Ror2 Signaling and Its Relevance in Breast Cancer Progression

Differential expression of WNT5A long and short isoforms in non-muscle-invasive bladder urothelial carcinoma

Wnt ligands belong to a family of secreted glycoproteins in which binding to a range of receptors/co-receptors activates several intracellular pathways. WNT5A, a member of the Wnt family, is classified as a non-canonical Wnt whose activation triggers planar cell polarity (PCP) and Ca+2 downstream pathways. Aberrant expression of WNT5A has been shown to play both protective and harmful roles in an array of conditions, such as inflammatory disease and cancer. In the present study, using histological, immunohistochemical, and molecular methods, we investigated the expression of two isoforms of WNT5A, WNT5A-Short (WNT5A-S) and WNT5A-Long (WNT5A-L) in bladder urothelial carcinoma (UC). Three UC cell lines (RT4, J82, and T24), as well as a normal urothelial cell line, and formalin-fixed, paraffin-embedded (FFPE) transurethral resection (TUR) tissue samples from 17 patients diagnosed with UC were included in the study. WNT5A-L was the predominantly expressed isoform in urothelial cells, although WNT5A-S was also detectable. Further, although no statistically significant difference was found between the percentage of WNT5A-S transcripts in low-grade versus high-grade tumors, we did find a difference between the percentage of WNT5A-S transcripts found in non-invasion versus invasion of the lamina propria, subgroups of non-muscle-invasive tumors. In conclusion, both WNT5A-S and WNT5A-L isoforms are expressed in UC, and the percentage of their expression levels suggests that a higher proportion of WNT5A-S transcription may be associated with lamina propria invasion, a process preceding muscle invasion.

Monoclonal Antibodies and Antibody-drug Conjugates as Emerging Therapeutics for Breast Cancer Treatment

When breast cells divide and multiply out of control, it is called breast cancer. Symptoms include lump formation in the breast, a change in the texture or color of the breast, or a discharge from the nipple. Local or systemic therapy is frequently used to treat breast cancer. Surgical and radiation procedures limited to the affected area are examples of local management. There has been significant worldwide progress in the development of monoclonal antibodies (mAbs) since 1986, when the first therapeutic mAb, Orthoclone OKT3, became commercially available. mAbs can resist the expansion of cancer cells by inducing the destruction of cellular membranes, blocking immune system inhibitors, and preventing the formation of new blood vessels. mAbs can also target growth factor receptors. Understanding the molecular pathways involved in tumor growth and its microenvironment is crucial for developing effective targeted cancer therapeutics. Due to their unique properties, mAbs have a wide range of clinical applications. Antibody-drug conjugates (ADCs) are drugs that improve the therapeutic index by combining an antigen-specific antibody with a payload. This review focuses on the therapeutic applications, mechanistic insights, characteristics, safety aspects, and adverse events of mAbs like trastuzumab, bevacizumab, pertuzumab, ertumaxomab, and atezolizumab in breast cancer treatment. The creation of novel technologies utilizing modified antibodies, such as fragments, conjugates, and multi-specific antibodies, must be a central focus of future studies. This review will help scientists working on developing mAbs to treat cancers more effectively.

ROR2 deficit may induce the tetralogy of Fallot via down-regulating of β-catenin/SOX3/HSPA6 in vitro and in vivo

Tetralogy of Fallot (TOF) is the highly conventional appearance of cyanotic congenital heart disease. Our study aimed to assess the involvement of receptor tyrosine kinase-like orphan receptor 2 (ROR2) in TOF and elucidate the specific mechanism. Upon investigation of human tissue samples, we observed a decrease in ROR2 expression in TOF patients compared to healthy control individuals. Transcriptome analysis revealed diminished ROR2 expression in TOF pathological samples relative to normal tissues. Of the 2246 genes that exhibited altered expression, 886 were upregulated, while 1360 were down-regulated. KEGG analysis and GO analysis of the differentially expressed genes indicated that these genes were significantly enriched in the Wnt signalling pathway, apoptosis and cardiac development function. Importantly, ROR2 was the only gene shared among the three pathways. Furthermore, interference with ROR2 promotes apoptosis and curtails cell proliferation in vitro. The knockdown of the ROR2 gene in AC16 cells resulted in a significant decrease in Edu-positive cells. Flow cytometry studies indicated an increase in the percentage of cells in the S phase. In contrast, the G2/M cell cycle transition was blocked in the ROR2-knockdown group, leading to a significant increase in apoptosis. Moreover, the CCK-8 cell viability assay demonstrated a reduced proliferation in the ROR2-knockdown group. Furthermore, both in vivo and in vitro data indicated that the expression of HSPA6 (Recombinant Heat Shock 70 kDa Protein6), an essential gene enriched in cardiac tissue and associated with apoptosis, was down-regulated following ROR2 knockdown mediated by the β-catenin/SOX3 signalling pathway. In conclusion, low expression of ROR2 plays a crucial role in the occurrence and development of TOF, which may be related to the downregulation of HSPA6 through the β-catenin/SOX3 signalling pathway.

Association of baseline ROR1 and ROR2 gene expression with clinical outcomes in the I-SPY2 neoadjuvant breast cancer trial

PURPOSE

ROR1 and ROR2 are Type 1 tyrosine kinase-like orphan receptors for Wnt5a that are associated with breast cancer progression. Experimental agents targeting ROR1 and ROR2 are in clinical trials. This study evaluated whether expression levels of ROR1 or ROR2 correlated with one another or with clinical outcomes.

