Nectin 4 overexpression in ovarian cancer tissues and serum: potential role as a serum biomarker

Development and validation of bioanalytical assays for the quantification of 9MW2821, a nectin-4-targeting antibody-drug conjugate

We designed and developed 9MW2821, an anti-Nectin-4 antibody-drug conjugate (ADC) with an enzymatically cleavable valine-citrulline linker and monomethyl auristatin E (MMAE) as the payload. Four bioanalytical assays for total antibodies, conjugated antibodies, conjugated payload, and free payload were then developed and validated for the comprehensive evaluation of the multiple drug forms of 9MW2821. Specific sandwich enzyme-linked immunosorbent assays were used to quantify total antibodies and conjugated antibody, showing good drug-to-antibody ratio (DAR) tolerance. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine free MMAE, and conjugated MMAE was quantified using a combination of ligand-binding assay (LBA) and LC-MS/MS. Based on these four assays, we studied the serum stability and monkey pharmacokinetic profiles of 9MW2821, and the in vivo DAR of 9MW2821 was calculated and dynamically monitored. In conclusion, we developed and validated series of bioanalytical assays to quantify multiple forms of 9MW2821, a new ADC, and used the assays to evaluate the serum stability and monkey pharmacokinetic characteristics. The results indicate good linker stability and suggest that the developed assays can be further used in clinical settings.

Nectin-4-directed antibody-drug conjugates (ADCs): Spotlight on preclinical and clinical evidence

Nectin-4 (Nectin cell adhesion molecule 4), a type I transmembrane cell adhesion protein, was demonstrated to be overexpressed in a variety of tumors, making it an attractive antigen for targeted therapies such as antibody-drug conjugates (ADCs). Of great note, the US Food and Drug Administration (FDA)-approval of the first Nectin-4-directed ADC, enfortumab vedotin (EV), in urothelial cancer (UC) not only introduced Nectin-4 as a clinically validated and reliable target antigen but also confirmed the evolving role of Nectin-4-directed ADCs as novel and promising cancer therapeutics. In addition to EV, there have been or are currently being seven and eleven Nectin-4-directed ADCs, respectively, in various stages of clinical trials and preclinical development, offering a promising future for the treatment of Nectin-4-positive cancer patients. This study reviewed clinical- and preclinical-stage Nectin-4-directed ADCs.

Translational PET Imaging of Nectin-4 Expression in Multiple Different Cancers with 68Ga-N188

Nectin cell adhesion molecule 4 (nectin-4) is a transmembrane protein overexpressed on a variety of cancers and plays an important role in oncogenic and metastatic processes. The nectin-4-targeted antibody-drug conjugate enfortumab vedotin has been approved for treating locally advanced or metastatic urothelial cancer, but the efficacy in other types of cancer remains to be explored. The aim of this study was to evaluate the feasibility of nectin-4-targeted PET imaging with 68Ga-N188 as a noninvasive method to quantify membranous nectin-4 expression in multiple tumor types-an approach that may provide insight for patient stratification and treatment selection. Methods: Sixty-two patients with 16 types of cancer underwent head-to-head 68Ga-N188 and 18F-FDG PET/CT imaging for initial staging or detection of recurrence and metastases. Correlation between lesion SUVmax and nectin-4 expression determined by immunohistochemistry staining was analyzed in 36 of 62 patients. Results: The SUVmax of 68Ga-N188 had a positive correlation with membranous nectin-4 expression in the various tumor types tested (r = 0.458; P = 0.005), whereas no association was observed between the SUVmax and cytoplasmic nectin-4 expression. The detection rates for patient-based analysis of 68Ga-N188 and 18F-FDG PET/CT examinations were comparable (95.00% [57/60] vs. 93.33% [56/60]). In patients with pancreatic cancer, 68Ga-N188 exhibited a potential advantage for detecting residual or locally recurrent tumors; this advantage may assist in clinical decision-making. Conclusion: The correlation between nectin-4-targeted 68Ga-N188 PET imaging and membranous nectin-4 expression indicates the potential of 68Ga-N188 as an effective tool for selecting patients who may benefit from enfortumab vedotin treatment. The PET imaging results provided evidence to explore nectin-4-targeted therapy in a variety of tumors. 68Ga-N188 may improve the restaging of pancreatic cancer but requires further evaluation in a powered, prospective setting.

Therapeutic prospects of nectin-4 in cancer: applications and value

Nectin-4 is a Ca2+-independent immunoglobulin-like protein that exhibits significantly elevated expression in malignant tumors while maintaining extremely low levels in healthy adult tissues. In recent years, overexpression of Nectin-4 has been implicated in tumor occurrence and development of various cancers, including breast cancer, urothelial cancer, and lung cancer. In 2019, the Food and Drug Administration approved enfortumab vedotin, the first antibody-drug conjugate targeting Nectin-4, for the treatment of urothelial carcinoma. This has emphasized the value of Nectin-4 in tumor targeted therapy and promoted the implementation of more clinical trials of enfortumab vedotin. In addition, many new drugs targeting Nectin-4 for the treatment of malignant tumors have entered clinical trials, with the aim of exploring potential new indications. However, the exact mechanisms by which Nectin-4 affects tumorigenesis and progression are still unclear, and the emergence of drug resistance and treatment-related adverse reactions poses challenges. This article reviews the diagnostic potential, prognostic significance, and molecular role of Nectin-4 in tumors, with a focus on clinical trials in the field of Nectin-4-related tumor treatment and the development of new drugs targeting Nectin-4.

Combination of Oncolytic Virotherapy with Different Antitumor Approaches against Glioblastoma

Glioblastoma is one of the most malignant and aggressive tumors of the central nervous system. Despite the standard therapy consisting of maximal surgical resection and chemo- and radiotherapy, the median survival of patients with this diagnosis is about 15 months. Oncolytic virus therapy is one of the promising areas for the treatment of malignant neoplasms. In this review, we have focused on emphasizing recent achievements in virotherapy, both as a monotherapy and in combination with other therapeutic schemes to improve survival rate and quality of life among patients with glioblastoma.

Production and characterization of single-chain variable fragment antibodies targeting the breast cancer tumor marker nectin-4

Background

Nectin-4 is a novel biomarker overexpressed in various types of cancer, including breast cancer, in which it has been associated with poor prognosis. Current literature suggests that nectin-4 has a role in cancer progression and may have prognostic and therapeutic implications. The present study aims to produce nectin-4-specific single-chain variable fragment (scFv) antibodies and evaluate their applications in breast cancer cell lines and clinical specimens.

Methods

We generated recombinant nectin-4 ectodomain fragments as immunogens to immunize chickens and the chickens' immunoglobulin genes were amplified for construction of anti-nectin-4 scFv libraries using phage display. The binding capacities of the selected clones were evaluated with the recombinant nectin-4 fragments, breast cancer cell lines, and paraffin-embedded tissue sections using various laboratory approaches. The binding affinity and in silico docking profile were also characterized.

Results

We have selected two clones (S21 and L4) from the libraries with superior binding capacity. S21 yielded higher signals when used as the primry antibody for western blot analysis and flow cytometry, whereas clone L4 generated cleaner and stronger signals in immunofluorescence and immunohistochemistry staining. In addition, both scFvs could diminish attachment-free cell aggregation of nectin-4-positive breast cancer cells. As results from ELISA indicated that L4 bound more efficiently to fixed nectin-4 ectodomain, molecular docking analysis was further performed and demonstrated that L4 possesses multiple polar contacts with nectin-4 and diversity in interacting residues.

Conclusion

Overall, the nectin-4-specific scFvs could recognize nectin-4 expressed by breast cancer cells and have the merit of being further explored for potential diagnostic and therapeutic applications.

Quantification of putative ovarian cancer serum protein biomarkers using a multiplexed targeted mass spectrometry assay

BACKGROUND

Ovarian cancer is the most lethal gynecologic malignancy in women, and high-grade serous ovarian cancer (HGSOC) is the most common subtype. Currently, no clinical test has been approved by the FDA to screen the general population for ovarian cancer. This underscores the critical need for the development of a robust methodology combined with novel technology to detect diagnostic biomarkers for HGSOC in the sera of women. Targeted mass spectrometry (MS) can be used to identify and quantify specific peptides/proteins in complex biological samples with high accuracy, sensitivity, and reproducibility. In this study, we sought to develop and conduct analytical validation of a multiplexed Tier 2 targeted MS parallel reaction monitoring (PRM) assay for the relative quantification of 23 putative ovarian cancer protein biomarkers in sera.

