Monoclonal antibody Zt/g4 targeting RON receptor tyrosine kinase enhances chemosensitivity of bladder cancer cells to Epirubicin by promoting G1/S arrest and apoptosis

RON receptor tyrosine kinase as a critical determinant in promoting tumorigenic behaviors of bladder cancer cells through regulating MMP12 and HIF-2α pathways

The RON receptor tyrosine kinase is critical in the pathogenesis of various cancer types, however, its role in bladder cancer invasive growth is still largely unknown. Here, we found that over 90% of bladder cancer samples exhibit elevated levels of RON expression, with significantly higher expression levels observed in invasive bladder cancer compared to non-invasive bladder cancer. In vitro, RON activation resulted in increased bladder cancer cell migration and invasiveness. Results from mRNA sequencing and transcriptome analysis further demonstrated that MMP12, a downstream molecule of RON, is functionally involved in regulating RON-mediated bladder cancer cell migration and invasiveness. The underlying mechanism appeared to be the RON-mediated inhibition of HIF-2α ubiquitination, which is channeled through the activation of the JNK signaling pathway. Consequently, the activated JNK pathway increased MMP12 expression, ultimately driving bladder cancer cell migration and invasion. As evident in bioinformatics and dual-luciferase reporter assays, the RON mRNA at its 3'-untranslated regions specifically interacted with hsa-miR-659-3p. The binding of hsa-miR-659-3p downregulated the RON gene expression, attenuating the receptor-mediated tumorigenic activities of bladder cancer cells in vitro and in vivo. In conclusion, aberrant RON expression in bladder cancer cells and MMP12 and HIF-2α activities form a functional axis that causes increased bladder cancer cell migration and invasion. The fact that hsa-miR-659-3p downregulates RON expression indicates its critical role in attenuating RON-mediated tumorigenic effect on bladder cancer cells. These findings highlight the importance of RON targeting as a therapeutic means for potential bladder cancer therapy.

A novel anoikis-related gene signature identifies LYPD1 as a novel therapy target for bladder cancer

Bladder cancer (BLCA) is a malignant tumor associated with unfavorable outcomes. Studies suggest that anoikis plays a crucial role in tumor progression and cancer cell metastasis. However, its specific role in bladder cancer remains poorly understood. Our objective was to identify anoikis-related genes (ARGs) and subsequently construct a risk model to assess their potential for predicting the prognosis of bladder cancer.The transcriptome data and clinical data of BLCA patients were sourced from The Cancer Genome Atlas and GEO database. We then performed the differential expression analysis to screen differentially expressed ARGs. Subsequently, we conducted non-negative matrix factorization (NMF) clustering analysis to establish molecular subtypes based on the differentially expressed ARGs. The CIBERSORT algorithm was used to estimate the quantification of different cell infiltration in BLCA tumor microenviroment. A prognostic risk model containing 7 ARGs was established using Lasso-Cox regression analysis. The nomogram was built for predicting the survival probability of BLCA patients. To determine the drug sensitivity of each sample from the high- and low-risk groups, the R package "pRRophetic" was performed. Finally, the role of LYPD1 was explored in BLCA cell lines.We identified 90 differential expression ARGs and NMF clustering categorizated the BLCA patientss into two distinct groups (cluster A and B). Patients in cluster A had a better prognosis than those in cluster B. Then, we established a ARGs risk model including CALR, FASN, FOSL1, JUN, LYPD1, MST1R, and SATB1, which was validated in the train and test set. The results suggested overall survival rate was much higher in low risk group than high risk group. The cox regression analysis, ROC curve analysis, and nomogram collectively demonstrated that the risk model served as an independent prognostic factor. The high risk group had a higher level TME scores compared to the low risk group. Furthermore, LYPD1 was low expression in BLCA cells and overexpression of LYPD1 inhibits the prolifearation, migration and invasion.In the current study, we have identified differential expression ARGs and constructed a risk model with the promise for guiding prognostic predictions and provided a therapeutic target for patients with BLCA.

