AP Biology class blog for discussing current research in Biology

Author: cytokatiesis

In First, Scientists Use CRISPR for Personalized Cancer Treatment

Behold, have researchers found a groundbreaking method to fight tumors? Could genome-edited immune cells finally provide a way to defeat cancer?

In a recent clinical trial, immune cells were modified by CRISPR gene editing to recognize mutated proteins specific to tumors. When released into the body, the cells could target and kill the specific tumor cells. This cancer research utilized gene editing and T-cell engineering.

The trial involved 16 individuals who suffered from solid tumors (including breast and colon cancer). The results were published in Nature by Heidi Ledford and then presented on November 10, 2022 in Boston, Massachusetts at The Society for Immunotherapy of Cancer conference. The findings were later released in Scientific American.

According to Antoni Ribas, a co-author of the study and a cancer researcher and physician at the University of California, Los Angeles, ” It is probably the most complicated therapy ever attempted in the clinic.” He describes the process as “trying to make an army out of a participant’s own T cells.”

To begin the study, Ribas and his colleagues ran DNA sequencing on each patient’s blood sample and tumor biopsies. The goal was to identify unique mutations of the timer, but not present in the blood. Ribas notes that these mutations differ across different types of cancer, with only a few being shared. Then using algorithms, Ribas’s team predicted which mutations were the most likely to initiate a response from the T cells(a type of white blood cell that functions to notice and destroy irregular cells); however, immune systems rarely destroy cancerous tumors. With that being said, the team used CRISPR gene editing to insert designated t-cell receptors that recognized the tumor. Patients were given medication to reduce normal immune cells before the researchers infused the engineered cell.

Joseph Fraietta, who specializes in designing T-cell cancer therapies at the University of Pennsylvania in Philadelphia, describes the process as “tremendously complicated”, for some cases could take more than a year to complete in certain cases.

Each individual in the study received T cells engineered to target up to three sites, and after some time, the concentration of the engineered T cells was higher than the average T cells in the bloodstream near the tumors. A month after the treatment, five participants’ tumors had not progressed, and only 2 showed evidence of T-cell activity.

While the treatment’s effectiveness was limited, Ribas notes that a small dose of T cells was used at first and stronger doses would be proven more effective. Fraietta feels “The technology will get better and better.”

Although engineered T cells, also known as CAR T cells, were approved to treat certain blood and lymphatic cancers, CAR T cells only target proteins that are present on the surface of tumor cells, and According to Fraietta, no surface proteins have been discovered in solid tumors. Additionally, tumor cells may suppress immune responses by releasing immune-suppressing chemical signals and consuming local nutrient supplies to promote their rapid growth.

Researchers are hopeful to engineer T cells to not only recognize cancer mutations but also to become more active in the vicinity of the tumor. Potential techniques include ” removing the receptors that respond to immunosuppressive signals, or by tweaking their metabolism so that they can more easily find an energy source in the tumor environment,” as Heidi Ledford, writes in her article. With advances in CRISPR technology, researchers anticipate revolutionary ways of engineering immune cells in the next ten years.

In AP Biology this year, we learn about the Immune system. This topic is specifically related to the adaptive, or pathogen-specific, Immune response. T Lymphocytes, or T cells for short, are a part of the cell-mediated immune response where T-cells can identify, and kill infected or cancerous cells, while also preventing reinfecting.

How Diet Builds Better Bones: Surprising Findings on Vitamin D, Coffee, and More

Vitamins might seem like the key to those who want strong bones; however, studies have recently shown it vitamins contribute, but other foods you may never have known are helping.

Many women have a condition known as osteoporosis or osteopenia, both of which relate to bone weakening or bone loss. Claudia Wallis wrote in her article in Scientific American that around 20% of women aged 50 and up have osteoporosis, and more than 50% suffer from osteoporosis. Notably, men have lower cases of these bone-weakening conditions(4% develop osteoporosis, and 33% develop osteopenia). Many adults over 50 also develop an osteoporotic fracture ( a fracture in one hip, wrist, or vertebra). Wallis feels a cause for these high cases is the misunderstanding about what diet and supplements contribute.

One reason is the inconsistency in nutrition and bone health studies. Our bones are always changing and constantly replenishing themselves, so accurate data on bone health is hard to find. Calcium is the crucial nutrient involved in building bones. Vitamin D then allows the gut to absorb calcium from our food. Therefore, doctors recommend people take vitamin D supplements to treat and maybe prevent the bone loss that comes with aging.

