Ihab Abd-Elrahman

Transcriptomic analyses of public datasets (TCGA and GTEx) revealed that both CD74 and Cathepsin L (CTSL) are significantly overexpressed in diffuse large B-cell lymphoma (DLBCL) compared to normal tissues, and that their expression levels are highly correlated to each other (Spearman R = 0.64, p = 3 × 10⁻⁴⁶). Kaplan–Meier analysis showed that elevated expression of both genes is associated with reduced overall survival (OS), defining a high-risk CD74+/CTSL+ DLBCL subgroup. This is the first study demonstrating coordinated overexpression of CD74 and CTSL and proposing their dual targeting via antibody–drug conjugates (ADCs) to improve outcomes in relapsed or refractory DLBCL. Cysteine cathepsins, a family of proteases, are upregulated in many cancers, facilitating tumor invasion and metastasis. Cathepsins are overexpressed and play key roles in DLBCL progression. GB111-NH₂, a potent broad-spectrum cathepsin inhibitor, significantly reduced cathepsin activity in lymphoma cell lines and patient samples. GB111-NH₂ treatment increased apoptosis and caspase-3 activation in DLBCL patient cells and chronic lymphocytic leukemia (CLL) mononuclear cells. Here, we developed a modified cathepsin inhibitor, M-GB, containing a maleimide linker for site-specific antibody conjugation. While M-GB alone has poor cell permeability, when conjugated to an antibody, it forms an ADC (M-GB–ADC) that selectively induces lymphoma cell death. One M-GB–ADC demonstrated high specificity for CD74-expressing lymphoma cells while exhibiting minimal toxicity to non-target cells in vitro. Our findings highlight the potential of another M-GB–ADC as a targeted therapy for overcoming rituximab resistance and treatment failure in DLBCL. This strategy enhances therapeutic efficacy and represents a preclinical proof-of-concept treatment option by directing a cathepsin-inhibitor payload specifically to malignant B cells.

Transcriptomic analyses of public datasets (TCGA and GTEx) revealed that both CD74 and Cathepsin L (CTSL) are significantly overexpressed in diffuse large B-cell lymphoma (DLBCL) compared to normal tissues, and their expression levels are highly correlated (Spearman R = 0.64, p = 3×1046). Kaplan–Meier analysis showed that elevated expression of both genes is associated with reduced disease-free survival (DFS), defining a high-risk CD74+/CTSL+ DLBCL subgroup. This is the first study demonstrating coordinated overexpression of CD74 and CTSL, and proposing their dual targeting via antibody–drug conjugates (ADCs) to improve outcomes in relapsed or refractory DLBCL. Cysteine cathepsins, a family of proteases, are upregulated in many cancers, facilitating tumor invasion and metastasis. Cathepsins are overexpressed and play key roles in DLBCL progression. GB111-NH₂, a potent broad-spectrum cathepsin inhibitor, significantly reduced cathepsin activity in lymphoma cell lines and patient samples. GB111-NH₂ treatment increased apoptosis and caspase-3 activation in DLBCL patient cells and chronic lymphocytic leukemia (CLL) mononuclear cells. Here, we developed a modified cathepsin inhibitor, M-GB, containing a maleimide linker for site-specific antibody conjugation. While M-GB alone has poor cell permeability, when conjugated to an antibody, it forms an ADC (M-GB-ADC) that selectively induces lymphoma cell death. M-GB-ADC demonstrated high specificity for CD74-expressing lymphoma cells while exhibiting minimal toxicity to non-target cells. Our findings highlight the potential of M-GB–ADC as a targeted therapy for overcoming rituximab resistance and treatment failure in DLBCL. This strategy enhances therapeutic efficacy and provides a treatment option by directing a cathepsin inhibitor payload specifically to malignant B cells.

Drug resistance remains a major obstacle in cancer treatment despite advances in therapeutic regimens. To address this, we explored the potential of Doxorubicin (Dox) delivery in poly (lactide-co-glycolic acid) (PLGA) nanoparticles to enhance Diffuse large B-cell lymphoma (DLBCL) cell death. This research investigates the potential of Doxorubicin and advanced delivery methods. We used PLGA nanoparticles with Oleyl cysteineamide (OCA); its amphiphilic nature enables interfacial anchoring and thiol surface functionalization of PLGA NPs. Compared to PLGA-NPs, PLGA-OCA-NPs enhance immunity and induce tumor cell death. They also show significant apoptotic cell death and induced immune responses in DLBCL mouse models. Dox-conjugated PLGA-OCA-NPs (DOX-OCA) exhibit significant in vitro and in vivo anticancer activity compared to free DOX, showing remarkable antitumor effects with reduced systemic toxicity in mouse models. Our findings underscore the promising potential of PLGA-OCA-NPs in DLBCL treatment, offering a hopeful future in cancer therapy. This innovative delivery system offers enhanced immune responses and effectively addresses toxicity concerns, marking a significant step forward in cancer therapy.

