High expression of TROP2 is correlated with poor prognosis of oral squamous cell carcinoma

Trophoblast cell surface antigen-2: a promising new biomarker and potential therapeutic target in penile squamous cell carcinoma

OBJECTIVE

To evaluate the potential utility of antibody-drug conjugates targeting trophoblast cell surface antigen-2 (TROP-2) in patients with primary penile squamous cell carcinoma (PSCC), patients with recurrence (REC cohort), and patient-matched distant metastases (MET cohort), and to assess the potential use of TROP-2 as a predictive non-invasive biomarker in PSCC.

METHODS

A cohort comprising a PRIM (n = 37), REC (n = 5) and MET subcohort (n = 7), with MET including lymph node and lung metastases, was analysed using quantitative real-time PCR, ELISA and immunohistochemical staining with evaluation of H-score.

RESULTS

TROP-2 mRNA and serum protein levels were significantly increased in primary and recurrent PSCC compared to cancer-free controls (both P < 0.001). Immunohistochemical analysis revealed that most of the PRIM cohort (n = 34/37, median H-score 260, interquartile range [IQR] 210-300), as well as all patients in the REC (median [IQR] H-score 200 [165-290]) and MET cohorts (median [IQR] H-score 280 [260-300]) exhibited moderate to strong membranous TROP-2 expression. Additionally, The H-score (membranous TROP-2 expression) was positively correlated with TROP-2 mRNA (ρ = 0.69, P < 0.0001, R2 = 0.70) and protein levels (ρ = 0.86, P < 0.0001, R2 = 0.59), indicating its potential as a non-invasive biomarker in PSCC.

CONCLUSION

In summary, our results support further studies on TROP-2 as a diagnostic and therapeutic target in primary, recurrent and metastatic PSCC.

Elucidating the development, characterization, and antitumor potential of a novel humanized antibody against Trop2

Trophoblast cell surface antigen 2 (Trop2) has emerged as a potential target for effective cancer therapy. In this study, we report a novel anti-Trop2 antibody IMB1636, developed using hybridoma technology. It exhibited high affinity and specificity (KD = 0.483 nM) in binding both antigens and cancer cells, as well as human tumor tissues. hIMB1636 could induce endocytosis, and enabled targeted delivery to the tumor site with an in vivo retention time of 264 h. The humanized antibody hIMB1636, acquired using CDR grafting, exhibited the potential to directly inhibit cancer cell proliferation and migration, and to induce ADCC effects. Moreover, hIMB1636 significantly inhibited the growth of MDA-MB-468 xenograft tumors in vivo. Mechanistically, hIMB1636 induced cell cycle arrest and apoptosis by regulating cyclin-related proteins and the caspase cascade. In comparison to commercialized sacituzumab, hIMB1636 recognized a conformational epitope instead of a linear one, bound to antigen and cancer cells with similar binding affinity, induced significantly more potent ADCC effects against cancer cells, and displayed superior antitumor activities both in vitro and in vivo. The data presented in this study highlights the potential of hIMB1636 as a carrier for the formulation of antibody-based conjugates, or as a promising candidate for anticancer therapy.

Assessment of PD-L1, TROP2, and nectin-4 expression in penile squamous cell carcinoma

OBJECTIVES

There is an unmet need for therapeutically relevant biomarkers for advanced penile squamous cell carcinoma (pSCC). Proposed immunohistochemistry (IHC)-based biomarkers include programmed death-ligand 1 (PD-L1), trophoblast cell-surface antigen 2 (TROP2), and nectin-4; however, there is a paucity of data pertaining to these biomarkers. Herein, we investigated the expression of PD-L1, TROP2, and nectin-4 in a well-annotated cohort of pSCCs.

METHODS

A single-institution pathology archive was queried for patients who had a partial or total penectomy for pSCC between January 2000 and December 2022. Whole-slide sections were stained with antibodies against PD-L1 (22C3), TROP2, and nectin-4. Expression in tumor cells was quantified using H-scores (0-300). Associations between IHC expression, human papilloma virus (HPV) status, clinicopathologic findings, and outcome parameters were evaluated.

RESULTS

This study included 121 patients. For PD-L1, the median combined positive and H-scores were 1 and 0, respectively; 32.7 % of the cases had an H-score>0. Compared to PD-L1-negative tumors, PD-L1-positive tumors had higher pT stage and grade. The median TROP2 and nectin-4 H-scores were 230 and 140, respectively, with high TROP2 and nectin-4, defined by an H-score>200, noted in 80.7 % and 10.9 % of cases, respectively. High-risk HPV-positive cases had higher TROP2 and nectin-4 scores compared to HPV-negative cases. Patients with high TROP2 expression had significantly more disease progression, and patients with high nectin-4 expression had significantly fewer deaths due to disease.

CONCLUSIONS

High expression of TROP2 and nectin-4 in pSCC support evaluation of these markers as therapeutic targets pending validation of our findings.

Antibody-drug conjugates (ADCs) targeting TROP-2 in lung cancer

INTRODUCTION

The advent of antibody-drug conjugates (ADCs) represents a renewed strategy in the era of precision oncology. Several epithelial tumors harbor overexpression of the trophoblast cell-surface antigen 2 (TROP-2), which represents a predictor of poor prognosis and a promising target for anticancer therapy.

AREAS COVERED

In this review, we aim to collect the available preclinical and clinical data regarding anti-TROP-2 ADCs in lung cancer obtained through extensive literature research and screening of the available abstract/posters presented at recent meetings.

EXPERT OPINION

Anti-TROP-2 ADCs represent an innovative upcoming weapon against both non-small cell lung cancer and small cell lung cancer subtypes, pending the results of several ongoing trials. The proper combination and placement of this agent throughout the lung cancer treatment pathway, the identification of potentially predictive biomarkers of benefit, as well as the optimal management and impact of peculiar toxicity (i.e. interstitial lung disease) are the next questions to be answered.

Propionate-producing Veillonella parvula regulates the malignant properties of tumor cells of OSCC

Oral squamous cell carcinoma (OSCC), main head and neck squamous cell carcinomas (HNSCCs), remains a global health concern with unknown pathogenesis. Veillonella parvula NCTC11810 was observed to decrease in saliva microbiome of OSCC patients in this study and the aim was to detect the novel role of Veillonella parvula NCTC11810 in regulating the biological characteristics of OSCC through TROP2/PI3K/Akt pathway. Oral microbial community changes of OSCC patients were detected by 16S rDNA gene sequencing technology. CCK8 assay, Transwell assay, and Annexin V-FITC/PI staining were used for proliferation, invasion, and apoptosis analysis of OSCC cell lines. Expression of proteins were determined by Western blotting analysis. Veillonella parvula NCTC11810 showed decreased in saliva microbiome of TROP2 high-expressed OSCC patients. Culture supernatant of Veillonella parvula NCTC11810 promoted the apoptosis and inhibited the proliferation and invasion ability of HN6 cells, while sodium propionate (SP), the main metabolite of Veillonella parvula NCTC11810, played a similar role through the inhibition of TROP2/PI3K/Akt pathway. Studies above supported the proliferation-inhibiting, invasion-inhibiting, and apoptosis-promoting function of Veillonella parvula NCTC11810 in OSCC cells which provided new insights into oral microbiota and their metabolite as a therapeutic method for OSCC patients with TROP2 high expressing.

Oncostatin M receptor is overexpressed in oral squamous cell carcinoma and connected to poor prognosis

BACKGROUND

Oncostatin M receptor is an interleukin 6 receptor with great influence on inflammation and cancer progression. However, the function of oncostatin M receptor in oral squamous cell carcinoma remains unknown.

METHODS

Oncostatin M receptor expression was explored with TIMER and TCGA databases. The mRNA and protein expressions of oncostatin M receptor were detected in oral tissues. The association between oncostatin M receptor expression and clinicopathological characteristics was analyzed, and the prognostic value of oncostatin M receptor was determined. Immune statues of oncostatin M receptor were analyzed by TIMER and TISIDB. The underlying mechanisms of oncostatin M receptor in oral squamous cell carcinoma was also explored preliminarily.

RESULTS

Oncostatin M receptor was dysregulated in many cancers. Both mRNA and protein levels of oncostatin M receptor in oral squamous cell carcinoma tissues were significantly higher than that in normal oral tissues. Oncostatin M receptor expression was connected to differentiation, lymph node metastasis, tumor node metastasis (TNM) stage, perineural invasion and vascular invasion. Oncostatin M receptor expression was an independent prognostic factor associated with overall survivals. Oncostatin M receptor expression was significantly related to CD8⁺ T cell and interleukin 6 receptor. High oncostatin M receptor expression was associated with focal adhesion, extracellular matrix (ECM) receptor interaction, and JAK/STAT signaling pathway.

CONCLUSION

Oncostatin M receptor was overexpressed in oral squamous cell carcinoma and related to overall survival. Oncostatin M receptor expression has potential to become an effective prognostic biomarker for oral squamous cell carcinoma patients.

Advances in Trop2-targeted therapy: Novel agents and opportunities beyond breast cancer

Trop2 is a transmembrane glycoprotein and calcium signal transducer with limited expression in normal human tissues. It is consistently overexpressed in a variety of malignant tumors and participates in several oncogenic signaling pathways that lead to tumor development, invasion, and metastasis. As a result, Trop2 has become an attractive therapeutic target in cancer treatment. The anti-Trop2 antibody-drug conjugate (Trodelvy™, sacituzumab govitecan) has been approved to treat metastatic triple-negative breast cancer. However, it is still unclear whether the success observed in Trop2-positive breast cancer could be replicated in other tumor types, owing to the differences in the expression levels and functions of Trop2 across cancer types. In this review, we summarize the recent progress on the structures and functions of Trop2 and highlight the potential diagnostic and therapeutic value of Trop2 beyond breast cancer. In addition, the promising novel Trop2-targeted agents in the clinic were discussed, which will likely alter the therapeutic landscape of Trop2-positive tumors in the future.

TROP2 is a Good Indicator for Infiltrative Nature of Carcinoma Rather than Diagnosing Malignancy in Thyroid

TROP2 is a glycoprotein which is expressed in carcinomas rather than normal tissues and associated with poor prognosis. Immunohistohemical TROP2 staining was determined to be useful for diagnosing papillary thyroid carcinoma (PTC). In this study, we aimed to find out relationship between TROP-2 expression and the diagnosis of PTC, and clinico pathological parameters. This retrospective study was conducted on 270 cases (145 malignant and 124 benign). All histopathological parameters were re-evaluated blindly. We used 3 different scores for positivity for TROP2 expression (TES: Total estimation score, 5%, IRS:Immunoreactive score). Sensitivity was respectively according to TES, 5%and IRS; 55.5%, 54.1%, 51.4%. Specificity was 98.4% in all different scores. TROP2 positivity was correlated with older age in 5% score and TES. Absence of encapsulation, presence of infiltrating spreading, perineural invasion, extra thyroidal extension, tall cell and/or hobnail differentiation were associated with TROP2 expression in three different scores. Presence of lymphatic invasion was correlated with TROP2 positivity in 5% score and IRS. TROP2 expression was inversely proportional to follicular variant PTC and tumour size in 5% score. TROP-2 is a marker for aggressive behaviour rather than detecting malignancy, but if it stained and not malignant, it may also have potential for determining precursor lesion that demands further studies. Additionally, in 3 different scores, TES was most sensitive, but most variable that had correlation with TROP2 was seen at 5% score.

Selection of Payloads for Antibody-Drug Conjugates Targeting Ubiquitously Expressed Tumor-Associated Antigens: a Case Study

The main objective of this work was to demonstrate which kind of payload is the suitable choice for antibody-drug conjugates directed to widely expressed tumor-associated antigen. Trop-2 is overexpressed in various solid tumors, but it is also present on the epithelium of several normal tissues. A well-designed anti-Trop-2 ADC demands a good balance of efficacy and toxicity. In this research, MMAE, SN-38, and DXd were selected as candidates for payloads of the anti-Trop-2 mAb SY02. The antitumor activities and safety profiles of these ADCs were investigated to compare the therapeutic windows. Robust in vitro cytotoxicity was observed on human pancreatic cancer cell CFPAC-1 and breast cancer cell MDA-MB-468 with IC₅₀ generally in the subnanomolar range. Consistent with in vitro assay, SY02-DXd and SY02-SN-38 demonstrated superior efficacy in CFPAC-1 xenograft models with TGI rates of 98.2% and 87.3%, respectively. However, SY02-MMAE could hardly inhibit the tumor growth. Subsequently, antitumor activities of these ADCs were further compared in MDA-MB-468 xenograft model. Complete tumor regression was observed in SY02-DXd and SY02-MMAE groups, indicating their potent antitumor activities. In an exploratory safety and pharmacokinetic study, SY02-DXd demonstrated the best safety profile with minimal adverse events in cynomolgus monkeys, while SY02-MMAE exhibited severe on-target skin toxicity which caused death. In conclusion, SY02-DXd demonstrated superior efficacy and safety with the widest therapeutic window. Based on the efficacy and safety results, moderate cytotoxic payloads would be ideal choices for ADCs targeting ubiquitously expressed antigens.

