Biology subjects

Chatterjee, J.

Publications and source records attributed to Chatterjee, J..

7 recordsLinked to original sources

bioRxiv2026

Rational Redesign of an Fc-Binding Peptide for Multivalent Antibody Assembly

Multivalent antibody assemblies offer opportunities to enhance avidity, organize immune complexes, and modulate higher-order protein interactions, but constructing such architectures from existing immunoglobulin G (IgG) molecules without redesigning the antibody scaffold remains challenging. Here, we report the rational redesign of a Protein A-derived Fc-binding peptide into ADP1, a stable dimeric Fc-binding peptide that directs Fc-mediated antibody assembly. ADP1 was designed from the parent Fc-binding peptide Z34C by preserving the Fc-recognition surface while redesigning the opposite helical surface to promote peptide-peptide association. Biophysical characterization showed that ADP1 retained nanomolar Fc-binding affinity while exhibiting markedly enhanced chemical and proteolytic stability compared with the parent peptide. Structural analyses of ADP1-Fc complexes revealed that ADP1 bridges neighboring Fc regions through a combined ADP1-Fc and ADP1-ADP1 interface, generating spiral higher-order Fc assemblies. This assembly principle was further extended to full-length IgG, where ADP1 promoted higher-order antibody association in a concentration-sensitive manner. In addition, covalent ADP1 functionalization enabled Fc-directed modification of full-length IgG while retaining Fab-mediated antigen recognition, demonstrating the utility of ADP1 as an antibody assembly and functionalization module. Finally, competitive addition of the parent Z34C peptide modulated ADP1-driven antibody assembly, suggesting a potential route for tuning Fc-mediated assembly propagation. Together, this work establishes a redesigned Fc-binding peptide platform for directing multivalent antibody assembly and functionalization without genetic reengineering of the IgG scaffold. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=177 SRC="FIGDIR/small/737354v2_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@57cadeorg.highwire.dtl.DTLVardef@1c7d8e6org.highwire.dtl.DTLVardef@170fb85org.highwire.dtl.DTLVardef@90e6d6_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2026

Seizure-related gene 6 (SEZ6) encodes a Cancer stem cell-specific proangiogenic molecule: A novel glioma therapeutic target

Cancer stem-like cells (CSCs) not only initiate tumors but also orchestrate angiogenesis through multiple mechanisms, thereby sustaining vascularization and promoting tumor growth. In glioblastoma (GBM; WHO grade IV glioma), the most aggressive adult brain tumor, glioma stem-like cells (GSCs; glioma CSCs) are the main drivers of tumor progression, drug resistance, and recurrence. An interrogated multi-omic secretome analysis identified Wnt-{beta}-catenin signaling-regulated, membrane-localized Seizure Related 6 Homolog (SEZ6) as a patient-derived GSC-specific proangiogenic molecule. Silencing of SEZ6 inhibited the ability of the GSC secretome to induce angiogenic network formation by brain- and lung-derived endothelial cells, but not GSC growth as neurospheres in vitro. SEZ6 silencing also suppressed patient-derived GSC-initiated glioma tumors, resulting in reduced tumor vasculature in an orthotopic mouse model. We also found that SEZ6 induces TGF{beta}-dependent IL-8 expression in endothelial cells to promote angiogenesis. Coimmunoprecipitation and molecular dynamics simulation experiments determined that the Sushi 3 domain of SEZ6 mediates the interaction with TGF{beta} RII to activate the TGF{beta} pathway. Pharmacological inhibition of BACE1 with an in-house-developed small molecule, or blockade of the SEZ6-TGF{beta} RII interaction using a rationally designed peptide, markedly attenuated SEZ6-driven TGF{beta} signaling, and suppressed angiogenesis. Thus, our findings identify SEZ6 as a novel CSC-specific therapeutic target for GBM.

cancer biology↗

bioRxiv2026

Castration-resistant prostate cancer cells are addicted to the high activity of cyclin-dependent kinase 2