Drug resistance remains a major obstacle in cancer treatment despite advances in therapeutic regimens. To address this, we explored the potential of Doxorubicin (Dox) delivery in poly (lactide-co-glycolic acid) (PLGA) nanoparticles to enhance DLBCL cell death. This research investigates the potential of Doxorubicin (Dox) and advanced delivery methods. We used poly (lactide-co-glycolic acid) (PLGA) nanoparticles with Oleyl cysteine amide (OCA); its amphiphilic nature enables interfacial anchoring and thiol surface functionalization of PLGA NPs. Compared to PLGA-NPs, PLGA-OCA-NPs enhance immunity and induce tumour cell death. They also show significant apoptotic cell death and induced immune responses in DLBCL mouse models. Dox-conjugated PLGA-OCA-NPs (DOX-NPs) exhibit significant in-vitro and in-vivo anticancer activity compared to free DOX, showing remarkable antitumor effects with reduced systemic toxicity in mouse models. Our findings underscore the promising potential of PLGA-OCA-NPs in DLBCL treatment, offering a hopeful future in cancer therapy. These innovative delivery systems offer enhanced immune responses and effectively address toxicity concerns, marking a significant step forward in cancer therapy.

We previously showed that Livin, an inhibitor of apoptosis protein, is specifically cleaved to produce a truncated protein, tLivin, and demonstrated its paradoxical proapoptotic activity. We further demonstrated that mini-tLivin (MTV), a 70 amino acids derivative of tLivin, is a proapoptotic protein as potent as tLivin. Based on these findings, in this study we aimed to develop a venue to target MTV for the treatment of diffuse large B-cell lymphoma (DLBCL). MTV was conjugated to poly (lactide-co-glycolic acid) surface-activated nanoparticles (NPs). In order to target MTV-NPs we also conjugated CD40 ligand (CD40L) to the surface of the NPs and evaluated the efficacy of the bifunctional CD40L-MTV-NPs. In vitro, CD40L-MTV-NPs elicited significant apoptosis of DLBCL cells. In a disseminated mouse model of DLBCL, 37.5% of MTV-NPs treated mice survived at the end of the experiment. Targeting MTV-NPs using CD40L greatly improved survival and 71.4% of these mice survived. CD40L-MTV-NPs also greatly reduced CNS involvement of DLBCL. Only 20% of these mice presented infiltration of lymphoma to the brain in comparison to 77% of the MTV-NPs treated mice. In a subcutaneous mouse model, CD40L-MTV-NPs significantly reduced tumor volume in correlation with significant increased caspase-3 activity. Thus, targeted MTV-NPs suggest a novel approach to overcome apoptosis resistance in cancer.

Despite the common use of lipid-lowering medications, cardiovascular diseases continue to be a significant health concern. Atherosclerosis, one of the most frequent causes of cardiovascular morbidity, involves extensive inflammatory activity and remodeling of the vascular endothelium. This relentless inflammatory condition can ultimately give rise to clinical manifestations, such as ischemic heart disease or stroke. Accumulating evidence over the past decades implicates cysteine protease cathepsins in cardiovascular disorders. In particular, Cathepsins B, L, and S are over-expressed during vascular inflammation, and their activity is associated with impaired clinical outcomes. Here we took advantage of these molecular events to introduce a non-invasive detection and treatment approach to modulate vascular inflammation using a Photosensitizing quenched Activity-Based Probed (PS-qABP) that targets these proteases.