METHODS

To develop a PRM method for our target peptides in sera, we followed nationally recognized consensus guidelines for validating fit-for-purpose Tier 2 targeted MS assays. The endogenous target peptide concentrations were calculated using the calibration curves in serum for each target peptide. Receiver operating characteristic (ROC) curves were analyzed to evaluate the diagnostic performance of the biomarker candidates.

RESULTS

We describe an effort to develop and analytically validate a multiplexed Tier 2 targeted PRM MS assay to quantify candidate ovarian cancer protein biomarkers in sera. Among the 64 peptides corresponding to 23 proteins in our PRM assay, 24 peptides corresponding to 16 proteins passed the assay validation acceptability criteria. A total of 6 of these peptides from insulin-like growth factor-binding protein 2 (IBP2), sex hormone-binding globulin (SHBG), and TIMP metalloproteinase inhibitor 1 (TIMP1) were quantified in sera from a cohort of 69 patients with early-stage HGSOC, late-stage HGSOC, benign ovarian conditions, and healthy (non-cancer) controls. Confirming the results from previously published studies using orthogonal analytical approaches, IBP2 was identified as a diagnostic biomarker candidate based on its significantly increased abundance in the late-stage HGSOC patient sera compared to the healthy controls and patients with benign ovarian conditions.

CONCLUSIONS

A multiplexed targeted PRM MS assay was applied to detect candidate diagnostic biomarkers in HGSOC sera. To evaluate the clinical utility of the IBP2 PRM assay for HGSOC detection, further studies need to be performed using a larger patient cohort.

Expression of PVRL4, a molecular target for cancer treatment, is transcriptionally regulated by FOS

PVRL4 (or nectin‑4) is a promising therapeutic target since its upregulated expression is found in a wide range of human cancer types. Enfortumab vedotin, an antibody‑drug conjugate targeting PVRL4, is clinically used for the treatment of urothelial bladder cancer. In addition, rMV‑SLAMblind, a genetically engineered oncolytic measles virus, can infect cancer cells and induce apoptosis through interaction with PVRL4. Although PVRL4 transcript levels are elevated in breast, lung and ovarian cancer, the mechanisms of its upregulation have not yet been uncovered. To clarify the regulatory mechanisms of elevated PVRL4 expression in breast cancer cells, Assay for Transposase‑Accessible Chromatin‑sequencing and chromatin immunoprecipitation‑sequencing (ChIP‑seq) data were used to search for its regulatory regions. Using breast cancer cells, an enhancer region was ultimately identified. Additional analyses, including ChIP and reporter assays, demonstrated that FOS interacted with the PVRL4 enhancer region, and that alterations of the FOS‑binding motifs in the enhancer region decreased reporter activity. Consistent with these data, exogenous expression of FOS enhanced the reporter activity and PVRL4 expression in breast cancer cells. Furthermore, RNA‑seq analysis using breast cancer cells treated with PVRL4 small interfering RNA revealed its possible involvement in the cytokine response and immune system. These data suggested that FOS was involved, at least partly, in the regulation of PVRL4 expression in breast cancer cells, and that elevated PVRL4 expression may regulate the response of cancer cells to cytokines and the immune system.

Anti-tumor activity of a recombinant measles virus against canine lung cancer cells

Canine primary lung cancer with metastasis has a poor prognosis with no effective treatment. We previously generated a recombinant measles virus (MV) that lost binding affinity to a principal receptor, SLAM, to eliminate its virulence as a new cancer treatment strategy. The virus, rMV-SLAMblind, targets nectin-4, recently listed as a tumor marker, and exerts antitumor activity against nectin-4-positive canine mammary cancer and urinary bladder transitional cell carcinoma cells. However, the effectivity of rMV-SLAMblind for other types of canine cancers is still unknown. Here we evaluated the antitumor effect of rMV-SLAMblind to canine lung cancer. Nectin-4 is expressed on three canine lung cancer cell lines (CLAC, AZACL1, AZACL2) and rMV-SLAMblind was able to infect these cell lines. CLAC cells showed reduced cell viability after virus infection. In the CLAC xenograft nude mouse model, intratumoral administration of rMV-SLAMblind significantly suppressed tumor growth. In rMV-SLAMblind-treated mice, natural killer cells were activated, and Cxcl10 and Il12a levels were significantly increased in comparison with levels in the control group. In addition, the depletion of NK cells reduced the anti-tumor effect. To understand difference in efficacy among canine lung cancer cell lines, we compared virus growth and gene expression pattern after virus treatment in the three canine lung cancer cell lines; virus growth was highest in CLAC cells compared with the other cell lines and the induction of interferon (IFN)-beta and IFN-stimulated genes was at lower levels in CLAC cells. These results suggested that rMV-SLAMblind exhibits oncolytic effect against some canine lung cancer cells and the cellular response after the virus infection may influence its efficacy.

Nectin-4 is frequently expressed in primary salivary gland cancer and corresponding lymph node metastases and represents an important treatment-related biomarker

Many locally advanced and metastatic salivary gland carcinomas (SGC) lack therapeutic targets. Enfortumab vedotin, an antibody-drug conjugate binding to Nectin-4, recently gained FDA approval for third-line urothelial carcinoma. Therefore, the aim of this study was to assess the expression of Nectin-4 in primary SGC and corresponding lymph node metastases and to correlate it with clinicopathological data. Immunohistochemical staining for Nectin-4 was performed for patients who had undergone surgery with curative intent for primary SGC of the parotid or submandibular gland in a tertiary referral center between 1990 and 2019. One hundred twenty-two primary SGC and twenty corresponding lymph node metastases were included. Nectin-4 was expressed in 80.3% of primary SGC with a mean Histo(H-)score of 61.2 and in 90.0% of lymph node metastases with a mean H-score of 75.6. A moderate or high Nectin-4 expression was found in 25.9% of salivary duct carcinomas (SaDu) and in 30.7% of adenoid cystic carcinomas (ACC). SaDu patients with a lower T-stage (p = 0.04), no loco-regional lymph node metastases (p = 0.049), no vascular invasion (p = 0.04), and no perineural spread (p = 0.03) showed a significantly higher mean Nectin-4 H-score. There was a statistical tendency towards a more favorable disease-free survival among SaDu patients with a higher Nectin-4 expression (p = 0.09). Nectin-4 is expressed in SGC and therefore represents a potential therapeutic target, especially in entities with a high rate of local recurrence and metastatic spread such as SaDu and ACC.

First-in-Human Study of the Radioligand 68Ga-N188 Targeting Nectin-4 for PET/CT Imaging of Advanced Urothelial Carcinoma

PURPOSE

Nectin-4 is an emerging biomarker for cancer diagnosis and therapy. Recently, enfortumab vedotin (EV) was approved by the FDA as the first nectin-4 targeting antibody-drug conjugate for treating advanced urothelial carcinoma (UC). A PET imaging method to noninvasively quantify nectin-4 expression level would potentially help to select patients most likely to respond to EV and predict the response.

EXPERIMENTAL DESIGN

In this study, we designed a bicyclic peptide-based nectin-4 targeting radiotracer 68Ga-N188. Initially, we performed preclinical evaluations of 68Ga-N188 in UC cell lines and xenograft mouse models. Next, we performed the translational study in healthy volunteers and a pilot cohort of patients with advanced UC on uEXPLORER total-body PET/CT.

RESULTS

In the preclinical study, 68Ga-N188 showed high affinity to nectin-4, specific uptake in a nectin-4(+) xenograft mouse model, and suitable pharmacokinetic and safety profiles. In the translational study, 2 healthy volunteers and 14 patients with advanced UC were enrolled. The pharmacokinetic profile was determined for 68Ga-N188, and the nectin-4 relative expression level in different organs was quantitatively imaged.

CONCLUSIONS

A clear correlation between PET SUV value and nectin-4 expression was observed, supporting the application of 68Ga-N188 PET as a companion diagnostic tool for optimizing treatments that target nectin-4. See related commentary by Jiang et al., p. 3259.

