Rescue of secretion of rare-disease-associated misfolded mutant glycoproteins in UGGT1 knock-out mammalian cells.

Endoplasmic reticulum (ER) retention of misfolded glycoproteins is mediated by the ER-localized eukaryotic glycoprotein secretion checkpoint, UDP-glucose glycoprotein glucosyl-transferase (UGGT). The enzyme recognizes a misfolded glycoprotein and flags it for ER retention by re-glucosylating one of its N-linked glycans. In the background of a congenital mutation in a secreted glycoprotein gene, UGGT-mediated ER retention can cause rare disease, even if the mutant glycoprotein retains activity ("responsive mutant"). Using confocal laser scanning microscopy, we investigated here the subcellular localization of the human Trop-2-Q118E, E227K and L186P mutants, which cause gelatinous drop-like corneal dystrophy (GDLD). Compared with the wild-type Trop-2, which is correctly localized at the plasma membrane, these Trop-2 mutants are retained in the ER. We studied fluorescent chimeras of the Trop-2 Q118E, E227K and L186P mutants in mammalian cells harboring CRISPR/Cas9-mediated inhibition of the UGGT1 and/or UGGT2 genes. The membrane localization of the Trop-2 Q118E, E227K and L186P mutants was successfully rescued in UGGT1-/- cells. UGGT1 also efficiently reglucosylated Trop-2-Q118E-EYFP in cellula. The study supports the hypothesis that UGGT1 modulation would constitute a novel therapeutic strategy for the treatment of pathological conditions associated to misfolded membrane glycoproteins (whenever the mutation impairs but does not abrogate function), and it encourages the testing of modulators of ER glycoprotein folding quality control as broad-spectrum rescue-of-secretion drugs in rare diseases caused by responsive secreted glycoprotein mutants.

Antibody-drug conjugates transform the outcome of individuals with low-HER2-expression advanced breast cancer.

Antibody-drug conjugates (ADCs)-a groundbreaking class of agents for targeted oncological therapies-consist of monoclonal antibodies with strong antigenic specificity coupled with highly active cytotoxic agents (also referred to as "payloads"). Over the past 2 decades, breast cancer research has evolved into a focal point for the research and development of ADCs, leading to several recent landmark publications. These advancements are ushering in a transformative era in breast cancer treatment and redefining conventional classifications by introducing a prospective subtype termed "HER2-low." The latest iterations of ADCs have demonstrated enhanced efficacy in disease management through the optimization of various factors, notably the incorporation of the bystander effect. These conjugates are no longer limited to the oncogenic driver human epidermal growth factor receptor 2 (HER2). Other antigens, including human epidermal growth factor receptor 3 (HER3), trophoblast cell surface antigen 2 (Trop-2), zinc transporter ZIP6 (LIV-1), and folate receptor α (FRα), have recently emerged as intriguing tumor cell surface nondriver gene targets for ADCs, each with one or more specific ADCs that showed encouraging results in the breast cancer field. This article reviews recent advances in the application of ADCs in the treatment of HER2-low breast cancer. Additionally, this review explores the underlying factors contributing to the impact of target selection on ADC efficacy to provide new insights for optimizing the clinical application of ADCs in individuals with low HER2 expression in advanced breast cancer.

Top advances of the year: Uterine cancer.

Endometrial cancer continues to be the only gynecologic malignancy with a rising incidence and mortality, with both regional and global implications. Combination carboplatin and paclitaxel has been the recognized chemotherapy backbone for the treatment of advanced-stage or recurrent disease, with modest clinical outcomes. Over the last year, significant advances were achieved in improving oncologic outcomes by capitalizing on the molecular characterization of this heterogenous disease. These advances include incorporation of immunotherapy, identification of effective hormonal approaches, the evolution of antibody drug conjugates, and utilization of alternate targeted therapies. PLAIN LANGUAGE SUMMARY: The molecular characterization of endometrial cancer has been critical in informing novel treatment strategies. Over the past year, significant gains have been made via the incorporation of immunotherapy, hormonal combinations as well as antibody drug conjugates.