Prognostic impact of perineural invasion in oral cancer: a systematic review

Introduction

Numerous studies have evaluated the prognostic significance of perineural invasion (PNI) in oral cancer; however, the results are inconclusive.

Purpose

To identify the prognostic value of PNI in oral cancer through a metanalysis.

Methods

A literature review was carried out, searching the MedLine databases via Pubmed, Scielo, Lilacs, Cochrane and Websco.

Results

A total of 56 studies were included. The results indicate that PNI in oral cancer has an incidence of 28% (95% confidence interval (CI) 24-31%); 5-year survival with relative risk (RR) 0.67 (0.59-0.75); 5-year disease-free survival RR 0.71 (0.68-0.75); locoregional recurrence with RR 2.09 (1.86-2.35).

Conclusions

PNI is a negative prognostic factor in oral cancer.

Impact of Spatially Heterogeneous Trop-2 Expression on Prognosis in Oral Squamous Cell Carcinoma

Oral cancer often presents with aggressive behavior and a high risk of recurrence and metastasis. For oral squamous cell carcinoma (OSCC), which is the most frequent histological subtype, therapy strategies include surgery, radiation therapy, chemotherapy, immune checkpoint inhibitors, and EGFR inhibitors. Recently, a Trop-2 antibody-drug conjugate (ADC) has been approved in the United States of America for the treatment of advanced triple-negative breast cancer. However, this ADC has also been tested in other solid tumors including head & neck squamous cell carcinoma. The prognostic impact of Trop-2 has already been reported for several cancers. We studied the prognostic influence of Trop-2 protein expression on OSCC patients' survival. The cohort comprised n = 229 OSCC patients with available archived tumor tissue and corresponding non-neoplastic oral mucosa tissue. Using immunohistochemistry, we investigated Trop-2 expression in both the central and peripheral regions of each tumor and in corresponding non-neoplastic oral mucosa. In patients suffering from OSCC with combined high central and low peripheral Trop-2 expression, five-year overall survival (OS) was 41.2%, whereas 55.6% of OSCC patients who presented lower central and/or higher peripheral tumoral Trop-2 expression were alive after five years (p = 0.075). In multivariate Cox regression, the expression pattern of high central tumoral and lower peripheral Trop-2 expression was significantly correlated with impaired OS (HR = 1.802, 95%-CI: 1.134-2.864; p = 0.013) and recurrence-free survival (RFS) (HR = 1.633, 95%-CI: 1.042-2.560; p = 0.033), respectively, when adjusting for co-variables. Hence, Trop-2 may serve as an independent prognostic biomarker in OSCC. In subsequent studies, the pathophysiological meaning of downregulated Trop-2 expression in the OSCC periphery has to be analyzed.

Recent advances in trophoblast cell-surface antigen 2 targeted therapy for solid tumors

Trophoblast cell-surface antigen 2 (Trop 2) is a transmembrane glycoprotein that is highly expressed in various cancer types with relatively low or no baseline expression in most normal tissues. Its overexpression is associated with tumor growth and poor prognosis; Trop 2 is, therefore, an ideal therapeutic target for epithelial cancers. Several Trop 2 targeted therapeutics have recently been developed for the treatment of cancers, such as anti-Trop 2 antibodies and antibody-drug conjugates (ADCs), as well as Trop 2-specific cell therapy. In particular, the safety and clinical benefit of Trop 2-based ADCs have been demonstrated in clinical trials across multiple tumor types, including those with limited treatment options, such as triple-negative breast cancer, platinum-resistant urothelial cancer, and heavily pretreated non-small cell lung cancer. In this review, we elaborate on recent advances in Trop 2 targeted modalities and provide an overview of novel insights for future developments in this field.

