Trends in the Development of Antibody-Drug Conjugates for Cancer Therapy.

In cancer treatment, the first-generation, cytotoxic drugs, though effective against cancer cells, also harmed healthy ones. The second-generation targeted cancer cells precisely to inhibit their growth. Enter the third-generation, consisting of immuno-oncology drugs, designed to combat drug resistance and bolster the immune system's defenses. These advanced therapies operate by obstructing the uncontrolled growth and spread of cancer cells through the body, ultimately eliminating them effectively. Within the arsenal of cancer treatment, monoclonal antibodies offer several advantages, including inducing cancer cell apoptosis, precise targeting, prolonged presence in the body, and minimal side effects. A recent development in cancer therapy is Antibody-Drug Conjugates (ADCs), initially developed in the mid-20th century. The second generation of ADCs addressed this issue through innovative antibody modification techniques, such as DAR regulation, amino acid substitutions, incorporation of non-natural amino acids, and enzymatic drug attachment. Currently, a third generation of ADCs is in development. This study presents an overview of 12 available ADCs, reviews 71 recent research papers, and analyzes 128 clinical trial reports. The overarching objective is to gain insights into the prevailing trends in ADC research and development, with a particular focus on emerging frontiers like potential targets, linkers, and drug payloads within the realm of cancer treatment.

Improved Separation in Horizontal Protein SDS-PAGE with Double-Deck Flat Electrodes and a Field Inversion Gel Electrophoresis Module.

The horizontal flatbed electrophoresis method is employed to separate protein samples, providing greater flexibility for various electrophoretic applications and easier sample loading compared to its vertical counterpart. In the currently available equipment setup, cathode and anode electrodes are positioned on top of a gel at each end. Since an electric field enters the gel from the top, its strength gradually weakens from the top to the bottom of the gel. When examining the interior of gels following electrophoretic separation, the uneven electric field causes the protein bands to lie down forward in the direction of migration, leading to an increase in bandwidth. This issue has remained unaddressed for several decades. To address this problem, new clamp-shaped and double-deck electrodes were developed to apply an electric field simultaneously from both the top and bottom of the gel. Both of these new electrodes facilitated the formation of perpendicular protein band shapes and enhanced resolution at a comparable level. Due to their ease of use, double-deck electrodes are recommended. By combining these new electrodes with the field inversion gel electrophoresis (FIGE) technique, the protein bands could be focused and aligned nearly vertically, resulting in the highest level of electrophoretic resolution. Our electrodes are compatible with polyacrylamide gels of varying sizes, buffer systems, and sample well formats. They can be easily manufactured and seamlessly integrated into existing laboratory instruments for practical use.

Agonist (P1) Antibody Converts Stem Cells into Migrating Beta-Like Cells in Pancreatic Islets.

Tissue regeneration is the ultimate treatment for many degenerative diseases, however, repair and regeneration of damaged organs or tissues remains a challenge. Previously, we showed that B1 Ab and H3 Ab induce stem cells to differentiate into microglia and brown adipocyte-like cells, while trafficking to the brain and heart, respectively. Here, we present data showing that another selected agonist antibody, P1 antibody, induces the migration of cells to the pancreatic islets and differentiates human stem cells into beta-like cells. Interestingly, our results suggest the purified P1 Ab induces beta-like cells from fresh, human CD34+ hematopoietic stem cells and mouse bone marrow. In addition, stem cells with P1 Ab bound to expressed periostin (POSTN), an extracellular matrix protein that regulates tissue remodeling, selectively migrate to mouse pancreatic islets. Thus, these results confirm that our in vivo selection system can be used to identify antibodies from our library which are capable of inducing stem cell differentiation and cell migration to select tissues for the purpose of regenerating and remodeling damaged organ systems.

Anti-inflammatory clearance of amyloid-ß by a chimeric Gas6 fusion protein.

Clearing amyloid-ß (Aß) through immunotherapy is one of the most promising therapeutic approaches to Alzheimer's disease (AD). Although several monoclonal antibodies against Aß have been shown to substantially reduce Aß burden in patients with AD, their effects on improving cognitive function remain marginal. In addition, a significant portion of patients treated with Aß-targeting antibodies experience brain edema and microhemorrhage associated with antibody-mediated Fc receptor activation in the brain. Here, we develop a phagocytosis inducer for Aß consisting of a single-chain variable fragment of an Aß-targeting monoclonal antibody fused with a truncated receptor binding domain of growth arrest-specific 6 (Gas6), a bridging molecule for the clearance of dead cells via TAM (TYRO3, AXL, and MERTK) receptors. This chimeric fusion protein (αAß-Gas6) selectively eliminates Aß plaques through TAM receptor-dependent phagocytosis without inducing NF-kB-mediated inflammatory responses or reactive gliosis. Furthermore, αAß-Gas6 can induce synergistic clearance of Aß by activating both microglial and astrocytic phagocytosis, resulting in better behavioral outcomes with substantially reduced synapse elimination and microhemorrhage in AD and cerebral amyloid angiopathy model mice compared with Aß antibody treatment. Our results suggest that αAß-Gas6 could be a novel immunotherapeutic agent for AD that overcomes the side effects of conventional antibody therapy.