Genomic, immunologic, and prognostic associations of TROP2 (TACSTD2) expression in solid tumors.

BACKGROUND: TROP2 (TACSTD2) expression is associated with decreased overall survival (OS) in some solid tumors, and the TROP2-targeting antibody-drug conjugate (ADC) sacituzumab govitecan has been approved in breast and urothelial carcinomas. We aimed to explore the multi-omic landscape associated with TACSTD2 gene expression in various solid tumors to identify patients most likely to benefit from this approach. METHODS: Breast (N = 11 246), colorectal (N = 15 425), hepatocellular (N = 433), pancreatic (N = 5488), and urothelial (N = 4125) tumors were stratified into quartiles by TACSTD2 gene expression, analyzed by next-generation DNA sequencing, whole transcriptome sequencing, and immunohistochemistry at Caris Life Sciences (Phoenix, AZ). Survival data were obtained from insurance claims, and Kaplan-Meier estimates were calculated for molecularly defined cohorts. RESULTS: Several pathogenic mutations were associated with TACSTD2-high tumors, including TP53 in breast, colorectal (CRC), pancreatic, and hepatocellular cancers; KRAS in pancreatic and CRC cancers; ARID1A and FGFR3 in urothelial cancer; and CTNNB1 in hepatocellular cancer. TACSTD2-low breast tumors were enriched for copy number amplifications in CCND1 and FGF/R family member genes. TACSTD2 high was generally associated with more immune cell infiltration and greater T-cell inflammation scores. Patients with TACSTD2-high breast, CRC, and pancreatic cancers demonstrated a significantly shorter OS than TACSTD2-low tumors. This was restricted to CRC with microsatellite stable tumors and patients with pancreatic cancer with KRAS-mutant tumors. Patients with breast cancer with TACSTD2-high tumors also experienced significantly worse OS following immune checkpoint inhibitors. CONCLUSIONS: TACSTD2 expression is associated with key driver alterations and a more active immune microenvironment, suggesting possible combinatorial strategies with TROP2-targeting ADCs plus immunotherapy in various solid tumors.

Correlation between trophoblast cell-surface antigen-2 (Trop-2) expression and pathological complete response in patients with HER2-positive early breast cancer treated with neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab.

PURPOSE: The prognostic and predictive role of trophoblast cell-surface antigen-2 (Trop-2) overexpression in human epidermal growth factor receptor 2-positive (HER2-positive) breast cancer is currently unknown. We retrospectively analyzed Trop-2 expression and its correlation with clinicopathologic features and pathological complete response (pCR) in HER2-positive early breast cancer (EBC) patients treated with neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab in the PHERGain study. METHODS: Trop-2 expression at baseline was determined in formalin-fixed, paraffin-embedded primary tumor biopsies by immunohistochemistry and was first classified into expressing (Trop-2-positive) or not-expressing (Trop-2-negative) tumors. Then, it was classified by histochemical score (H-score) according to its intensity into low (0-9), intermediate (10-49), and high (≥ 50). The association between clinicopathologic features, pCR, and Trop-2 expression was performed with Fisher's exact test. RESULTS: Forty-one patients with tissue evaluable for Trop-2 expression were included, with 28 (68.3%) Trop-2-positive tumors. Overall, 17 (41.46%), 14 (34.15%), and 10 (24.40%) tumors were classified as low, intermediate, and high, respectively. Trop-2 expression was significantly associated with decreased pCR rates (50.0% vs. 92.3%; odds ratio [OR] 0.05; 95% CI, 0.002-0.360]; p adjusted = 0.01) but was not correlated with any clinicopathologic features (p ≥ 0.05). Tumors with the highest Trop-2 H-score were less likely to obtain a pCR (OR 0.03; 95% CI, 0.001-0.290, p adjusted < 0.01). This association was confirmed in univariate and multivariate regression analyses. CONCLUSION: These findings suggest a potential role of Trop-2 expression as a biomarker of resistance to neoadjuvant chemotherapy plus dual HER2 blockade and may become a strategic target for future combinations in HER2-positive EBC patients.

