Related Experiment Video

Updated: Jun 13, 2026

An In Vitro Protocol for Evaluating MicroRNA Levels, Functions, and Associated Target Genes in Tumor Cells
09:45

An In Vitro Protocol for Evaluating MicroRNA Levels, Functions, and Associated Target Genes in Tumor Cells

Published on: May 21, 2019

MicroRNA let-7 suppresses nasopharyngeal carcinoma cells proliferation through downregulating c-Myc expression

Thian-Sze Wong1, On-Ying Man, Chi-Man Tsang

  • 1Department of Surgery, Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, China. thiansze@graduate.hku.hk

Journal of Cancer Research and Clinical Oncology
|May 5, 2010
PubMed
Abstract

Insights

The microRNA let-7 family shows anti-proliferative effects in nasopharyngeal carcinoma (NPC) cells by downregulating c-Myc. DNA methylation may regulate let-7 expression in NPC, but further research is needed.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • Nasopharyngeal carcinoma (NPC) is a cancer with complex molecular underpinnings.
  • MicroRNAs (miRNAs) are key regulators of gene expression implicated in various cancers.
  • The let-7 miRNA family is known to play roles in cell differentiation and proliferation.

Purpose of the Study:

  • To evaluate the anti-proliferative potential of the let-7 miRNA family in NPC cells.
  • To investigate the association between let-7 suppression and DNA hypermethylation in NPC.

Main Methods:

  • Real-time quantitative PCR to measure let-7 family member levels in normal and NPC cells.
  • Cell proliferation assays and c-Myc immunohistochemical staining after transfecting NPC cells with let-7 precursors.
  • Assessing let-7 expression changes following treatment with demethylating agents (5-azacytidine and zebularine).

Main Results:

  • Reduced levels of let-7 family members (let-7a, -b, -d, -e, -g, -i) were observed in NPC cells compared to normal nasopharyngeal cells.
  • Ectopic expression of let-7 in NPC cells inhibited proliferation and downregulated c-Myc.
  • Demethylation treatment activated let-7 expression specifically in poorly differentiated NPC cells.

Conclusions:

  • The let-7 miRNA family may function as a tumor suppressor in NPC proliferation.
  • DNA methylation is a potential mechanism influencing let-7 expression in NPC.
  • Further investigation is required to fully understand the role of DNA methylation in regulating let-7 in NPC.

More Related Videos

Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library08:40

Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library

Published on: April 6, 2012

Related Concept Videos

MicroRNAs01:22

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns (non-coding regions of a gene) or intergenic regions (stretches of DNA present between genes). Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself, forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA...
MicroRNAs01:22

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA ends...
MicroRNAs01:22

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA ends...
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
Experimental RNAi02:15

Experimental RNAi

RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by suppressing its transcription or activating the RNA degradation process. The mechanism was discovered by Andrew Fire and Craig Mello in 1998 in plants. Today, it is observed in almost all eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. This precise cellular mechanism of gene silencing has been developed into a technique that provides an efficient way to identify and determine the...
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...