METHODS

We interrogated the clinical significance of high-level gene expression of ROR1 and/or ROR2 in the annotated transcriptome dataset from 989 patients with high-risk early breast cancer enrolled in one of nine completed/graduated/experimental and control arms in the neoadjuvant I-SPY2 clinical trial (NCT01042379).

RESULTS

High ROR1 or high ROR2 was associated with breast cancer subtypes. High ROR1 was more prevalent among hormone receptor-negative and human epidermal growth factor receptor 2-negative (HR-HER2-) tumors and high ROR2 was less prevalent in this subtype. Although not associated with pathologic complete response, high ROR1 or high ROR2 each was associated with event-free survival (EFS) in distinct subtypes. High ROR1 associated with a worse EFS in HR + HER2- patients with high post-treatment residual cancer burden (RCB-II/III) (HR 1.41, 95% CI = 1.11-1.80) but not in patients with minimal post-treatment disease (RCB-0/I) (HR 1.85, 95% CI = 0.74-4.61). High ROR2 associated with an increased risk of relapse in patients with HER2 + disease and RCB-0/I (HR 3.46, 95% CI = 1.33-9.020) but not RCB-II/III (HR 1.07, 95% CI = 0.69-1.64).

CONCLUSION

High ROR1 or high ROR2 distinctly identified subsets of breast cancer patients with adverse outcomes. Further studies are warranted to determine if high ROR1 or high ROR2 may identify high-risk populations for studies of targeted therapies.

Dynamic tumor microenvironment, molecular heterogeneity, and distinct immunologic portrait of triple-negative breast cancer: an impact on classification and treatment approaches

Heterogeneity of the tumor microenvironment (TME) and the lack of a definite targetable receptor in triple-negative breast cancer (TNBC) has carved a niche for this cancer as a particularly therapeutically challenging form of breast cancer. However, recent advances in high-throughput genomic analysis have provided new insights into the unique microenvironment and defining characteristics of various subsets of TNBC. This improved understanding has contributed to the development of novel therapeutic strategies including targeted therapies such as PARP inhibitors and CDK inhibitors. Moreover, the recent FDA approval of the immune checkpoint inhibitor against programmed cell death protein 1 (PD-1), pembrolizumab and atezolizumab, holds the promise of improving the quality of life and increasing the overall survival of TNBC patients. This recent approval is one of the many therapeutically novel strategies that are currently being exploited in clinical trials toward eventual contribution to the oncologist's toolbox against TNBC. In this review, we comprehensively discuss TNBC's distinct TME and its immunophenotype. Furthermore, we highlight the histological and molecular classification of this cancer. More importantly, we describe how these characteristics and classifications contribute to the current standards of care and how they steer the development of newer and more targeted therapies toward achieving peak therapeutic goals in the treatment of TNBC.

The evolving therapeutic landscape of antibody-drug conjugates in breast cancer

INTRODUCTION

Antibody-drug conjugates (ADCs) are a relatively new class of anti-cancer therapies approved for a number of malignancies, including breast cancer. Their unique structure, consisting of a monoclonal antibody connected via a linker to a toxic payload, combines characteristics of both targeted therapy and chemotherapy.

AREAS COVERED

In this review, we discuss the unique molecular structure and pharmacologic principles of ADCs and present the clinical efficacy and relevant toxicities of ADCs both approved and in development. While HER2 is the most studied target with approved agents for both HER2-positive and HER2-low expressing tumors, novel targets in HER2-negative disease have expanded our therapeutic capabilities significantly.

EXPERT OPINION

ADCs are a promising, novel drug class with significant efficacy in all breast cancer subtypes. They are generally safe and well-tolerated. However, further research is necessary to improve their therapeutic potential. The development of predictive biomarkers to identify patients with greatest benefit, improved understanding of drug resistance to advance combination therapies, and novel targets are needed to further the field.

High-Throughput Profiling of Colorectal Cancer Liver Metastases Reveals Intra- and Inter-Patient Heterogeneity in the EGFR and WNT Pathways Associated with Clinical Outcome

Simple Summary

Tumor heterogeneity can greatly influence therapy outcome and patient survival. In this study, we aimed at unraveling inter- and intra-patient heterogeneity of colorectal cancer liver metastases (CRLM). To this end, we comprehensively characterized CRLM using state-of-the-art high-throughput technologies combined with bioinformatics analyses. We found a high degree of inter- and intra-patient heterogeneity among the metastases, in particular in genes of the WNT and EGFR pathways. Through analyzing the master regulators and effectors associated with the regulation of these genes, we identified a specific gene signature that was highly expressed in a large cohort of colorectal cancer patients and associated with clinical outcome.

Abstract

Seventy percent of patients with colorectal cancer develop liver metastases (CRLM), which are a decisive factor in cancer progression. Therapy outcome is largely influenced by tumor heterogeneity, but the intra- and inter-patient heterogeneity of CRLM has been poorly studied. In particular, the contribution of the WNT and EGFR pathways, which are both frequently deregulated in colorectal cancer, has not yet been addressed in this context. To this end, we comprehensively characterized normal liver tissue and eight CRLM from two patients by standardized histopathological, molecular, and proteomic subtyping. Suitable fresh-frozen tissue samples were profiled by transcriptome sequencing (RNA-Seq) and proteomic profiling with reverse phase protein arrays (RPPA) combined with bioinformatic analyses to assess tumor heterogeneity and identify WNT- and EGFR-related master regulators and metastatic effectors. A standardized data analysis pipeline for integrating RNA-Seq with clinical, proteomic, and genetic data was established. Dimensionality reduction of the transcriptome data revealed a distinct signature for CRLM differing from normal liver tissue and indicated a high degree of tumor heterogeneity. WNT and EGFR signaling were highly active in CRLM and the genes of both pathways were heterogeneously expressed between the two patients as well as between the synchronous metastases of a single patient. An analysis of the master regulators and metastatic effectors implicated in the regulation of these genes revealed a set of four genes (SFN, IGF2BP1, STAT1, PIK3CG) that were differentially expressed in CRLM and were associated with clinical outcome in a large cohort of colorectal cancer patients as well as CRLM samples. In conclusion, high-throughput profiling enabled us to define a CRLM-specific signature and revealed the genes of the WNT and EGFR pathways associated with inter- and intra-patient heterogeneity, which were validated as prognostic biomarkers in CRC primary tumors as well as liver metastases.

