Biology subjects

Ahan, R. E.

Publications and source records attributed to Ahan, R. E..

6 recordsLinked to original sources

bioRxiv2025

Developing Anti-EGFR/Anti-HER2 Bifunctional Antibody for Solid Tumors by Protein Engineering

Overexpression of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) is common in solid tumors like breast, colorectal, and head and neck cancers, driving oncogenic signaling, therapy resistance, and poor prognosis. Monotherapies often fall short in fully suppressing tumor progression, particularly in cases with EGFR/HER2 co-amplification. Dual-targeting strategies offer enhanced efficacy by mitigating resistance and amplifying antitumor responses. Our study focused on developing and characterizing a bispecific anti-EGFR/HER2 antibody designed to simultaneously block ligand binding and receptor activation while harnessing Fc-mediated immune effector functions. Utilizing knob-into-hole and CrossMab technologies, we engineered a bispecific antibody capable of binding the extracellular domains of both EGFR and HER2. In vitro analyses confirmed its dual-binding capacity. Comparative studies revealed that this bispecific construct outperformed its monospecific counterparts in suppressing proliferation and, notably, in increasing the expression of apoptotic markers in EGFR/HER2-expressing tumor cells. Together, these findings highlight the synergistic therapeutic potential of bispecific antibodies as a promising modality for overcoming the limitations of current monotherapies. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/696462v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@192972corg.highwire.dtl.DTLVardef@102f9b2org.highwire.dtl.DTLVardef@57377corg.highwire.dtl.DTLVardef@1fbeb9d_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2025

Engineering butyrate-producing Lachnospiraceae to treat metabolic disease

Engineering native gut bacteria offers a route to persistent, programmable therapeutics, yet many dominant taxa remain genetically intractable. Lachnospiraceae are a prevalent and abundant family in the human gut microbiome, possessing metabolic functions generally associated with health1. Despite their promise as engineered live biotherapeutics, genetic manipulation of Lachnospiraceae remains challenging. Here, we develop a modular toolkit for Lachnospiraceae engineering, including constitutive and inducible expression and chromosomal integration systems. Applying this toolkit to the native commensal Coprococcus comes, we program secretion of the mammalian cytokine interleukin-22 (IL-22) in the mouse intestinal tract where it elicits ileal transcriptional responses consistent with cytokine signaling. In a mouse model of metabolic associated steatotic liver disease, IL-22-secreting C. comes improves glucose homeostasis and attenuates hepatic steatosis. This work demonstrates that a native Lachnospiraceae chassis can be genetically programmed to modulate host metabolic and immune physiology. The toolkit provides a generalizable foundation for Lachnospiraceae-derived microbiome therapeutics and for probing causal links between Lachnospiraceae gene programs and host phenotypes.

synthetic biology↗

bioRxiv2023

A Synthetic Protein Secretion System for Living Bacterial Therapeutics

Bacteria species can thrive and colonize different parts of the human body. Those naturally residing at disease sites e.g., tumors and gut can be designed for targeted protein delivery which can provide better clinical profiles for protein-based therapies. Therefore, a generalizable, efficient, and safe protein secretion system would a be valuable tool to engineer therapeutically active microbes, especially for gram-negative species due to the presence of the second cell wall. Here, we propose an approach called iLOM-SS, an acronym for inducible Leaky Outer Membrane based Secretion System, to secrete proteins in gram-negative bacteria (GNB). In iLOM-SS, the outer membrane of GNB is made permeable by transient suppression of structural protein(s) to enable free diffusion of cargo proteins expressed at the periplasm. To validate this approach, an iLOM-SS is constructed in Escherichia coli Nissle 1917 (EcN) strain. Proteins including enzymes and a human cytokine were proven to be secreted with iLOM-SS by EcN in vitro. Further characterizations of iLOM-SS in ECN showed that fast and titratable secretion, a stop switch design for secretion, and functional implementation of the secretion system in different genetic circuit architectures were possible. We foresee that this work will pave the way for designing GNB to secrete proteins for diverse arrays of applications including but not limited to the development of sentinel cells for therapeutic purposes.