Associations of TACSTD2/TROP2 and NECTIN-4/NECTIN-4 with molecular subtypes, PD-L1 expression, and FGFR3 mutational status in two advanced urothelial bladder cancer cohorts.

AIMS: Treatment options for advanced urothelial carcinoma (aUC) rapidly evolved: besides immunomodulative therapeutic options and inhibitors targeting Fibroblast growth factor receptor (FGFR) alterations, two new antibody-drug conjugates (ADC), sacituzumab govitecan (SG) and enfortumab vedotin (EV), have been approved. However, little is known about the associations of specific aUC properties and the surface target expression of TROP2 and NECTIN-4. Our aim was to characterize associations of TACSTD2/TROP2 and NECTIN-4/NECTIN-4 protein and gene expression with morphomolecular and clinicopathological characteristics of aUC in two large independent cohorts. METHODS AND RESULTS: The TCGA BLCA (n = 405) and the CCC-EMN (n = 247) cohorts were retrospectively analysed. TROP2/TACSTD2 and NECTIN-4/NECTIN-4 are highly expressed at the protein and transcript level in aUC, and their expression status did not correlate with patient survival in both cohorts. NECTIN-4/NECTIN-4 expression was higher in luminal tumours and reduced in squamous aUCs. NECTIN-4 was negative in 10.6% of samples, and 18.4% of samples had low expression (H-score <15). The TROP2 negativity rate amounted to 6.5%. TACSTD2 and NECTIN-4 expression was reduced in neuroendocrine-like and/or protein-based double-negative tumours. TROP2- and NECTIN-4-negative tumours included one sarcomatoid and four neuroendocrine aUC. FGFR3 alterations and PD-L1 expression on tumour and immune cells did not associate with TROP2 or NECTIN-4 expression. CONCLUSIONS: TACSTD2/TROP2 and NECTIN-4/NECTIN-4 are widely expressed in aUC, independent of FGFR3 alterations or PD-L1 expression, thus representing a suitable target for ADC treatment in the majority of aUC. The expression loss was associated with aggressive morphomolecular aUC subtypes, i.e. neuroendocrine(-like) and sarcomatoid aUC.

Preclinical activity of datopotamab deruxtecan, a novel TROP2 directed antibody-drug conjugate targeting trophoblast cell-surface antigen 2 (TROP2) in ovarian carcinoma.

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Dato-DXd shows promising preclinical activity against TROP2 overexpressing ovarian cancers. Future clinical trials in ovarian cancer patients are warranted.

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.

Feasibility study of ADCs targeting TROP-2, HER2, and CD46 in Ductal Adenocarcinoma and Intraductal Carcinoma of the prostate.

BACKGROUND: Ductal Adenocarcinoma (DAC) and Intraductal Carcinoma of the Prostate (IDC-P) respond poorly to all the currently available conventional therapies. Given their accurate and efficient elimination of cancer cells, Antibody-Drug Conjugates (ADCs) have become one of the most promising anticancer treatments. However, no ADCs have so far been approved for Prostate Cancer (PCa) treatment. This study investigated TROP-2, HER2, and CD46 expression in DAC/IDC-P samples, indirectly analyzing their preliminary feasibility as therapeutic targets for future treatment of the two conditions. PATIENTS AND METHODS: We conducted a retrospective study involving 184 participants (87 DAC/IDC-P patients and 97 Prostatic Acinar Adenocarcinoma (PAC) patients with a Gleason score ≥ 8) without prior treatment between August 2017 and August 2022. Immunohistochemical staining was employed to detect the differential protein expressions of TROP-2, HER2, and CD46 in DAC/IDC-P, PAC, and normal prostate tissues. RESULTS: Compared to pure PAC tissues, TROP-2 expression was significantly higher in DAC/IDC-P and DAC/IDC-P-adjacent PAC tissues (H-score 68.8 vs. 43.8, p < 0.001, and 59.8 vs. 43.8, p = 0.022, respectively). No significant differences in HER2 expression were observed across different cancer tissues. Compared to both DAC/IDC-P-adjacent PAC and pure PAC tissues, CD46 expression was significantly higher in DAC/IDC-P tissues (42.3 vs. 28.6, p = 0.041, and 42.3 vs. 24.3, p = 0.0035, respectively). CONCLUSIONS: Herein, TROP-2 and CD46 expression was higher in DAC/IDC-P tissues than in pure PAC and normal prostate tissues. This finding implies that ADCs targeting the two proteins hold significant promise as potential future treatments for DAC/IDC-P.

