2021 Fiscal Year Research-status Report
Novel viral noncoding RNAs in head and neck cancers
Project/Area Number |
20K18289
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Research Institution | University of the Ryukyus |
Principal Investigator |
小杉 隆誠 琉球大学, 医学部, 非常勤講師 (10867047)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | human papillomavirus / ncRNA (noncoding RNA) / head and neck cancer |
Outline of Annual Research Achievements |
High-risk types of human papillomaviruses (HR-HPVs) such as HPV16 and HPV18, are a significant causing agent of oropharyngeal cancers and understanding how their oncoproteins E6/E7 control multiple intracellular molecules for cellular transformation is vitally important. In short, the viral gene expression is the central trait of HPV-positive squamous cell carcinomas (SCCs) and therapeutic targeting of E6/E7 has primarily been pursued. However, what specific intracellular contexts reflect distinctive cancer phenotypes (such as cancer aggressiveness and chemo/radiotherapy resistance) in HPV-positive SCCs remain largely undefined. To unravel this issue will be demanded for developing more effective therapies for HPV-related SCCs. Uncovering structure and function of newly identified HPV-derived lncRNA in this research is expected to provide a significant clue for this type of issue. Expression analyses demonstrated that HPV lncRNAs exist in squamous cell carcinomas and their subcellular distribution patterns suggest that they function in the nucleus and may be associated with certain phenotypes of HPV-positive SCCs. Cell-based assays indicated differential expression patterns in distinct cellular conditions, suggesting that the lncRNAs may provide a certain intracellular environment inclined to maintain functional HPV oncoprotein expression in SCCs. Further analyses will identify the details and specific functions of the lncRNAs.
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Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
The proposed study aims to establish three primary goals, which are (1) structural identification of the viral ncRNAs, (2) functional characterization of the viral ncRNA expression, and (3) determination of functional roles of the viral ncRNAs in cancers (SCC). In the last two years, experiments for the goal (1) and (2) have continuously been performed and the data support the evidence that HPV lncRNAs are expressed in some (but not all) HPV-positive SCCs. This suggests that differential expression of HPV lncRNA may reflect distinct phenotypes of SCCs. Furthermore, cell-based assays mimicking in vivo cancer environments such as nutrition deprivation, hypoxic condition and genotoxic stress of HPV-positive SCCs revealed that their expression are not completely correlated with HPV oncogene expression and may rather be linked to some types of cellular stress responses. On-going and planned experiments will determine the details of the ncRNA function in SCCs.
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Strategy for Future Research Activity |
Results of cell-based assays characterizing HPV lncRNA expression suggested several candidate mechanisms reflecting some cancer phenotypes in which the lncRNAs may be involved. Therefore, planned experiments will assess functional roles of the lncRNA in these cellular contexts. In order to achieve this goal (goal (3)), the planned experiments involve knockdown of HPV lncRNA with antisense oligonucleotides (ASO) and siRNAs. In addition, the study needs to answer why some but not all HPV-positive SCCs express the lncRNAs. To achieve this, the experiments involve analyses to determine what specific intracellular environments enable the lncRNA to be expressed in cancer cells. Therefore, some epigenetic analyses (such as chromatin immunoprecipitation) will be conducted.
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Causes of Carryover |
Data from the goals (1) & (2) experiments are critical for successful experiments for the goal (3). For example, the experimental settings of RNA silencing such as choice of target sequences are completely dependent on the data from the goals (1) & (2). In addition, the goal (3) experiments such as RNA silencing and epigenetic analyses are the costliest experiments in this project. So, I needed to save the cost of the goals (1) & (2) experiments as much as possible but to gain significant information for the goal (3) experiments. Consequently, it took much more time to complete the goals (1) & (2) than previously expected. As such, I needed the significant amount of budget brought to the next year for the costly experiments.
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