One Microarray Helps to Treat Brain Cancer in a Unique Way (Day 2)!

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Objective

Students will utilize and develop models of Microarray Technologies to differentiate gene activity between cancerous cells and healthy cells in the brain.

Big Idea

Microarrays help to specify gene expression activity in cells, and thus, posesses the potential for doctors to prescribe specific medical tracks for individuals with brain cancer.

Introduction

Lesson Background & Justification: 

        Cancer, also known as a malignant tumor, is a group of diseases involving abnormal  cell growth with the potential to invade or spread to other parts of the body. Not all tumors are cancerous; benign tumors do not spread to other parts of the body. Brain and spinal cord tumors in particular may be either benign (not cancer) or malignant (cancer). However, since neurons generally cease cellular division after early childhood, cancer ensues in the actively dividing cells in the Brain and CNS (eg. Glial cells) which advances into abnormal growing/dividing masses or tumors. In this lesson "Microarray, etc.", the second half of a two part lesson (Lesson 1) aims to introduce students to the genetic and molecular activities  activities which distinguishes cancer cells from normal cells in the body. It helps to reinforce and expound the experiences that students has in the first lesson. 

Essential Prior Knowledge: Prior to experiencing this lesson, students should be familiar with the following content/concepts: a) Structure and Function of DNA, b) Cell Structure and Function, c) Cellular Division and Cancer development basics.

Lesson Preparations:

In the effort to prepare for this lesson, I make certain that I have the following items in place: 

a) 1 Class Set of Edvotek's Microarray Simulation Lab Kit Materials 

b) Student lab books.

c) A class set of hand held UV wands

Common Core and NGSS Standards:

HS-LS1-1- Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

HS-LS3-2- Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

HS-LS1-4-Use a model to illustrate the role of cellular division (mitosis) and differentiation in producing and maintaining complex organisms. 

SP2- Developing and using models.  

SP4- Analyzing and interpreting data.

SP8- Obtaining, evaluating, and communicating information. 

Standards Rationale:

      Modeling is the process by which scientists represent ideas about the natural world to each other, and then collaboratively make changes to these representations over time in response to new evidence and understandings. It is intimately connected to other scientific processes (asking questions, communicating information, etc.) and improves students ability to recall scientific jargon through association. In the classroom, it is important that teachers engage students in modeling practices, to set the foundation of success in a lesson or instructional unit. In this lesson modeling is used in concert with other science practices in the classroom to promote students’ reasoning and understanding of core science idea presented (evaluating the genetic underpinnings of cancer cells.)  

Engage and Review

20 minutes

Section Sequence:

a) Slide 1: Ask students to share their last definition of cancer from the previous lesson. Allow at least 4-5 students to share their definitions.

b) Then, ask the class why their definitions changed over the course of last period. Ask them to specifically to provide statements or characteristics that helped them to refine their definitions that can be used to fill in the venn diagram on the screen. Direct them to the images on the left to help them to uniquely classify each type of cell and to provide overlapping qualities as well.

c) Slide's 2-3: Review the general stages of the cell cycle using the image on slide 2 and layer it with specific molecular events that maintain the cycle using the image on slide 3. Ask: What if any of these maintenance events or molecules could lead to cancer if they are disrupted? Discuss as a class and provide leading questions for students if they seem stammered. (eg. What do you think would happen if p53 was dysfunctional in the cell? What are some downstream consequences? Could this lead to cancer as we defined it?)

d) Slide 4: Ask students to think about what cancer is and to consider if cancer is possible in the brain. Instruct for them to refer to their brain development timelines (from a previous lesson) and pinpoint the time when your brain stops making neurons. Once students, avail this answer ask "If cancer is the abnormal growth or division of cells, how can an adult like the young man in the video develop brain cancer if brain cells stop growing (with some exceptions of synpatic terminal development) and dividing at an early stage in life?" Take responses from the class. 

e) Present the images on slide four and ask students to consider that the following images represents the diversity of cells in brains. Review the functions of the cells and ask if they think that any could become cancerous. Discuss as a class. Once responses emerge such as glia cells or astrocyctes (those cells that function as support cells and have to replenish), confirm their responses and move on. 

f) Project the Classification scheme for brain tumours (Image A, page 783) within the Brain Tumors and Microarray Article and help students to understand the schematic, specifically how to target which cells in the brain can become cancerous (their names end in -oma). Finally, share or iterate that the case study watched at the beginning of the lesson reflects a young man with Astrocytoma. 