The Ror-Family Receptors in Development, Tissue Regeneration and Age-Related Disease

The Ror-family proteins, Ror1 and Ror2, act as receptors or co-receptors for Wnt5a and its related Wnt proteins to activate non-canonical Wnt signaling. Ror1 and/or Ror2-mediated signaling plays essential roles in regulating cell polarity, migration, proliferation and differentiation during developmental morphogenesis, tissue-/organo-genesis and regeneration of adult tissues following injury. Ror1 and Ror2 are expressed abundantly in developing tissues in an overlapping, yet distinct manner, and their expression in adult tissues is restricted to specific cell types such as tissue stem/progenitor cells. Expression levels of Ror1 and/or Ror2 in the adult tissues are increased following injury, thereby promoting regeneration or repair of these injured tissues. On the other hand, disruption of Wnt5a-Ror2 signaling is implicated in senescence of tissue stem/progenitor cells that is related to the impaired regeneration capacity of aged tissues. In fact, Ror1 and Ror2 are implicated in age-related diseases, including tissue fibrosis, atherosclerosis (or arteriosclerosis), neurodegenerative diseases, and cancers. In these diseases, enhanced and/or sustained (chronic) expression of Ror1 and/or Ror2 is observed, and they might contribute to the progression of these diseases through Wnt5a-dependent and -independent manners. In this article, we overview recent advances in our understanding of the roles of Ror1 and Ror2-mediated signaling in the development, tissue regeneration and age-related diseases, and discuss their potential to be therapeutic targets for chronic inflammatory diseases and cancers.

VIVA1: a more invasive subclone of MDA-MB-134VI invasive lobular carcinoma cells with increased metastatic potential in xenograft models

BACKGROUND

Invasive lobular carcinoma (ILC) is the second most common type of breast cancer. As few tools exist to study ILC metastasis, we isolated ILC cells with increased invasive properties to establish a spontaneously metastasising xenograft model.

METHODS

MDA-MB-134VI ILC cells were placed in transwells for 7 days. Migrated cells were isolated and expanded to create the VIVA1 cell line. VIVA1 cells were compared to parental MDA-MB-134VI cells in vitro for ILC marker expression and relative proliferative and invasive ability. An intraductally injected orthotopic xenograft model was used to assess primary and metastatic tumour growth in vivo.

RESULTS

Similar to MDA-MB-134VI, VIVA1 cells retained expression of oestrogen receptor (ER) and lacked expression of E-cadherin, however showed increased invasion in vitro. Following intraductal injection, VIVA1 and MDA-MB-134VI cells had similar primary tumour growth and survival kinetics. However, macrometastases were apparent in 7/10 VIVA1-injected animals. Cells from a primary orthotopic tumour (VIVA-LIG43) were isolated and showed similar proliferative rates but were also more invasive than parental cells. Upon re-injection intraductally, VIVA-LIG43 cells had more rapid tumour growth with similar metastatic incidence and location.

CONCLUSIONS

We generated a new orthotopic spontaneously metastasising xenograft model for ER+ ILC amenable for the study of ILC metastasis.

Cellular and molecular mechanisms implicated in the dual role of ROR2 in cancer

ROR1 and ROR2 are Wnt receptors that are critical for β-catenin-independent Wnt pathways and have been linked to processes driving tumor progression, such as cell proliferation, survival, invasion, and therapy resistance. Both receptors have garnered interest as potential therapeutic targets since they are largely absent in adult tissue, are overexpressed in several cancers, and, as members of the receptor tyrosine kinase family, are easier to target than all other components of the pathway. Unlike ROR1 which always promotes tumorigenesis, ROR2 has a very complex role in cancer acting either to promote or inhibit tumor progression in different tumor types. In the present article, we summarize the findings on ROR2 expression in cancer patients and its impact on clinical outcome. Further, we review the biological processes and signaling pathways regulated by ROR2 that explain its dual role in cancer. Finally, we describe the ongoing strategies to target ROR2 in cancer.

WNT11/ROR2 signaling is associated with tumor invasion and poor survival in breast cancer

BACKGROUND

Breast cancer has been associated with activation of the WNT signaling pathway, although no driver mutations in WNT genes have been found yet. Instead, a high expression of the alternative WNT receptor ROR2 was observed, in particular in breast cancer brain metastases. However, its respective ligand and downstream signaling in this context remained unknown.

METHODS

We modulated the expression of ROR2 in human breast cancer cells and characterized their gene and protein expression by RNA-Seq, qRT-PCR, immunoblots and reverse phase protein array (RPPA) combined with network analyses to understand the molecular basis of ROR2 signaling in breast cancer. Using co-immunoprecipitations, we verified the interaction of ROR2 with the identified ligand, WNT11. The functional consequences of WNT11/ROR2 signaling for tumor cell aggressiveness were assessed by microscopy, impedance sensing as well as viability and invasion assays. To evaluate the translational significance of our findings, we performed gene set enrichment, expression and survival analyses on human breast cancer brain metastases.