Physiologically based pharmacokinetic model to predict drug-drug interactions with the antibody-drug conjugate enfortumab vedotin

Enfortumab vedotin is an antibody-drug conjugate (ADC) comprised of a Nectin-4-directed antibody and monomethyl auristatin E (MMAE), which is primarily eliminated through P-glycoprotein (P-gp)-mediated excretion and cytochrome P450 3A4 (CYP3A4)-mediated metabolism. A physiologically based pharmacokinetic (PBPK) model was developed to predict effects of combined P-gp with CYP3A4 inhibitor/inducer (ketoconazole/rifampin) on MMAE exposure when coadministered with enfortumab vedotin and study enfortumab vedotin with CYP3A4 (midazolam) and P-gp (digoxin) substrate exposure. A PBPK model was built for enfortumab vedotin and unconjugated MMAE using the PBPK simulator ADC module. A similar model was developed with brentuximab vedotin, an ADC with the same valine-citrulline-MMAE linker as enfortumab vedotin, for MMAE drug-drug interaction (DDI) verification using clinical data. The DDI simulation predicted a less-than-2-fold increase in MMAE exposure with enfortumab vedotin plus ketoconazole (MMAE geometric mean ratio [GMR] for maximum concentration [Cmax], 1.15; GMR for area under the time-concentration curve from time 0 to last quantifiable concentration [AUClast], 1.38). Decreased MMAE exposure above 50% but below 80% was observed with enfortumab vedotin plus rifampin (MMAE GMR Cmax, 0.72; GMR AUClast, 0.47). No effect of enfortumab vedotin on midazolam or digoxin systemic exposure was predicted. Results suggest that combination enfortumab vedotin, P-gp, and a CYP3A4 inhibitor may result in increased MMAE exposure and patients should be monitored for potential adverse effects. Combination P-gp and a CYP3A4 inducer may result in decreased MMAE exposure. No exposure change is expected for CYP3A4 or P-gp substrates when combined with enfortumab vedotin.ClinicalTrials.gov identifier Not applicable.

Increased levels of nectin-4 as a serological marker for pre-eclampsia

OBJECTIVES

Nectin-4 is a cell adhesion molecule with vital functions at adherens and tight junctions. Cumulative evidence now indicates that the NECTIN4 gene is overexpressed in a variety of cancers, and that the nectin-4 protein is both a disease marker and therapeutic target in a subset of these cancers. We previously demonstrated that NECTIN4 is overexpressed in placenta during pre-eclamptic pregnancy, which is one of the most serious obstetric disorders.

METHODS

Nectin-4 protein levels were measured in maternal sera from pregnant women with pre-eclampsia and its related disorder, unexplained fetal growth retardation.

RESULTS

Maternal serum concentrations of nectin-4 were significantly elevated in pre-eclamptic women compared with those with an uncomplicated normotensive pregnancy. However, no increase was observed in pregnancies with unexplained fetal growth retardation. Serum nectin-4 levels were higher in cases with early-onset pre-eclampsia that generally showed more severe clinical symptoms, but levels were not correlated to other clinical indicators of disease severity.

CONCLUSIONS

Nectin-4 is a potential new diagnostic and predictive biomarker for severe pre-eclampsia.

Targeting Peptides: The New Generation of Targeted Drug Delivery Systems

Peptides can act as targeting molecules, analogously to oligonucleotide aptamers and antibodies. They are particularly efficient in terms of production and stability in physiological environments; in recent years, they have been increasingly studied as targeting agents for several diseases, from tumors to central nervous system disorders, also thanks to the ability of some of them to cross the blood-brain barrier. In this review, we will describe the techniques employed for their experimental and in silico design, as well as their possible applications. We will also discuss advancements in their formulation and chemical modifications that make them even more stable and effective. Finally, we will discuss how their use could effectively help to overcome various physiological problems and improve existing treatments.

Nectin-4 as a Predictive Marker for Poor Prognosis of Endometrial Cancer with Mismatch Repair Impairment

The adhesion molecule Nectin-4 is a new potential therapeutic target for different types of cancer; however, little is known about its diagnosis significance in endometrial cancer (EC). We found that Nectin-4 expression was significantly higher in EC tissues than in nonadjacent normal tissue. The area under the receiver operating characteristic curve value of 0.922 indicated good diagnostic accuracy for Nectin-4 expression in EC. Furthermore, Nectin-4 expression was associated with DNA mismatch repair (MMR) protein deficiency. Notably, the high Nectin-4 expression group of patients with MSH2/6-deficient EC had shorter progression-free survival than that of the low Nectin-4 expression group. The number of lymphovascular space invasion-positive patients in groups with MMR deficiency and high Nectin-4 expression was also increased compared with that in the low Nectin-4 expression group. Bioinformatics analysis revealed that alteration in Nectin-4 and MMR genes is associated with Nectin-4 expression in EC. To the best of our knowledge, this is the first study to show that Nectin-4 expression may be a potential biomarker for EC diagnosis and that high Nectin-4 expression in MMR-deficient patients with EC can predict short progression-free survival, thus providing clues to identify patients for adjuvant therapy.

Diagnostic and Prognostic Roles of Urine Nectin-2 and Nectin-4 in Human Bladder Cancer

The clinical utility of urine nectins in bladder cancer (BCa) is unclear. We investigated the potential diagnostic and prognostic values of urine Nectin-2 and Nectin-4. Levels of urine Nectin-2, Nectin-4, and NMP-22 were quantified using an enzyme-linked immunosorbent assay in 122 patients with BCa, consisting of 78 with non-muscle-invasive BCa (NMIBC) and 44 with muscle-invasive BCa (MIBC), and ten healthy controls. Tumor nectin expression in MIBC was evaluated with immunohistochemical staining of transurethral resection specimens. The level of urine Nectin-4 (mean: 18.3 ng/mL) was much higher than that of urine Nectin-2 (mean: 0.40 ng/mL). The sensitivities of Nectin-2, Nectin-4, NMP-22, and cytology assays were 84%, 98%, 52%, and 47%, respectively; their specificities were 40%, 80%, 100%, and 100%, respectively. Both urine Nectin-2 and Nectin-4, though not NMP-22, were found to be significantly more sensitive than cytology. A four-titer grouping based on levels of urine Nectin-2/Nectin-4 (low/high, high/high, low/low, and high/low) showed a high capability for discriminating between NMIBC and MIBC. Neither urine Nectin-2 nor Nectin-4 levels had a significant prognostic value in NMIBC or MIBC. Urine levels correlated with tumor expression and serum levels in the Nectin-4 analysis, but not in the Nectin-2 analysis. Urine nectins are potential diagnostic biomarkers for BCa.

Nectin-4: a Tumor Cell Target and Status of Inhibitor Development

PURPOSE OF REVIEW

This study aims to gather the current state of the literature about anti-Nectin-4 innovative associations in solid tumors and to investigate underlying resistance mechanisms.

RECENT FINDINGS

Antibody-drug conjugate (ADC) targeting Nectin-4 efficacy gained attention and offers a promising association with other antineoplastic drugs especially in urothelial carcinoma. The heterogeneity of Nectin-4 expression across the molecular subtypes was highlighted especially in urothelial cancers. A unique study using preclinical models demonstrated an upregulation of P-gp expression, which may explain the anti-Nectin-4 resistance mechanisms. Further studies are urgently needed to understand anti-Nectin-4 sensitivity and resistance phenomenon. The growing therapeutic associations of enfortumab vedotin offer optimistic opportunities in management and treatment of wide range of solid tumors including rare aggressive malignancies.

Immune response elicited in the tumor microenvironment upon rMV-SLAMblind cancer virotherapy

Oncolytic virotherapy is a promising therapy for cancer. We previously established a recombinant measles virus (rMV-SLAMblind) that targets NECTIN4-expressing cancer cells and demonstrated its antitumor effects using a xenograft model in an immunodeficient mouse. In the current study, to investigate the immune response after rMV-SLAMblind therapy, we developed an immunocompetent cancer mouse model by introducing the NECTIN4 gene into mouse cancer cell lines. NECTIN4-expressing mouse cancer cells were successfully killed by rMV-SLAMblind in vitro. After transplantation of the NECTIN4-expressing tumor cells, rMV-SLAMblind significantly suppressed tumor growth in immunocompetent mice. Thus, this immunocompetent mouse cancer model could be a powerful tool in which to study the effect of rMV-SLAMblind therapy on the immune response. Using this model we found that rMV-SLAMblind elicited significant activation of natural killer cells, type 1 helper T cells and the tumor-specific CD8⁺ T-cell response in the tumor microenvironment. Immune cell depletion study revealed that CD8⁺ cells particularly played significant roles in the therapeutic efficacy of rMV-SLAMblind. Thus, rMV-SLAMblind exerts a therapeutic effect, not only directly by tumor cell killing, but also indirectly by efficient induction of antitumor immunity.