Antibodies Regulate Dual-Function Enzyme IYD to Induce Functional Synergy between Metabolism and Thermogenesis.

Iodotyrosine deiodinase (IYD) is a type of deiodinase enzyme that scavenges iodide from the thyroid gland. Previously, we showed that H3 Ab acts as an agonist on IYD to induce migration of cells to the heart and differentiate human stem cells into brown adipocyte-like cells. To continue this study, we investigated the dual function of IYD in hypothyroidism by blocking IYD and in thermogenesis by looking at the induction of brown adipocyte-like cells by treatment with H3 Ab in a mouse model. Surprisingly, our results suggest H3 Ab acts on IYD as both an antagonist and agonist to reduce T4 and increase core body temperature in the mouse model. Taken together, the data suggest IYD has a dual function that can regulate physiological metabolism and enhance thermogenesis.

Sestrin2 protects against cholestatic liver injury by inhibiting endoplasmic reticulum stress and NLRP3 inflammasome-mediated pyroptosis.

Chronic exposure to bile acid in the liver due to impaired bile flow induces cholestatic liver disease, resulting in hepatotoxicity and liver fibrosis. Sestrin2, a highly conserved, stress-inducible protein, has been implicated in cellular responses to multiple stress conditions and the maintenance of cellular homeostasis. However, its role in cholestatic liver injury is not fully understood. In this study, we investigated the role of hepatic Sestrin2 in cholestatic liver injury and its underlying mechanisms using in vivo and in vitro approaches. Hepatic Sestrin2 expression was upregulated by activating transcription factor 4 (ATF4) and CCAAT/enhancer-binding protein-ß (C/EBP-ß) after treatment with bile acids and correlated with endoplasmic reticulum (ER) stress responses. Bile-duct ligation (BDL)-induced hepatocellular apoptosis and liver fibrosis were exacerbated in Sestrin2-knockout (Sesn2-/-) mice. Moreover, Sestrin2 deficiency enhanced cholestasis-induced hepatic ER stress, whereas Sestrin2 overexpression ameliorated bile acid-induced ER stress. Notably, the mammalian target of rapamycin (mTOR) inhibitor rapamycin and the AMP-activated protein kinase (AMPK) activator AICAR reversed bile acid-induced ER stress in Sestrin2-deficient cells. Furthermore, Sestrin2 deficiency promoted cholestasis-induced hepatic pyroptosis by activating NLRP3 inflammasomes. Thus, our study provides evidence for the biological significance of Sestrin2 and its relationship with cholestatic liver injury, suggesting the potential role of Sestrin2 in regulating ER stress and inflammasome activation during cholestatic liver injury.

Postbiotics Enhance NK Cell Activation in Stress-Induced Mice through Gut Microbiome Regulation.

Recent studies have revealed that probiotics and their metabolites are present under various conditions; however, the role of probiotic metabolites (i.e., postbiotics in pathological states) is controversial. Natural killer (NK) cells play a key role in innate and adaptive immunity. In this study, we examined NK cell activation influenced by a postbiotics mixture in response to gut microbiome modulation in stress-induced mice. In vivo activation of NK cells increased in the postbiotics mixture treatment group in accordance with Th1/Th2 expression level. Meanwhile, the Red Ginseng treatment group, a reference group, showed very little expression of NK cell activation. Moreover, the postbiotics mixture treatment group in particular changed the gut microbiome composition. Although the exact role of the postbiotics mixture in regulating the immune system of stress-induced mice remains unclear, the postbiotics mixture-induced NK cell activation might have affected gut microbiome modulation.

Evaluation of human papillomavirus (HPV) genotyping assays using type-specific HPV L1 reference DNA.