We found that Livin, an Inhibitor of Apoptosis Protein, is specifically cleaved to produce a truncated Livin protein (tLivin) and demonstrated the paradoxical pro-apoptotic activity of tLivin. mini-tLivin (mtLivin) is a 70 aa derivative of tLivin that remarkably, exhibits a pro-apoptotic activity as potent as tLivin. Our findings regarding tLivin and mtLivin suggest unique therapeutic avenue against cancer. To improve the delivery and efficacy of mtLivin for treatment we conjugated mtLivin-to nanoparticles (NPs) of poly (lactide-co-glycolide) (PLGA) and targeted the nano-delivery system to diffuse large B-cell lymphoma (DLBCL) using CD40L. Delivery of mtLivin with nanoparticles should enhance stability, provide prolonged bioavailability, intracellular uptake and efficacy. We generated bifunctional mtLivin-CD40L-NPs to target mtLivin-NPs to DLBCL cells. Various cell lines were used to evaluate the biological activity of free and conjugated (targeted or not) mtLivin including 293T, 721.221 B cells, L428 Hodgkin's lymphoma, OCI-LY19 DLBCL cells and OCI-LY19- GLuc cells that constitutively express a gaussia luciferase reporter. Targeted, bifunctional mtLivin-CD40L-NPs elicited significant cell death of DLBCL cells while monofunctional mtLivin-NPs had a lower effect. mtLivin-NPs may induce cell death of some cell lines without targeting (e.g. 293T) yet targeting is required to induce marked cell death of DLBCL cells. To best mimic lymphoma disease in humans, a disseminated lymphoma model was used to evaluate the antitumor effect of targeted mtLivin treatment. NOD/SCID mice were injected with OCI-LY19- GLuc cells or into the tail vein. Gaussia luciferase reporter allows IVIS imaging to monitor tumor size and location in mice. Mice were treated approximately once a week with various mtLivin-NPs formulations. Luciferase signal was observed as early as day 2 after tumor cells injection. Immunohistochemistry for anti-CD20, a human B-cell marker, showed infiltration of OCI-ly19-Gluc cells in spleen and brain close to tumor cells injection (Day 2). With time, lymphoma infiltrations were detected in brain, bone marrow, lungs, spleen and liver. All control mice exhibited paralysis and did not survive beyond 28 days. In contrast, 37.5% of animals receiving mtLivin-NPs and 71.4 % of animals receiving mtLivin-CD40L-NPs achieved complete pathological tumor response and survived significantly longer. All treatments in this study were well-tolerated. In terms of mechanism, we show high caspase-3 activity in tumors from mice that were treated with mtLivin-CD40L-NPs demonstrating the ability of the nanoparticles to target the tumors and to induce apoptotic tumor cell death. The resistance of tumor cells to drug-induced apoptosis is a major cause of cancer treatment failure. We designed mtLitvin targeted nanoparticles constituting novel personalized therapeutic approach for resistant cancer. Disclosures: No relevant conflicts of interest to declare.

Cardiovascular disease is the leading cause of death worldwide, mainly due to an increasing prevalence of atherosclerosis characterized by inflammatory plaques. Plaques with high levels of macrophage infiltration are considered “vulnerable” while those that do not have significant inflammation are considered stable; cathepsin protease activity is highly elevated in macrophages of vulnerable plaques and contributes to plaque instability. Establishing novel tools for non-invasive molecular imaging of macrophages in plaques could aid in preclinical studies and evaluation of therapeutics. Furthermore, compounds that reduce the macrophage content within plaques should ultimately impact care for this disease. We have applied quenched fluorescent cathepsin activity-based probes (ABPs) to a murine atherosclerosis model and evaluated their use for in vivo imaging using fluorescent molecular tomography (FMT), as well as ex vivo fluorescence imaging and fluorescent microscopy. Additionally, freshly dissected human carotid plaques were treated with our potent cathepsin inhibitor and macrophage apoptosis was evaluated by fluorescent microscopy. We demonstrate that our ABPs accurately detect murine atherosclerotic plaques non-invasively, identifying cathepsin activity within plaque macrophages. In addition, our cathepsin inhibitor selectively induced cell apoptosis of 55%±10% of the macrophage within excised human atherosclerotic plaques. Cathepsin ABPs present a rapid diagnostic tool for macrophage detection in atherosclerotic plaque. Our inhibitor confirms cathepsin-targeting as a promising approach to treat atherosclerotic plaque inflammation.

Vascular endothelial cell (VEC) senescence is considered an early event in the development of atherosclerotic lesions. Stressful stimuli, in particular oxidative stress, have been linked to premature senescence in the vasculature. Foam cells are a major source of reactive oxygen species and may play a role in the induction of VEC senescence; hence, we investigated their involvement in the induction of VEC senescence in a co‐culture transwell system. Primary bovine aortic endothelial cells, exposed to the secretome of THP‐1 monocyte‐derived foam cells, were analysed for the induction of senescence. Senescence associated β‐galactosidase activity and the expression of p16 and p21 were increased, whereas phosphorylated retinoblastoma protein was reduced. This senescent phenotype was mediated by 4‐hydroxnonenal (4‐HNE), a lipid peroxidation product secreted from foam cells; scavenging of 4‐HNE in the co‐culture medium blunted this effect. Furthermore, both foam cells and 4‐HNE increased the expression of the pro‐oxidant thioredoxin‐interacting protein (TXNIP). Molecular manipulation of TXNIP expression confirmed its involvement in foam cell‐induced senescence. Previous studies showed that peroxisome proliferator‐activated receptor (PPAR)δ was activated by 4‐hydroalkenals, such as 4‐HNE. Pharmacological interventions supported the involvement of the 4‐HNE‐PPARδ axis in the induction of TXNIP and VEC senescence. The association of TXNIP with VEC senescence was further supported by immunofluorescent staining of human carotid plaques in which the expression of both TXNIP and p21 was augmented in endothelial cells. Collectively, these findings suggest that foam cell‐released 4‐HNE activates PPARδ in VEC, leading to increased TXNIP expression and consequently to senescence.