Target Selection for T-Cell Therapy in Epithelial Ovarian Cancer: Systematic Prioritization of Self-Antigens

Adoptive T cell-receptor therapy (ACT) could represent a promising approach in the targeted treatment of epithelial ovarian cancer (EOC). However, the identification of suitable tumor-associated antigens (TAAs) as targets is challenging. We identified and prioritized TAAs for ACT and other immunotherapeutic interventions in EOC. A comprehensive list of pre-described TAAs was created and candidates were prioritized, using predefined weighted criteria. Highly ranked TAAs were immunohistochemically stained in a tissue microarray of 58 EOC samples to identify associations of TAA expression with grade, stage, response to platinum, and prognosis. Preselection based on expression data resulted in 38 TAAs, which were prioritized. Along with already published Cyclin A1, the TAAs KIF20A, CT45, and LY6K emerged as most promising targets, with high expression in EOC samples and several identified peptides in ligandome analysis. Expression of these TAAs showed prognostic relevance independent of molecular subtypes. By using a systematic vetting algorithm, we identified KIF20A, CT45, and LY6K to be promising candidates for immunotherapy in EOC. Results are supported by IHC and HLA-ligandome data. The described method might be helpful for the prioritization of TAAs in other tumor entities.

Multiparameter single-cell proteomic technologies give new insights into the biology of ovarian tumors

High-grade serous ovarian cancer (HGSOC) is the most lethal gynecological malignancy. Its diagnosis at advanced stage compounded with its excessive genomic and cellular heterogeneity make curative treatment challenging. Two critical therapeutic challenges to overcome are carboplatin resistance and lack of response to immunotherapy. Carboplatin resistance results from diverse cell autonomous mechanisms which operate in different combinations within and across tumors. The lack of response to immunotherapy is highly likely to be related to an immunosuppressive HGSOC tumor microenvironment which overrides any clinical benefit. Results from a number of studies, mainly using transcriptomics, indicate that the immune tumor microenvironment (iTME) plays a role in carboplatin response. However, in patients receiving treatment, the exact mechanistic details are unclear. During the past decade, multiplex single-cell proteomic technologies have come to the forefront of biomedical research. Mass cytometry or cytometry by time-of-flight, measures up to 60 parameters in single cells that are in suspension. Multiplex cellular imaging technologies allow simultaneous measurement of up to 60 proteins in single cells with spatial resolution and interrogation of cell-cell interactions. This review suggests that functional interplay between cell autonomous responses to carboplatin and the HGSOC immune tumor microenvironment could be clarified through the application of multiplex single-cell proteomic technologies. We conclude that for better clinical care, multiplex single-cell proteomic technologies could be an integral component of multimodal biomarker development that also includes genomics and radiomics. Collection of matched samples from patients before and on treatment will be critical to the success of these efforts.

BT8009; A Nectin-4 Targeting Bicycle Toxin Conjugate for Treatment of Solid Tumors

Multiple tumor types overexpress Nectin-4 and the antibody-drug conjugate (ADC), enfortumab vedotin (EV) shows striking efficacy in clinical trials for metastatic urothelial cancer, which expresses high levels of Nectin-4, validating Nectin-4 as a clinical target for toxin delivery in this indication. Despite excellent data in urothelial cancer, little efficacy data are reported for EV in other Nectin-4 expressing tumors and EV therapy can produce significant toxicities in many patients, frequently leading to discontinuation of treatment. Thus, additional approaches to this target with the potential to extend utility and reduce toxicity are warranted. We describe the preclinical development of BT8009, a "Bicycle Toxin Conjugate" (BTC) consisting of a Nectin-4-binding bicyclic peptide, a cleavable linker system and the cell penetrant toxin mono-methylauristatin E (MMAE). BT8009 shows significant antitumor activity in preclinical tumor models, across a variety of cancer indications and is well tolerated in preclinical safety studies. In several models, it shows superior or equivalent antitumor activity to an EV analog. As a small hydrophilic peptide-based drug BT8009 rapidly diffuses from the systemic circulation, through tissues to penetrate the tumor and target tumor cells. It is renally eliminated from the circulation, with a half-life of 1-2 hours in rat and non-human primate. These physical and PK characteristics differentiate BT8009 from ADCs and may provide benefit in terms of tumor penetration and reduced systemic exposure. BT8009 is currently in a Phase 1/2 multicenter clinical trial across the US, Canada, and Europe, enrolling patients with advanced solid tumors associated with Nectin-4 expression.

Nectin-4 as Blood-Based Biomarker Enables Detection of Early Ovarian Cancer Stages

Ovarian cancer is the third most common gynecological malignancy and has the highest mortality rate. Owing to unspecific symptoms, ovarian cancer is not detected until an advanced stage in about two-thirds of cases. Therefore, it is crucial to establish reliable biomarkers for the early stages to improve the patients’ prognosis. The aim of this study is to investigate whether the ADAM17 substrates Nectin-4, Heparin-binding EGF-like growth factor (HB-EGF) and Amphiregulin (AREG) could function as potential tumor markers for ovarian cancer. In this study a set of 231 sera consisting of 131 ovarian cancer patients and 100 healthy age-matched controls were assembled. Nectin-4, HB-EGF and AREG levels of preoperatively collected sera were determined by enzyme-linked immunosorbent assay (ELISA). Our analysis revealed that Nectin-4 and HB-EGF were significantly increased compared to the age-matched control group (p < 0.0001, p = 0.016). Strikingly, significantly higher Nectin-4 and HB-EGF levels were detected in early-stage FIGO I/II (p <0.001; p = 0.025) compared to healthy controls. Eighty-four percent (16/19) of patients with low Ca-125 levels showed increased Nectin-4 levels. Our study proposes Nectin-4 and HB-EGF as promising blood-based biomarkers for the detection of early stages of ovarian cancer patients that would not have been detected by Ca-125.

Nectin-4 is widely expressed in head and neck squamous cell carcinoma

Purpose: Nectin-4 has been successfully established as a target molecule in locally advanced and metastatic bladder cancer. An antibody-drug conjugate (enfortumab-vedotin) directed against nectin-4 has shown marked tumor remission rates in this tumor type, which is known for high expression rates of nectin-4. As head and neck cancer and urothelial carcinomas share morphological and molecular similarities, we aimed to evaluate Nectin-4 expression in head and neck squamous cell carcinoma (HNSCC).

Material and Methods: A previously described and clinically characterized cohort of HNSCC (n = 159) was analyzed by immunohistochemistry for Nectin-4 expression. The expression data was correlated to clinico-pathological parameters including patient outcome.

Results: Nectin-4 was found in 86.2% of HNSCC, with medium/high expression seen in 32.7% of cases. Non smokers and p16 positive HNSCC showed a higher expression of Nectin-4 (p < 0.005). There was no correlation of Nectin-4 with grading or tumor stage. Nectin-4 positive tumors showed a significant better survival (log rank p = 0.006).

Conclusions: Similar to urothelial carcinoma, Nectin-4 is found in the majority of HNSCC, which clearly warrants further studies to clarify if HNSCC also respond to targeted therapy with enfortumab-vedotin. Moreover, expression of Nectin-4 is associated with HPV infection and may serve as a prognostic marker in HNSCC.

Nectin-4 promotes osteosarcoma progression and metastasis through activating PI3K/AKT/NF-κB signaling by down-regulation of miR-520c-3p

Purpose

Nectin-4 is specifically up-regulated in various tumors, exert crucial effects on tumor occurrence and development. Nevertheless, the role and molecular mechanism of Nectin-4 in osteosarcoma (OS) are rarely studied.

Methods

The expression of Nectin-4 and its relationship with clinical characteristics of OS were investigated using OS clinical tissues, tissue microarrays, TCGA, and GEO databases. Moreover, the effect of Nectin-4 on cell growth and mobility was detected by CCK-8, colony formation, transwell, and wound-healing assays. The RT-qPCR, Western blotting, and luciferase reporter assays were performed to explore molecular mechanisms through which Nectin-4 mediates the expression of miR-520c-3p, thus modulating PI3K/AKT/NF-κB signaling. In vivo mice models constructed by subcutaneous transplantation and tail vein injection were used to validate the functional roles of Nectin-4 and miR-520c-3p.

Results

Nectin-4 displayed a higher expression in OS tumor tissues compared with normal tissues, and its overexpression was positively associated with tumor stage and metastasis in OS patients. Functionally, Nectin-4 enhanced OS cells growth and mobility in vitro. Mechanistically, Nectin-4 down-regulated the levels of miR-520c-3p that directly targeted AKT-1 and P65, thus leading to the stimulation of PI3K/AKT/NF-κB signaling. In addition, the expression of miR-520c-3p was apparently lower in OS tissues than in normal tissues, and its low expression was significantly related to tumor metastasis. Furthermore, ectopic expression of miR-520c-3p markedly blocked the effect of Nectin-4 on OS cell growth and mobility. Knockdown of Nectin-4 could suppress the tumorigenesis and metastasis in vivo, which could be remarkably reversed by miR-520c-3p silencing.

