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Tumor-Busting Viruses
Current Issues in Biology, Volume 2
Scientific American
PowerPoint® Lectures
Lectures by April Lynch
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Concept Review
• How can doctors kill cancer cells without harming healthy
ones? Such targeted treatment is one of the biggest
challenges in cancer care.
• This image shows how cancerous cells intermingle with
healthy ones. Melanoma, or skin cancer cells, are shown in
green amid healthy cells, shown in red.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Concept Review
• A new answer may lie in virotherapy. This type of treatment
uses scientifically-engineered viruses to target cancer cells.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Concept Review
• Some viruses, such as engineered adenoviruses, show
promise at selecting and destroying cancer cells.
• They kill tumor cells by invading through unique receptors
on the surface of cancer cells, and then burst the cells open
or make them more vulnerable to traditional chemotherapy.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Concept Review
• Here are examples of cancer experiments involving
virotherapy.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Concept Review
• But more research is needed to prevent engineered
adenovirus therapies from having dangerous side effects.
• Normal adenoviruses are common, causing illnesses such
as colds. Many people could have immune systems already
primed to fight adenoviruses, and suffer severe immune
reactions from engineered ones.
• In 1999, an 18-year-old patient died after suffering a severe
immune reaction in an adenovirus experiment.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Testing Your Comprehension
What is virotherapy?
a)
b)
c)
d)
stimulating cancer tissue with sonic pulses
exposing patients to cold viruses to boost their immunity
applying engineered viruses to infect and kill cancer cells
putting patients in a pressure chamber during treatment
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Testing Your Comprehension
What is virotherapy?
c) applying engineered viruses to infect and kill cancer cells
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Testing Your Comprehension
Which of these structures would you not find in a virus?
a)
b)
c)
d)
mitochondrion
ribosome
nucleus
all of the above
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Testing Your Comprehension
Which of these structures would you not find in a virus?
d) all of the above
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Testing Your Comprehension
How do viruses selectively attach to target cells?
a)
b)
c)
d)
target cells display unique cell-surface receptors
target cells secrete unique identification proteins
viruses attach to specific materials engulfed by cells
viruses are not selective about target cells
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Testing Your Comprehension
How do viruses selectively attach to target cells?
a) target cells display unique cell-surface receptors
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Testing Your Comprehension
What would be the purpose of giving patients immunosuppressive drugs during virotherapy with adenoviruses?
a)
b)
c)
d)
adenovirus can damage a normal immune system
to hold the immune system in reserve after therapy
to minimize side effects caused by immune response
none of the above is correct
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Testing Your Comprehension
What would be the purpose of giving patients immunosuppressive drugs during virotherapy with adenoviruses?
c) to minimize side effects caused by immune response
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Biology and Society
If I were diagnosed with a deadly form of cancer, and were
offered the chance to join a virotherapy research trial, I’d be
willing to try this experimental therapy.
Strongly
Agree
A.
B.
C.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
D.
E.
Strongly
Disagree
Tumor-Busting Viruses
Thinking about Science
What would be important medical safety steps to include in a
research trial studying whether a certain brain cancer could
be fought with engineered adenovirus?
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Tumor-Busting Viruses
Interpreting Data and Graphs
Using this illustration
as a guide, describe
how an engineered
virus can infect and
kill a cancer cell,
while leaving a
healthy cell alone.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings