradiation. © Wiley‐Liss, Inc.