Conformation specific antagonistic high affinity antibodies to the RON receptor kinase for imaging and therapy

The RON receptor tyrosine kinase is an exceptionally interesting target in oncology and immunology. It is not only overexpressed in a wide variety of tumors but also has been shown to be expressed on myeloid cells associated with tumor infiltration, where it serves to dampen tumour immune responses and reduce the efficacy of anti-CTLA4 therapy. Potent and selective inhibitory antibodies to RON might therefore both inhibit tumor cell growth and stimulate immune rejection of tumors. We derived cloned and sequenced a new panel of exceptionally avid anti-RON antibodies with picomolar binding affinities that inhibit MSP-induced RON signaling and show remarkable potency in antibody dependent cellular cytotoxicity. Antibody specificity was validated by cloning the antibody genes and creating recombinant antibodies and by the use of RON knock out cell lines. When radiolabeled with 89-Zirconium, the new antibodies 3F8 and 10G1 allow effective immuno-positron emission tomography (immunoPET) imaging of RON-expressing tumors and recognize universally exposed RON epitopes at the cell surface. The 10G1 was further developed into a novel bispecific T cell engager with a 15 pM EC50 in cytotoxic T cell killing assays.

Tyrosine kinase receptor RON activates MAPK/RSK/CREB signal pathway to enhance CXCR4 expression and promote cell migration and invasion in bladder cancer

Bladder cancer (BC) is one of the most lethal malignancies worldwide. The poor survival may be due to a high proportion of tumor metastasis. RON and CXCR4 are the key regulators of cell motility in BC, while the relationship between RON and CXCR4 remains elusive. In the present study, immunohistochemistry analysis of BC and adjacent normal tissues found that higher RON expression was positively correlated with CXCR4 expression. Inhibiting and replenishing RON level were used to regulate CXCR4 expression, observing the effects on migration and invasion of BC cells. Overexpression of RON reversed the inhibited cell migration and invasion following siCXCR4 treatment. Conversely, overexpression of CXCR4 restored the inhibition of cell migration and invasion caused by shRON. The activation of RON-MAPK/RSK/CREB pathway was demonstrated in BC cells under MSP treatment. Dual luciferase and CHIP assay showed that p-CREB targeted CXCR4 by binding to its CRE sequence. RON knockdown suppressed BC tumor growth in xenograft mouse tumors, accompanied by reduced expression of CXCR4. In conclusion, our data adds evidence that RON, a membrane tyrosine kinase receptor, promotes BC migration and invasion not only by itself, but also by activating MAPK/RSK/CREB signaling pathway to enhance CXCR4 expression.

Antibody drug conjugates in gastrointestinal cancer: From lab to clinical development

The antibody-drug conjugates (ADCs) are one the fastest growing biotherapeutics in oncology and are still in their infancy in gastrointestinal (GI) cancer for clinical applications to improve patient survival. The ADC based approach is developed with tumor specific antigen, antibody carrying cytotoxic agents to precisely target and deliver chemotherapeutics at the tumor site. To date, 11 ADCs have been approved by US-FDA, and more than 80 are in the clinical development phase for different oncological indications. However, The ADCs based therapies in GI cancers are still far from having high-efficient clinical outcomes. The limited success of these ADCs and lessons learned from the past are now being used to develop a newer generation of ADC against GI cancers. In this review, we did a comprehensive assessment of the key components of ADCs, including tumor marker, antibody, cytotoxic payload, and linkage strategy, with a focus on technical improvement and some future trends in the pipeline for clinical translation. The various preclinical and clinical ADCs used in gastrointestinal malignancies, their target, composition and bioconjugation, along with preclinical and clinical outcomes, are discussed. The emphasis is also given to new generation ADCs employing novel mAb, payload, linker, and bioconjugation methods are also included.

Short-form RON (sf-RON) enhances glucose metabolism to promote cell proliferation via activating β-catenin/SIX1 signaling pathway in gastric cancer

Recepteur d'origine nantais (RON) has been implicated in cell proliferation, metastasis, and chemoresistance of various human malignancies. The short-form RON (sf-RON) encoded by RON transcripts was overexpressed in gastric cancer tissues, but its regulatory functions remain illustrated. Here, we found that sf-RON promoted gastric cancer cell proliferation by enhancing glucose metabolism. Furthermore, sf-RON was proved to induce the β-catenin expression level through the AKT1/GSK3β signaling pathway. Meanwhile, the binding sites of β-catenin were identified in the promoter region of SIX1 and it was also demonstrated that β-catenin positively regulated SIX1 expression. SIX1 enhanced the promoter activity of key proteins in glucose metabolism, such as GLUT1 and LDHA. Results indicated that sf-RON regulated the cell proliferation and glucose metabolism of gastric cancer by participating in a sf-RON/β-catenin/SIX1 signaling axis and had significant implications for choosing the therapeutic target of gastric cancer.

