Glypican-1 Is a Novel Target for Stroma and Tumor Cell Dual-Targeting Antibody-Drug Conjugates in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a stroma-rich cancer. Extracellular matrix proteins produced by cancer-associated fibroblasts (CAFs) found in tumor stroma that impedes effective delivery of chemotherapeutic agents results in poor response in patients with PDAC. Previously, our group reported that glypican-1 (GPC1) was overexpressed in human PDAC and negatively correlated with patient survival. Immunohistochemical analysis of 25 patients with PDAC tumor specimens revealed elevated expression of GPC1 in stromal cells and pancreatic cancer cells in 80% of patients. Interestingly, GPC1 was expressed on CAFs in PDAC. We generated a GPC1 antibody-drug conjugate conjugated with monomethyl auristatin E [GPC1-ADC(MMAE)] and evaluated its preclinical antitumor activity by targeting GPC1-positive CAF and cancer cells in PDAC. GPC1-ADC(MMAE) inhibited the growth of GPC1-positive PDAC cell lines in vitro Furthermore, GPC1-ADC(MMAE) showed a potent antitumor effect in the PDAC patient-derived tumor xenograft (PDX) model against GPC1-positive CAF and heterogeneous GPC1-expressing cancer cells. Notably, GPC1-ADC(MMAE) showed robust preclinical efficacy against GPC1 in a stroma-positive/cancer-negative PDAC PDX model. GPC1-ADC(MMAE) was delivered and internalized to CAFs. Although apoptosis was not observed in CAFs, the released MMAE from CAFs via MDR-1 induced apoptosis of cancer cells neighboring CAFs and efficiently inhibited PDAC tumor growth. GPC1-ADC(MMAE) exhibited potent and unique antitumor activity in GPC1-positive PDAC PDX models, which suggests that GPC1 is a novel therapeutic target in PDAC and other stromal GPC1-positive solid tumors. These findings show that targeting GPC1 on CAF using GPC1-ADC(MMAE) is a useful approach in case of stroma-rich tumors such as PDAC.

Preclinical optimization of a GPC2-targeting CAR T-cell therapy for neuroblastoma

BACKGROUND

Although most patients with newly diagnosed high-risk neuroblastoma (NB) achieve remission after initial therapy, more than 50% experience late relapses caused by minimal residual disease (MRD) and succumb to their cancer. Therapeutic strategies to target MRD may benefit these children. We developed a new chimeric antigen receptor (CAR) targeting glypican-2 (GPC2) and conducted iterative preclinical engineering of the CAR structure to maximize its anti-tumor efficacy before clinical translation.

METHODS

We evaluated different GPC2-CAR constructs by measuring the CAR activity in vitro. NOD-SCID mice engrafted orthotopically with human NB cell lines or patient-derived xenografts and treated with human CAR T cells served as in vivo models. Mechanistic studies were performed using single-cell RNA-sequencing.

RESULTS

Applying stringent in vitro assays and orthotopic in vivo NB models, we demonstrated that our single-chain variable fragment, CT3, integrated into a CAR vector with a CD28 hinge, CD28 transmembrane, and 4-1BB co-stimulatory domain (CT3.28H.BBζ) elicits the best preclinical anti-NB activity compared with other tested CAR constructs. This enhanced activity was associated with an enrichment of CD8+ effector T cells in the tumor-microenvironment and upregulation of several effector molecules such as GNLY, GZMB, ZNF683, and HMGN2. Finally, we also showed that the CT3.28H.BBζ CAR we developed was more potent than a recently clinically tested GD2-targeted CAR to control NB growth in vivo.

CONCLUSION

Given the robust preclinical activity of CT3.28H.BBζ, these results form a promising basis for further clinical testing in children with NB.

Titania nanotube-based protein delivery system to inhibit cranial bone regeneration in Crouzon model of craniosynostosis

BACKGROUND

Craniosynostosis is a developmental disorder characterized by the premature fusion of skull sutures, necessitating repetitive, high-risk neurosurgical interventions throughout infancy. This study used protein-releasing Titania nanotubular implant (TNT/Ti) loaded with glypican 3 (GPC3) in the cranial critical-sized defects (CSDs) in Crouzon murine model (Fgfr2c342y/+ knock-in mutation) to address a key challenge of delaying post-operative bone regeneration in craniosynostosis.

MATERIALS AND METHODS

A 3 mm wide circular CSD was created in two murine models of Crouzon syndrome: (i) surgical control (CSDs without TNT/Ti or any protein, n=6) and (ii) experimental groups with TNT/Ti loaded with GPC3, further subdivided into the presence or absence of chitosan coating (on nanotubes) (n=12 in each group). The bone volume percentage in CSDs was assessed 90 days post-implantation using micro-computed tomography (micro-CT) and histological analysis.

