Antisense RNA-mediated inhibition of gene expression was used to investigate the biological function of the c-raf-1 gene in a radiation-resistant human squamous carcinoma cell line, SQ-20B. S1 nuclease protection assays revealed that transfection of full-length raf complementary DNA in the antisense orientation (AS) leads to a specific reduction (greater than tenfold) of steady-state levels of the endogenous c-raf-1 sense (S) transcript in SQ-20B cells. In nude mice, the malignant potential of SQ-20B cells transfected with raf (S) was significantly increased relative to that of SQ-20B cells transfected with raf (AS). SQ-20B cells containing transfected raf (S) maintained a radiation-resistant phenotype as compared to those cells harboring the AS version, which appeared to have enhanced radiation sensitivity. These data indicate that the reduced expression of endogenous c-raf-1 is sufficient to modulate the tumorigenicity and the radiation-resistant phenotype of SQ-20B cells, thus implicating c-raf-1 in a pathway important to the genesis of this type of cancer.
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http://dx.doi.org/10.1126/science.2466340 | DOI Listing |
Toxicol Rep
February 2016
Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, 228 ERML, MC-051, 1201 W. Gregory Drive, Urbana, IL 61801,USA.
cell proliferation, cell cycle arrest and induction of apoptosis were investigated, using three human head and neck squamous cell carcinoma (HNSCC) cell lines (OSCC-3, SCC-61, and SQ-20B). Aqueous extracts of , , and were tested and (-) epigallocatechin-3-gallate (EGCG) was used for comparison. For EGCG the IC values were between 80 and 166 μM and for the extracts among 75 and 505 μM eq.
View Article and Find Full Text PDFInt J Oncol
May 2013
Department of Pathology and Cell Biology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa 903-0215, Japan.
Head and neck squamous cell carcinoma (HNSCC) is the sixth most common non-skin cancer worldwide. Despite improvement in therapeutic strategies, the prognosis of advanced HNSCC remains poor. The extacellular lipid mediators known as lysophosphatidic acids (LPAs) have been implicated in tumorigenesis of HNSCC.
View Article and Find Full Text PDFMol Cancer Ther
October 2010
Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, Illinois, USA.
The number of targeted small molecules being developed in oncology is increasing rapidly. Many of these are designed to inhibit multiple kinases, and thus the mechanisms of responsiveness and predictive biomarkers can be difficult to discern. In fact, with few exceptions, multi-kinase inhibitors are developed with limited mechanism-based patient selection.
View Article and Find Full Text PDFInt J Mol Med
January 2010
Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki 300-0394, Japan.
A group of histone deacetylase (HDAC) inhibitors has been shown to suppress the growth of a variety of human tumor lines in vitro and in vivo and they are among the most promising candidates for anti-cancer therapeutic agents. We investigated the ability of scriptaid, a novel HDAC inhibitor and trichostatin A (TSA) to enhance cell killing by radiation in radioresistant SQ-20B cells derived from human head and neck squamous carcinoma. SQ-20B cells were treated with scriptaid or TSA in combination with radiation.
View Article and Find Full Text PDFInt J Radiat Oncol Biol Phys
November 2009
Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60657, USA.
Purpose: To experimentally validate how temporal modification of the applied dose pattern within a single fraction of radiation therapy affects cell survival.
Method And Materials: Using the linear-quadratic model, we have previously demonstrated that the greatest difference in cell survival results from comparing a temporal dose pattern delivering the highest doses during the middle of a fraction and the lowest at the beginning and end ("Triangle") to one with the lowest doses at the middle and the highest at the beginning and end ("V-shaped"). Also, these differences would be greatest in situations with low alpha/beta and large dose/fraction and fraction length.
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