RESULTS

We found ROR2 to be highly expressed in aggressive breast tumors and associated with worse metastasis-free survival. ROR2 overexpression induced a BRCAness-like phenotype in a cell-context specific manner and rendered cells resistant to PARP inhibition. High levels of ROR2 were furthermore associated with defects in cell morphology and cell-cell-contacts leading to increased tumor invasiveness. On a molecular level, ROR2 overexpression upregulated several non-canonical WNT ligands, in particular WNT11. Co-immunoprecipitation confirmed that WNT11 indeed interacts with the cysteine-rich domain of ROR2 and triggers its invasion-promoting signaling via RHO/ROCK. Knockdown of WNT11 reversed the pro-invasive phenotype and the cellular changes in ROR2-overexpressing cells.

CONCLUSIONS

Taken together, our study revealed a novel auto-stimulatory loop in which ROR2 triggers the expression of its own ligand, WNT11, resulting in enhanced tumor invasion associated with breast cancer metastasis.

ROR2 has a protective role in melanoma by inhibiting Akt activity, cell-cycle progression, and proliferation

BACKGROUND

Receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a Wnt5a receptor aberrantly expressed in cancer that was shown to either suppress or promote carcinogenesis in different tumor types. Our goal was to study the role of ROR2 in melanoma.

METHODS

Gain and loss-of-function strategies were applied to study the biological function of ROR2 in melanoma. Proliferation assays, flow cytometry, and western blotting were used to evaluate cell proliferation and changes in expression levels of cell-cycle and proliferation markers. The role of ROR2 in tumor growth was assessed in xenotransplantation experiments followed by immunohistochemistry analysis of the tumors. The role of ROR2 in melanoma patients was assessed by analysis of clinical data from the Leeds Melanoma Cohort.

RESULTS

Unlike previous findings describing ROR2 as an oncogene in melanoma, we describe that ROR2 prevents tumor growth by inhibiting cell-cycle progression and the proliferation of melanoma cells. The effect of ROR2 is mediated by inhibition of Akt phosphorylation and activity which, in turn, regulates the expression, phosphorylation, and localization of major cell-cycle regulators including cyclins (A, B, D, and E), CDK1, CDK4, RB, p21, and p27. Xenotransplantation experiments demonstrated that ROR2 also reduces proliferation in vivo, resulting in inhibition of tumor growth. In agreement with these findings, a higher ROR2 level favors thin and non-ulcerated primary melanomas with reduced mitotic rate and better prognosis.

CONCLUSION

We conclude that the expression of ROR2 slows down the growth of primary tumors and contributes to prolonging melanoma survival. Our results demonstrate that ROR2 has a far more complex role than originally described.

ROR1 and ROR2 expression in pancreatic cancer

BACKGROUND

The Wnt receptors ROR1 and ROR2 are generating increased interest as cancer therapeutic targets but remain understudied in pancreatic ductal adenocarcinoma (PDAC). Compared to canonical Wnt/ β-catenin signalling, the role of noncanonical Wnt signalling in PDAC remains largely unknown. Only one study has investigated the prognostic significance of the noncanonical Wnt signalling receptor, ROR2 in PDAC. No studies have investigated the prognostic role of ROR1 in PDAC.

METHODS

Here, we performed analysis of ROR1 and ROR2 mRNA expression in three publicly available datasets ICGC-PACA-AU (n = 81), TCGA-PAAD (n = 150) and CPTAC-PDAC (n = 137). ROR1 and ROR2 protein expression from the CPTAC-PDAC discovery cohort were also analysed. Immunohistochemistry (IHC) using the validated anti ROR1 monoclonal antibody (4A5) was performed on the Australian Pancreatic Cancer Genome Initiative (APGI) cohort of PDAC samples (n = 152). Association between ROR1 cytoplasmic staining intensity and clinicopathological parameters including stage, grade and overall survival (OS) was investigated.

RESULTS

High ROR1 mRNA expression levels correlated with a favourable OS outcome in all of the ICGC-PACA-AU, TCGA-PAAD and CPTAC-PDAC cohorts. ROR1 protein expression was not associated with stage, grade or OS in the APGI cohort.

CONCLUSION

ROR1 and ROR2 have potential as prognostic markers when measured at the mRNA level in PDAC. Our IHC cohort did not support ROR1 protein expression in predicting OS, and highlighted the discrepancy of prognostic biomarkers when measured by MS, IHC and RNAseq.

Breast cancer resistance mechanisms: challenges to immunotherapy

PURPOSE

The clinical implementation of immunotherapy has profoundly transformed cancer treatment. Targeting the immune system to mount anti-tumor responses can elicit a systemically durable response. Employing immune checkpoint blockade (ICB) has suppressed tumor growth and vastly improved patient overall and progression-free survival in several cancer types, most notably melanoma and non-small cell lung carcinoma. Despite widescale clinical success, ICB response is heterogeneously efficacious across tumor types. Many cancers, including breast cancer, are frequently refractory to ICB. In this review, we will discuss the challenges facing immunotherapy success and address the underlying mechanisms responsible for primary and acquired breast cancer resistance to immunotherapy.

FINDINGS

Even in initially ICB-responsive tumors, many acquire resistance due to tumor-specific alterations, loss of tumor-specific antigens, and extrinsic mechanisms that reshape the immune landscape within the tumor microenvironment (TME). The tumor immune interaction circumvents the benefits of immunotherapy; tumors rewire the tumor-suppressive functions of activated immune cells within their stroma to propagate tumor growth and progression.