RESULTS

Nano-implants retrieved after 90 days post-operatively depicted well-adhered, hexagonally arranged, and densely packed nanotubes with average diameter of 120±10 nm. The nanotubular architecture was generally well-preserved. Compared with the control bone volume percentage data (without GPC3), GPC3-loaded TNT/Ti without chitosan coating displayed a significantly lower volume percent in cranial CSDs (P<0.001). Histological assessment showed relatively less bone regeneration (healing) in GPC3-loaded CSDs than control CSDs.

CONCLUSION

The finding of inhibition of cranial bone regeneration by GPC3-loaded TNT/Ti in vivo is an important advance in the novel field of minimally-invasive craniosynostosis therapy and holds the prospect of altering the whole paradigm of treatment for affected children. Future animal studies on a larger sample are indicated to refine the dosage and duration of drug delivery across different ages and both sexes with the view to undertake human clinical trials.

Smart glypican-3-targeting peptide-chlorin e6 conjugates for targeted photodynamic therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly aggressive and lethal malignancy with poor prognosis, necessitating the urgent development of effective treatments. Targeted photodynamic therapy (PDT) offers a promising way to selectively eradicate tumor cells without affecting normal cells. Inspired by promising features of peptide-drug conjugates (PDCs) in targeted cancer therapy, herein a novel glypican-3 (GPC3)-targeting PDC-PDT strategy was developed for the precise PDT treatment of HCC. The GPC3-targeting photosensitizer conjugates were developed by attaching GPC3-targeting peptides to chlorin e6. Conjugate 8b demonstrated the ability to penetrate HCC cells via GPC3-mediated entry process, exhibiting remarkable tumor-targeting capacity, superior antitumor efficacy, and minimal toxicity towards normal cells. Notably, conjugate 8b achieved complete tumor elimination upon light illumination in a HepG2 xenograft model without harm to normal tissues. Overall, this innovative GPC3-targeting conjugation strategy demonstrates considerable promise for clinical applications for the treatment of HCC.

The Role of microRNAs in Regulating Cancer Cell Response to Oxaliplatin-Containing Regimens

Oxaliplatin (cyclohexane-1,2-diamine; oxalate; platinum [2+]) is a third-generation chemotherapeutic drug with anticancer effects. Oxaliplatin has a role in the treatment of several cancers. It is one of the few drugs which can eliminate the neoplastic cells of colorectal cancer. Also, it has an influential role in breast cancer, lung cancer, bladder cancer, prostate cancer, and gastric cancer. Although oxaliplatin has many beneficial effects in cancer treatment, resistance to this drug is in the way to cure neoplastic cells and reduce treatment efficacy. microRNAs are a subtype of small noncoding RNAs with ∼22 nucleotides that exist among species. They have diverse roles in physiological processes, including cellular proliferation and cell death. Moreover, miRNAs have essential roles in resistance to cancer treatment and can strengthen sensitivity to chemotherapeutic drugs and regimens. In colorectal cancer, the co-treatment of oxaliplatin with anti-miR-19a can partially reverse the oxaliplatin resistance through the upregulation of phosphatase and tensin homolog (PTEN). Moreover, by preventing the spread of gastric cancer cells and downregulating glypican-3 (GPC3), MiR-4510 may modify immunosuppressive signals in the tumor microenvironment. Treatment with oxaliplatin may develop into a specialized therapeutic drug for patients with miR-4510 inhibition and glypican-3-expressing gastric cancer. Eventually, miR-122 upregulation or Wnt/β-catenin signaling suppression boosted the death of HCC cells and made them more sensitive to oxaliplatin. Herein, we have reviewed the role of microRNAs in regulating cancer cells' response to oxaliplatin, with particular attention to gastrointestinal cancers. We also discussed the role of these noncoding RNAs in the pathophysiology of oxaliplatin-induced neuropathic pain.

A novel complement-fixing IgM antibody targeting GPC1 as a useful immunotherapeutic strategy for the treatment of pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with a very low survival rate at 5 years. The use of chemotherapeutic agents results in only modest prolongation of survival and is generally associated with the occurrence of toxicity effects. Antibody-based immunotherapy has been proposed for the treatment of PDAC, but its efficacy has so far proved limited. The proteoglycan glypican-1 (GPC1) may be a useful immunotherapeutic target because it is highly expressed on the surface of PDAC cells, whereas it is not expressed or is expressed at very low levels in benign neoplastic lesions, chronic pancreatitis, and normal adult tissues. Here, we developed and characterized a specific mouse IgM antibody (AT101) targeting GPC1.