CEACAM5 and TROP2 define metaplastic and dysplastic transitions in human antral gastric precancerous lesions and tumors.

BACKGROUND: Mucosal gastric atrophy and intestinal metaplasia (IM) increase the risk for the development of gastric cancer (GC) as they represent a field for development of dysplasia and intestinal-type gastric adenocarcinoma. METHODS: We have investigated the expression of two dysplasia markers, CEACAM5 and TROP2, in human antral IM and gastric tumors to assess their potential as molecular markers. RESULTS: In the normal antral mucosa, weak CEACAM5 and TROP2 expression was only observed in the foveolar epithelium, while inflamed antrum exhibited increased expression of both markers. Complete IM exhibited weak CEACAM5 expression at the apical surface, but no basolateral TROP2 expression. On the other hand, incomplete IM demonstrated high levels of both CEACAM5 and TROP2 expression. Notably, incomplete IM with dysplastic morphology (dysplastic incomplete IM) exhibited higher levels of CEACAM5 and TROP2 expression compared to incomplete IM without dysplastic features (simple incomplete IM). In addition, dysplastic incomplete IM showed diminished SOX2 and elevated CDX2 expression compared to simple incomplete IM. CEACAM5 and TROP2 positivity in incomplete IM was similar to that of gastric adenomas and GC. Significant association was found between CEACAM5 and TROP2 positivity and histology of GC. CONCLUSIONS: These findings support the concept that incomplete IM is more likely associated with GC development. Overall, our study provides evidence of the heterogeneity of gastric IM and the distinct expression profiles of CEACAM5 and TROP2 in dysplastic incomplete IM. Our findings support the potential use of CEACAM5 and TROP2 as molecular markers for identifying individuals with a higher risk of GC development in the context of incomplete IM.

Design and synthesis of novel site-specific antibody-drug conjugates that target TROP2.

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.

A plain language summary of the TROPiCS-02 study in patients with breast cancer (HR-positive/HER2-negative).

WHAT IS THIS SUMMARY ABOUT?: Sacituzumab govitecan (brand name: TRODELVY®) is a new treatment for certain types of advanced or metastatic breast cancer. One common type of breast cancer has at least 1 of 2 hormone receptors (HR positive) and does not have human epidermal growth factor 2 (HER2 negative). The HR and HER2 receptors are known to influence how severe a case of breast cancer is. Certain treatments will only work if a specific receptor is present on breast cancer cells. HR-positive/HER2-negative advanced or metastatic breast cancer can be treated with sacituzumab govitecan. This is a summary of the results of the TROPiCS-02 study. This study compared sacituzumab govitecan with standard chemotherapy in participants with HR-positive/HER2-negative advanced or metastatic breast cancer. WHAT WERE THE RESULTS?: The study showed that participants treated with sacituzumab govitecan lived significantly longer without their cancer getting worse than participants treated with chemotherapy. Participants also survived significantly longer and their tumors became significantly smaller in more participants treated with sacituzumab govitecan than with chemotherapy. In general, participants treated with sacituzumab govitecan were more likely to have side effects and had more severe side effects. These side effects included low levels of a type of white blood cell known as neutrophils and diarrhea. Oncologists (doctors that treat cancer) know of these side effects as they are common among people being treated for cancer. Doctors can control these side effects by following standard treatment guidelines and the package insert for sacituzumab govitecan. Participants treated with sacituzumab govitecan maintained their sense of well-being and ability to do daily activities (quality of life) longer than participants treated with chemotherapy. It also took longer for fatigue and other symptoms of cancer to worsen in participants treated with sacituzumab govitecan compared with chemotherapy. WHAT DO THE RESULTS MEAN?: Sacituzumab govitecan is more effective than standard chemotherapies for people who have already received multiple treatments for HR-positive/ HER2-negative advanced breast cancer. The side effects from sacituzumab govitecan could generally be managed well by doctors. Although there were more side effects with sacituzumab govitecan than with chemotherapy, they were generally mild to moderate.