Surprisingly, this past summer New England Journal of Medicine discovered that taking vitamin D over 5 years showed no reduction in the rates of fractures in adults aged 50 and older in a huge study. Research conducted by the same team showed that vitamin D supplements did not affect improving bone density. As a matter of fact, the study showed vitamin d did not improve the risk of cancer or heart disease either.

Following these significant findings, theNew England Journal of Medicine published an article stating that medical professionals need to put an end to ordering unnecessaryblood tests on vitamin D levels. Leader of the study, Meryl LeBoff of Brigham and Women’s Hospital in Boston told Scientific American, “Food and incidental sun exposure likely provide enough vitamin D for healthy adults.” However, she noted that the study was not done on patients who had osteoporosis in the past, and for some people, it is smart to continue taking vitamin D and calcium supplements.


For the majority of people, calcium-rich food help maintains strong bones. LeBoff feels the best source of calcium is food, for she stated, “because there are so many other nutrients, and you have a more continuous absorption than with a pill.” One unusual source of calcium if from coffee. Although over consuming coffee can have harmful effects(over six cups of coffee can cause calcium to be lost in urine), a moderate about could overall benefit your bones. Ching-Lung Cheung of Hong Kong University said “Coffee intake, if not excessive, should be safe for bone,” he says, “and if you still have concerns, add milk! He led a study that showed that people who drink have a greater bone density in their upper thigh bone and lumbar spine. Alcohol is the same way in that moderate intake will promote strong bones, but excessive drinking can disrupt hormones that promote healthy bones.

Overall, the best way to take care of your bones is to live a healthy lifestyle incorporated with a balanced diet, and exercise. Weight-bearing exercises boost healthy bone formation all through your lifetime. You don’t have to stress about it though; just make sure you’re moving your body and making nutritious choices and your bones won’t cause you any bone-breaking problems.

In AP Biology this year, we talked about feedback loops and how they function to maintain the regulation of homeostasis and how hormones and feedback loops function in the body’s endocrine systems. When you break or fracture a bone, your body uses hormones to stimulate a feedback loop to reinforce a stimulus that leads to the replenishment of the bone.

Got a weird COVID-19 symptom? You’re not alone

COVID-19 is one of the most commonly known diseases of the decade, for most people today are familiar with its many symptoms, including chills, cough, difficulty breathing, etc. Rarely, SARS-CoV-2 will affect people in ways not expected by a respiratory virus; however, people are starting to see it cause odd symptoms. Peter Chin-Hong, an infectious diseases physician at the University of California, San Francisco said that people have developed patchy tongues, puffy digits, and hair loss as a result of SARS-CoV-2.  Chin-Hong still notes that these symptoms may be less dangerous because they are capable of going away on their own.

It is not always confirmed that COVID tongue, COVID toe, COVID eye, or other strange symptoms are due to COVID-19, but the large scale of coronavirus infections means that SARS-CoV-2 has many chances to show the public how it affects people differently. The U.S. announced they already have had 98 million cases confirmed, and Chin-Hong informed Science New that “statistically speaking, you’re going to find people with more and more weird things.” 

In October, the  Journal of Medical Case Reports released a study done by Saira Chaughtai, an Internal medicine doctor, after a patient obtained unbelievable symptoms after ten days of testing positive for COVID-19. Their tongues swell up and eventually erupted in white-ringed lesions. Chaughtai told Science News “I was like, ‘Oh my god, COVID can do anything.'”

Chin-Hong has also seen patients with unusual tongues; however, they had that looked “as if they’d chewed a mouthful of tortilla chips.”  

Changhai was perplexed about how she was going to treat her patients with COVID tongue. She began by researching scientific literature while giving her patients various types of mouthwash to help in the meantime. She even went to such great lengths in teaming up with a sports medicine doctor who shined a low-level laser light on patients’ tongues, a photobiomodulation therapy normally used to treat muscle injury. Chaughtai thought laser light therapy could heal swollen tongues because it increases blood flow. It showed good results as her patient’s tongue lesions healed even though she still feels some sensitivity. 

Another abnormal effect of COVID-19 is COVID finger or toe which causes swelling in peoples’ fingers or toes. The symptoms also included toes or fingers turning a pink, red, or purplish color. It is know to be very painful. Michael Nirenberg of Friendly Foot Care has seen at least 40 people with this symptom who have been exposed to the coronavirus. He found that fingers or toes will normally heal within a couple of months. Nirenberg told his patient to apply nitroglycerin ointment which he thinks increases blood flow to their fingers or toes. 

