Browsing by Author "Dhawan, Deepika"

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    A novel, safe, fast and efficient treatment for Her2-positive and negative bladder cancer utilizing an EGF-anthrax toxin chimera
    (Wiley, 2020) Jack, Sherwin; Madhivanan, Kayalvizhi; Ramadesika, Swetha; Subramanian, Sneha; Edwards, Daniel F., II; Elzey, Bennett D.; Dhawan, Deepika; McCluskey, Andrew; Kischuk, Erin M.; Loftis, Alexander R.; Truex, Nicholas; Santos, Michael; Lu, Mike; Rabideau, Amy; Pentelute, Bradley; Collier, John; Kaimakliotis, Hristos; Koch, Michael; Ratliff, Timothy L.; Knapp, Deborah W.; Aguilar, Ruben C.; Urology, School of Medicine
    Bladder cancer is the sixth most common cancer in the United States, and it exhibits an alarming 70% recurrence rate. Thus, the development of more efficient antibladder cancer approaches is a high priority. Accordingly, this work provides the basis for a transformative anticancer strategy that takes advantage of the unique characteristics of the bladder. Unlike mucin-shielded normal bladder cells, cancer cells are exposed to the bladder lumen and overexpress EGFR. Therefore, we used an EGF-conjugated anthrax toxin that after targeting EGFR was internalized and triggered apoptosis in exposed bladder cancer cells. This unique agent presented advantages over other EGF-based technologies and other toxin-derivatives. In contrast to known agents, this EGF-toxin conjugate promoted its own uptake via receptor microclustering even in the presence of Her2 and induced cell death with a LC50 < 1 nM. Furthermore, our data showed that exposures as short as ≈3 min were enough to commit human (T24), mouse (MB49) and canine (primary) bladder cancer cells to apoptosis. Exposure of tumor-free mice and dogs with the agent resulted in no toxicity. In addition, the EGF-toxin was able to eliminate cells from human patient tumor samples. Importantly, the administration of EGF-toxin to dogs with spontaneous bladder cancer, who had failed or were not eligible for other therapies, resulted in ~30% average tumor reduction after one treatment cycle. Because of its in vitro and in vivo high efficiency, fast action (reducing treatment time from hours to minutes) and safety, we propose that this EGF–anthrax toxin conjugate provides the basis for new, transformative approaches against bladder cancer.
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    Targeted elastin-like polypeptide fusion protein for near-infrared imaging of human and canine urothelial carcinoma
    (Impact Journals, 2022-09-06) Aayush, Aayush; Darji, Saloni; Dhawan, Deepika; Enstrom, Alexander; Broman, Meaghan M.; Idrees, Muhammad T.; Kaimakliotis, Hristos; Ratliff, Timothy; Knapp, Deborah; Thompson, David; Pathology and Laboratory Medicine, School of Medicine
    Cystoscopic visualization of bladder cancer is an essential method for initial bladder cancer detection and diagnosis, transurethral resection, and monitoring for recurrence. We sought to develop a new intravesical imaging agent that is more specific and sensitive using a polypeptide based NIR (near-infrared) probe designed to detect cells bearing epidermal growth factor receptors (EGFR) that are overexpressed in 80% of urothelial carcinoma (UC) cases. The NIR imaging agent consisted of an elastin like polypeptide (ELP) fused with epidermal growth factor (EGF) and conjugated to Cy5.5 to give Cy5.5-N24-EGF as a NIR contrast agent. In addition to evaluation in human cells and tissues, the agent was tested in canine cell lines and tissue samples with naturally occurring invasive UC. Flow cytometry and confocal microscopy were used to test cell-associated fluorescence of the probe in T24 human UC cells, and in K9TCC-SH (high EGFR expression) and K9TCC-Original (low EGF expression) canine cell lines. The probe specifically engages these cells through EGFR within 15 min of incubation and reached saturation within a clinically relevant 1 h timeframe. Furthermore, ex vivo studies with resected canine and human bladder tissues showed minimal signal from normal adjacent tissue and significant NIR fluorescence labeling of tumor tissue, in good agreement with our in vitro findings. Differential expression of EGFR ex vivo was revealed by our probe and confirmed by anti-EGFR immunohistochemical staining. Taken together, our data suggests Cy5.5-ELP-EGF is a NIR probe with improved sensitivity and selectivity towards BC that shows excellent potential for clinical translation.