BACKGROUND: Human papillomaviruses (HPV) are known to play a central etiological role in the development of cervical cancer. General HPV genotyping methods consist of PCR with consensus primers combined with various detection methods. OBJECTIVE: The aim was to develop HPV L1 DNA reference materials to evaluate the sensitivity, specificity, and accuracy of genotyping results obtained from the HPV DNA Genotyping Chip (HPV CHIP) and RFMP assays. METHODS: In this study, the Ministry of Food and Drug Safety (MFDS) established reference DNA materials for the L1 gene from 41 subtypes of anogenital HPV to aid in genotyping human papillomavirus (HPV) strains. Of these, 22 subtypes were obtained from cervical scrape samples of Korean women and 19 subtypes were synthesized. These reference materials include 13 high-risk types (HPV-16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68), 3 probable high-risk types (HPV-26, 53, and 66), 16 low-risk types (HPV-6, 10, 11, 27, 34, 40, 42, 43, 44, 54, 55, 61, 70, 72, 73, and 81), and 8 undetermined-risk types (HPV-3, 57, 62, 67, 69, 71, 74, and 84). After confirming the sequences by standard methods, these HPV L1 DNA reference materials were then used to compare results from the HPV DNA Genotyping Chip (HPV CHIP) and restriction fragment mass polymorphism (RFMP) assays. RESULTS: Data collected from the HPV CHIP and RFMP assay showed comparably high sensitivity and accuracy. Both assays could detect 102 or more copies/µl of HPV L1 DNA from 39 types of HPV, with higher accuracy in detecting samples with mixed types of HPV. CONCLUSION: The present study confirms the HPV L1 DNA reference materials developed by MFDS are reliable and useful for the evaluation of HPV genotyping assays.

Spreader-CDR system for efficient, reproducible, and frugal western blot.

Efficient antibody incubation is a vital step for successful western blot. During the incubation, a thin antibody-depleted layer is created around the blotting membrane, which limits antibody binding. Although the conventional batch shaking method is ineffective against it, this layer can be easily disrupted by cyclic draining and replenishing (CDR) of the antibody solution during membrane incubation. Previously, we introduced a closed and rotating cylindrical chamber as a tool to implement CDR for western blots (rCDR). A new open bucket-style chamber was devised for easier operation and the possibility of process automation. Instead of rotation as in rCDR, rocking it back and forth achieved the CDR antibody incubation (R-CDR). The chamber was then equipped with a spreader-rod to facilitate the uniform movement of the antibody solution across the membrane surface. Hence, it was named spreader CDR (S-CDR). Compared to the batch incubation method, both the S-CDR and R-CDR devices produced significantly enhanced signals and developed faster results. There were several additional benefits of using the spreader-rod, which included uniform antibody binding across the membrane, reduced usage of antibodies, and the ability to recover results even from mishandled, creased membranes. The S-CDR device ensures better blots and can be easily implemented in existing western blot protocols.

Nucleic acid nanotechnology for cancer treatment.

Cancer is one of the most prevalent potentially lethal diseases. With the increase in the number of investigations into the uses of nanotechnology, many nucleic acid (NA)-based nanostructures such as small interfering RNA, microRNA, aptamers, and immune adjuvant NA have been applied to treat cancer. Here, we discuss studies on the applications of NA in cancer treatment, recent research trends, and the limitations and prospects of specific NA-mediated gene therapy and immunotherapy for cancer treatment. The NA structures used for cancer therapy consist only of NA or hybrids comprising organic or inorganic substances integrated with functional NA. We also discuss delivery vehicles for therapeutic NA and anti-cancer agents, and recent trends in NA-based gene therapy and immunotherapy against cancer.

4-1BBL Regulates the Polarization of Macrophages, and Inhibition of 4-1BBL Signaling Alleviates Imiquimod-Induced Psoriasis.

4-1BBL, a member of the TNF superfamily, regulates the sustained production of inflammatory cytokines in macrophages triggered by TLR signaling. In this study, we have investigated the role of 4-1BBL in macrophage metabolism and polarization and in skin inflammation using a model of imiquimod-induced psoriasis in mice. Genetic ablation or blocking of 4-1BBL signaling by Ab or 4-1BB-Fc alleviated the pathology of psoriasis by regulating the expression of inflammatory cytokines associated with macrophage activation and regulated the polarization of macrophages in vitro. We further linked this result with macrophage by finding that 4-1BBL expression during the immediate TLR response was dependent on glycolysis, mitochondrial oxidative phosphorylation, and fatty acid metabolism, whereas the late-phase 4-1BBL-mediated sustained inflammatory response was dependent on glycolysis and fatty acid synthesis. Correlating with this, administration of a fatty acid synthase inhibitor, cerulenin, also alleviated the pathology of psoriasis. We further found that 4-1BBL-mediated psoriasis development is independent of its receptor 4-1BB, as a deficiency of 4-1BB augmented the severity of psoriasis linked to a reduced regulatory T cell population and increased IL-17A expression in γδ T cells. Additionally, coblocking of 4-1BBL signaling and IL-17A activity additively ameliorated psoriasis. Taken together, 4-1BBL signaling regulates macrophage polarization and contributes to imiquimod-induced psoriasis by sustaining inflammation, providing a possible avenue for psoriasis treatment in patients.