CONCLUSIONS

The breast cancer immune TME is complex and the mechanisms driving resistance to ICB are multifaceted. Continued study in both preclinical models and clinical trials should help elucidate these mechanisms so they can be targeted to benefit more breast cancer patients.

Text mining-based word representations for biomedical data analysis and protein-protein interaction networks in machine learning tasks

Biomedical and life science literature is an essential way to publish experimental results. With the rapid growth of the number of new publications, the amount of scientific knowledge represented in free text is increasing remarkably. There has been much interest in developing techniques that can extract this knowledge and make it accessible to aid scientists in discovering new relationships between biological entities and answering biological questions. Making use of the word2vec approach, we generated word vector representations based on a corpus consisting of over 16 million PubMed abstracts. We developed a text mining pipeline to produce word2vec embeddings with different properties and performed validation experiments to assess their utility for biomedical analysis. An important pre-processing step consisted in the substitution of synonymous terms by their preferred terms in biomedical databases. Furthermore, we extracted gene-gene networks from two embedding versions and used them as prior knowledge to train Graph-Convolutional Neural Networks (CNNs) on large breast cancer gene expression data and on other cancer datasets. Performances of resulting models were compared to Graph-CNNs trained with protein-protein interaction (PPI) networks or with networks derived using other word embedding algorithms. We also assessed the effect of corpus size on the variability of word representations. Finally, we created a web service with a graphical and a RESTful interface to extract and explore relations between biomedical terms using annotated embeddings. Comparisons to biological databases showed that relations between entities such as known PPIs, signaling pathways and cellular functions, or narrower disease ontology groups correlated with higher cosine similarity. Graph-CNNs trained with word2vec-embedding-derived networks performed sufficiently good for the metastatic event prediction tasks compared to other networks. Such performance was good enough to validate the utility of our generated word embeddings in constructing biological networks. Word representations as produced by text mining algorithms like word2vec, therefore are able to capture biologically meaningful relations between entities. Our generated embeddings are publicly available at https://github.com/genexplain/Word2vec-based-Networks/blob/main/README.md.

The Cell Surface Receptors Ror1/2 Control Cardiac Myofibroblast Differentiation

Background A hallmark of heart failure is cardiac fibrosis, which results from the injury-induced differentiation response of resident fibroblasts to myofibroblasts that deposit extracellular matrix. During myofibroblast differentiation, fibroblasts progress through polarization stages of early proinflammation, intermediate proliferation, and late maturation, but the regulators of this progression are poorly understood. Planar cell polarity receptors, receptor tyrosine kinase-like orphan receptor 1 and 2 (Ror1/2), can function to promote cell differentiation and transformation. In this study, we investigated the role of the Ror1/2 in a model of heart failure with emphasis on myofibroblast differentiation. Methods and Results The role of Ror1/2 during cardiac myofibroblast differentiation was studied in cell culture models of primary murine cardiac fibroblast activation and in knockout mouse models that underwent transverse aortic constriction surgery to induce cardiac injury by pressure overload. Expression of Ror1 and Ror2 were robustly and exclusively induced in fibroblasts in hearts after transverse aortic constriction surgery, and both were rapidly upregulated after early activation of primary murine cardiac fibroblasts in culture. Cultured fibroblasts isolated from Ror1/2 knockout mice displayed a proinflammatory phenotype indicative of impaired myofibroblast differentiation. Although the combined ablation of Ror1/2 in mice did not result in a detectable baseline phenotype, transverse aortic constriction surgery led to the death of all mice by day 6 that was associated with myocardial hyperinflammation and vascular leakage. Conclusions Together, these results show that Ror1/2 are essential for the progression of myofibroblast differentiation and for the adaptive remodeling of the heart in response to pressure overload.

Antibody-Drug Conjugates Used in Breast Cancers

The prognosis of breast cancer has radically changed in recent years and continues to improve due to the broad application of effective therapies. New targeting strategies including targeted delivery of cytotoxic drugs via receptor-targeting agents have been developed. We summarize recent publications and developments of novel antibody-drug conjugates (ADCs) used to control breast cancer.

Wnt signaling related transcripts and their relationship to energy metabolism in C2C12 myoblasts under temperature stress

Temperature stress is one of the main environmental stressors affecting the welfare, health and productivity of livestock. Temperature changes can modify cell membrane components, disrupting the crosstalk between the cell and its surroundings by affecting signaling pathways including Wnt signaling pathway, which subsequently disrupts cell energy metabolism. The present study aims to understand the effect of temperature stress on the expression of genes involved in Wnt signaling pathways, and their interaction with energy metabolism in C2C12 myoblasts cells. The C2C12 cells were exposed to cold stress (35 °C), mild heat stress (39 °C) and severe heat stress (41 °C), whereas 37 °C was used as control temperature. Transcript levels of important genes involved in Wnt signaling including Axin2, Tnks2, Sfrp1, Dkk1, Dact1, Cby1, Wnt5a, Wnt7a, Wnt11, Porcn, Ror2, Daam1, and Ppp3ca were significantly altered under severe heat stress (41 °C), whereas eight Wnt signaling-related transcripts (Daam1, Ppp3ca, Fzd7, Wnt5a, Porcn, Tnks2, Lrp6, and Aes) were significantly altered under cold stress (35 °C) compared to control. Under heat stress transcripts of the Wnt/β-catenin inhibitors (Sfrp1, Dkk1, and Cby1) and negative regulators (Dact1 and Axin2) are activated. A positive correlation between oxidative phosphorylation and Wnt-related transcripts was found under high temperatures. Transcripts of the cell membrane receptors, including Lrp6 and Fzd7, and the members of Wnt/Ca⁺² signaling pathway, including Ppp3ca and Porcn were downregulated under cold stress. Many Wnt signaling-related transcripts were positively correlated with glycolysis under cold stress. These findings indicate a cross-talk between Wnt signaling and energy metabolism under thermal stress.

