Trop2 is a transmembrane glycoprotein encoded by the Tacstd2 gene. It is an intracellular calcium signal transducer that is differentially expressed in many cancers. It signals cells for ...self-renewal, proliferation, invasion, and survival. It has stem cell-like qualities. Trop2 is expressed in many normal tissues, though in contrast, it is overexpressed in many cancers and the overexpression of Trop2 is of prognostic significance. Several ligands have been proposed that interact with Trop2. Trop2 signals the cells via different pathways and it is transcriptionally regulated by a complex network of several transcription factors. Trop2 expression in cancer cells has been correlated with drug resistance. Several strategies target Trop2 on cancer cells that include antibodies, antibody fusion proteins, chemical inhibitors, nanoparticles, etc. The in vitro studies and pre-clinical studies, using these various therapeutic treatments, have resulted in significant inhibition of tumor cell growth both in vitro and in vivo in mice. A clinical study is underway using IMMU-132 (hrS7 linked to SN38) in patients with epithelial cancers. This review describes briefly the various characteristics of cancer cells overexpressing Trop2 and the potential application of Trop2 as both a prognostic biomarker and as a therapeutic target to reverse resistance.
Epithelial ovarian cancer (EOC) is associated with the highest gynecologic cancer mortality. The development of novel, effective combinations of targeted therapeutics remains an unmet medical need. ...We evaluated the preclinical activity of datopotamab deruxtecan (Dato-Dxd), a novel TROP2 targeting antibody drug conjugate (ADC) in ovarian cancer cell lines and xenografts with variable TROP2 expression.
In vitro cell viability with Dato-DXd was assessed using flow-cytometry based assays against a panel of EOC primary cell lines with variable TROP2 expression. Fluorescent anti-phospho-histone H2A.X antibody was used to detect dsDNA breaks by flow-cytometry. The in vivo antitumor activity of Dato-DXd was tested in TROP2 overexpressing xenografts.
TROP2 overexpressing (3+) and moderate (2+) expressing EOC cell lines demonstrated higher sensitivity to Dato-DXd when compared to TROP2 negative tumors. Dato-DXd exposed TROP2+ EOC demonstrated increased dsDNA breaks and Annexin-V positivity (a marker of apoptosis) when compared to tumor cells exposed to the non-binding conjugate (p = 0.001 and p = 0.016, respectively). Dato-DXd induced significant antibody-dependent cellular cytotoxicity (ADCC) in the presence of peripheral-blood-lymphocytes. While negligible activity was detected against EOC cell lines with low TROP2 expression, Dato-DXd demonstrated significant bystander killing against tumor cells with low/negligible TROP2 when such cells were admixed with TROP2 3+ tumor cells in vitro. Dato-DXd showed tumor growth suppression against EOC cell line derived xenograft models that overexpress TROP2 at 3+ levels, prolonging survival when compared to controls, with minimal toxicity.
Dato-DXd shows promising preclinical activity against TROP2 overexpressing ovarian cancers. Future clinical trials in ovarian cancer patients are warranted.
•Dato-DXd exhibited marked cytotoxicity in vitro among TROP2-overexpressing ovarian cancer cell lines.•TROP2 negative cells are receptive to bystander killing from Dato-DXd when mixed with TROP2 expressing cells.•Dato-DXd inhibits TROP2-overexpressing ovarian cancer tumor growth in patient-derived xenografts.•Dato-DXd shows promising preclinical activity against TROP2 overexpressing ovarian cancers.
Background & Aims: Metaplasia in the stomach is highly associated with development of intestinal-type gastric cancer. Two types of metaplasias, spasmolytic polypeptide-expressing metaplasia (SPEM) ...and intestinal metaplasia (IM), are considered precancerous lesions. However, it remains unclear how SPEM and IM are related. Here we investigated a new lineage-specific marker for SPEM cells, aquaporin 5 (AQP5), to assist in the identification of these 2 metaplasias. Methods: Drug- or Helicobacter felis (H felis) infection-induced mouse models were used to identify the expression pattern of AQP5 in acute or chronic SPEM. Gene-manipulated mice treated with or without drug were used to investigate how AQP5 expression is regulated in metaplastic lesions. Metaplastic samples from transgenic mice and human gastric cancer patients were evaluated for AQP5 expression. Immunostaining with lineage-specific markers was used to differentiate metaplastic gland characteristics. Results: Our results revealed that AQP5 is a novel lineage-specific marker for SPEM cells that are localized at the base of metaplastic glands initially and expand to dominate glands after chronic H felis infection. In addition, AQP5 expression was up-regulated early in chief cell reprogramming and was promoted by interleukin 13. In humans, metaplastic corpus showed highly branched structures with AQP5-positive SPEM. Human SPEM cells strongly expressing AQP5 were present at the bases of incomplete IM glands marked by TROP2 but were absent from complete IM glands. Conclusions: AQP5-expressing SPEM cells are present in pyloric metaplasia and TROP2-positive incomplete IM and may be an important component of metaplasia that can predict a higher risk for gastric cancer development.