Therapeutic anti-cancer activity of antibodies targeting sulfhydryl bond constrained epitopes on unglycosylated RON receptor tyrosine kinase

Recepteur d'origine nantais (RON) receptor tyrosine kinase (RTK) and its ligand, serum macrophage-stimulating protein (MSP), are well-established oncogenic drivers for tumorigenesis and metastasis. RON is often found to be alternatively spliced resulting in various isoforms that are constitutively active. RON is therefore an attractive target for cancer therapeutics, including small molecular inhibitors and monoclonal antibodies. While small molecule inhibitors of RON may inhibit other protein kinases including the highly similar MET kinase, monoclonal antibodies targeting RON are more specific, potentially inducing fewer side effects. Although anti-RON monoclonal antibody therapies have been developed and tested in clinical trials, they were met with limited success. Cancer cells have been associated with aberrant glycosylation mechanisms. Notably for RON, the loss of N-bisected glycosylation is a direct cause for tumorigenesis and poorer prognosis in cancer patients. Particularly in gastric cancer, aberrant RON glycosylation augments RON activation. Here, we present a novel panel of monoclonal antibodies which potentially widens the specific targeting of not only the glycosylated RON, but also unglycosylated and aberrantly glycosylated RON. Our antibodies can bind strongly to deglycosylated RON from tunicamycin treated cells, recognise RON in IHC/IF and possess superior therapeutic efficacy in RON expressing xenograft tumours. Our most potent antibody in xenograft assays, is directed to the RON alpha chain and targets a sulfhydryl bond constrained epitope that appears to be cryptic in the crystal structure. This establishes the paradigm that such constrained and cryptic epitopes represent good targets for therapeutic antibodies.

Receptor tyrosine kinase, RON, promotes tumor progression by regulating EMT and the MAPK signaling pathway in human oral squamous cell carcinoma

The receptor tyrosine kinase, recepteur d'origine nantais (RON), is known to be associated with the progression, metastasis, and prognosis of various types of cancers. Nevertheless, the role of RON in human oral squamous cell carcinoma (OSCC) is unclear. This study evaluated whether RON affects oncogenic behavior, oncogenic signaling pathways, and clinical outcomes, including survival, in human OSCC. Reverse transcription‑PCR, quantitative PCR, western blotting and immunohistochemical staining were used to determine mRNA and protein expression levels of RON. Cell invasion, migration and apoptosis assays were used to assess the functional effects of small interfering RNA‑mediated knockdown of RON or snail family transcriptional repressor 2 (SLUG). RON knockdown suppressed tumor cell invasion and migration and enhanced apoptosis in human OSCC cells. RON knockdown also decreased the phosphorylation of MAPK signaling proteins, such as ERK1/2, JNK and p38. In addition, RON knockdown suppressed the expression of the epithelial mesenchymal transition (EMT)‑related transcription factor, SLUG. SLUG knockdown blocked the enhancement of cell invasion and migration induced by macrophage‑stimulation protein (MSP)‑mediated RON activation in OSCC cells. The cell morphology was changed to spindle‑like shape under MSP‑mediated RON activation in OSCC cells. RON was overexpressed in both fresh and paraffin‑embedded human OSCC tissues. Taken together, these results indicate that RON contributed to tumor progression by regulating the EMT‑related factor, SLUG, and the MAPK pathway in OSCC. This study may provide a theoretical basis for the application of RON‑targeting agents, currently being studied in various cancer fields, for the treatment of OSCC.

RON is overexpressed in bladder cancer and contributes to tumorigenic phenotypes in 5637 cells

Tyrosine kinase receptor macrophage stimulating 1 receptor (MST1R, also known as RON) contributes to the transformation and malignant progression observed in epithelial cells. The purpose of the present study is to assess the value of RON as a potential target in bladder cancer (BC) therapeutics. The expression profile of RON in BC tissues and adjacent noncancerous tissues was detected via immunohistochemistry. The rate of positive RON expression differed significantly between bladder urothelial cancer tissues (54.7%) and paraneoplastic tissues (29.4%) (P<0.05). RON expression was positively associated with the number of tumors per patient, histological grading, pathological stage and distant metastasis (all P<0.05). Downregulation of RON expression using small interfering RNAs inhibited cell growth, cell migration and promoted cell apoptosis in the 5637 cell line. RON inhibition induced cell cycle arrest at the G₁/S boundary following an increase of cyclin-dependent kinase inhibitor 1B and cyclin-dependent kinase inhibitor 1A, and a decrease of cyclin D1, cyclin D3 and cyclin-dependent kinase 4 expression. Furthermore, knockdown of RON significantly blocked signal transduction, including downstream protein kinase B and mitogen-activated protein kinase pathways. These results indicated that RON serves a notable role in BC and is a potential target of therapeutic intervention.