sditelberg's blog

Regarding the liposome decorated with TAB004 and an antibody for CA 19-9 on the exterior and ONC201 along with another synergistic drug on the interior, blood tests for antigen biomarkers could be run and evaluated. The CA 19-9 radioimmunoassay (RIA) measures the amount of CA 19-9 in the blood (Pancreatic Cancer Action Network, 2019). CA 19-9 can either be bound to the surface of pancreatic adenocarcinoma cells or secreted by them, so this test can serve as a marker for treatment success. Changes in the levels of CA 19-9 in the blood would allow the researchers to assess the progression of the tumor and see if it is growing, shrinking, or maintaining its size. The normal CA 19-9 range in a healthy individual is 0-37 units per millimeter. Rising levels would indicate progression of the cancer, consistent levels would indicate the cancer has stabilized, and declining CA 19-9 levels would indicate shrinkage (Pancreatic Cancer Action Network, 2019). The researchers would assess this biomarker biweekly. An analogous test for MUC-1 will also be developed and performed by the researchers in an effort to fully assay the targeted treatment. An increase of MUC-1 in the blood would indicate growth, consistent levels would indicate stability, and decreasing levels would imply shrinkage of the tumor. The researchers would also like to develop a method to assess binding affinities of pancreatic adenocarcinoma-specific antigens to the respective antibodies in order to determine the efficacy of the treatment.

On page 25, there are a lot of differences between the two figure compilations created. I observe that the group on the left is smaller in size than the one on the right. The images of the flower in the compilation on the left have longer widths and shorter heights than the ones on the right. The image compilation on the right has labels in the top left corner of each image while the compilation on the left does not. The spacing between the images in each compilation is also different: the compilation on the left is more spaced while the one on the right is closer together. These could all be a result of lack of specificity when formatting the images on Inkscape. For example, the heights and widths of the image, as well as their spacing apart from each other, may not have been described in adequate detail.
There are also subtle differences between the two compilations that become apparent upon closer examination. In the compilation on the right, the image of the map has a slight blue background as opposed to the image of the map on the left, that has a white background. This causes the map on the left to blend into the background of the entire compilation. The map on the right also has less of Middle America highlighted in red than the image of the map on the left. These could also be due to a lack of specificity in formatting description, but could also just be a result of forgetfulness since the details are so minor.
The orientations of each image are also different between the two compilations. The image of the single flower on the left is more zoomed out and in a birds-eye-view orientation in comparison to the corresponding image on the right, which is more zoomed in and has a perspective set on the top and side of the flower. The image of the entire plant on the left is more zoomed out than the one on the right and includes more surroundings of the plant. The image of the entire plant on the right is slightly more zoomed in and oriented to the right. The last image of the map is zoomed in more on the right in comparison to the corresponding image on the left. These could all be due to height differences in the photographer or zoom capabilities of the camera. Perhaps there were different obstacles in the surrounding areas of each plant that caused this contrast in orientation of the images as well.

TNF-related apoptotic-inducing ligand (TRAIL) is a naturally-occurring cytokine that assists in initiating the extrinsic apoptotic process. TRAIL is a useful aspect of cancer therapy due to its death receptor binding properties for DR4 and DR5. This must be taken into account when engineering targeted treatments so normal, healthy tissue is not targeted and subsequently destroyed. ONC201, a hydrophilic small molecule, regulates the expression of TRAIL and can be put inside a liposome and transported into pancreatic adenocarcinomas. In an effort to regulate the specificity of this therapy, receptors as well as antibodies can be incorporated into the surface of the liposome that bind to pancreatic adenocarcinoma-specific antigens, such as MUC-1 and CA 19-9. In this way, a more resistant, targeted treatment for this cancer can be developed.

ONC201 also demonstrates synergistic effects with other cancer therapeutics to induce apoptosis in various types of cancers. In a study of glioblastoma, ONC201 synergized with ABT263 (Navitoclax), a small molecule inhibitor of the Bcl-2 protein family and BH3-mimetic, to induce apoptosis. Reduction of tumors were observed in vivo without any adverse side effects or toxicity (Karpel-Massler et al. 2015). In another study involving pancreatic adenocarcinoma, ONC201 activated both extrinsic (TRAIL-caspase-8-dependent) and intrinsic (caspase-9-dependent) apoptosis pathways while synergizing with gemcitabine, a common chemotherapy for this cancer, to inhibit Panc-1 xenograft growth in mice (Zhang et al. 2016). This combination therapy also increased the mice’s survivability.