Conclusions

Nectin-4 as an oncogene can promote OS progression and metastasis by activating PI3K/AKT/NF-κB signaling via down-regulation of miR-520c-3p, which could represent a novel avenue for identifying a potential therapeutic target for improving patient outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02669-w.

What Inhibits Natural Killers’ Performance in Tumour

Natural killer cells are innate lymphocytes with the ability to lyse tumour cells depending on the balance of their activating and inhibiting receptors. Growing numbers of clinical trials show promising results of NK cell-based immunotherapies. Unlike T cells, NK cells can lyse tumour cells independent of antigen presentation, based simply on their activation and inhibition receptors. Various strategies to improve NK cell-based therapies are being developed, all with one goal: to shift the balance to activation. In this review, we discuss the current understanding of ways NK cells can lyse tumour cells and all the inhibitory signals stopping their cytotoxic potential.

Development of a Multiprotein Classifier for the Detection of Early Stage Ovarian Cancer

BACKGROUND

Individual serum biomarkers are neither adequately sensitive nor specific for use in screening the general population for ovarian cancer. The purpose of this study was to develop a multiprotein classifier to detect the early stages of ovarian cancer, when it is most treatable.

METHODS

The Olink Proseek Multiplex Oncology II panel was used to simultaneously quantify the expression levels of 92 cancer-related proteins in sera.

RESULTS

In the discovery phase, we generated a multiprotein classifier that included CA125, HE4, ITGAV, and SEZ6L, based on an analysis of sera from 116 women with early stage ovarian cancer and 336 age-matched healthy women. CA125 alone achieved a sensitivity of 87.9% at a specificity of 95%, while the multiprotein classifier resulted in an increased sensitivity of 91.4%, while holding the specificity fixed at 95%. The performance of the multiprotein classifier was validated in a second cohort comprised of 192 women with early stage ovarian cancer and 467 age-matched healthy women. The sensitivity at 95% specificity increased from 74.5% (CA125 alone) to 79.2% with the multiprotein classifier. In addition, the multiprotein classifier had a sensitivity of 95.1% at 98% specificity for late stage ovarian cancer samples and correctly classified 80.5% of the benign samples using the 98% specificity cutpoint.

CONCLUSIONS

The inclusion of the proteins HE4, ITGAV, and SEZ6L improved the sensitivity and specificity of CA125 alone for the detection of early stages of ovarian cancer in serum samples. Furthermore, we identified several proteins that may be novel biomarkers of early stage ovarian cancer.

Overcoming Resistance to Anti-nectin-4 Antibody-Drug Conjugate

Antibody-drug conjugates (ADCs) represent a fast-growing drug class in oncology. However, ADCs are associated with resistance, and therapies able to overcome it are of utmost importance. Recently, enfortumab vedotin-ejfv (EV) was approved in nectin-4+ metastatic urothelial cancer. We previously described PVRL4/nectin-4, as a new therapeutic target in breast cancer (BC), and produced an efficient EV-like ADC comprising a human anti-nectin-4 monoclonal antibody conjugated to monomethyl auristatin-E (MMAE) named N41mab-vcMMAE. To study the consequence of the long-term treatment with this ADC, we developed a preclinical BC model in mice, and report a mechanism of resistance to N41mab-vcMMAE after a 9- months treatment and a way to reverse it. RNA-sequencing pointed to an upregulation in resistant tumors of ABCB1 expression, encoding the multidrug resistance protein MDR-1/P-glycoprotein (P-gp), associated with focal gene amplification and high protein expression. Sensitivity to N41mab-vcMMAE of the resistant model was restored in vitro by P-gp pharmacological inhibitors, like tariquidar. P-gp is expressed in a variety of normal tissues. By delivering the drug to the tumor more specifically than does classical chemotherapy, we hypothesized that the combined use of ADC with P-gp inhibitors might reverse resistance in vivo without toxicity. Indeed, we showed that the tariquidar/N41mab-vcMMAE combination was well tolerated and induced a rapid regression of ADC-resistant tumors in mice. By contrast, the tariquidar/docetaxel combination was toxic and poorly efficient. These results show that ABC transporter inhibitors can be safely used with ADC to reverse ADC-induced resistance and open new opportunities in the fight against multidrug resistance.

Prospective evaluation of 92 serum protein biomarkers for early detection of ovarian cancer

BACKGROUND

CA125 is the best available yet insufficiently sensitive biomarker for early detection of ovarian cancer. There is a need to identify novel biomarkers, which individually or in combination with CA125 can achieve adequate sensitivity and specificity for the detection of earlier-stage ovarian cancer.

METHODS

In the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, we measured serum levels of 92 preselected proteins for 91 women who had blood sampled ≤18 months prior to ovarian cancer diagnosis, and 182 matched controls. We evaluated the discriminatory performance of the proteins as potential early diagnostic biomarkers of ovarian cancer.

RESULTS

Nine of the 92 markers; CA125, HE4, FOLR1, KLK11, WISP1, MDK, CXCL13, MSLN and ADAM8 showed an area under the ROC curve (AUC) of ≥0.70 for discriminating between women diagnosed with ovarian cancer and women who remained cancer-free. All, except ADAM8, had shown at least equal discrimination in previous case-control comparisons. The discrimination of the biomarkers, however, was low for the lag-time of >9-18 months and paired combinations of CA125 with any of the 8 markers did not improve discrimination compared to CA125 alone.

CONCLUSION

Using pre-diagnostic serum samples, this study identified markers with good discrimination for the lag-time of 0-9 months. However, the discrimination was low in blood samples collected more than 9 months prior to diagnosis, and none of the markers showed major improvement in discrimination when added to CA125.

Clinical development of antibody-drug conjugates in triple negative breast cancer: Can we jump higher?

INTRODUCTION

Triple negative breast cancer (TNBC) is an aggressive BC subtype, associated with higher rates of relapse in the primary disease setting and shorter overall survival upon metastatic relapse. The advent of antibody-drug conjugates (ADC), able to deliver selectively potent chemotherapeutic agents, has demonstrated promising clinical activity, with the first approval of an ADC, i.e. Sacituzumab Govitecan, in the metastatic setting. The main scope of this paper is to provide the most recent data indicating the promise of this novel class of drugs, as potential tools to improve clinical outcomes of patients diagnosed with TNBC.

AREAS COVERED

In this article, upon review of the main characteristics of TNBC, and those of ADCs, an overview of the data from clinical trials assessing ADCs in TNBC will be provided, including those that led to the first approval of such a drug for patients with metastatic disease; furthermore, several other ADCs targeting different proteins (over)expressed by TNBC undergo clinical development. Combinations of ADCs with other targeted agents are discussed; the most pertinent considerations for improving the chances of successful clinical development of ADCs in TNBC are provided.

EXPERT OPINION

ADCs are a potent class of targeted anticancer assets, with demonstrated efficacy against metastatic TNBC. Such assets could further improve clinical outcomes of patients with TNBC, and successful development depends upon: i) successful triaging of patients with the right ADC, ii) technical optimization of ADCs to maximize the efficacy, while reducing toxicity, and iii) assess rationally chosen combinations with synergistic antitumor activity and acceptable safety profile.

The Anti-Nectin 4: A Promising Tumor Cells Target. A Systematic Review

The nectin cell adhesion protein 4 (Nectin-4) is overexpressed in multiple human malignancies. Such aberrant expression is correlated with cancer progression and poor prognostic. Nectin-4 has emerged as a potential biomarker and promising targeted therapy. This review aimed to gather the current state of the literature about Nectin-4 relevance in preclinical tumor models and to summarize its clinical relevance regarding cancer. A systematic assessment of literature articles was performed by searching in PUBMED (MEDLINE) from the database inception to May 2021, following PRISMA guidelines. Preclinical models unanimously demonstrated membrane and cytoplasmic location of the Nectin-4. Furthermore, Nectin-4 was overexpressed whatever the location of the solid tumors. Interestingly, a heterogeneity of Nectin-4 expression has been highlighted in bladder urothelial carcinoma. High serum Nectin-4 level was correlated with treatment efficiency and disease progression. Finally, generated Anti-drug-Conjugated targeting Nectin-4 induced cell death in multiple tumor cell lines. Nectin-4 emerge as a promising target for anti-cancer drugs development because of its central role in tumorigenesis, and lymphangiogenesis. Enfortumab vedotin targeting Nectin-4 demonstrated encouraging results and should be extended to other types of solid tumors.

