Antibody-mediated blockade for galectin-3 binding protein in tumor secretome abrogates PDAC metastasis

Is Immunohistochemical Galectin-3 Expression Associated with the Epithelial-Mesenchymal Transition in High- and Low-Grade Invasive Urothelial Carcinomas of the Bladder?

Background/Objectives: Bladder cancer, predominantly urothelial carcinoma, is an important malignancy of the urinary system. Despite the same histologic grade and stage, some patients seem to have a worse prognosis. In this context, the epithelial-mesenchymal transition (EMT), characterized by the loss of E-cadherin and gain of vimentin expression, is an important process in tumor progression. Galectin-3, a lactose-binding protein involved in various cellular processes, has been associated with increased tumor cell migration, invasion, and treatment resistance. Methods: In this study, 223 bladder cancer cases were examined, and E-cadherin, vimentin, and galectin-3 expression was evaluated by immunohistochemical staining in tumor budding areas and invasive components. These markers were also correlated with clinicopathological parameters, including tumor grade and stage. Results: The results indicated a significant decrease in E-cadherin expression and an increase in vimentin staining in higher-grade and higher-stage tumors, supporting EMT involvement. Galectin-3 expression was notably higher in T1 high-grade tumors but decreased in T2 stage tumors. Despite this, no significant correlation was found between galectin-3 and E-cadherin or vimentin, suggesting a complex role of galectin-3 in EMT. Conclusions: High galectin-3 expression in T1 high-grade tumors highlights its potential role in early tumor progression and as a therapeutic target. However, the decrease in its expression in advanced stages underscores the need for further research to understand its multifaceted involvement in bladder cancer. These findings suggest that while galectin-3 may contribute to the EMT and early tumor progression, its exact role and potential as a therapeutic target require more detailed investigation.

Functional structural domain synthesis of anti-pancreatic carcinoma pectin-like polysaccharide RN1

The great structural and functional diversity supports polysaccharides as favorable candidates for new drug development. Previously we reported that a drug candidate pectin-like natural polysaccharide, RN1 might target galectin-3 (Gal-3) to impede pancreatic cancer cell growth in vivo. However, the quality control of polysaccharide-based drug research faces great challenges due to the heterogeneity. A potential solution is to synthesize structurally identified subfragments of this polysaccharide as alternatives. In this work, we took RN1 as an example, and synthesized five subfragments derived from the putative repeating units of RN1. Among them, pentasaccharide 4 showed an approximative binding affinity to Gal-3 in vitro, as well as an antiproliferative activity against pancreatic BxPC-3 cells comparable to that of RN1. Further, we scaled up pentasaccharide 4 to gram-scale in an efficient synthetic route with a 6.9 % yield from D-galactose. Importantly, pentasaccharide 4 significantly suppressed the growth of pancreatic tumor in vivo. Based on the mechanism complementarity of galactin-3 inhibitor and docetaxel, the combination administration of pentasaccharide 4 and docetaxel afforded better result. The result suggested pentasaccharide 4 was one of the functional structural domains of polysaccharide RN1 and might be a leading compound for anti-pancreatic cancer new drug development.

GABARAPL1 is essential in extracellular vesicle cargo loading and metastasis development

BACKGROUND AND PURPOSE

Hypoxia is a common feature of tumours, associated with poor prognosis due to increased resistance to radio- and chemotherapy and enhanced metastasis development. Previously we demonstrated that GABARAPL1 is required for the secretion of extracellular vesicles (EV) with pro-angiogenic properties during hypoxia. Here, we explored the role of GABARAPL1+ EV in the metastatic cascade.

MATERIALS AND METHODS

GABARAPL1 deficient or control MDA-MB-231 cells were injected in murine mammary fat pads. Lungs were dissected and analysed for human cytokeratin 18. EV from control and GABARAPL1 deficient cells exposed to normoxia (21% O2) or hypoxia (O2 < 0.02%) were isolated and analysed by immunoblot, nanoparticle tracking analysis, high resolution flow cytometry, mass spectrometry and next-generation sequencing. Cellular migration and invasion were analysed using scratch assays and transwell-invasion assays, respectively.

RESULTS

The number of pulmonary metastases derived from GABARAPL1 deficient tumours decreased by 84%. GABARAPL1 deficient cells migrate slower but display a comparable invasive capacity. Both normoxic and hypoxic EV contain proteins and miRNAs associated with metastasis development and, in line, increase cancer cell invasiveness. Although GABARAPL1 deficiency alters EV content, it does not alter the EV-induced increase in cancer cell invasiveness.

CONCLUSION

GABARAPL1 is essential for metastasis development. This is unrelated to changes in migration and invasion and suggests that GABARAPL1 or GABARAPL1+ EV are essential in other processes related to the metastatic cascade.

Galectin-3's Complex Interactions in Pancreatic Ductal Adenocarcinoma: From Cellular Signaling to Therapeutic Potential

Galectin-3 (Gal-3) plays a multifaceted role in the development, progression, and prognosis of pancreatic ductal adenocarcinoma (PDAC). This review offers a comprehensive examination of its expression in PDAC, its interaction with various immune cells, signaling pathways, effects on apoptosis, and therapeutic resistance. Additionally, the prognostic significance of serum levels of Gal-3 is discussed, providing insights into its potential utilization as a biomarker. Critical analysis is also extended to the inhibitors of Gal-3 and their potential therapeutic applications in PDAC, offering new avenues for targeted treatments. The intricate nature of Gal-3's role in PDAC reveals a complex landscape that demands a nuanced understanding for potential therapeutic interventions and monitoring.

Functional and Clinical Proteomic Exploration of Pancreatic Cancer

Pancreatic cancer, most cases being pancreatic ductal adenocarcinoma (PDAC), is one of the most lethal cancers with a median survival time of less than 6 months. Therapeutic options are very limited for PDAC patients, and surgery is still the most effective treatment, making improvements in early diagnosis critical. One typical characteristic of PDAC is the desmoplastic reaction of its stroma microenvironment, which actively interacts with cancer cells to orchestrate key components in tumorigenesis, metastasis, and chemoresistance. Global exploration of cancer-stroma crosstalk is essential to decipher PDAC biology and design intervention strategies. Over the past decade, the dramatic improvement of proteomics technologies has enabled profiling of proteins, post-translational modifications (PTMs), and their protein complexes at unprecedented sensitivity and dimensionality. Here, starting with our current understanding of PDAC characteristics, including precursor lesions, progression models, tumor microenvironment, and therapeutic advancements, we describe how proteomics contributes to the functional and clinical exploration of PDAC, providing insights into PDAC carcinogenesis, progression, and chemoresistance. We summarize recent achievements enabled by proteomics to systematically investigate PTMs-mediated intracellular signaling in PDAC, cancer-stroma interactions, and potential therapeutic targets revealed by these functional studies. We also highlight proteomic profiling of clinical tissue and plasma samples to discover and verify useful biomarkers that can aid early detection and molecular classification of patients. In addition, we introduce spatial proteomic technology and its applications in PDAC for deconvolving tumor heterogeneity. Finally, we discuss future prospects of applying new proteomic technologies in comprehensively understanding PDAC heterogeneity and intercellular signaling networks. Importantly, we expect advances in clinical functional proteomics for exploring mechanisms of cancer biology directly by high-sensitivity functional proteomic approaches starting from clinical samples.