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

Sacituzumab govitecan in triple-negative breast cancer: from bench to bedside, and back

Triple-negative breast cancer (TNBC) represents a major therapeutic challenge due to its heterogeneous and aggressive phenotype, and limited target-specific treatment options. The trophoblast cell surface antigen (Trop-2), a transmembrane glycoprotein overexpressed in various cancers, has emerged as a promising target for TNBC. Sacituzumab govitecan (SG), an antibody-drug conjugate (ADC) that targets Trop-2, has recently entered treatment algorithms for advanced and metastatic TNBC, independently from Trop-2 expression status, with manageable toxicity. Despite the impressive results, questions remain unsolved regarding its efficacy, safety profile, and Trop-2 biological role in cancer. Currently, Trop-2 cannot be designated as a predictive biomarker in SG treatment, albeit its expression correlates with disease outcome, yet its levels are not uniform across all TNBCs. Additionally, data regarding Trop-2 expression variations in primary and metastatic sites, and its interplay with other biomarkers are still ambiguous but mandatory in light of future applications of SG in other indications and settings. This poses the questions of a careful evaluation of the efficacy and toxicity profile of SG in such early stages of disease, and in personalized and combinatorial strategies. Research and clinical data are mandatory to address SG drawbacks and minimize its benefits, to realize its full potential as therapeutic agent in different epithelial tumors.

ImmunoPET imaging of Trop2 in patients with solid tumours

Accurately predicting and selecting patients who can benefit from targeted or immunotherapy is crucial for precision therapy. Trophoblast cell surface antigen 2 (Trop2) has been extensively investigated as a pan-cancer biomarker expressed in various tumours and plays a crucial role in tumorigenesis through multiple signalling pathways. Our laboratory successfully developed two 68Ga-labelled nanobody tracers that can rapidly and specifically target Trop2. Of the two tracers, [68Ga]Ga-NOTA-T4, demonstrated excellent pharmacokinetics in preclinical mouse models and a beagle dog. Moreover, [68Ga]Ga-NOTA-T4 immuno-positron emission tomography (immunoPET) allowed noninvasive visualisation of Trop2 heterogeneous and differential expression in preclinical solid tumour models and ten patients with solid tumours. [68Ga]Ga-NOTA-T4 immunoPET could facilitate clinical decision-making through patient stratification and response monitoring during Trop2-targeted therapies.

Decoding TROP2 in breast cancer: significance, clinical implications, and therapeutic advancements

Breast cancer is a heterogeneous disease characterized by distinct molecular subtypes, varied prognoses, and differential treatment responses. Understanding the molecular landscape and identifying therapeutic targets, such as trophoblast cell-surface antigen 2 (TROP2), is vital. TROP2 is notably overexpressed in breast cancer, playing a significant role in tumor growth, invasion, metastasis, and treatment resistance. While significant progress has been made in targeting TROP2 in breast cancer, several challenges and knowledge gaps remain. These challenges include the heterogeneity of TROP2 expression within breast cancer subtypes, resistance to its targeted therapies, potential off-target effects, limited therapeutic agents, and identifying optimal combination treatments. Integrating findings from clinical trials into clinical practice further complicates the landscape. This review article delves deep into TROP2 in breast cancer, highlighting its expression patterns, clinical implications, and therapeutic advancements. By understanding the role of TROP2, we can pave the way for personalized treatments, and transform the landscape of breast cancer care.

An assembly of TROP2-mediated signaling events

Trophoblast cell surface antigen 2 (TROP2) is a calcium-transducing transmembrane protein mainly involved in embryo development. The aberrant expression of TROP2 is observed in numerous cancers, including triple-negative breast cancer, gastric, colorectal, pancreatic, squamous cell carcinoma of the oral cavity, and prostate cancers. The main signaling pathways mediated by TROP2 are calcium signaling, PI3K/AKT, JAK/STAT, MAPKs, and β-catenin signaling. However, collective information about the TROP2-mediated signaling pathway is not available for visualization or analysis. In this study, we constructed a TROP2 signaling map with respect to its role in different cancers. The data curation was done manually by following the NetPath annotation criteria. The described map consists of different molecular events, including 8 activation/inhibition, 16 enzyme catalysis, 19 gene regulations, 12 molecular associations, 39 induced-protein expressions, and 2 protein translocation. The data of the TROP2 pathway map is made freely accessible through the WikiPathways Database ( https://www.wikipathways.org/index.php/Pathway:WP5300 ). Development of TROP2 signaling pathway map.

