Presenter's Name(s)

Caroline AdamsFollow

Primary Faculty Mentor Name

Nicholas Farina

Project Collaborators

Nicholas Farina, Areg Zingiryan, Terri L. Messier, Jane B. Lian, Janet L. Stein, Gary s. Stein

Status

Graduate

Student College

Graduate College

Program/Major

Pharmacology

Primary Research Category

Health Sciences

Presentation Title

TsRNA in Aggressive Breast Cancer

Time

9:00 AM

Location

Silver Maple Ballroom - Health Sciences

Abstract

Breast cancer is highly prevalent in the United States with an estimated 260,000 women diagnosed with invasive breast cancer in 2018. There is a growing need to identify the molecular drivers of metastatic breast cancer as the molecular mechanisms responsible for the transition from normal mammary epithelial cells to aggressive cancer cells remain poorly understood. New knowledge about this transition may reveal a therapeutic target for aggressive breast cancer. Small, noncoding RNAs (ncRNA), such as microRNAs (miRNAs), have recently been discovered to promote initiation, progression, and metastasis of breast cancer. Similar in size to miRNAs, tRNA-derived small RNAs (tsRNAs) are a novel class of small ncRNA whose expression differentiates cancer types and cancer cell lines. TsRNAs are created during the maturation process of primary tRNA transcripts, where the 3-prime end of the tRNA is cleaved by RNaseZ, resulting in a 16-48 nucleotide long strand of RNA. Although similar in size to miRNA, the functions of tsRNA are largely unknown. We previously identified two tsRNAs, ts-2 and ts-112, that are expressed at 10-fold higher levels in the MCF10CA1a aggressive breast cancer cell line than in the normal-like MCF10A mammary epithelial cell line. Further, ts-2 and ts-112 are detected at similarly high levels in female human embryonic stem cells, displaying oncofetal expression. For these reasons, we hypothesized that ts-2 and ts-112 promote breast cancer characteristics. To test this hypothesis, we transfected custom inhibitors of ts-2 and ts-112 into MCF10CA1a cells in vitro. The following phenotypic assays were conducted to determine the function of ts-2 and ts-112 in the MCF10CA1a cell line: proliferation, cell cycle, and wound healing. The results of the proliferation assay following inhibitor transfection showed a 15-20% reduction in aggressive cancer cells. Population doubling time of ts-2 after inhibition increased 7% from 12 to 14 hours. Lastly the inhibition of ts-2 increased cell death by 7%. Ts-112 did not show as robust differences from negative controls. These results suggest that ts-2 may play a role in cell cycle progression. Following ts-112 inhibition, cell cycle analysis revealed that there was a decrease in the number of cells in G1 phase and subsequent increase in S phase. Using a candidate approach we analyzed the effects of ts-2 and ts-112 inhibition on G1/S phase and S/G2 phase checkpoints by qPCR. Inhibition of these tsRNAs showed no effect on the mRNA levels of candidates. Combined, these data support the hypothesis that ts-2 and ts-112 have a functional role in aggressive breast cancer. Analyzing the outcomes of ts-2 and ts-112 inhibition helps us to understand the molecular mechanisms that are responsible for aggressive breast cancer phenotypesThus, understanding the molecular mechanisms of tsRNA in metastatic breast cancer may lead to their use as a possible biomarker or therapeutic target.

This document is currently not available here.

Share

COinS
 

TsRNA in Aggressive Breast Cancer

Breast cancer is highly prevalent in the United States with an estimated 260,000 women diagnosed with invasive breast cancer in 2018. There is a growing need to identify the molecular drivers of metastatic breast cancer as the molecular mechanisms responsible for the transition from normal mammary epithelial cells to aggressive cancer cells remain poorly understood. New knowledge about this transition may reveal a therapeutic target for aggressive breast cancer. Small, noncoding RNAs (ncRNA), such as microRNAs (miRNAs), have recently been discovered to promote initiation, progression, and metastasis of breast cancer. Similar in size to miRNAs, tRNA-derived small RNAs (tsRNAs) are a novel class of small ncRNA whose expression differentiates cancer types and cancer cell lines. TsRNAs are created during the maturation process of primary tRNA transcripts, where the 3-prime end of the tRNA is cleaved by RNaseZ, resulting in a 16-48 nucleotide long strand of RNA. Although similar in size to miRNA, the functions of tsRNA are largely unknown. We previously identified two tsRNAs, ts-2 and ts-112, that are expressed at 10-fold higher levels in the MCF10CA1a aggressive breast cancer cell line than in the normal-like MCF10A mammary epithelial cell line. Further, ts-2 and ts-112 are detected at similarly high levels in female human embryonic stem cells, displaying oncofetal expression. For these reasons, we hypothesized that ts-2 and ts-112 promote breast cancer characteristics. To test this hypothesis, we transfected custom inhibitors of ts-2 and ts-112 into MCF10CA1a cells in vitro. The following phenotypic assays were conducted to determine the function of ts-2 and ts-112 in the MCF10CA1a cell line: proliferation, cell cycle, and wound healing. The results of the proliferation assay following inhibitor transfection showed a 15-20% reduction in aggressive cancer cells. Population doubling time of ts-2 after inhibition increased 7% from 12 to 14 hours. Lastly the inhibition of ts-2 increased cell death by 7%. Ts-112 did not show as robust differences from negative controls. These results suggest that ts-2 may play a role in cell cycle progression. Following ts-112 inhibition, cell cycle analysis revealed that there was a decrease in the number of cells in G1 phase and subsequent increase in S phase. Using a candidate approach we analyzed the effects of ts-2 and ts-112 inhibition on G1/S phase and S/G2 phase checkpoints by qPCR. Inhibition of these tsRNAs showed no effect on the mRNA levels of candidates. Combined, these data support the hypothesis that ts-2 and ts-112 have a functional role in aggressive breast cancer. Analyzing the outcomes of ts-2 and ts-112 inhibition helps us to understand the molecular mechanisms that are responsible for aggressive breast cancer phenotypesThus, understanding the molecular mechanisms of tsRNA in metastatic breast cancer may lead to their use as a possible biomarker or therapeutic target.