Explaining decisions of graph convolutional neural networks: patient-specific molecular subnetworks responsible for metastasis prediction in breast cancer

Background

Contemporary deep learning approaches show cutting-edge performance in a variety of complex prediction tasks. Nonetheless, the application of deep learning in healthcare remains limited since deep learning methods are often considered as non-interpretable black-box models. However, the machine learning community made recent elaborations on interpretability methods explaining data point-specific decisions of deep learning techniques. We believe that such explanations can assist the need in personalized precision medicine decisions via explaining patient-specific predictions.

Methods

Layer-wise Relevance Propagation (LRP) is a technique to explain decisions of deep learning methods. It is widely used to interpret Convolutional Neural Networks (CNNs) applied on image data. Recently, CNNs started to extend towards non-Euclidean domains like graphs. Molecular networks are commonly represented as graphs detailing interactions between molecules. Gene expression data can be assigned to the vertices of these graphs. In other words, gene expression data can be structured by utilizing molecular network information as prior knowledge. Graph-CNNs can be applied to structured gene expression data, for example, to predict metastatic events in breast cancer. Therefore, there is a need for explanations showing which part of a molecular network is relevant for predicting an event, e.g., distant metastasis in cancer, for each individual patient.

Results

We extended the procedure of LRP to make it available for Graph-CNN and tested its applicability on a large breast cancer dataset. We present Graph Layer-wise Relevance Propagation (GLRP) as a new method to explain the decisions made by Graph-CNNs. We demonstrate a sanity check of the developed GLRP on a hand-written digits dataset and then apply the method on gene expression data. We show that GLRP provides patient-specific molecular subnetworks that largely agree with clinical knowledge and identify common as well as novel, and potentially druggable, drivers of tumor progression.

Conclusions

The developed method could be potentially highly useful on interpreting classification results in the context of different omics data and prior knowledge molecular networks on the individual patient level, as for example in precision medicine approaches or a molecular tumor board.

Supplementary Information

The online version contains supplementary material available at (10.1186/s13073-021-00845-7).

The WNT/ROR Pathway in Cancer: From Signaling to Therapeutic Intervention

The WNT pathway is one of the major signaling cascades frequently deregulated in human cancer. While research had initially focused on signal transduction centered on β-catenin as a key effector activating a pro-tumorigenic transcriptional response, nowadays it is known that WNT ligands can also induce a multitude of β-catenin-independent cellular pathways. Traditionally, these comprise WNT/planar cell polarity (PCP) and WNT/Ca²⁺ signaling. In addition, signaling via the receptor tyrosine kinase-like orphan receptors (RORs) has gained increasing attention in cancer research due to their overexpression in a multitude of tumor entities. Active WNT/ROR signaling has been linked to processes driving tumor development and progression, such as cell proliferation, survival, invasion, or therapy resistance. In adult tissue, the RORs are largely absent, which has spiked the interest in them for targeted cancer therapy. Promising results in preclinical and initial clinical studies are beginning to unravel the great potential of such treatment approaches. In this review, we summarize seminal findings on the structure and expression of the RORs in cancer, their downstream signaling, and its output in regard to tumor cell function. Furthermore, we present the current clinical anti-ROR treatment strategies and discuss the state-of-the-art, as well as the challenges of the different approaches.

Non-Canonical WNT5A Signaling Through RYK Contributes to Aggressive Phenotype of the Rheumatoid Fibroblast-Like Synoviocytes

We hypothesized that WNT5A could contribute to the enhanced migration and invasiveness of rheumatoid arthritis fibroblast-like synoviocytes (RA FLS), which is one of the incompletely understood aspects of the RA FLS aggressive phenotype. This hypothesis is based on the previous evidence of a WNT5A role in both, RA and cell migration. Migration and invasion of RA FLS were assessed after incubation with recombinant Wnt5a (rWnt5a) or silencing of the endogenous WNT5A expression. The expression of WNT5A, WNT receptors, cytokines, chemokines, and metalloproteinases was quantified with RT-PCR. The WNT pathway was explored with gene silencing, antibody and pharmacological inhibition followed by migration assays and phosphoprotein western blots. Here, we reported that rWnt5a promoted migration and invasion of RA FLS, whereas knockdown of the endogenous WNT5A reduced them. These effects were specific to the RA FLS since they were not observed in FLS from osteoarthritis (OA) patients. Also, rWnt5a induced the expression of IL6, IL8, CCL2, CXCL5, MMP1, MMP3, MMP9, and MMP13 from baseline or potentiating the TNF induction, WNT5A signaling required the RYK receptor and was mediated through the WNT/Ca²⁺ and the ROCK pathway. These pathways involved the RYK and ROCK dependent activation of the p38, ERK, AKT, and GSK3β kinases, but not the activation of JNK. Together these findings indicate that WNT5A contributes to the enhanced migration and invasiveness of RA FLS through RYK and the specific activation of ROCK and downstream kinases.