BackgroundCyclin-dependent kinases drive the progression through the cell cycle and thereby form classical targets for cancer therapy. In prostate cancer (PC), the first line of therapy typically targets androgen receptor (AR), but it frequently leads to development of incurable form of the disease, castration-resistant PC (CRPC). Here, we sought to understand if CRPC cells are selectively addicted to a specific cell cycle kinase. MethodsWe used PC and CRPC patient data to evaluate transcriptional changes and modeled the responses in vitro using multiple models of PC, CRPC and normal cells. Development of a CDK2 inhibitor-resistant CRPC cell line, and a compound screen were used to identify chronic and acute vulnerabilities to augment the efficacy of our candidate therapy in multiple PC, CRPC and also normal cells, to assure selectivity. ResultsWe show that the emergence of CRPC is associated with significant upregulation of cyclins that positively regulate cyclin-dependent kinase 2 (CDK2) and downregulation of CDK4 cyclins. Accordingly, CDK2-specific inhibitors and its knock down efficiently reduce proliferation of PC and CRPC cells. CDK2 inhibitor-resistant CRPC model displayed transcriptional rewiring of cell cycle regulators, characterized by a shift towards CDK4/6-dependency and increased AR-signaling. Combinatorial drug screen discovered both antagonistic and additive combinations, and we show that AR inhibitors selectively augment the efficacy of CDK2 inhibitors against PC and CRPC cells, but the combination is not toxic to normal cells. ConclusionWe discovered that CRPC cells are addicted to high CDK2 activity and show that combination of CDK2 inhibitors with the currently used anti-CRPC therapies selectively augment their efficacy.

cancer biology↗

bioRxiv2025

Calcitonin-Driven Reactivation of the Hippo Tumor-Suppressor Cascade Attenuates YAP/TAZ Oncogenic Signaling in Glioblastoma

Activation of WT calcitonin receptor (WT CTR) by Calcitonin (CT) acts as growth inhibitory axis in GBM, while the patient-derived loss-of-function CTR mutants promote tumor growth and lower patient survival. The precise mechanisms that orchestrate CTR activation, modulate its downstream signaling dynamics, and give rise to structural anomalies in mutant variants remain incompletely defined and warrant comprehensive investigation. Here, we found that salmon CT treatment suppressed the growth of patient-derived glioma stem cells (GSCs) by activating the Hippo pathway through the CTR/cAMP/PKA/LATS1 signaling cascade, while simultaneously inhibiting the oncogenic YAP/TAZ transcription factors. However, GSCs expressing a phosphorylation-resistant YAP mutant were refractory to growth inhibition by CT in vitro. GSCs, unlike differentiated glioma cells (DGCs), expressed high levels of CTR thus making them suitable for CT-based therapy. Furthermore, the intranasal delivery of salmon CT inhibited glioma growth initiated by GSCs in an intracranial orthotopic mouse model, resulting in increased survival in the mice. In addition, unlike the WT, the CTR mutants failed to activate the Hippo pathway. A large-scale, microsecond-long all-atom molecular dynamics simulation study of mutant CTR systems revealed remarkable changes in CTR interactions with the CT and G-GTPase domains. Packing and conformational dynamics data from simulation studies of the WT and mutant CTR systems could explain the perturbed cAMP/PKA signaling that may compromise downstream signaling. Together, we demonstrate that the CT/CTR axis inhibits glioma by activating the Hippo pathway, provide evidence for the structural defects in the loss-of-function CTR mutants, and propose a CT-based therapeutic strategy for GBM. Statement of significanceCT/CTR axis targets YAP/TAZ through Hippo pathway activation. Patient-derived GSCs express higher CTR levels, and intranasally delivered CT suppresses GSC-initiated tumors. All-atom molecular dynamics simulation uncovers structural perturbations in the CTR mutants.

cancer biology↗

bioRxiv2025

Development of Severity Index for Oral Epithelial Dysplasia Using Fuzzy Group Decision Making Algorithm

BackgroundOral epithelial dysplasia (OED) grading suffers from several levels of uncertainties and imprecision. An index is preferred in this context to improve reliability and reduce subjectivity in diagnostic decision making. In this study, a fuzzy logic-based disease severity index (SI) is formulated considering standard histopathological features used in OED grading. MethodsOral onco-pathologists were asked to independently provide weights of different features, according to their clinical significance in the context of dysplasia. Aggregated weight of each feature was calculated from individual assessment of different onco-pathologists by a fuzzy logic-based group decision making algorithm. Confidence levels of experts were also included to improve robustness of the method. SI was generated by integrating abnormality score of each feature with its weight. Abnormality degree of each feature was expressed in linguistic terms by onco-pathologists which were subsequently represented by a triangular fuzzy number. Fuzzy membership function was used as it can capture the ambiguity of experts opinion regarding abnormality of individual feature. Finally, defuzzification was used to get a crisp index from weighted sum of all features. ResultSI was found to be statistically different (p<0.01) for different grades of dysplasia i.e mild, moderate and severe with added advantage of stratifying each grade in low and high subcategory. ConclusionKey contribution of our work is that we have developed a fuzzy logic-based group consensus process regarding weights of histopathological features for OED grading. Present methodology of developing SI can be applied to other medical decision-making problems as well. HighlightsO_LIA severity index is proposed to improve reproducibility of oral epithelial dysplasia grading. C_LIO_LIClinical significance of each histopathological and cytopathological feature in the context of dysplasia is reflected by its weight. C_LIO_LIA fuzzy logic-based group decision making algorithm is used to reduce subjectivity of features weights. C_LIO_LIConfidence level of oral onco-pathologists are given due importance in derivation of aggregated weight of each feature. C_LIO_LIAbnormality score of each feature is evaluated in fuzzy scale to capture clinicians ambiguity. C_LIO_LIPresent methodology may be useful for developing indices of other diseases. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/633806v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@5a5e28org.highwire.dtl.DTLVardef@dba3a9org.highwire.dtl.DTLVardef@1d5cc7corg.highwire.dtl.DTLVardef@16404b5_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

