Abstract 4082: U6 upregulation in cancer

Abstract

Abstract Background: U6 snRNA is a non-coding RNA that is a component of the splicesome, which is involved in RNA splicing of the pre-mRNA. In view of the critical function performed by U6 snRNA in RNA splicing and therefore cellular proliferation, it is possible that U6 would play a role in cancer development. In this study, U6 levels were examined across various tumor types. Methods: Detection of U6 snRNA in various normal and tumor tissue was performed with Tissue Microarray by In Situ Hybridization technique. The 5′-DIG-labeled U6 LNA probe (sequence 5′-CACGAATTTGCGTGTCATCCTT-3′) from Exiqon was used for this study and the Vector Red was used as substrate. The U6 stained tissue microarray was then scanned by GenePix 6.0 (Molecular Devices) at 532 nm to detect the staining intensity from each tissue sample. Each sample on the TMA was also visually scored by the intensity on a scale of 0 to 4. A quantitative real-time PCR assay was also used to confirm the overexpression of U6 snRNA in breast and other cancers. Results: A baseline study using tumor microarrays and visual scoring suggested that U6 snRNA levels were increased in tumors relative to normal tissues. This was confirmed using the rapid U6 snRNA ISH for colon carcinoma, melanoma, pancreatic carcinoma, renal carcinoma, and lung carcinoma. In all cases, U6 levels were significantly elevated in tumor versus normal by t-test. By RT-PCR, U6 snRNA levels were also found to be increased relative to the corresponding normal tissue in carcinoma of the breast, colon, kidney, liver, lung, and ovary. No increase over the corresponding normal tissue was found in prostate and thyroid carcinomas. In breast carcinoma, there was no correlation between U6 snRNA levels and estrogen receptor status, progesterone receptor status or erb-B2 expression levels. Conclusions: Using a scanning system and tumor tissue array, we were able to demonstrate the use of microarray scanner to quantitate ISH signal. Application of this technology to U6 snRNA demonstrated that U6 is significantly elevated in most cancer types examined. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4082.