CD27 enhances the killing effect of CAR T cells targeting trophoblast cell surface antigen 2 in the treatment of solid tumors

Chimeric antigen receptor (CAR) T cell therapy, a type of adoptive cell therapy, has been successfully used when treating lymphoma malignancies, but not nearly as successful in treating solid tumors. Trophoblast cell surface antigen 2 (Trop2) is expressed in various solid tumors and plays a role in tumor growth, invasion, and metastasis. In this study, a CAR targeting Trop2 (T2-CAR) was developed with different co-stimulatory intercellular domains. T2-CAR T cells demonstrated a powerful killing ability in the presence of Trop2-positive cells following an in vitro assay. Moreover, T2-CAR T cells produced multiple effector cytokines under antigen stimulation. In tumor-bearing mouse models, the CD27-based T2-CAR T cells showed a higher antitumor activity. Additionally, more CD27-based T2-CAR T cells survived in tumor-bearing mice spleens as well as in the tumor tissue. CD27-based T2-CAR T cells were also found to upregulate IL-7Rα expression, while downregulating PD-1 expression. In conclusion, the CD27 intercellular domain can enhance the T2-CAR T cell killing effect via multiple mechanisms, thus indicating that a CD27-based T2-CAR T cell approach is suitable for clinical applications.

Can TROP2 be used as a prognostic marker in endometrioid endometrial carcinoma?

Background

Endometrioid-type endometrial carcinoma is the most common malignancy of the female genital tract in developed countries. The prognosis greatly depends on the grade and stage of the disease.

Aims

In some patients, the disease recurs in a short time after the surgical/medical therapy. Hence, it is important to predict the patients who will have worse prognosis at the beginning, to choose the appropriate treatment; resuming the search of new prognostic markers. Therefore, our study aimed to detect trophoblast cell surface antigen 2 (TROP2) as a new prognostic marker.

Settings and Design

The patients who underwent a hysterectomy and diagnosed with endometrioid-type endometrial carcinoma were evaluated retrospectively and TROP2 immunostain was performed to their tumoral slides.

Materials and Methods

We evaluated TROP2 expressions in 102 patients immunohistochemically who underwent hysterectomy with the diagnosis of endometrioid-type endometrial carcinoma histopathologically and correlated them with the other generally accepted prognostic parameters.

Statistical Analysis

The Kolmogorov-Smirnov test and Q-Q plot test were used to verify the normality of the distribution of continuous variables. The Chi-square/Fisher's exact tests were used for categorical variables. Analyses were performed with SPSS Statistics for Windows, Version 20.

Results

High overexpression of TROP2 was seen in larger, higher-grade, deeper-invasive tumors, tumors with vascular invasion, and pelvic-lymph-node metastasis. These results were statistically significant (P ≤ 0.05).

Conclusion

Overexpression of TROP2 in endometrioid-type endometrial carcinoma seems to be a poor prognostic factor; it may be useful in determining the biologically more aggressive tumors before the treatment. This early determination is very important to choose the appropriate surgery, adjuvant-treatments, and follow-up.

The Role of TROP2 in BCC and Cutaneous SCC: A Clinical and Immunohistochemical Study

BACKGROUND

Nonmelanoma skin cancer (NMSC) mainly includes basal (BCC) and squamous (SCC) cell carcinoma. Trophoblast cell-surface antigen2 (TROP2), a cell-signal transduction, is one of the tumor-related calcium signal transducer gene family. TROP2 was highly expressed in many cancers, however, its role in BCC and SCC has not yet been studied.

OBJECTIVE

To investigate TROP2 immunohistochemical expression in BCC and SCC (lesional and peri-lesional) skin compared to controls and correlates its expression with the clinicopathologic parameters of the studied cases.

METHODS

This case-control study included 17 BCC and 15 SCC patients as well as 12 age and sex matched controls. History and clinical examination were completed. Histological examination of skin biopsies was done together with TROP2 immune-staining.

