Presentation by erica green dr ely biology 303 august 25 th 2011
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“Discovery Of Gene Ripple Effect Which Causes Cervical Cancer to Advance And Spread” May 19 th , 2011 Presentation By: Erica Green Dr. Ely Biology 303 August 25 th , 2011. Background Of News Article .

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“Discovery Of Gene Ripple Effect Which Causes Cervical Cancer to Advance And Spread”May 19th, 2011

Presentation By: Erica Green

Dr. Ely

Biology 303

August 25th, 2011

Background Of News Article

  • Research Scientists at Cambridge University have discovered that a common gene fault in cervical cancer cells triggers a ripple of molecular signals, which makes cervical cancer more aggressive.

  • The scientist increased and decreased the activity of the Drosha gene in cervical cancer cells.

  • They also discovered that when Drosha is present in greater quantities in cervical cancer cells that there is a change in the production levels of microRNAs (miRNAs).

Drosha Gene

  • Located on chromosome five.

  • Is overabundant in the majority of advanced cervical cancer tumors.

  • Cells require this gene to make tiny cell signaling molecules called miRNAs, which control the activity of hundreds of genes vital to life.

  • The changes in miRNAs levels can have the knock-on effect of triggering unusual behavior in hundreds of important cell signaling genes.

Location of Drosha gene: 5p13.3

-chromosome 5

-short arm

-region #1

-band #3

-sub-band #3

MicroRNAs & Cancer

  • MicroRNAs (miRNAs) are small, non-coding RNA molecules that inhibit gene expression post-transcriptionally, resulting in either the degradation or inhibition of translation of messengerRNA (mRNA).

  • Some miRNAs are thought to have oncogenic activity while others have tumor suppressor activity; some miRNAs may express either activity, depending on the situation and tissue type.

Cervical Cancer

  • Cancer that forms in tissues of the cervix. The cells of the cervix become abnormal and start to grow uncontrollably, forming tumors.

  • It’s almost always caused by human papillomavirus (HPV) infection.

  • Most of the time, early cervical cancer has no symptoms.

  • Benign growths (polyps, cysts, or genital warts).

  • Malignant growths (cervical cancer).

  • In the U.S., it is the fifth most common cancer among women aged 35-54, and the third most common cancer of the female reproductive tract.

  • U.S. 2011 New cases:12,710 and Deaths:4,290.

Journal Referenced

Functional evidence that Drosha overexpression in cervical squamous cell carcinoma affects cell phenotype and microRNA profiles

Muralidhar et al.

Article published May 18th, 2011


The Journal of Pathology

Volume 224, Issue 4, pages 496-507, August 2011

Introduction Key Points

  • They demonstrated that Drosha copy-number gain and overexpression occur frequently in cervical squamous cell carcinoma (SCC) samples and cell lines, and are associated with substantial differences in microRNA profiles, with increased levels of some microRNAs (the most significant being miR-31) and decreased levels of others.

  • Interestingly, Drosha overexpression in SCC of the esophagus correlates with metastasis and adverse survival, independently of tumor stage.

  • They demonstrate, using gene depletion/overexpression experiments, that alteration of Drosha levels in cervical SCC cells causes significant changes in cell phenotype in vitro and differential expression of key microRNAs.

  • Their data provides direct experimental evidence of the significance of Drosha overexpression in advanced cervical SCC.

Effects of Drosha depletion on cervical SCC cell migration in vitro.


Effects of Drosha depletion on cervical SCC cell invasion in vitro.

Phenotype rescue of the effects of Drosha depletion on SW756 cell invasion

Hierarchical clustering of global microRNA profiles in cervical SCC cells based on all 319 microRNAs on the array.

Hierarchical clustering based on the 45 differentially expressed microRNAs.

miR-31 expression levels in cervical SCC cell lines.

Discussion Key Points

  • Together, these experimental data indicate that Drosha may represent an important oncogene in cervical and potentially other SCCs.

  • Though Drosha is not the sole determinate of the phenotypes observed, findings do indicate that in cervical SCC cells where Drosha is overexpressed, the protein makes a significant contribution to cell motility/ invasion, via altered expression of cancer-related microRNAs that can affect large numbers of protein coding genes.

  • Future goal: Defining the role of specific microRNAs in cervical carcinogenesis, such as miR-31.

Why I Chose This Article?

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