synthetic biology↗

bioRxiv2023

A Bacterial Living Therapeutics with Engineered Protein Secretion Circuits To Eliminate Breast Cancer Cells

Cancer therapy can be limited by potential side effects, and bacteria-based living cancer therapeutics have gained scientific interest in recent years. However, the full potential of bacteria as therapeutics has yet to be explored due to engineering challenges. n this study, we present a bacterial device designed to specifically target and eliminate breast cancer cells. We have engineered Escherichia coli (E. coli) to secrete a Shiga toxin, HlyE, which is a pore-forming protein that binds to HER2 receptors on breast cancer cells. This binding is facilitated by a nanobody expressed on the bacterias surface via the Ag43 autotransporter protein system. Our findings demonstrate that the nanobody efficiently binds to HER2+ cells in vitro, and we have utilized the YebF secretion system to secrete HlyE and kill the target cancer cells. Overall, our results highlight the potential of our engineered bacteria as an innovative strategy for breast cancer treatment.

synthetic biology↗

bioRxiv2023

Synergistic Screening of Peptide-Based Biotechnological Drug Candidates for Neurodegenerative Diseases using Yeast Display and Phage Display

Peptide therapeutics are robust and promising molecules for treating diverse disease conditions. These molecules can be developed from naturally occurring or mimicking native peptides, through rational design and peptide libraries. We developed a new platform for the rapid screening of the peptide therapeutics for disease targets. In the course of the study, we aimed to employ our platform to screen a new generation of peptide therapeutics candidates against aggregation prone protein targets. Two peptide drug candidates for the protein aggregation prone diseases namely Parkinsons and Alzheimers diseases were screened. Currently, there are several therapeutic applications that are only effective in masking or slowing down symptom development. Nonetheless, different approaches are developed for inhibiting amyloid aggregation in the secondary nucleation phase, which is critical for amyloid fibril formation. Instead of targeting secondary nucleated protein structures, we tried to inhibit monomeric amyloid units as a novel approach for halting disease-condition. To achieve this, we combined yeast surface display and phage display library platforms. We expressed -synuclein, amyloid {beta}40, and amyloid {beta}42 on yeast surface, and we selected peptides by using phage display library. After iterative biopanning cycles optimized for yeast cells, several peptides were selected for interaction studies. All of the peptides have been used in vitro characterization methods which are QCM-D measurement, AFM imaging, and ThT assay, and they have yielded promising results in order to block fibrillization or interact with amyloid units as a sensor molecule candidate. Therefore, peptides are good choice for diverse disease-prone molecule inhibition particularly those inhibiting fibrillization. Additionally, these selected peptides can be used as drugs and sensors to detect disease quickly and halt disease progression. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=77 SRC="FIGDIR/small/536742v1_ufig1.gif" ALT="Figure 1"> View larger version (18K): org.highwire.dtl.DTLVardef@50c81dorg.highwire.dtl.DTLVardef@181fea5org.highwire.dtl.DTLVardef@17539c7org.highwire.dtl.DTLVardef@1244a00_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2021

A Highly Potent SARS-CoV-2 Blocking Lectin Protein

COVID-19 pandemic effected more than 180 million people around the globe causing more than four million deaths as of July 2021. Sars-CoV-2, the new coronavirus, has been identified as the primary cause of the infection. The number of vaccinated people is increasing however prophylactic drugs are highly demanded to ensure a secure social contact. There have been a number of drug molecules repurposed to fight against Sars-CoV-2, however the proofs for the effectiveness of these drug candidates is limited. Here we demonstrated griffithsin (GRFT), a lectin protein, to block the entry of the Sars-CoV2 into the Vero6 cell lines and IFNAR-/-mouse models by attaching to spike protein of the Sars-CoV-2. Given the current mutation frequency of the Sars-CoV-2 we believe that GRFT protein-based drugs will have a high impact in preventing the transmission both on Wuhan strain as well as any other emerging variants including delta variant causing high speed spread of COVID-19.

biochemistry↗