“We can’t predict who’s going to get what,” Chin-Hong states, for he feels people should be aware that COVID-19 is capable of causing a wide variety of symptoms. He noted that strange symptoms occur mainly with unvaccinated people. “If this is a reason why some people might get vaccinated,” Chin-Hong says, “I think that would be great,” for these symptoms may seem less severe and harmful as symptoms involving the heart or lungs, but they still can be alarming to see. 

In AP Biology this year, we discussed how there are specific receptor proteins integrated into the plasma membrane. The binding between the receptor protein and a ligand, or signaling molecule, is highly specific. Recent studies found that SARS-CoV-2 enters the cell through a specific receptor protein called ACE2. SARS-CoV-2 spike binds to its receptor human ACE2 (hACE2) and an enzyme called proteases activates it. We also talked about enzymes in AP Biology; they are proteins that function and set off reactions or processes. It is important to understand how the unfamiliar virus enters into cells to learn more about its influence on the human body; this can help scientists discover more information on how and why these strange symptoms occur.

Are Skittles Toxic from Titanium Dioxide?



A lawsuit came out in recent months that made claims of the chemical titanium dioxide, a toxin known to scientists being found in a popular candy, Skittles. A consumer filed a suit against Skittles manufacturer, Mars, for titanium dioxide is now a banned chemical according to the European Union. However, in many countries, such as the United States and Canada, titanium dioxide is still considered to be safe to consume. There still needs to be regulations put about the amount of the chemical that can be found in food, but in limited amounts, many think it is relatively harmless in small doses. Toxicologists who are studying the chemical found research indicating that using chemicals. Agnes Oomen, a senior scientist at the Netherlands’ National Institute for Public Health and the Environment, told Scientific American that saying we’re not certain that it’s safe is very different from saying it’s unsafe.” When the European Union placed the ban on titanium dioxide, they were just being overly cautious.

What is Titanium dioxide? It is a white powder that is used as a pigment in many candies and other consumer items, such as makeup and paints. Titanium dioxide is good at scattering visible light. This causes products that contain the chemical a brighter and more vibrant color. What raised skepticism for consumers was the fact that Titanium dioxide is also used in many sunscreens because it is an efficient barrier to ultraviolet light.

The United States Food and Drug Administration had deemed the chemical safe in food, but it still must be a regulated amount of not being able to be more than 1% by weight of the product. In contrast, Europe is going through a period of “great detox”, for the European Food Safety Authority (EFSA), an organization that researches the risks of foods, is banning many chemicals previously found in products. In 2021, EFSA found in a report that titanium dioxide can be genotoxic. That means the drug could alter genetic materials such as DNA. This possibility is what causes the EFSA to ban the use of titanium dioxide in products. Oomen participated in making the report about titanium dioxide saying the decision “is on the cautious side.” The European Union’s decision to ban the chemical was based on a slight possibility that titanium dioxide is harmful, for there has been no evidence so far that proves it could cause people any significant dangers.

Saji George, from McGill University, said researchers are “ missing other big parts of the picture. There are so many other things that could be happening with small, consistent amounts of titanium dioxide in a diet over a long period of time.” Along with his colleagues, they recently discovered that the chemical could amplify allergies to some proteins in foods, making titanium  dioxide still a concern. George also mentioned that the studies done on titanium dioxide were done mainly on rates, not humans. “We don’t know how titanium dioxide could enhance certain diseases—for example, inflammatory bowel disease in people with preexisting conditions,” he states. This just goes to show there is still a lot we don’t know about the drug.

Oomen agrees with the European Union’s decision to ban the use of titanium dioxide because researchers have not made any conclusive findings that confirm if the drug is safe or could be harmful. She feels there needs to be a more suitable method to study the chemical. Norb Kaminski, director of the Institute for Integrative Toxicology at Michigan State University said “I think that titanium dioxide in the amount that it’s used in Skittles and food products is of no toxicological concern or health concern to the public. There’s just not the evidence to support that currently.”

This topic relates to our most recent unit in Biology because one of the concerns regarding titanium dioxide involved the alteration of DNA. We learned about DNA in this unit when we learned about organic compounds. DNA is one of the nucleic acids we learned about when we studied different organic compounds. DNA functions to store all our hereditary information, and it plays an essential role in our cells. Also, that titanium dioxide had the potential to cause allergies to proteins found in certain foods. We learned about protein being another organic compound vital to the cell. We learned about all the different functions of proteins that are crucial for all cells to function properly.


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