Extracellular Vesicle Molecular Signatures Characterize Metastatic Dynamicity in Ovarian Cancer

BACKGROUND

Late-stage diagnosis of ovarian cancer, a disease that originates in the ovaries and spreads to the peritoneal cavity, lowers 5-year survival rate from 90% to 30%. Early screening tools that can: i) detect with high specificity and sensitivity before conventional tools such as transvaginal ultrasound and CA-125, ii) use non-invasive sampling methods and iii) longitudinally significantly increase survival rates in ovarian cancer are needed. Studies that employ blood-based screening tools using circulating tumor-cells, -DNA, and most recently tumor-derived small extracellular vesicles (sEVs) have shown promise in non-invasive detection of cancer before standard of care. Our findings in this study show the promise of a sEV-derived signature as a non-invasive longitudinal screening tool in ovarian cancer.

METHODS

Human serum samples as well as plasma and ascites from a mouse model of ovarian cancer were collected at various disease stages. Small extracellular vesicles (sEVs) were extracted using a commercially available kit. RNA was isolated from lysed sEVs, and quantitative RT-PCR was performed to identify specific metastatic gene expression.

CONCLUSION

This paper highlights the potential of sEVs in monitoring ovarian cancer progression and metastatic development. We identified a 7-gene panel in sEVs derived from plasma, serum, and ascites that overlapped with an established metastatic ovarian carcinoma signature. We found the 7-gene panel to be differentially expressed with tumor development and metastatic spread in a mouse model of ovarian cancer. The most notable finding was a significant change in the ascites-derived sEV gene signature that overlapped with that of the plasma-derived sEV signature at varying stages of disease progression. While there were quantifiable changes in genes from the 7-gene panel in serum-derived sEVs from ovarian cancer patients, we were unable to establish a definitive signature due to low sample number. Taken together our findings show that differential expression of metastatic genes derived from circulating sEVs present a minimally invasive screening tool for ovarian cancer detection and longitudinal monitoring of molecular changes associated with progression and metastatic spread.

Nectin cell adhesion molecule-4 (NECTIN-4): A potential target for cancer therapy

NECTIN-4 [a poliovirus receptor-related-4 (pvrl-4) encoded protein] is a Ca²⁺ independent immunoglobulin-like protein. Along with other Nectins (Nectin-1, -2 and -3), it is primarily involved in cell-cell adhesion. In contrast to other Nectins, Nectin-4 is specifically enriched in the embryonic and placental tissues but its expression significantly declines in adult life. In recent years, it has been found that Nectin-4 is especially overexpressed and served as a tumor associated inducer in various malignant tumors including breast, lung, colorectal, pancreatic, ovarian cancers etc. Over-expression of Nectin-4 is associated with various aspects of tumor progression like proliferation, angiogenesis, epithelial to mesenchymal transition, metastasis, DNA repair, tumor relapse, poor prognosis in several types of cancer. This review systematically highlights the implications of Nectin-4 in every possible aspect of cancer and the molecular mechanism of Nectin-4 mediated cancer progression. We have further emphasized on the therapeutic strategies that are being proposed to specifically target Nectin-4.

ADAM17-A Potential Blood-Based Biomarker for Detection of Early-Stage Ovarian Cancer

Simple Summary

Ovarian cancer has the highest lethality among gynecological tumors. Therefore, it is essential to find reliable biomarkers to improve early detection. This is the first report describing ADAM17 detection in serum and ascites fluid of ovarian cancer patients. A high ADAM17 concentration in serum at primary diagnosis is associated with early FIGO stages and predicts complete resection of the tumor mass. In addition, ADAM17 and CA-125 complement each other, especially in the diagnosis of early stages. In summary, ADAM17 appears to be a promising screening marker for detecting early-stage ovarian cancer.

Abstract

Ovarian cancer has the highest mortality rate among gynecological tumors. This is based on late diagnosis and the lack of early symptoms. To improve early detection, it is essential to find reliable biomarkers. The metalloprotease ADAM17 could be a potential marker, as it is highly expressed in many solid tumors, including ovarian and breast cancer. The aim of this work is to evaluate the relevance of ADAM17 as a potential diagnostic blood-based biomarker in ovarian cancer. Ovarian cancer cell lines IGROV-1 and A2780, as well as primary patient-derived tumor cells obtained from tumor tissue and ascitic fluid, were cultured to analyze ADAM17 abundance in the culture supernatant. In a translational approach, a cohort of 117 well-characterized ovarian cancer patients was assembled and ADAM17 levels in serum and corresponding ascitic fluid were determined at primary diagnosis. ADAM17 was quantified by enzyme-linked immunosorbent assay (ELISA). In the present study, ADAM17 was detected in the culture supernatant of ovarian cancer cell lines and primary cells. In addition, ADAM17 was found in serum and ascites of ovarian cancer patients. ADAM17 level was significantly increased in ovarian cancer patients compared to an age-matched control group (p < 0.0001). Importantly early FIGO I/II stages, which would not have been detected by CA-125, were associated with higher ADAM17 concentrations (p = 0.007). This is the first study proposing ADAM17 as a serum tumor marker in the setting of a gynecological tumor disease. Usage of ADAM17 in combination with CA-125 and other markers could help detect early stages of ovarian cancer.

Role of Nectin‑4 protein in cancer (Review)

The Nectin cell adhesion molecule (Nectin) family members are Ca2+‑independent immunoglobulin‑like cellular adhesion molecules (including Nectins 1‑4), involved in cell adhesion via homophilic/heterophilic interplay. In addition, the Nectin family plays a significant role in enhancing cellular viability and movement ability. In contrast to enrichment of Nectins 1‑3 in normal tissues, Nectin‑4 is particularly overexpressed in a number of tumor types, including breast, lung, urothelial, colorectal, pancreatic and ovarian cancer. Moreover, the upregulation of Nectin‑4 is an independent biomarker for overall survival in numerous cancer types. A large number of studies have revealed that high expression of Nectin‑4 is closely related to tumor occurrence and development in various cancer types, but the manner in which Nectin‑4 protein contributes to the onset and development of these malignancies is yet unknown. The present review summarizes the molecular mechanisms and functions of Nectin‑4 protein in the biological processes and current advances with regard to its expression and regulation in various cancer types.

Comparative Cancer Cell Signaling in Muscle-Invasive Urothelial Carcinoma of the Bladder in Dogs and Humans

Muscle-invasive urothelial carcinoma (MIUC) is the most common type of bladder malignancy in humans, but also in dogs that represent a naturally occurring model for this disease. Dogs are immunocompetent animals that share risk factors, pathophysiological features, clinical signs and response to chemotherapeutics with human cancer patients. This review summarizes the fundamental pathways for canine MIUC initiation, progression, and metastasis, emerging therapeutic targets and mechanisms of drug resistance, and proposes new opportunities for potential prognostic and diagnostic biomarkers and therapeutics. Identifying similarities and differences between cancer signaling in dogs and humans is of utmost importance for the efficient translation of in vitro research to successful clinical trials for both species.

High-grade serous ovarian tumor cells modulate NK cell function to create an immune-tolerant microenvironment

Tubo-ovarian high-grade serous carcinoma (HGSC) is unresponsive to immune checkpoint blockade despite significant frequencies of exhausted T cells. Here we apply mass cytometry and uncover decidual-like natural killer (dl-NK) cell subpopulations (CD56+CD9+CXCR3+KIR+CD3-CD16-) in newly diagnosed HGSC samples that correlate with both tumor and transitioning epithelial-mesenchymal cell abundance. We show different combinatorial expression patterns of ligands for activating and inhibitory NK receptors within three HGSC tumor compartments: epithelial (E), transitioning epithelial-mesenchymal (EV), and mesenchymal (vimentin expressing [V]), with a more inhibitory ligand phenotype in V cells. In cocultures, NK-92 natural killer cells acquire CD9 from HGSC tumor cells by trogocytosis, resulting in reduced anti-tumor cytokine production and cytotoxicity. Cytotoxicity in these cocultures is restored with a CD9-blocking antibody or CD9 CRISPR knockout, thereby identifying mechanisms of immune suppression in HGSC. CD9 is widely expressed in HGSC tumors and so represents an important new therapeutic target with immediate relevance for NK immunotherapy.

Emerging roles of the nectin family of cell adhesion molecules in tumour-associated pathways

Tumour cells achieve maximum survival by modifying cellular machineries associated with processes such as cell division, migration, survival, and apoptosis, resulting in genetically complex and heterogeneous populations. While nectin and nectin-like cell adhesion molecules control development and maintenance of multicellular organisation in higher vertebrates by mediating cell-cell adhesion and related signalling processes, recent studies indicate that they also critically regulate growth and development of different types of cancers. In this review, we detail current knowledge about the role of nectin family members in various tumours. Furthermore, we also analyse the seemingly opposing roles of some members of nectin family in tumour-associated pathways, as they function as both tumour suppressors and oncogenes. Understanding this functional duality of nectin family in tumours will further our knowledge of molecular mechanisms regulating tumour development and progression, and contribute to the advancement of tumour diagnosis and therapy.