Epigenetically upregulating TROP2 and SLFN11 enhances therapeutic efficacy of TROP2 antibody drug conjugate sacitizumab govitecan

TROP2 antibody drug conjugates (ADCs) are under active development. We seek to determine whether we can enhance activity of TROP2 ADCs by increasing TROP2 expression. In metaplastic breast cancers (MpBC), there is limited expression of TROP2, and downregulating transcription factor ZEB1 upregulates E-cad and TROP2, thus sensitizing cancers to TROP2 ADC sacituzumab govitecan (SG). Demethylating agent decitabine decreases DNA methyltransferase expression and TROP2 promoter methylation and subsequently increases TROP2 expression. Decitabine treatment as well as overexpression of TROP2 significantly enhance SG antitumor activity. Decitabine also increases SLFN11, a biomarker of topoisomerase 1 inhibitor (TOP1) sensitivity and is synergistic with SG which has a TOP1 payload, in TROP2-expressing SLFN11-low BC cells. In conclusion, TROP2 and SLFN11 expression can be epigenetically modulated and the combination of demethylating agent decitabine with TROP2 ADCs may represent a novel therapeutic approach for tumors with low TROP2 or SLFN11 expression.

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.

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.

Role of PI3K/AKT pathway in squamous cell carcinoma with an especial focus on head and neck cancers

PI3K/AKT pathway is an important pathway in the carcinogenesis since it has central impacts in the regulation of metabolic pathways, cell proliferation and survival, gene expression and protein synthesis. This pathway has been reported to be dysregulated in several types of cancers. In the current review, we summarize the role of this signaling pathway in squamous cell carcinomas (SCCs) originated from different parts of body cervix, oral cavity, head and neck and skin. The data presented in the current review shows the impact of dysregulation of PI3K/AKT pathway in survival of patients with SCC. Moreover, targeted therapies against this pathway have been found to be effective in reduction of tumor burden both in animal models and clinical settings. Finally, a number of molecules that regulate PI3K/AKT pathway can be used as diagnostic markers for different types of SCCs.

Trophoblast Cell Surface Antigen 2 gene (TACSTD2) expression in primary breast cancer

PURPOSE

Trophoblast Cell Surface Antigen 2 (TROP2) is a glycoprotein expressed in many cancers. A TROP2 antibody-drug conjugate (ADC) was effective in metastatic triple-negative breast cancer (TNBC). We studied TROP2 gene (TACSTD2) expression and associations with tumor and clinical characteristics, as well as selected external genes in primary breast cancer.

METHODS

TACSTD2 gene expression was evaluated using microarray data from I-SPY 1 (n = 149), METABRIC (n = 1992), and TCGA (n = 817). Associations with clinical features (Kruskal-Wallis test, all datasets), chemotherapy response (Wilcoxon rank sum test, I-SPY 1), recurrence free survival (Cox proportional hazard model, I-SPY 1 and METABRIC), and selected genes (Pearson correlations, all datasets) were determined.

RESULTS

TACSTD2 gene expression was detectable in all breast cancer subtypes, with a wide range of expression (all datasets). TACSTD2 gene expression was lower in HER2 + than HR + /HER2- and TNBC (METABRIC: p = 0.03, TCGA p = 0.007), and in HER2 + enriched and luminal B breast cancer (METABRIC: p < 0.001, TCGA: p < 0.001). TACSTD2 expression was higher in grade I vs. II/III tumors (METABRIC: p < 0.001). No association with chemotherapy response (I-SPY 1) or recurrence free survival (I-SPY 1 and METABRIC) was seen. TACSTD2 has significant positive correlations with the expression of epithelial/adhesion genes and proliferative genes, but was inversely correlated with immune genes.

CONCLUSION

TACSTD2 gene expression was seen in all breast cancer subtypes particularly luminal A and TNBC, and correlated with the expression of genes involved in cell epithelial transformation, adhesion, and proliferation, which contribute to tumor growth. These results support the investigation of TROP2 ADC in all subtypes of breast cancer.

TACSTD2 upregulation is an early reaction to lung infection

TACSTD2 encodes a transmembrane glycoprotein Trop2 commonly overexpressed in carcinomas. While the Trop2 protein was discovered already in 1981 and first antibody–drug conjugate targeting Trop2 were recently approved for cancer therapy, the physiological role of Trop2 is still not fully understood. In this article, we show that TACSTD2/Trop2 expression is evolutionarily conserved in lungs of various vertebrates. By analysis of publicly available transcriptomic data we demonstrate that TACSTD2 level consistently increases in lungs infected with miscellaneous, but mainly viral pathogens. Single cell and subpopulation based transcriptomic data revealed that the major source of TACSTD2 transcript are lung epithelial cells and their progenitors and that TACSTD2 is induced directly in lung epithelial cells following infection. Increase in TACSTD2 expression may represent a mechanism to maintain/restore epithelial barrier function and contribute to regeneration process in infected/damaged lungs.

