# Presentation: 191800

## Hunting a Killer

- Cell Biologist Yuri Lazebnik: *Pursuing the Roots of Cancer *

## Yuri Lazebnik Fuses Cells

*Cell biologist Lazebnik explores links between cell fusion and cancer.*

*Cell Fusion*
- Is rare in most healthy cells
- Can cause genetic changes
- May be linked to cancer

*Question:*
- What is another name for cell suicide?

## Answer: Apoptosis

**Apoptosis under normal conditions**

- Sculpts fingers and toes
- Streamlines nerve connections in brain during development

- Removes old, worn-out cells from the body

- During development

- Throughout lifetime

## Hunting Down a Serial Killer

- Cancer cells
- Move into neighboring tissues
- Damage or shut down vital organs
- Can be deadly
- Don’t die off like normal cells do

- What makes cancer cells act like they do?

## Investigation Guided by Surprise

**David Rubenstein, a high school student working in Lazebnik’s lab as part of Cold Spring Harbor Laboratory’s *****Partner’s for the Future***** program, sets up an experiment with a normal cell and a cancer-prone cell.**

**The experiment yielded a surprise finding: new cells that appeared to be fused together.**

**Rubenstein repeats the experiment and gets the same results.**

**Lazebnik starts investigating cell fusion**

## Cell Fusion

- Only five known examples of healthy cell fusion
- Fertilized eggs are the only fused cells that continue to divide
- Sometimes, healthy cells accidentally fuse

**Name the five known examples of healthy cell fusion.**

**What would happen if other healthy fused cells continued to divide?**

**Do accidentally fused cells continue to divide?**

## Spontaneous Cell Fusion

- Some cancerous and cancer-prone cells
- Do not avoid cell fusion like normal cells
- Readily merge together
- Continue to reproduce
- Could be the cause of diversity of cells with unpredictable characteristics in tumors

## What Makes Cells Fuse?

- Fluorescent microscope

**Lazebnik and Duelli investigate genes and molecules in fused cells**

**Hypothesis:** **The virus might trigger cell fusion. **

**Hypothesis:** **Some of the mutations can chart a course toward cancer.**

**Observation #2:** **Fused cells develop genetic changes, or mutations.**

**Observation #1:** **Cancer-prone cells squirt out a virus that causes an AIDS-like disease in monkeys.**

## Viruses Can Make Cells Fuse

**Measles and mumps viruses cause a type of cell fusion**
**Also seen in some types of cancer**
**Don’t continue to divide; die and are reabsorbed by the body**
**≥****10%**** cancers at least partially caused by viruses**
**Human papillomavirus (HPV)**
**Hepatitis B and C**
**Epstein-Barr virus (mononucleosis, or “mono”)**

- What are syncytia?

- Is there a link between viruses and cancer?

## Questions About Viruses

- Do all cancer-causing viruses turn into cancer?
- No.  Only 1-2% of women with HPV develop cervical cancer.
- Can scientists prevent virus-caused cancers by developing vaccines against the viruses?
- In some cases, yes.  Vaccines already exist for HPV and hepatitis B.

- What factors other than viruses contribute to cancer?
- Do viruses cause some of our cells to fuse?
- Does cell fusion cause, or contribute to, cancer?

**What We Know**

**What We Don’t Know**

## Research Applications

- What are the implications of using viruses as vehicles to deliver genes or medications to specific tissues if such a strategy relies on cell fusion?