ROR2 knockdown suppresses breast cancer growth through PI3K/ATK signaling

The receptor tyrosine kinase like orphan receptor 2 (ROR2) has been implicated in the pathogenesis of a variety of human cancers, including breast cancer. Here, we analyzed the clinical significance of ROR2 in breast cancer (BC) progression, and its function in the regulation of BC cell proliferation and growth. Analysis of ROR2 mRNA levels in 45 BC tissues and adjacent non-tumor tissues revealed that ROR2 expression was significantly increased in BC tissues, and that it correlated with tumor diameter. Kaplan-Meier disease-free survival (DFS) analysis demonstrated that BC patients with higher ROR2 expression had lower DFS. Knockdown of ROR2 suppressed in vitro proliferation of BC cells and promoted apoptosis, while ROR2 overexpression induced BC cell proliferation and suppressed apoptosis. Importantly, ROR2 suppression also reduced the tumor growth in mouse BC xenografts, indicating that ROR2 promotes BC tumorigenesis in vivo. In addition, our data revealed that ROR2 promotes proliferation of BC cells by activating the PI3K/AKT signaling pathway. Together, our results indicate that ROR2 acts as an oncogenic gene in breast cancer, and suggest that the ROR2/PI3K/AKT regulatory network contributes to breast cancer progression.

Novel antibody-drug conjugates for triple negative breast cancer

Triple negative breast cancer (TNBC) is a heterogenous subtype of breast cancer often associated with an aggressive phenotype and poor prognosis. Antibody–drug conjugate (ADC), comprising of a monoclonal antibody linked to a cytotoxic payload by a linker, is gaining increasing traction as an anti-cancer therapeutic. Emerging ADC drugs such as sacituzumab govitecan (IMMU-132) and trastuzumab deruxtecan (DS-8201a) are in late stages of clinical development for patients with metastatic breast cancer, including TNBC. In this article, we review and discuss the development and clinical application of ADCs in patients with advanced TNBC.

ROR2 promotes the epithelial-mesenchymal transition by regulating MAPK/p38 signaling pathway in breast cancer

Receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a tyrosine-protein kinase receptor highly implicated in the growth plate and cartilage development, which may be involved in epithelial-mesenchymal transition (EMT) in breast cancer (BC) cells. Although ROR2 is known to promote the migration of BC cells, the detailed mechanism of this event is still not clear. Here, we found that ROR2 expression was significantly increased in BC lymphatic metastatic tissue as well as BC samples compared to normal adjacent breast tissues. A higher expression of ROR2 in MDA-MB-231 and a lower expression of ROR2 in MCF-7 cells were observed. MDA-MB-231-siROR2 cells with ROR2 knockdown inhibited MDA-MB-231 cell invasion, migration, and clonal formation, while MCF-7-OvROR2 cells with overexpression showed the opposite results. The underlying mechanisms involved in ROR2-induced EMT in MDA-MB-231 and MCF-7 cells were further investigated. ROR2 may activate EMT progression in BC cells by altering MAPK kinase 3/6 (MKK3/6) expression. The expressions of transforming growth factor-β, matrix metalloproteinase-2 (MMP-2), and MMP-9, which were related to tumor cell invasion activities, were notably increased in MCF-7-OvROR2 cells. The EMT markers, including snail, N-cadherin, tissue inhibitor of metalloproteinases-1, and vimentin, were significantly upregulated in MCF-7-OvROR2 cells. On the contrary, E-cadherin was obviously reduced expressed in MCF-7-OvROR2 cells. ROR2 may regulate the malignant phenotype of BC cells possibly via activation of mitogen-activated protein kinase (MAPK)/p38 signaling pathway. Collectively, ROR2 promotes BC carcinogenesis by mediating the MAPK/p38 pathway, which is independent of Wnt5α.

Purification and characterization of the extracellular region of human receptor tyrosine kinase like orphan receptor 2 (ROR2)

Receptor tyrosine kinase like orphan receptor 2 (ROR2) is a co-receptor for some Wnt proteins including Wnt5a that activate the noncanonical Wnt/planar cell polarity (PCP) signaling pathway. Upregulation of ROR2 is associated with several cancer forms. The extracellular region of ROR2, which contains an immunoglobulin (Ig)-like domain, a Frizzled like cysteine-rich domain (CRD) and a Kringle domain, is a potential anticancer drug target. The structural and biochemical properties of the ROR2 extracellular region remain largely unexplored. Here we describe the mapping and purification, using a baculovirus - insect cell system, of a near-full-length ROR2 extracellular fragment (residues 53-402), which is well-behaved and suitable for future structural and biochemical analysis. We show that the extracellular region of ROR2 per se is monomeric in solution. Different monoclonal antibodies raised against the purified ROR2 protein can specifically recognize the protein and can either inhibit or activate the PCP activity in a cell-based assay, and are thus potentially useful for future mechanistic and therapeutic/diagnostic studies. The biological relevance of these antibodies further demonstrates that the purified recombinant ROR2 protein is properly folded and biochemically active.

A high-throughput integrated microfluidics method enables tyrosine autophosphorylation discovery

Autophosphorylation of receptor and non-receptor tyrosine kinases is a common molecular switch with broad implications for pathogeneses and therapy of cancer and other human diseases. Technologies for large-scale discovery and analysis of autophosphorylation are limited by the inherent difficulty to distinguish between phosphorylation and autophosphorylation in vivo and by the complexity associated with functional assays of receptors kinases in vitro. Here, we report a method for the direct detection and analysis of tyrosine autophosphorylation using integrated microfluidics and freshly synthesized protein arrays. We demonstrate the efficacy of our platform in detecting autophosphorylation activity of soluble and transmembrane tyrosine kinases, and the dependency of in vitro autophosphorylation assays on membranes. Our method, Integrated Microfluidics for Autophosphorylation Discovery (IMAD), is high-throughput, requires low reaction volumes and can be applied in basic and translational research settings. To our knowledge, it is the first demonstration of posttranslational modification analysis of membrane protein arrays.