RESULTS

In the studied BCC and SCC cases, there was a significant stepwise up-regulation of TROP2 H score from control to peri-lesional, ended by lesional epidermis in one hand (p=0.003 for BCC and p<0.001 for SCC) and tumor island in another hand (p=0.001 for BCC and p=0.003 for SCC). TROP2 expression in both BCC and SCC tumor tissues was not affected by any of the studied clinicopathological parameters of the investigated cases.

CONCLUSION

TROP2 could have an important role in BCC and SCC pathogenesis. TROP2 targeting may have appraising effect in clinical application in BCC and SCC management.

Trophoblast cell surface antigen 2 expression predicts outcome in oral squamous cell carcinomas

BACKGROUND

Trophoblast cell surface antigen 2 (TROP2) has unclear clinical role in oral squamous cell carcinomas (OSCC). Here, we investigated the association of TROP2 immunoexpression with clinicopathological parameters and survival of OSCC patients.

SUBJECTS AND METHODS

Cancer-specific survival (CSS) and disease-free survival (DFS) were assessed in a cohort composed of 266 OSCC. An independent cohort with 88 OSCC samples matched with the normal oral tissue, as well as 17 metastatic lymph nodes, was used for validation.

RESULTS

Multivariate analysis showed TROP2 as an independent marker of favorable prognosis for both CSS (HR: 0.60, 95% CI: 0.40-0.90, p = .01) and DFS (HR: 0.57, 95% CI: 0.36-0.89, p = .01). Furthermore, TROP2 protein expression was significantly higher in morphologically normal tissues compared to primary tumors (p < .0001) and lymph node metastases (p = .001), and it was significantly associated with CSS (HR: 0.26, 95% CI: 0.09-0.74, p = .008) in the validation cohort. A pooled mRNA analysis performed on the Oncomine™ database confirmed the underexpression in OSCC compared with normal tissues (p = .014).

CONCLUSIONS

In summary, our results point to a favorable prognostic significance of TROP2 overexpression in a large cohort of oral cancer patients, suggesting it as an attractive clinical marker.

Mechanistic Insights into Trop2 Clustering on Lung Cancer Cell Membranes Revealed by Super-resolution Imaging

The transmembrane glycoprotein Trop2 plays important roles in various types of human cancers, especially lung cancer. Although it has been found to form clusters on cancer cell membranes, the factors that affect its clustering are not yet fully understood. Here, using direct stochastic optical reconstruction microscopy (dSTORM), we found that Trop2 generated more, larger, and denser clusters on apical cell membranes than on basal membranes and that the differences might be related to the different membrane structures. Moreover, dual-color dSTORM imaging revealed significant colocalization of Trop2 and lipid rafts, and methyl-β-cyclodextrin disruption dramatically impaired the formation of Trop2 clusters, indicating a key role of lipid rafts in Trop2 clustering. Additionally, depolymerization of the actin cytoskeleton decreased Trop2 cluster numbers and areas, revealing that actin can stabilize the clusters. More importantly, stimulation of Trop2 in cancer cells hardly changed the cluster morphology, suggesting that Trop2 is activated and forms clusters in cancer cells. Altogether, our work links the spatial organization of Trop2 to different membrane structures and Trop activation and uncovers the essential roles of lipid rafts and actin in Trop2 cluster maintenance.

Could trop-2 overexpression indicate tumor aggressiveness among prostatic adenocarcinomas?

BACKGROUND

TROP-2, a novel marker of trophoblastic cells, is being widely analyzed for its possible role in carcinogenesis and clinical behavior of various carcinomas. In this study, we aimed to evaluate the relationship between clinicopathologic parameters and TROP2 expression in prostatic adenocarcinomas.

METHODS

101 prostatic adenocarcinomas treated by radical prostatectomy in our hospital between 2013 and 2018 were reviewed retrospectively for histopathological features, and one representative block of each case was stained with TROP2 antibody. Histopathologic prognostic features were assessed for their relationship with TROP2 expression.

RESULTS

The mean age was found as 64.11 year. TROP2 was stained in over 10% of the tumoral cells in 64 (63.4.%) cases. Gleason grade group, perineural invasion, lymphovascular invasion, ganglionic and seminal vesicle involvement, lateral and basal surgical margin positivity showed a significant relationship with TROP2 staining.