Standards Covered:

HS-LS1-1- Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

HS-LS1-4-Use a model to illustrate the role of cellular division (mitosis) and differentiation in producing and maintaining complex organisms. 

SP2- Developing and using models.  

SP4- Analyzing and interpreting data.

SP8- Obtaining, evaluating, and communicating information. 

Extend

60 minutes

Section Primer:

         A DNA Microarray is a collection of microscopic DNA spots attached to a solid surface. Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously. Each DNA spot contains a specific DNA sequence, known as probes, which hybridizes onto a complimentary expressed gene strand (on the surface) and is usually detected and quantified by detection of chemo-luminescence-labeled targets to determine relative abundance of nucleic acid sequences in the target. In this section of the lesson, students simulate this technology to evaluate the genetic activity of tumor cells and normal cells in the brain. 

Section Sequence:

a) Slide 5: Ask: "Now that we know which cells in the brain that are capable of leading to tumors in the brain, how do we know that it is cancerous?" Allow students to provide suggestions (encourage them to use some of their observations made in the previous lesson). Exhaust all possibilities and suggest (if not suggested), examining the genetic underpinnings of these cells. Ask "But how do we look at these genes and their activities easily?". 

b)Provide students with a copy of the Brain Tumors and Microarray Article abstract (page 782) and grant them 3-5 minutes to read it. Ask "How can we better understand the genetics of a brain tumor?". Once DNA microarray and an explanation of how it helps are offered, move to the next step. 

c) Project the Box 1 DNA Micoarray Image (page 784) from the Brain Tumors and Microarray Article and talk students through the overall microarray process. Then use the image on slide 5 to provide more specifics to the process. Share that we will simulate this process to assess fictional patients with brain tumors to see if their tumors are potentially cancerous.  

d) Slide 6: Provide student pairs with lab materials and request that they record their patient # in their lab books alongside the drawn strip as it appears on the screen. Explain the division of control and experimental groups on the screen/test strip. Read and describe the role of the genes that are being tested for and provide students with instructions (pages 8-9) on how to execute the lab. (See Structuring & Labeling Microarray Example)

e) After students record the results of their own strips, instruct them to switch out different test strips with other partner sets, visualize and record their results. Continue until all four patients results are documented. Students should observe the following results and make the following implications (with specific focus on red or tumor data):

Patient 1: The brain cells (glia or astrocytes) have active oncogenes and is attempting to reverse DNA damage. See Microarray Results 1

Patient 2: The brain cells (glia or astrocyteshave active oncogenes and is attempting to reverse DNA damage. See Microarray Results 1

Patient 3: The brain cells (glia or astrocytes) have no active cancer related genes. See Microarray Results 1 

Patient 4: The brain cells (glia or astrocytes) have no active cancer related genes. See Microarray Results 1

f) Slide 7: Instruct students to complete the questions projected on the screen. Review responses as a class to ascertain students comprehension and implications of the test results. If students results somehow different, allow students to discuss the results as presented in their data. See Microarray Results 2

Standards Covered:

HS-LS1-1- Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

HS-LS3-2- Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

HS-LS1-4-Use a model to illustrate the role of cellular division (mitosis) and differentiation in producing and maintaining complex organisms. 

SP2- Developing and using models.  

SP4- Analyzing and interpreting data.

SP8- Obtaining, evaluating, and communicating information. 

Evaluate

10 minutes

Section Sequence:

a) Slide 7: Instruct students to revisit their last set of characteristics that defined cancer and normal cells and to update their criteria based on the results of their tests or at least expected results (if the results produces any type of discrepancies). 

b) Slide 8: Instruct students to produce their final definition of cancer based on their collections of evidences from both day 1 and day 2 of the lesson. 

Standards Covered:

HS-LS1-1- Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

HS-LS3-2- Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

HS-LS1-4-Use a model to illustrate the role of cellular division (mitosis) and differentiation in producing and maintaining complex organisms. 

SP4- Analyzing and interpreting data.

SP8- Obtaining, evaluating, and communicating information.