Shedding light on triple-negative breast cancer with Trop2-targeted antibody-drug conjugates

Triple-negative breast cancer (TNBC) is well-known as the most aggressive subtype of breast cancer. Because TNBC does not express Her2, estrogen receptor, and progesterone receptors, there had been no effective U.S. Food and Drug Administration-approved targeted therapy for it until PARP inhibitors and two PD-1/PD-L1 monoclonal antibodies were approved for treatment of TNBC. Most recently, an antibody-drug conjugate (ADC), called sacituzumab govitecan (SG), was approved for the treatment of TNBC patients previously received chemotherapy with advanced disease. SG consists of an anti-trophoblast cell-surface antigen 2 (Trop2) antibody conjugated with a topoisomerase I inhibitor, SN-38, which is diffused out of the targeted Trop2 positive cancer cells and induces the bystander killing effect on surrounding cells regardless of their Trop2 expression status. In the Phase III clinical trial, TNBC patients treated with SG showed significantly longer progression-free and overall survival compared to those who were received chemotherapy. In the present review, we summarized the cellular function and signaling of Trop2, the mechanism of action of SG, and the clinical trials of SG that led to its quick approval for TNBC. In addition, we introduced the current ongoing clinical trials of SG as well as another Trop2 ADC, which has potential to overcome some disadvantages of SG.

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.

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.

Toxicarioside O Inhibits Cell Proliferation and Epithelial-Mesenchymal Transition by Downregulation of Trop2 in Lung Cancer Cells

Toxicarioside O (TCO), a natural product derived from Antiaris toxicaria, has been identified to be a promising anticancer agent. In this study, we aimed to investigate the effect of TCO on the proliferation and epithelial-mesenchymal transition (EMT) of lung cancer cells and its molecular mechanisms. Here, we indicated that TCO inhibits the proliferation of lung cancer cells both in vitro and in vivo. Our results demonstrated that TCO induces apoptosis in lung cancer cells. Moreover, we found that TCO suppresses EMT program and inhibits cell migration in vitro. Mechanistically, TCO decreases the expression of trophoblast cell surface antigen 2 (Trop2), resulting in inhibition of the PI3K/Akt pathway and EMT program. Overexpression of Trop2 rescues TCO-induced inhibition of cell proliferation and EMT. Our findings demonstrate that TCO markedly inhibits cell proliferation and EMT in lung cancer cells and provides guidance for its drug development.

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.

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.

Tissue mechanics and expression of TROP2 in oral squamous cell carcinoma with varying differentiation

Background

Trophoblast cell surface antigen 2 (TROP2) is overexpressed in many squamous cell carcinomas and promotes tumor development and invasion. The association between TROP2 expression and occurrence and development of oral squamous cell carcinoma (OSCC) remains to be understood.

Methods

We investigated the role of TROP2 in OSCC patients using a combination of biophysical approaches. A total of 108 OSCC patient specimens with varying degrees of differentiation were subjected to hematoxylin and eosin staining, immunohistochemistry, Kaplan-Meier survival curve analysis, and atomic force microscopy to analyze TROP2 expression, morphology, and mechanical properties of OSCC tissues.

Results

TROP2 was overexpressed in 34% of poorly differentiated OSCC samples. High levels of TROP2 were associated with 10.2% survival rate lower than 45.4% and patient age (odds ratio [OR] = 0.437, P = 0.039, 95% confidence interval [CI, 0.198–0.966]), tumor size (OR = 13.148, P = 0.000, 95% CI [5.060–34.168]), and TNM stage (OR = 0.141, P = 0.000, 95% CI [0.082–0.244]). Average surface roughness of low, medium, and highly differentiated OSCC tissues were 448.9 ± 54.8, 792.7 ± 83.6, and 993.0 ± 104.3 nm, respectively. The Pearson coefficient revealed a negative association between tumor stiffness and TROP2 expression (r = − 0.84, P < 0.01).

Conclusion

Overexpression of TROP2 negatively associated with patient survival, degree of tumor differentiation, and tissue mechanics. Taken together, our findings demonstrated that TROP2 may be an indicator of OSCC differentiation leading to the altered mechanical properties of OSCC tissues.

ET-1 promotes the growth and metastasis of esophageal squamous cell carcinoma via activating PI3K/Akt pathway

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the prevalent and deadly cancers worldwide. Previous studies confirmed that endothelin-1 (ET-1) serves as an oncogene and therapeutic target in various tumors. However, the role and mechanism of ET-1 in the progression of ESCC remains largely unclear.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA level of ET-1 in ESCC tissues and cell lines. Cell counting kit-8 (CCK-8), flow cytometry and Transwell assay were performed to examine the proliferation, cell cycle arrest, invasion and migration capacity of ESCC cells. Western blot was applied to measure the expression of ET-1 and PI3K/Akt pathway-related proteins. Furthermore, we also assessed the effect of ET-1 on tumor growth in vivo.

RESULTS

ET-1 was highly expressed in ESCC tissues and associated with poor outcomes. Knockdown of ET-1 significantly inhibited the proliferation, migration and invasion capacity of ESCC cells and promoted cell cycle arrest. Mechanistically, silencing of ET-1 exerts anti-proliferation and anti-metastasis activities via inactivation of the PI3K/Akt signaling pathway in ESCC in vitro and in vivo.

CONCLUSIONS

These findings uncover the effective suppression of cell proliferation and metastasis through silencing of ET-1 and blocking the PI3K/Akt signaling pathway, which is an attractive therapeutic regimen for the treatment of ESCC.