Novel Antibody Drug Conjugates Targeting Tumor-Associated Receptor Tyrosine Kinase ROR2 by Functional Screening of Fully Human Antibody Libraries Using Transpo-mAb Display on Progenitor B Cells

Receptor tyrosine kinase-like orphan receptor 2 (ROR2) has been identified as a highly relevant tumor-associated antigen in a variety of cancer indications of high unmet medical need, including renal cell carcinoma and osteosarcoma, making it an attractive target for targeted cancer therapy. Here, we describe the de novo discovery of fully human ROR2-specific antibodies and potent antibody drug conjugates (ADCs) derived thereof by combining antibody discovery from immune libraries of human immunoglobulin transgenic animals using the Transpo-mAb mammalian cell-based IgG display platform with functional screening for internalizing antibodies using a secondary ADC assay. The discovery strategy entailed immunization of transgenic mice with the cancer antigen ROR2, harboring transgenic IgH and IgL chain gene loci with limited number of fully human V, D, and J gene segments. This was followed by recovering antibody repertoires from the immunized animals, expressing and screening them as full-length human IgG libraries by transposon-mediated display in progenitor B lymphocytes ("Transpo-mAb Display") for ROR2 binding. Individual cellular "Transpo-mAb" clones isolated by single cell sorting and capable of expressing membrane-bound as well as secreted human IgG were directly screened during antibody discovery, not only for high affinity binding to human ROR2, but also functionally as ADCs using a cytotoxicity assay with a secondary anti-human IgG-toxin-conjugate. Using this strategy, we identified and validated 12 fully human, monoclonal anti-human ROR2 antibodies with nanomolar affinities that are highly potent as ADCs and could be promising candidates for the therapy of human cancer. The screening for functional and internalizing antibodies during the early phase of antibody discovery demonstrates the utility of the mammalian cell-based Transpo-mAb Display platform to select for functional binders and as a powerful tool to improve the efficiency for the development of therapeutically relevant ADCs.

The biochemistry, signalling and disease relevance of RYK and other WNT-binding receptor tyrosine kinases

The receptor tyrosine kinases (RTKs) are a well-characterized family of growth factor receptors that have central roles in human disease and are frequently therapeutically targeted. The RYK, ROR, PTK7 and MuSK subfamilies make up an understudied subset of WNT-binding RTKs. Numerous developmental, stem cell and pathological roles of WNTs, in particular WNT5A, involve signalling via these WNT receptors. The WNT-binding RTKs have highly context-dependent signalling outputs and stimulate the β-catenin-dependent, planar cell polarity and/or WNT/Ca²⁺ pathways. RYK, ROR and PTK7 members have a pseudokinase domain in their intracellular regions. Alternative signalling mechanisms, including proteolytic cleavage and protein scaffolding functions, have been identified for these receptors. This review explores the structure, signalling, physiological and pathological roles of RYK, with particular attention paid to cancer and the possibility of therapeutically targeting RYK. The other WNT-binding RTKs are compared with RYK throughout to highlight the similarities and differences within this subset of WNT receptors.

WNT5A promotes migration and invasion of human osteosarcoma cells via SRC/ERK/MMP-14 pathway

WNT5A, a representative ligand of activating several non-canonical WNT signal pathways, plays significant roles in oncogenesis and tumor inhibition. It has been shown that the non-receptor tyrosine kinase SRC is required for WNT5A-induced invasion of osteosarcoma cells. However, the precise molecular mechanism underlying WNT5A/SRC-mediated osteosarcoma cells invasion remains poorly defined. The study was designed to explore the role of ERK1/2 in WNT5A/SRC-induced osteosarcoma cells invasion and the downstream target of the SRC/ERK1/2 signalings. We found that WNT5A (100 ng/mL) remarkably stimulated migration and invasion of human osteosarcoma MG-63 cells, whereas inhibiting either SRC kinase activity by siRNA-mediated SRC silence or ERK1/2 phosphorylation by PD98059 treatment suppressed these effects, which suggested that the activation of SRC and ERK1/2 is essential for WNT5A-induced MG-63 cells migration and invasion. Furthermore, ERK1/2 phosphorylation induced by WNT5A was dramatically blocked by SRC siRNA. Additionally, our study further demonstrated that MMP-14 was upregulated after exposure to WNT5A in MG-63 cells, and the increased expression was blocked by SRC siRNA or PD98059. Collectively, these results indicate that WNT5A activates SRC/ERK1/2 signal pathway, leading to the upregulation of MMP-14 expression and MG-63 cells migration and invasion.

Breast cancer: Lesser-known facets and hypotheses

Breast cancer is the most common cancer in females. The deteriorating environment, and lifestyle flaws are raising the frequency of this cancer. Existing therapies are not universally-effective, and they cause side effects, relapses, and high mortality rate. Alternative medications may be milder, but are less effective or are inadequate for a complex disease like the breast cancer. So, it requires the understanding that drugs are not the solution of this cancer, but prevention is the sustainable solution. In the past decades, an enormous quantum of insights on this disease has been obtained. A lifestyle based on the template of estrogenic compounds and, the resultant endocrine disruption, and acidosis, is elevating aromatase level, promoting the deleterious forms of estrogen, and inducing epithelial proliferation. This review provids a holistic account of breast cancer as a inflammatory endocrinopathy, and how it can be curbed by discipline, and awareness.