METHODS

We developed a mouse monoclonal antibody of the IgM class directed against an epitope of GPC1 in close proximity to the cell membrane. For this purpose, a 46 amino acid long peptide of the C-terminal region was used to immunize mice by an in-vivo electroporation protocol followed by serum titer and hybridoma formation.

RESULTS

The ability of AT101 to bind the GPC1 protein was demonstrated by ELISA, and by flow cytometry and immunofluorescence analysis in the GPC1-expressing "PDAC-like" BXPC3 cell line. In-vivo experiments in the BXPC3 xenograft model showed that AT101 was able to bind GPC1 on the cell surface and accumulate in the BXPC3 tumor masses. Ex-vivo analyses of BXPC3 tumor masses showed that AT101 was able to recruit immunological effectors (complement system components, NK cells, macrophages) to the tumor site and damage PDAC tumor tissue. In-vivo treatment with AT101 reduced tumor growth and prolonged survival of mice with BXPC3 tumor (p < 0.0001).

CONCLUSIONS

These results indicate that AT101, an IgM specific for an epitope of GPC1 close to PDAC cell surface, is a promising immunotherapeutic agent for GPC1-expressing PDAC, being able to selectively activate the complement system and recruit effector cells in the tumor microenvironment, thus allowing to reduce tumor mass growth and improve survival in treated mice.

Glutamine synthetase and hepatocellular carcinoma

Glutamine synthetase (GS) is an enzyme that converts ammonia and glutamate to glutamine using adenosine triphosphate. GS is expressed in the brain, kidney, and liver tissues under normal physiological conditions. GS is involved in abnormal lipid metabolism of the liver by catalyzing de novo synthesis of glutamine, thereby inducing liver inflammation. Metabolic dysfunction-associated steatotic liver diseases (MASLD), such as Metabolic Associated Fatty Liver Disease and Metabolic Associated Steato Hepatitis, are considered risk factors for HCC. GS may also be involved in the development and progression of hepatocellular carcinoma (HCC) through other signaling pathways, including the rapamycin (mTOR) and Wnt/β-catenin signaling pathways. Furthermore, the correct combination of HSP70, GPC3, and GS can improve the accuracy and precision of HCC diagnosis. However, the prognostic value of GS in different HCC populations remains controversial. The expression of GS affects the sensitivity of HCC cells to radiotherapy and chemotherapy. In addition, immunotherapy has been approved for the treatment of advanced HCC. This article delves into the development and application of GS in HCC, laying a theoretical foundation for the subsequent exploration of GS as a potential target for treating HCC.

Gut Microbiota-Based Immunotherapy: Engineered Escherichia coli Nissle 1917 for Oral Delivery of Glypican-1 in Pancreatic Cancer

Background and Objectives: The administration of oral vaccines offers a potential strategy for cancer immunotherapy; yet, the development of effective platforms continues to pose a difficulty. This study examines Escherichia coli Nissle 1917 (EcN) as a microbial vector for the precise delivery of Glypican-1 (GPC1), a tumor-associated antigen significantly overexpressed in pancreatic ductal adenocarcinoma (PDAC).To evaluate the effectiveness of EcN as a vector for the delivery of GPC1 and assess its potential as an oral vaccination platform for cancer immunotherapy. Materials and Methods: EcN was genetically modified to produce a GPC1-flagellin fusion protein (GPC1-FL) to augment antigen immunogenicity. The expression and stability of GPC1 were confirmed in modified PANC02 cells using Western blot and flow cytometry, indicating that GPC1 expression did not influence tumor cell growth. A mouse model was employed to test immunogenicity post-oral delivery, measuring systemic IgG, IL-10, IL-2, and IFN-γ levels to indicate immune activation. Results: Oral immunization with EcN GPC1-FL elicited a robust systemic immune response, demonstrated by markedly increased levels of IgG and IL-10. IL-2 and IFN-γ concentrations were elevated in vaccinated mice relative to controls; however, the differences lacked statistical significance. Western blot examination of fecal samples verified consistent antigen expression in the gastrointestinal tract, indicating effective bacterial colonization and antigen retention. No detrimental impacts were noted, hence substantiating the safety of this methodology. Conclusions: These findings confirm EcN as a feasible and patient-friendly oral vaccination platform for cancer immunotherapy. The effective production of GPC1 in tumor cells, along with continuous antigen delivery and immune activation, underscores the promise of this approach for PDAC and other cancers. This study promotes microbial-based antigen delivery as a scalable, non-invasive substitute for traditional vaccine platforms.