CONCLUSION

TROP2 is overexpressed in various human cancers and TROP2 overexpression appears to correlate with poor prognosis leading to the suggestion that TROP2 could be a therapeutic target for various carcinomas. Our results suggest that TROP2 expression is higher in advanced tumors and these results need to be supported by larger studies.

Trop2: Jack of All Trades, Master of None

Trophoblast cell surface antigen 2 (Trop2) is a widely expressed glycoprotein and an epithelial cell adhesion molecule (EpCAM) family member. Although initially identified as a transmembrane protein, other subcellular localizations and processed forms were described. Its congenital mutations cause a gelatinous drop-like corneal dystrophy, a disease characterized by loss of barrier function in corneal epithelial cells. Trop2 is considered a stem cell marker and its expression associates with regenerative capacity in various tissues. Trop2 overexpression was described in tumors of different origins; however, functional studies revealed both oncogenic and tumor suppressor roles. Nevertheless, therapeutic potential of Trop2 was recognized and clinical studies with drug-antibody conjugates have been initiated in various cancer types. One of these agents, sacituzumab govitecan, has been recently granted an accelerated approval for therapy of metastatic triple-negative breast cancer. In this article, we review the current knowledge about the yet controversial function of Trop2 in homeostasis and pathology.

Trop2 is upregulated in the transition to dysplasia in the metaplastic gastric mucosa

Intestinal-type gastric adenocarcinoma arises in a field of pre-existing metaplasia. While biomarkers of cancer and metaplasia have been identified, the definition of dysplastic transition as a critical point in the evolution of cancer has remained obscure. We have evaluated Trop2 as a putative marker of the transition from metaplasia to dysplasia in the stomach in multiple mouse models of metaplasia induction and progression. In addition, TROP2 expression was evaluated in human samples by immunostaining tissue microarrays for metaplasia, dysplasia, and gastric cancer. Dysplastic mouse organoids were evaluated in vitro following shRNA knockdown of Trop2 expression. In mouse models, no Trop2 was observed in the normal corpus and Trop2 was not induced in acute models of metaplasia induction with either L635 or DMP-777. In Mist1-Kras mice, Trop2 expression was not observed in metaplasia at 1 month after Kras induction, but was observed in dysplastic glands at 3-4 months after Kras induction. In human tissues, no Trop2 was observed in normal corpus mucosa or SPEM, but Trop2 expression was observed in incomplete intestinal metaplasia, with significantly less expression in complete intestinal metaplasia. Trop2 expression was observed in all dysplastic and 84% of gastric cancer lesions, although expression levels were variable. Dysplastic mouse organoids from Mist1-Kras mice expressed Trop2 strongly. Knockdown of Trop2 with shRNA markedly reduced organoid growth and budding behavior, and induced the upregulation of apical villin expression. We conclude that Trop2 is upregulated in the transition to dysplasia in the stomach and promotes dysplastic cell behaviors. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Knockdown of Trop2 inhibits proliferation and migration and induces apoptosis of endometrial cancer cells via AKT/β-catenin pathway

Endometrial cancer (EC) is the most common gynaecologic malignancy in western countries and has been reported to account for about 7% of female malignant tumours and 20% to 30% of female genital system malignant tumours. Accumulating evidence showed the expression of human trophoblast cell surface antigen 2 (Trop2) was abnormal in many cancers; however, the expression and role of Trop2 in EC are not clear. The Trop-2 protein expression was detected by western blot in EC cells. Cell proliferation, apoptosis, and migration were measured by CCK-8, flow cytometry, and Transwell assay, respectively. The epithelial mesenchymal transition (EMT) and AKT/β-catenin signalling pathway-related proteins in EC cell lines were detected by western blot assay following Trop2 gene silencing. The present study revealed that the Trop2 protein was highly expressed in EC cell lines compared with human endometrial epithelial cells. The Trop2 mRNA and protein were obviously decreased following transfection with Trop2-siRNA sequence in KLE and Ishikawa cells. Meanwhile, Trop2 gene silencing in KLE and Ishikawa cells strongly inhibited cell proliferation and migration and increased cell apoptosis. Investigation into the molecular mechanism indicated that the Trop2 gene silencing suppressed EMT and AKT/β-catenin signalling pathway activation. SIGNIFICANCE OF THE STUDY: These findings suggested that Trop2 silencing inhibited EC cell proliferation and migration and promoted cell apoptosis. The mechanism might be related to the inhibition of the AKT/β-catenin signalling pathway in EC cells. Therefore, Trop2 may be a potential therapeutic target for the treatment of EC.