Improving the prognosis for patients with metastatic HR+/HER2- breast cancer remains an unmet need. Patients with tumors that have progressed on endocrine therapy and/or are not eligible for ...endocrine therapy had limited treatment options beyond chemotherapy. Antibody-drug conjugates are a novel and promising treatment class in this setting. Datopotamab deruxtecan (Dato-DXd) consists of a TROP2-directed humanized IgG1 monoclonal antibody attached
a serum-stable cleavable linker to a topoisomerase I inhibitor payload. TROPION-Breast01 is an ongoing phase III study that is evaluating the efficacy and safety of Dato-DXd compared with investigator's choice of standard-of-care chemotherapy in patients with inoperable or metastatic HR+/HER2- breast cancer who have received one or two prior lines of systemic chemotherapy in the inoperable or metastatic setting.
NCT05104866 (ClinicalTrials.gov).
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•Based on our previous work, site-specific ADCs targeting TROP2 were synthesized via IgG glycoengineering or affinity-directed traceless conjugation. These site-specific conjugation ...methods of modifying IgG Fc fragment were unique.•With improved homogeneity, hydrophilicity & stability, the one-step-made gsADC 3b showed superior in vitro &in vivo anti-tumor efficacy.•The reduced in vivo efficacy was observed in two-step site-specific gsADCs. One way to retain in vivo anti-tumor activity is by balancing the cyclooctyne-functionalized linker fragment with the hydrophilicity fragment mPEG24 (gsADC 5b vs. gsADC 5d).
The approval of Trodelvy® validates TROP2 as a druggable but challenging target for antibody-drug conjugates (ADCs) to treat metastatic triple-negative breast cancer (mTNBC). Here, based on the TROP2-targeted antibody sacituzumab, we designed and developed several site-specific ADC candidates, which employ MMAE (monomethyl auristatin E) as the toxin, via IgG glycoengineering or affinity-directed traceless conjugation. Systematic evaluation of these site-specific ADCs in homogeneity, hydrophilicity, stability, and antitumor efficiency was conducted. The results indicate that the site-specific ADCs gsADC 3b made from one-step glycoengineering exhibit good aggregation stability and in vivo efficacy, providing a new format of ADCs that target TROP2.
RNA modifications, including adenine methylation (m6A) of mRNA and guanine methylation (m7G) of tRNA, are crucial for the biological function of RNA. However, the mechanism underlying the translation ...of specific genes synergistically mediated by dual m6A/m7G RNA modifications in bladder cancer (BCa) remains unclear. We demonstrated that m6A methyltransferase METTL3-mediated programmable m6A modification of oncogene trophoblast cell surface protein 2 (TROP2) mRNA promoted its translation during malignant transformation of bladder epithelial cells. m7G methyltransferase METTL1 enhanced TROP2 translation by mediating m7G modification of certain tRNAs. TROP2 protein inhibition decreased the proliferation and invasion of BCa cells in vitro and in vivo. Moreover, synergistical knockout of METTL3/METTL1 inhibited BCa cell proliferation, migration, and invasion; however, TROP2 overexpression partially abrogated its effect. Furthermore, TROP2 expression was significantly positively correlated with the expression levels of METTL3 and METTL1 in BCa patients. Overall, our results revealed that METTL3/METTL1-mediated dual m6A/m7G RNA modifications enhanced TROP2 translation and promoted BCa development, indicating a novel RNA epigenetic mechanism in BCa.
•METTL3/METTL1-mediated dual m6A/m7G RNA modifications enhance TROP2 translation.•METTL1-and METTL3-mediated RNA modifications synergize in BCa development.•TROP2 promotes the proliferation and invasion of BCa cells in vitro and in vivo.•The study clarifies a novel RNA epigenetic mechanism of BCa.
Trophoblastic cell surface antigen 2 (TROP2) has been reported to be upregulated in several types of carcinomas and is associated with aggressive behavior and poor survival. However, TROP2 expression ...and its clinical significance in ampullary adenocarcinoma (AA) have not been investigated.
We examined TROP2 expression by immunohistochemistry in 112 patients with AAs. The associations of TROP2 expression with clinicopathologic characteristics were evaluated by Chi-squared analyses or Fischer’ exact tests. The associations of TROP2 expression and pathologic parameters with survival were evaluated by Kaplan-Meier method, univariate and multivariate cox regression analyses. Eighty-six AAs (76.8%) were positive for TROP2, which showed a membranous and cytoplasmic staining. TROP2 expression was associated with higher frequency (P=0.04) and higher number (P=0.03) of lymph node metastasis, higher pN stage (P=0.03), less frequent adenoma (P=0.04), and higher frequency of recurrence/metastasis (P=0.004). TROP2 expression was associated with shorter disease-free survival (P=0.02) and overall survival (P=0.03). TROP2 expression was an independent prognostic factor for disease-free survival (P=0.04).
We demonstrated TROP2 was expressed in 76.8% of AAs. TROP2 expression was associated with higher frequency and high number of lymph node metastasis and higher pN stage. More importantly, TROP2 expression was associated with higher frequency of recurrence/metastasis, shorter disease-free and overall survival and was an independent prognostic factor for disease-free survival. Our results suggest that TROP2 may be used both as a prognostic marker and therapeutic target for patients with AAs.
OBJECTIVESThere 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.METHODSA 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.RESULTSThis 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.CONCLUSIONSHigh expression of TROP2 and nectin-4 in pSCC support evaluation of these markers as therapeutic targets pending validation of our findings.
