Give full reference information

1. Give full reference information Decrease in actin gene expression in melanoma cells compared to melanocytes is partly counteracted by BrdU-induced cell adhesion and antagonized by L-tyrosine induction of terminal differentiation.Gomez LA, Rieber MS, Rieber M. 995Biochem and Biophys Res Comm 216:84-89 Bob Smith and Alicia Applegate Fall 2011

2. Purpose of study What factors are important to the metastasis of melanoma cells Key Question Do the effects of BrdU on cell shape involve changes to the actin cytoskeleton Purpose: is the broadest reason for performing the investigation Key Question: specific topic of the investigation

3. Experimental system • Used normal mouse melanocytes and B16 melanoma cells • Cultured • Studied effects of BruU and/or tyrosine on actin gene expression Description of the experimental system is broad and generally applies to all experiments in the study

4. Why do researchers study effects of BrdU? • Bromodeoxyuridine (BrdU) • Thymidine nucleoside analog • Causes mutations • Induced by UV radiation • Previous Studies have shown BrdU • Effects cell adhesion • Change melanocyte shape and invasiveness • Potential treatment? Give enough background information for your audience to understand key terms and concepts

5. Why is L-Tyrosine studied? • Amino Acid • Involved in melanin pigment synthesis - Characteristic of melanocytes • Induces differentiation of melanoma cells Supplement with relevant graphics whenever possible pdrhealth.com

6. In the following presentation of different experiments each section includes the relevant Methodology, Results, and Interpretations Avoid unnecessarily using slide titles like “Procedures” “Results” “Description” (especially big ugly titles that take up an entire slide or a large portion of one) Introduce each experiment with the specific question it seeks to answer It is generally obvious what will be procedures, results etc.

7. How did BrdU and tyrosine affect cell attachment? • To cultures of B16 melanoma cells were added: • BrdU, L-tyrosine, or BrdU + L-tyrosine • Treated cultures with trypsin to cause detachment No need for “Procedures” label – you can simply state it.

8. Results 1) % attachment reduced by BrdU 2) Effect inhibited or reversed by tyrosine Explanation: Tyrosine believed to cause differentiation of cells, reducing BrdU incorporation Combine Description of Results and Interpreations on same slide (whenever possible) State key results (above), and point out data in Figure to the audience as you do so. Explanations of results are essential.

9. How did BrdU and tyrosine affect actin gene expression? • BrdU, L-tyrosine or BrdU + L-tyrosine treated B16 • Compared to normal melanocytes • BrdU, L-tyrosine or BrdU + L-tyrosine • After 5 days • total RNA extracted • Ethidium bromide staining (total RNA) Actin mRNA • Actin mRNA identified with actin probe • Labeled with P32 • Northern blot performed • Autoradiaography and densitometry You must be very judicious in the level of detail included with procedures Include what is necessary for your audience to understand the results You can verbally add procedural details

10. Results C = untreated B16 mel = normal melanocytes Notice that Figures do not have lengthy legends, as would be found in original article You may need to supply a key to abbreviations (as above), but you should talk through rest of figure details EtBr stained actin mRNA

11. mel BrdU Quantification of mRNA expression data Notice additional labels added to this figure for clarity Northern blot subject to densitometry Results -- BrdU increased actin mRNA -- Tyr or BrdU + Tyr similar to control -- not as much mRNA as in normal cells • Explanation • Effect of BrdU is to increased actin mRNA expression in B16 • Reversed again by Tyr induced differentiation

12. How does UV light exposure effect actin mRNA expression? • BrdU treated cells exposed to UV light • Relative expression of actin mRNA • GAPDH mRNA used as a control

13. Results UV light treatment Increased the amount of actin expressed in the BrdU cells vs. the BrdU/UV cells. Explanation BrdU treated cells are more sensitive to UV light induced damage

14. Overall conclusions Effect of BrdU • BrdU affects actin cytoskeleton • BrdU increases actin gene expression • UV light affect Effect of tyrosine • cell differentiation • less cell division • less BrdU incorporation Thus, changes in gene expression may be important factor in melanoma metastasis The overall conclusions summarize findings for all experiments And indicate how those results relate back to broad purpose of the article

15. Critique of Investigation • Cell attachment methodology and measurements not clearly explained • Which type of actin is probed? • No statistical analysis performed • Medical significance of UV treatment is unclear • BrdU is a mutagen; thus seems unlikely candidate as drug Critique of the article reflects how well you really understand it. Avoid shallow critiques like: “It was confusing” “Not much background was given about…” “They did not explain their results…”

16. Overall Conclusions • BrdU exposed to UV light decreases actin expression • BrdU increases actin expression and cellular adhesion • L-tyrosine with BrdU decreases actin expression • Conclusions support idea that actin gene involved in melanoma growth.