TROP2 increases growth and metastasis of human oral squamous cell carcinoma through activation of the PI3K/Akt signaling pathway

Most malignant neoplasms of the oral cavity are oral squamous cell carcinoma (OSCC), which is a type of highly malignant tumor with a propensity for forming distant metastases. Trophoblast cell surface antigen 2 (TROP2) is a transmembrane protein that is overexpressed in several types of tumor cells, although its role and regulatory mechanism in OSCC have not been determined. The aim of the present study was to examine the effects of TROP2 in human OSCC cell lines. The present study demonstrated that TROP2 protein expression was upregulated in OSCC cell lines. Transfection of short hairpin RNA (shRNA) targeting TROP2 (sh‑TROP2) reduced cell proliferation, migration and invasion of OSCC cell lines, whereas overexpression of TROP2 increased proliferation, migration and invasion. sh‑TROP2 transfection in OSCC cell lines inhibited tumor growth in OSCC mouse models. Furthermore, TROP2 expression activated the phosphoinositide 3‑kinase (PI3K)/Akt signaling pathway in human OSCC cells. These results suggest that TROP2 induces cell growth, migration and invasion through activation of the PI3K/Akt signaling pathway in OSCC cells.

Screening and identification of biomarkers associated with clinicopathological parameters and prognosis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a major type of malignant tumor of the oral cavity. Despite marked advances in the management and diagnosis of OSCC, the associated overall survival ratio has only exhibited a modest increase in recent years. The present study aimed to identify potential crucial genes associated with clinical features and prognosis for OSCC, and to provide a basis for further investigation. RNA-sequencing data and corresponding clinical information were downloaded from The Cancer Genome Atlas database and differentially expressed mRNAs (DEmRNAs) were identified using the edgeR package. Bioinformatics analysis was performed to identify differentially expressed clinical features-associated mRNAs (CFmRNAs) and enhance the current knowledge of the function of them. Functional enrichment analysis and protein-protein interplay (PPI) network analysis were then performed to better understand CFmRNAs. Survival-associated genes were analyzed with Kaplan-Meier survival curves and the log-rank test. A total of 2,013 DEmRNAs between OSCC samples and normal tissues were identified, 180 of which were associated with clinical features. A total of 17 GO terms and 4 KEGG pathways were significantly enriched in functional enrichment analysis. A total of 4 hub genes (albumin, statherin, neurotensin and mucin 7) were identified in the PPI network analysis. A total of 6 genes (DDB1 and CUL4 associated factor 4 like 2, opiorphin prepropeptide, R3H domain containing like, transmembrane phosphatase with tensin homology, actin like 8 and protocadherin α 11) were observed to have an influence on survival. The DEmRNAs identified may have a crucial role in the genesis and development of OSCC and may be further developed for diagnostic, therapeutic and prognostic applications for OSCC in the future.

POM121 is identified as a novel prognostic marker of oral squamous cell carcinoma

Background: The aim of this study was to confirm the role of nuclear pore membrane protein 121(POM121) in oral squamous cell carcinoma and to explore the underlying mechanism. Methods: POM121mRNA and protein expressions were evaluated in OSCC tissues and normal oral tissues by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. The relationship between POM121 expression and clinical characteristics was analyzed. Bioinformatics analysis was performed to explore the possible mechanisms how POM121 affected OSCC. Results: We confirmed that POM121 mRNA expression in OSCC tissues was significantly higher than that in non-tumorous tissues, as was POM121 protein expression. POM121 expression was associated with distant metastasis and TNM stage. Multivariate analysis confirmed POM121 expression as an independent prognostic factor for OSCC patients. OSCC patients with high POM121 expression had a worse overall survival (OS) compared with patients with low POM121 expression. Bioinformatics analysis indicated POM121 may regulate OSCC through hedgehog and /or p53 signaling pathway. Conclusion: Targeting of POM121 expression levels could provide new diagnostic and therapeutic strategies for OSCC patients.