During the winter season, I often walk by the campus pond on my way to classes along the path from the ILC to the Fine Arts Center. This path is typically surrounded by numerous flocks of geese feeding on grass, and I make multiple observations and inferences as I pass through. Regardless of my distance from the geese, I observe crescendos of honking as I walk along this path. On days I happen to pass closer to the flocks, I observe approximately one goose per flock stop feeding on the grass and crane its neck upwards. On days I pass further away from the flock, I do not observe this behavior. When this behavior occurs, the rest of the flock continues eating. I have also observed that if I make eye contact with this goose, some additional geese in the flock pause their feeding and start to turn towards me as well. From these objective observations, I infer that the goose craning its neck is in charge of the flock in some way, perhaps the alpha male, and is on guard in case I come too close.

ONC201, also called TIC10, is a small molecule inhibitor that is water soluble, orally bioavailable, and can cross the blood brain barrier. It functions as an Akt/ERK inhibitor and can assist in inhibiting apoptosis mediated by TRAIL. This makes it an intriguing factor for the treatment of pancreatic adenocarcinoma. Studies have also shown that ONC201 has a synergistic effect in vivo with ABT263, a Bcl-2 inhibitor in various types of cancers (2). Further research of pancreatic adenocarcinoma treatments show a beneficial synergistic interaction between ONC201 and gemcitabine, another chemotherapy (1). The researchers would like to expand on synergy between ONC201 and additional therapies to target pancreatic adenocarcinoma. The use of gemcitabine is not ideal as it is not specifically targeted to the cancer, and therefore may cause many adverse clinical side effects.

1. https://www.sciencedirect.com/science/article/pii/S0006291X16308142

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4742189/

Apoptosis can be activated extrinsically by both the TNF and Fas pathways. Ligands can bind to either the TNF receptor or the Fas receptor, which have different downstream elements. In the TNF pathway, binding of the TNF-alpha ligand to receptor 1 activates caspases via death domains. TNF-alpha binding can also lead to the activation of transcription factors that are expressed in apoptosis and the inflammatory response. In the Fas pathway, the binding of the Fas ligand forms the death inducing signaling complex, which includes caspases. The formation of this complex also activates a positive feedback loop that keeps the apoptotic process moving forwards. Understanding how apoptosis works both extrinsically and intrinsically is crucial to developing targeted cancer treatments that can induce these pathways in tumors.

Apoptosis can be activated through two pathways: intrinsic and extrinsic. When the cell is under stress, intracellular signals are released from the mitochondria, activating the intrinsic pathway. The extrinsic pathway's activation relies on ligands binding to extracellular death receptors. In the intrinsic pathway, second mitochondria-derived activator of caspases (SMACs) proteins are released into the cytosol and bind to proteins that inhibit apoptosis (IAPs), which inhibits them. Caspases can then be activated and apoptosis can proceed. Cytochrome c is also released from the mitochondria and binds to apoptotic protease activating factor 1 (APAF-1) and procaspase 9 to form the apoptosome, which subsequently activates caspase 3. The extrinsic pathway can be activated through TNF as well as Fas signaling, two pathways that activate transcription factors as well as caspases involved in the inflammatory response and apoptosis.

TNF-related apoptotic-inducing ligand (TRAIL), a naturally-occurring cytokine, assists in initiating the apoptotic process. TRAIL may be useful as a cancer therapy due to its death receptor binding properties for DR4 and DR5. This must be taken into account when engineering targeted treatments so normal, healthy tissue is not targeted and subsequently destroyed. TRAIL also binds to decoy apoptotic receptors such as DCR1 and DCR2, allowing for the activation of the inflammatory response and further leading the cell to apoptosis via transcription of specific genes. TRAIL may serve as part of a possible targeted treatment for pancreatic adenocarcinoma. If the protein can be transported to only cancerous cells via liposome and binding to extracellular cancer antigens, it may be able to assist in the design of an effective, holistic treatment for the patient.

Figure 1: Volvox. Volvox are a chlorophytic green algae that live in freshwater environments. They form spherical colonies of up to 50,000 and diverged from unicellular ancestors approximately 200 million years ago. Photo by Specious Reasons, available at: https://www.flickr.com/photos/28594931@N03/20108157326/