TROP-2, NECTIN-4 and predictive biomarkers in sarcomatoid and rhabdoid bladder urothelial carcinoma.

Introduction: The surface protein TROP-2/TACSTD2 and the cell adhesion protein NECTIN-4/NECTIN4 are responsible for the efficacy of anticancer therapies based on antibody-drug conjugates (ADC) targeting intracellular microtubules. In contrast with common histologic subtypes of bladder urothelial carcinoma (BUC), little is known of TROP-2 and NECTIN-4 expression in sarcomatoid and rhabdoid BUC. Aims: In this study, we aimed to analyze TROP-2 and NECTIN-4 expression and additional predictive biomarkers by immunohistochemistry and fluorescence in situ hybridization (FISH) on 35 undifferentiated BUC (28 sarcomatoid and 7 rhabdoid). Wide genomic investigation was also performed on 411 BUC cases of the PanCancer Atlas, focusing on genes related to the microtubule pathways. Results: Seven of 35 (20%) undifferentiated BUC showed expression of TROP-2. NECTIN-4 was expressed in 10 cases (29%). Seven cases (20%) co-expressed TROP-2 and NECTIN-4. HER-2 FISH was amplified in 5 cases (14%) while HER-2 immunoexpression was observed in 14 cases (40%). PD-L1 scored positive for combined proportion score (CPS) in 66% of cases and for tumor proportion score (TPS) in 51% of cases. Pan-NTRK1-2/3 was elevated in 9 cases (26%) and FGFR-2/3 was broken in 7 of 35 cases (20%). Of 28 sarcomatoid BUC, 9 (32%) were negative for all (TROP-2, NECTIN-4, PD-L1, HER-2, FGFR and pan-NTRK) biomarkers and 3 (11%) expressed all five biomarkers. Among cases with rhabdoid dedifferentiation, 1 of 7 (14%) showed activation of all biomarkers, whereas 2 of 7 (28%) showed none. The mRNA analysis identified microtubule-related genes and pathways suitable for combined ADC treatments in BUC. Conclusion: Sarcomatoid and rhabdoid BUC do harbor positive expression of the ADC targets TROP-2 or NECTIN-4 in a relatively modest subset of cases, whereas the majority do not. Different combinations of other positive biomarkers may help the choice of medical therapies. Overall, these findings have important clinical implications for targeted therapy for BUC.

The Relationship between Trop-2, Chemotherapeutic Drugs, and Chemoresistance.

Trop-2 is a highly conserved one-pass transmembrane mammalian glycoprotein that is normally expressed in tissues such as the lung, intestines, and kidney during embryonic development. It is overexpressed in many epithelial cancers but is absent in non-epithelial tumors. Trop-2 is an intracellular calcium signal transducer that participates in the promotion of cell proliferation, migration, invasion, metastasis, and probably stemness. It also has some tumor suppressor effects. The pro-tumoral actions have been thoroughly investigated and reported. However, Trop-2's activity in chemoresistance is less well known. We review a possible relationship between Trop-2, chemotherapy, and chemoresistance. We conclude that there is a clear role for Trop-2 in some specific chemoresistance events. On the other hand, there is no clear evidence for its participation in multidrug resistance through direct drug transport. The development of antibody conjugate drugs (ACD) centered on anti-Trop-2 monoclonal antibodies opened the gates for the treatment of some tumors resistant to classic chemotherapies. Advanced urothelial tumors and breast cancer were among the first malignancies for which these ACDs have been employed. However, there is a wide group of other tumors that may benefit from anti-Trop-2 therapy as soon as clinical trials are completed.

Antibody-Drug Conjugates in Triple Negative Breast Cancer.