Treating Bladder Cancer: Engineering of Current and Next Generation Antibody-, Fusion Protein-, mRNA-, Cell- and Viral-Based Therapeutics

Bladder cancer is a frequent malignancy and has a clinical need for new therapeutic approaches. Antibody and protein technologies came a long way in recent years and new engineering approaches were applied to generate innovative therapeutic entities with novel mechanisms of action. Furthermore, mRNA-based pharmaceuticals recently reached the market and CAR-T cells and viral-based gene therapy remain a major focus of biomedical research. This review focuses on the engineering of biologics, particularly therapeutic antibodies and their application in preclinical development and clinical trials, as well as approved monoclonal antibodies for the treatment of bladder cancer. Besides, newly emerging entities in the realm of bladder cancer like mRNA, gene therapy or cell-based therapeutics are discussed and evaluated. As many discussed molecules exhibit unique mechanisms of action based on innovative protein engineering, they reflect the next generation of cancer drugs. This review will shed light on the engineering strategies applied to develop these next generation treatments and provides deeper insights into their preclinical profiles, clinical stages, and ongoing trials. Furthermore, the distribution and expression of the targeted antigens and the intended mechanisms of action are elucidated.

Targeting nectin-4 by antibody-drug conjugates for the treatment of urothelial carcinoma

INTRODUCTION

Nectin-4 is a tumor-associated antigen overexpressed in urothelial carcinoma and several other malignancies. It has emerged as a compelling target for novel tumor-directed therapies, particularly as a component of antibody-drug conjugates (ADCs), a growing class of anti-cancer therapeutic agents. Development of nectin-4-directed therapies has been led by enfortumab vedotin (EV), an ADC comprised of a fully human monoclonal antibody specific for nectin-4 conjugated via a cleavable linker to the microtubule inhibitor MMAE. EV was approved in 2019 as a first-in-class agent for the treatment of urothelial carcinoma.

AREAS COVERED

This article discusses general principles relevant to ADC design and our current understanding of nectin-4 in normal physiology and malignancy, followed by a review of the development of EV as well as additional drug conjugate strategies targeting nectin-4.

EXPERT OPINION

EV offers proof-of-concept for the clinical utility of nectin-4-directed therapies and provides further support for ADCs as an important class of anti-cancer agents. Future development of nectin-4-targeted approaches will benefit from a deeper understanding of nectin-4 biology in both health and disease, as well as a detailed exploration of the mechanisms underlying therapeutic activity and resistance.

Emerging agents for the treatment of metastatic urothelial cancer

Over the past few decades, platinum-based combination chemotherapy (PBCC) has been the preferred initial therapy for metastatic urothelial cancer (mUC). However, despite a response rate of approximately 50%, a small proportion of patients with distant metastases may be cured by cisplatin-based combination chemotherapy (CBCC). In addition, up to 50% of patients are not eligible for CBCC due to age or comorbidities. Furthermore, adverse effects from PBCC are a major concern. The emergence of check-point inhibitors (CPIs), particularly those with antibodies directed against programmed cell death 1 protein (PD-1) or its ligand (PD-L1), advanced the treatment of mUC. Avelumab switch-maintenance therapy is recommended in patients with locally advanced or mUC who did not progress on initial PBCC. With the recent advances in tumor molecular biology and the discovery of actionable therapeutic targets, the clinical application of targeted therapy is now being explored for mUC. Erdafitinib, a tyrosine kinase inhibitor of FGFR1-4, has shown positive outcomes in patients with advanced UC with FGFR alterations. Another recent technological development is antibody-drug conjugates (ADCs), which are complex molecules composed of an antibody linked to a biologically active cytotoxic drug (payload) that targets and kills tumor cells while sparing healthy cells. Enfortumab vedotin, a monoclonal antibody targeting nectin-4 conjugated to monomethyl auristatin E, has demonstrated clinically significant efficacy in patients who do not respond to both cytotoxic chemotherapy and CPIs. In this review, we describe switch-maintenance therapies using CPI, various targeted agents, and ADCs that have been investigated for mUC treatment.

Nectin-4 and p95-ErbB2 cooperatively regulate Hippo signaling-dependent SOX2 gene expression, enhancing anchorage-independent T47D cell proliferation

Nectin-4, upregulated in various cancer cells, cis-interacts with ErbB2 and its trastuzumab-resistant splice variants, p95-ErbB2 and ErbB2∆Ex16, enhancing DNA synthesis through the PI3K-AKT signaling in human breast cancer T47D cells in an adherent culture. We found here that nectin-4 and p95-ErbB2, but not nectin-4 and either ErbB2 or ErbB2∆Ex16, cooperatively enhanced SOX2 gene expression and cell proliferation in a suspension culture. This enhancement of T47D cell proliferation in a suspension culture by nectin-4 and p95-ErbB2 was dependent on the SOX2 gene expression. In T47D cells, nectin-4 and any one of p95-ErbB2, ErbB2, or ErbB2∆Ex16 cooperatively activated the PI3K-AKT signaling, known to induce the SOX2 gene expression, to similar extents. However, only a combination of nectin-4 and p95-ErbB2, but not that of nectin-4 and either ErbB2 or ErbB2∆Ex16, cooperatively enhanced the SOX2 gene expression. Detailed studies revealed that only nectin-4 and p95-ErbB2 cooperatively activated the Hippo signaling. YAP inhibited the SOX2 gene expression in this cell line and thus the MST1/2-LATS1/2 signaling-mediated YAP inactivation increased the SOX2 gene expression. These results indicate that only the combination of nectin-4 and p95-ErbB2, but not that of nectin-4 and either ErbB2 or ErbB2∆Ex16, cooperatively regulates the Hippo signaling-dependent SOX2 gene expression, enhancing anchorage-independent T47D cell proliferation.

PARP inhibitor Veliparib (ABT-888) enhances the anti-angiogenic potentiality of Curcumin through deregulation of NECTIN-4 in oral cancer: Role of nitric oxide (NO)

Concurrent use of DNA damaging agents with PARP inhibitors contribute to the effectiveness of the anticancer therapy. But there is a dearth of reports on the antiangiogenic effects of PARP inhibitors and the suppression of angiogenesis by this drug combination is not yet reported. For the successful development of cancer therapeutics, anti-cancer drugs ought to have anti-angiogenic potentiality along with their DNA damaging abilities. In this current piece of work, we investigated the in vitro and in ovo anti-angiogenic effect of Curcumin and Veliparib (a PARP inhibitor) in oral cancer. Recent evidences suggest an involvement of the NECTIN-4 in cancer angiogenesis and the exact molecular pathway of this involvement remains to be delineated. We observed that the soluble NECTIN-4 secreted from H357 oral cancer cells enhanced the angiogenesis of endothelial cells (HUVECs) and this was inhibited by Curcumin-Veliparib combination. NECTIN-4 enhanced vascularization, induced vasodilation and triggered the angiogenic sprouting via endothelial tip cell filopodia. Data indicated that NECTIN-4 mediated angiogenesis is associated with PI3K-AKT-mediated nitric oxide (NO) formation. A noticeable increase in the NO enhanced epithelial NO level through HIF-1α mediated iNOS activation. We observed that increased NO enhanced the NECTIN-4 mediated eNOS expression and thereby elicited further angiogenesis. Curcumin antagonised the NECTIN-4-induced angiogenesis through inhibition of PI3K-AKT mediated eNOS pathway and Veliparib synergized the effect of Curcumin. Our observations indicate that NO is cardinal in inducing NECTIN-4 mediated angiogenesis in H357 cells. Thus, Curcumin-Veliparib combination suppresses angiogenesis through deregulation of the PI3K-AKT-eNOS pathway downstream to the NECTIN-4.

Antibody-drug conjugates in solid tumors: a look into novel targets

Antibody-drug conjugates (ADCs) are a relatively new class of anticancer agents designed to merge the selectivity of monoclonal antibodies with cell killing properties of chemotherapy. They are commonly described as the "Trojan Horses" of therapeutic armamentarium, because of their capability of directly conveying cytotoxic drug (payloads) into the tumor space, thus transforming chemotherapy into a targeted agent. Three novel ADCs have been recently approved, i.e., trastuzumab deruxtecan, sacituzumab govitecan and enfortumab vedotin, respectively, targeting HER2, Trop2 and Nectin4. Thanks to progressive advances in engineering technologies these drugs rely on, the spectrum of diseases sensitive to these drugs as well as their indications are in continuous expansion. Several novel ADCs are under evaluation, exploring new potential targets along with innovative payloads. This review aims at providing a summary of the technology behind these compounds and at presenting the latest ADCs approved in solid tumors, as well as at describing novel targets for ADCs under investigation and new strategies to optimize their efficacy in solid tumors.