Agonist Antibody Converts Stem Cells into Migrating Brown Adipocyte-Like Cells in Heart.

We present data showing that Iodotyrosine Deiodinase (IYD) is a dual-function enzyme acting as a catalyst in metabolism and a receptor for cooperative stem cell differentiation. IYD is present both in thyroid cells where it is critical for scavenging iodine from halogenated by-products of thyroid hormone production and on hematopoietic stem cells. To close the cooperative loop, the mono- and di-Iodotyrosine (MIT and DIT) substrates of IYD in the thyroid are also agonists for IYD now acting as a receptor on bone marrow stem cells. While studying intracellular combinatorial antibody libraries, we discovered an agonist antibody, H3 Ab, of which the target is the enzyme IYD. When agonized by H3 Ab, IYD expressed on stem cells induces differentiation of the cells into brown adipocyte-like cells, which selectively migrate to mouse heart tissue. H3 Ab also binds to IYD expressed on human myocardium. Thus, one has a single enzyme acting in different ways on different cells for the cooperative purpose of enhancing thermogenesis or of regenerating damaged heart tissue.

Immunity against cancer cells may promote their proliferation and metastasis.

Herein we present a concept in cancer where an immune response is detrimental rather than helpful. In the cancer setting, the immune system is generally considered to be helpful in curtailing the initiation and progression of tumors. In this work we show that a patient's immune response to their tumor can, in fact, either enhance or inhibit tumor cell growth. Two closely related autoantibodies to the growth factor receptor TrkB were isolated from cancer patients' B cells. Although highly similar in sequence, one antibody was an agonist while the other was an antagonist. The agonist antibody was shown to increase breast cancer cell growth both in vitro and in vivo, whereas the antagonist antibody inhibited growth. From a mechanistic point of view, we showed that binding of the agonist antibody to the TrkB receptor was functional in that it initiated downstream signaling identical to its natural growth factor ligand, brain-derived neurotrophic factor (BDNF). Our study shows that individual autoantibodies may play a role in cancer patients.

BRC-mediated RNAi targeting of USE1 inhibits tumor growth in vitro and in vivo.

USE1 has been demonstrated to play crucial roles in the development and progression of human lung cancer. However, the antitumor efficacy of RNA interference (RNAi) targeting of USE1 has not yet been evaluated as a possible clinical application. We here synthesized USE1 targeting bubbled RNA-based cargo (BRC) composed of densely packed multimeric pre-siRNAs with specific Dicer cleavage sites to enable efficient siRNA release upon entry to target cells. The physical entanglement and continuous networking of RNAs via hybridization during enzymatic replication serve as a driving force for the self-assembly of BRCs. These molecules effectively suppressed the transcription of their target genes, leading to tumor growth suppression in vitro and in vivo. Moreover, their repeated intravenous administration efficiently inhibited the growth of A549 tumor xenografts. Based on these findings of a reduced cancer cell viability following a USE1 knockdown, we further explored cell cycle arrest and apoptosis pathways. The observed tumor cell growth suppression was found to be controlled by cell cycle arrest and apoptosis signals induced by the USE1 reduction. These results suggest that USE1 BRCs may have future clinical applications as an RNAi-based cancer therapy.

The protein tyrosine kinase SYK regulates the alternative p38 activation in liver during acute liver inflammation.

Two distinct p38 signaling pathways, classical and alternative, have been identified to regulate inflammatory responses in host defense and disease development. The role of alternative p38 activation in liver inflammation is elusive, while classical p38 signaling in hepatocytes plays a role in regulating the induction of cell death in autoimmune-mediated acute liver injury. In this study, we found that a mutation of alternative p38 in mice augmented the severity of acute liver inflammation. Moreover, TNF-induced hepatocyte death was augmented by a mutation of alternative p38, suggesting that alternative p38 signaling in hepatocytes contributed more significantly to the pathology of acute liver injury. Furthermore, SYK-Vav-1 signaling regulates alternative p38 activation and the downregulation of cell death in hepatocytes. Therefore, it is suggested that alternative p38 signaling in the liver plays a critical role in the induction and subsequent pathological changes of acute liver injury. Collectively, our results imply that p38 signaling in hepatocytes plays a crucial role to prevent excessive liver injury by regulating the induction of cell death and inflammation.