Triple negative breast cancer (TNBC) accounts for 15%-20% of all breast cancer. It is a heterogeneous breast cancer subtype with a poor prognosis. Given these negative features, there is a need for new treatment options beyond conventional chemotherapy in both the early stage and palliative setting. Impressive results have been reported with antibody-drug conjugates (ADCs) that link a cytotoxic payload to a monoclonal antibody, such as sacituzumab govitecan and trastuzumab deruxtecan, in the metastatic stage. The focus of this review is to discuss completed and ongoing trials involving ADCs in TNBC.

Sacituzumab govitecan plus platinum-based chemotherapy mediates significant antitumor effects in triple-negative breast, urinary bladder, and small-cell lung carcinomas.

Sacituzumab govitecan (SG) is an antibody-drug conjugate composed of an anti-Trop-2-directed antibody conjugated with the topoisomerase I inhibitory drug, SN-38, via a proprietary hydrolysable linker. SG has received United States Food and Drug Administration (FDA) approval to treat metastatic triple-negative breast cancer (TNBC), unresectable locally advanced or metastatic hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer, and accelerated approval for metastatic urothelial cancer. We investigated the utility of combining SG with platinum-based chemotherapeutics in TNBC, urinary bladder carcinoma (UBC), and small-cell lung carcinoma (SCLC). SG plus carboplatin or cisplatin produced additive growth-inhibitory effects in vitro that trended towards synergy. Immunoblot analysis of cell lysates suggests perturbation of the cell-cycle and a shift towards pro-apoptotic signaling evidenced by an increased Bax to Bcl-2 ratio and down-regulation of two anti-apoptotic proteins, Mcl-1 and survivin. Significant antitumor effects were observed with SG plus carboplatin in mice bearing TNBC or SCLC tumors compared to all controls (P < 0.0062 and P < 0.0017, respectively) and with SG plus cisplatin in UBC and SCLC tumor-bearing animals (P < 0.0362 and P < 0.0001, respectively). These combinations were well tolerated by the animals. Combining SG with platinum-based chemotherapeutics demonstrates the benefit in these indications and warrants further clinical investigation.

TROP2 in colorectal carcinoma: associations with histopathology, molecular phenotype, and patient prognosis.

Antibody-drug conjugates (ADCs) directed to trophoblast cell surface antigen 2 (TROP2) have gained approval as a therapeutic option for advanced triple-negative breast cancer, and TROP2 expression has been linked to unfavourable outcomes in various malignancies. In colorectal carcinoma (CRC), there is still a lack of comprehensive studies on its expression frequency and its prognostic implications in relation to the main clinicopathological parameters. We examined the expression of TROP2 in a large cohort of 1,052 CRC cases and correlated our findings with histopathological and molecular parameters, tumour stage, and patient outcomes. TROP2 was heterogeneously expressed in 214/1,052 CRCs (20.3%), with only a fraction of strongly positive tumours. TROP2 expression significantly correlated with an invasive histological phenotype (e.g. increased tumour budding/aggressive histopathological subtypes), advanced tumour stage, microsatellite stable tumours, and p53 alterations. While TROP2 expression was prognostic in univariable analyses of the overall cohort (e.g. for disease-free survival, p < 0.001), it exhibited distinct variations among important clinicopathological subgroups (e.g. right- versus left-sided CRC, microsatellite stable versus unstable CRC, Union for International Cancer Control [UICC] stages) and lost its significance in multivariable analyses that included stage and CRC histopathology. In summary, TROP2 is quite frequently expressed in CRC and associated with an aggressive histopathological phenotype and microsatellite stable tumours. Future clinical trials investigating anti-TROP2 ADCs should acknowledge the observed intratumoural heterogeneity, given that only a subset of TROP2-expressing CRC show strong positivity. The prognostic implications of TROP2 are complex and show substantial variations across crucial clinicopathological subgroups, thus indicating that TROP2 is a suboptimal parameter to predict patient prognosis.

Unveiling the placental secrets: Exploring histopathological changes and TROP2 expression in intrahepatic cholestasis of pregnancy.