Evaluation of the potential of Pap test fluid and cervical swabs to serve as clinical diagnostic biospecimens for the detection of ovarian cancer by mass spectrometry-based proteomics

BACKGROUND

The purpose of this study was to determine whether the residual fixative from a liquid-based Pap test or a swab of the cervix contained proteins that were also found in the primary tumor of a woman with high grade serous ovarian cancer. This study is the first step in determining the feasibility of using the liquid-based Pap test or a cervical swab for the detection of ovarian cancer protein biomarkers.

METHODS

Proteins were concentrated by acetone precipitation from the cell-free supernatant of the liquid-based Pap test fixative or eluted from the cervical swab. Protein was also extracted from the patient's tumor tissue. The protein samples were digested into peptides with trypsin, then the peptides were run on 2D-liquid chromatography mass spectrometry (2D-LCMS). The data was searched against a human protein database for the identification of peptides and proteins in each biospecimen. The proteins that were identified were classified for cellular localization and molecular function by bioinformatics integration.

RESULTS

We identified almost 5000 proteins total in the three matched biospecimens. More than 2000 proteins were expressed in each of the three biospecimens, including several known ovarian cancer biomarkers such as CA125, HE4, and mesothelin. By Scaffold analysis of the protein Gene Ontology categories and functional analysis using PANTHER, the proteins were classified by cellular localization and molecular function, demonstrating that the Pap test fluid and cervical swab proteins are similar to each other, and also to the tumor extract.

CONCLUSIONS

Our results suggest that Pap test fixatives and cervical swabs are a rich source of tumor-specific biomarkers for ovarian cancer, which could be developed as a test for ovarian cancer detection.

Ursolic Acid and Its Nanoparticles Are Potentiators of Oncolytic Measles Virotherapy against Breast Cancer Cells

Simple Summary

Despite the advancing treatments, female breast cancer is one of the most common cancers and a leading cause of cancer deaths in women. To help broaden the therapeutic spectrum of breast cancer, we identified the natural compound ursolic acid (UA) as a potentiator that enhances the oncolytic activity of measles virus (MV) against breast cancer cells through the induction of apoptosis. In addition, to increase clinical applicability, we further generated UA nanoparticles that achieved improved solubility. UA nanoparticles similarly synergized with MV in killing breast cancer cells by triggering apoptosis, and this synergistic anticancer effect was also observed in various breast cancer cell types. This study demonstrates for the first time that UA and its nanoparticles enhance MV’s oncolytic activity in breast cancer cells, suggesting that such combinations may be worth further exploring as an anticancer strategy against breast cancer.

Abstract

Oncolytic viruses (OVs) and phytochemical ursolic acid (UA) are two efficacious therapeutic candidates in development against breast cancer, the deadliest women’s cancer worldwide. However, as single agents, OVs and UA have limited clinical efficacies. As a common strategy of enhancing monotherapeutic anticancer efficacy, we explored the combinatorial chemovirotherapeutic approach of combining oncolytic measles virus (MV), which targets the breast tumor marker Nectin-4, and the anticancer UA against breast adenocarcinoma. Our findings revealed that in vitro co-treatment with UA synergistically potentiated the killing of human breast cancer cells by oncolytic MV, without UA interfering the various steps of the viral infection. Mechanistic studies revealed that the synergistic outcome from the combined treatment was mediated through UA’s potentiation of apoptotic killing by MV. To circumvent UA’s poor solubility and bioavailability and strengthen its clinical applicability, we further developed UA nanoparticles (UA-NP) by nanoemulsification. Compared to the non-formulated UA, UA-NP exhibited improved drug dissolution property and similarly synergized with oncolytic MV in inducing apoptotic breast cancer cell death. This oncolytic potentiation was partly attributed to the enhanced autophagic flux induced by the UA-NP and MV combined treatment. Finally, the synergistic effect from the UA-NP and MV combination was also observed in BT-474 and MDA-MB-468 breast cancer cells. Our study thus highlights the potential value of oncolytic MV and UA-based chemovirotherapy for further development as a treatment strategy against breast cancer, and the feasibility of employing nanoformulation to enhance UA’s applicability.

Prospects for Using Expression Patterns of Paramyxovirus Receptors as Biomarkers for Oncolytic Virotherapy

Simple Summary

Some non-pathogenic viruses that do not cause serious illness in humans can efficiently target and kill cancer cells and may be considered candidates for cancer treatment with virotherapy. However, many cancer cells are protected from viruses. An important goal of personalized cancer treatment is to identify viruses that can kill a certain type of cancer cells. To this end, researchers investigate expression patterns of cell entry receptors, which viruses use to bind to and enter host cells. We summarized and analyzed the receptor expression patterns of two paramyxoviruses: The non-pathogenic measles and the Sendai viruses. The receptors for these viruses are different and can be proteins or lipids with attached carbohydrates. This review discusses the prospects for using these paramyxovirus receptors as biomarkers for successful personalized virotherapy for certain types of cancer.

Abstract

The effectiveness of oncolytic virotherapy in cancer treatment depends on several factors, including successful virus delivery to the tumor, ability of the virus to enter the target malignant cell, virus replication, and the release of progeny virions from infected cells. The multi-stage process is influenced by the efficiency with which the virus enters host cells via specific receptors. This review describes natural and artificial receptors for two oncolytic paramyxoviruses, nonpathogenic measles, and Sendai viruses. Cell entry receptors are proteins for measles virus (MV) and sialylated glycans (sialylated glycoproteins or glycolipids/gangliosides) for Sendai virus (SeV). Accumulated published data reviewed here show different levels of expression of cell surface receptors for both viruses in different malignancies. Patients whose tumor cells have low or no expression of receptors for a specific oncolytic virus cannot be successfully treated with the virus. Recent published studies have revealed that an expression signature for immune genes is another important factor that determines the vulnerability of tumor cells to viral infection. In the future, a combination of expression signatures of immune and receptor genes could be used to find a set of oncolytic viruses that are more effective for specific malignancies.

Pseudotyping Lentiviral Vectors: When the Clothes Make the Virus

Delivering transgenes to human cells through transduction with viral vectors constitutes one of the most encouraging approaches in gene therapy. Lentivirus-derived vectors are among the most promising vectors for these approaches. When the genetic modification of the cell must be performed in vivo, efficient specific transduction of the cell targets of the therapy in the absence of off-targeting constitutes the Holy Grail of gene therapy. For viral therapy, this is largely determined by the characteristics of the surface proteins carried by the vector. In this regard, an important property of lentiviral vectors is the possibility of being pseudotyped by envelopes of other viruses, widening the panel of proteins with which they can be armed. Here, we discuss how this is achieved at the molecular level and what the properties and the potentialities of the different envelope proteins that can be used for pseudotyping these vectors are.

Recombinant SLAMblind Measles Virus Is a Promising Candidate for Nectin-4-Positive Triple Negative Breast Cancer Therapy

One of the most refractory breast cancer types is triple negative (TN) breast cancer, in which cells are resistant to both hormone and Herceptin treatments and, thus, often cause recurrence and metastasis. Effective treatments are needed to treat TN breast cancer. We previously demonstrated that rMV-SLAMblind, a recombinant measles virus, showed anti-tumor activity against breast cancer cells. Here, we examined whether rMV-SLAMblind is effective for treating TN breast cancer. Nectin-4, a receptor for rMV-SLAMblind, was expressed on the surface of 75% of the analyzed TN breast cancer cell lines. rMV-SLAMblind infected the nectin-4-expressing TN breast cancer cell lines, and significantly decreased the viability in half of the analyzed cell lines in vitro. Additionally, intratumoral injection of rMV-SLAMblind suppressed tumor growth in xenografts of MDA-MB-468 and HCC70 cells. To assess treatment for metastatic breast cancer, we performed intravenous administration of the luciferase-expressing-rMV-SLAMblind to MDA xenografted mice. Virus replicated in the tumor and resulted in significant suppression of the tumor growth. The safety of the virus was tested by its intravenous injection into healthy cynomolgus monkeys, which did not cause any measles-like symptoms. These results suggest that rMV-SLAMblind is a promising candidate as a therapeutic agent for treating metastatic and/or TN type breast cancer.