USP14 Inhibition Regulates Tumorigenesis by Inducing Autophagy in Lung Cancer In Vitro.

The ubiquitin-proteasome system is an essential regulator of several cellular pathways involving oncogenes. Deubiquitination negatively regulates target proteins or substrates linked to both hereditary and sporadic forms of cancer. The deubiquitinating enzyme ubiquitin-specific protease 14 (USP14) is associated with proteasomes where it trims the ubiquitin chain on the substrate. Here, we found that USP14 is highly expressed in patients with lung cancer. We also demonstrated that USP14 inhibitors (IU1-47 and siRNA-USP14) significantly decreased cell proliferation, migration, and invasion in lung cancer. Remarkably, we found that USP14 negatively regulates lung tumorigenesis not only through apoptosis but also through the autophagy pathway. Our findings suggest that USP14 plays a crucial role in lung tumorigenesis and that USP14 inhibitors are potent drugs in lung cancer treatment.

Early-stage paired housing improves social interaction in neuronal Uba6-deficient mice.

UBA6 is an alternative enzyme for ubiquitin activation in vertebrates that plays a pivotal role in early mouse development. Previously, we reported that the Uba6 brain-specific knockout (NKO) mouse is a novel autism spectrum disorder (ASD) mouse model that displays decreased social behavior and communication. To determine the therapeutic impact of environmental stimulation in ASDs, we investigated the behavioral and molecular changes of the NKO and control mice after exposure to environmental enrichment and paired housing in different developmental phases. Our results demonstrated that early paired housing could diminish the ASD phenotypes of NKO mice such as impaired nest building and social interaction and anxiety. Additionally, increased histone acetylation in the amygdala was observed in NKO mice after paired housing without a change in Ube3a levels. Our data suggest that paired housing at an early time point can play a crucial role in ameliorating ASD behavior and can be applied in other ASD animal models or clinical settings.

An agonist antibody prefers relapsed AML for induction of cells that kill each other.

Previously, we reported an agonist antibody to a cytokine receptor, Thrombopoietin receptor (TPOR) that effectively induces cytotoxic killer cells from precursor tumor cells isolated from newly diagnosed AML patients. Here, we show that the TPOR agonist antibody can induce even relapsed AML cells into killer cells more potently than newly diagnosed AML cells. After stimulation by the agonist antibody, these relapsed leukemic cells enter into a differentiation process of killer cells. The antibody-induced killer cells express, Granzyme B and Perforin that assault and kill other members of the AML cell population. Particularly, the agonist antibody showed potent efficacy on the AML xenograft model in mice using the NOD/LtSz-scid IL2Rγc null (NSG) mice. These results show that the TPOR agonist antibody that induces AML cells to kill each other is effective on both relapsed AML cells and in vivo. Therefore, this study suggests a new strategy for the treatment of cancer relapse after chemotherapy.

Migration-based selections of antibodies that convert bone marrow into trafficking microglia-like cells that reduce brain amyloid ß.

One goal of regenerative medicine is to repair damaged tissue. This requires not only generating new cells of the proper phenotype, but also selecting for those that properly integrate into sites of injury. In our laboratory we are using a cell-migration-based in vivo selection system to generate antibodies that induce cells to both differentiate and selectively localize to different tissues. Here we describe an antibody that induces bone marrow stem cells to differentiate into microglia-like cells that traffic to the brain where they organize into typical networks. Interestingly, in the APP/PS1 Alzheimer's disease mouse model, these induced microglia-like cells are found at sites of plaque formation and significantly reduce their number. These results raise the intriguing question as to whether one can use such antibody-induced differentiation of stem cells to essentially recapitulate embryogenesis in adults to discover cells that can regenerate damaged organ systems.

An agonist antibody that blocks autoimmunity by inducing anti-inflammatory macrophages.

We have devised a method of using intracellular combinatorial libraries to select antibodies that control cell fates. Many agonist antibodies have been selected with this method, and the process appears to be limited only by the availability of a phenotypic selection system. We demonstrate the utility of this approach to discover agonist antibodies that engage an unanticipated target and regulate macrophage polarization by selective induction of anti-inflammatory M2 macrophages. This antibody was used therapeutically to block autoimmunity in a classic mouse model of spontaneous systemic lupus erythematosus.