cancer biology↗

bioRxiv2022

A Single Multipurpose FSH-Blocking Therapeutic for Osteoporosis and Obesity

Pharmacological and genetic studies over the past decade have established FSH as an actionable target for diseases affecting millions, notably osteoporosis, obesity and Alzheimers disease (AD). Blocking FSH action prevents bone loss, fat gain and AD-like features in mice. We recently developed a first-in-class, humanized, epitope-specific FSH blocking antibody, MS-Hu6, with a KD of 7.52 nM. Using a GLP-compliant platform, we now report the efficacy of MS-Hu6 in preventing obesity and osteoporosis in mice, and parameters of acute safety in monkeys. Biodistribution studies using 89Zr-labelled, biotinylated or unconjugated MS-Hu6 in mice and monkeys showed localization to bone, bone marrow and fat depots. MS-Hu6 displayed a {beta} phase t[1/2] of 13 days (316 hours) in humanized Tg32 mice, and bound endogenous FSH. We tested 215 variations of excipients using the protein thermal shift assay to generate a final formulation that rendered MS-Hu6 stable in solution upon freeze-thaw and at different temperatures, with minimal aggregation, and without self-, cross-, or hydrophobic interactions or appreciable binding to relevant human antigens. MS-Hu6 showed the same level of "humanness" as human IgG1 in silico, and was non-immunogenic in ELISPOT assays for IL-2 and IFN{gamma} in human peripheral blood mononuclear cell cultures. We conclude that MS-Hu6 is efficacious, durable and manufacturable, and is therefore poised for future human testing as a multipurpose therapeutic.

pharmacology and toxicology↗

bioRxiv2017

Optical Coherence Tomography Reveals Mechanobiologically Stable Self-Organizing Di-Fork Architecture of Mice Cutaneous Scars

Scientific studies report crucial impacts of biomechanical effectors to modulate wound healing either by scarring or regeneration. Further, the biological decision to predominantly favor the former is still cryptic. Real-time visualization of biomechanical manifestations in situ in scarring is hence necessary. Endorsed by nanostructural testing, synthetic phantom analysis, and computational simulations, we found strong mechanobiological correlates for Swept Source Optical Coherence Tomography (SS-OCT) speckles in mice cutaneous repair (full-thickness) up to 10 months. The theoretical basis of the optomechanics to provide insights into scar form-factor and evolution is proposed. Optomechanical changes have been considered as the resultant of intrinsic (e.g. fiber elastic modulus) and gross tissue mechanics (extracellular matrix (ECM)) in maturing scars. Non-invasive optomechanics supported with microscopic findings reveal scars cross-sectional self-organizing di-fork architecture. Dual-compartment heterogeneity of di-fork exhibits stress-evading features with a dichotomy in inhabitant cellular stress-fiber distributions. This differential interactivity of scar with adjoining tissues reflects its architectural intelligence to compensate tissue loss (hypodermis/muscle) by assembling into a di-fork. Gradual establishment of baseline shifted lasting mechanobiological steady-state, later in scarring, expose scar as an alternate stable state within the skin. Significance StatementWound repair in mammals, predominantly culminates into function compromising scar that is occasionally fatal in vital organs. How the biological system often adopts scarring over a restorative regeneration is yet a conundrum. Wound and ambient mechanics play a pivotal role in deciding the healing fate. SS-OCT is hence demonstrated here as a non-invasive window to such mechanical manifestations during skin wound healing. This exposed gradual emergence of temporally maintained and stress-resilient di-fork architecture of the scar with differential neighborhood interfaces. Accommodation of such an alternate self-organizing steady-state of scar sheds light on its sustenance and paradoxical selection.

biophysics↗