INTRODUCTION: Gestational cholestasis, also known as intrahepatic cholestasis of pregnancy (ICP) or obstetric cholestasis, is a liver disease that can manifest in late pregnancy. Trophoblast cell surface antigen (TROP2) is a type I transmembrane glycoprotein identified in placental trophoblast cells that plays a critical role in trophoblast invasion of the decidua upon implantation into the placenta. Our study aims to investigate the role of TROP2 in pregnancy cholestasis. MATERIALS AND METHODS: Study groups: Group 1 (control group) (n = 10): consists of healthy normal pregnant women without any disease, Group 2 (cholestasis group) (n = 10): consists of pregnant women diagnosed with cholestasis. After routine histological follow-up, hematoxylin and eosin staining and TROP2 immunostaining were performed and scored. RESULTS: In the cholestasis group, in contrast to the control group, thrombus structures were observed in the intervillous space. In the cholestasis group compared to the control group, villus mesenchymal connective tissue cells, capillary endothelium and trophoblasts around the villus showed significantly stronger anti-TROP2 staining (p < 0.05). DISCUSSION: Cholestasis, a condition that may manifest during pregnancy, may be associated not only with observable pathological changes in placental tissues at the light microscopic level, but also with an increase in TROP2 expression. Given the critical role of TROP2 in trophoblast invasion during placental implantation, we hypothesize that TROP2 may serve as a key marker of the cholestatic processes occurring during pregnancy.

On the shoulder of ADC: The development of 124I-IMMU-132, an iodine-124-labelled Trop-2-targeting molecular probe for micro-PET imaging.

BACKGROUND: Trop-2 is closely related to the development and progression of a variety of tumours and poor prognosis. This study aimed to construct an iodine-124 (124I)-labelled antibody-drug conjugate (ADC) positron emission tomography (PET) probe which could noninvasively image Trop-2 in vivo, providing an important method for the diagnosis of tumours with high Trop-2 expression in clinical practice and monitoring their treatment. METHODS: In this study, a novel Trop-2-targeting molecular probe, 124I-IMMU-132, was constructed to better reveal the expression of Trop-2. The targeting and binding abilities of the probe to Trop-2-positive tumours were investigated in Capan-1/MDA-MB-468/Mcf-7 cells and their animal models. RESULTS: The constructed 124I-IMMU-132 probe maintained both reliable radiochemical characteristics and binding affinity (Kd = 2.200 nmol/L). The uptake of the probe by Trop-2-positive Capan-1/MDA-MB-468 cells increased in a time-dependent manner. The probe bound specifically to Capan-1/MDA-MB-468 tumours in vivo. The SUVmax Tumour/muscle ratio gradually increased with time, from 4.30 ± 0.55-10.78 ± 1.80 (p < 0.01) in the Capan-1 model and from 8.84 ± 0.95-32.20 ± 2.9 (p < 0.001) in the MDA-MB-468 model. The biodistribution and pharmacokinetics of 124I-IMMU-132 in a mouse model were consistent with the imaging results, and the dosimetry estimation in humans was acceptable. CONCLUSIONS: 124I-IMMU-132 PET is a promising imaging technique for delineating Trop-2-positive tumours. It has great potential in early diagnosis and targeted selection of patients that could benefit from its application.

Preclinical evaluation of the theranostic potential of 89Zr/177Lu-labeled anti-TROP-2 antibody in triple-negative breast cancer model.

BACKGROUND: Triple-negative breast cancer (TNBC) is one of the most lethal malignant tumors among women, characterized by high invasiveness, high heterogeneity, and lack of specific therapeutic targets such as estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Trophoblast cell-surface antigen-2 (TROP-2) is a transmembrane glycoprotein over-expressed in 80% of TNBC patients and is associated with the occurrence, progress, and poor prognosis of TNBC. The TROP-2 targeted immunoPET imaging allows non-invasive quantification of the TROP-2 expression levels of tumors, which could help to screen beneficiaries most likely to respond to SG and predict the response. This study aimed to develop a 89Zr/177Lu-radiolabeled anti-TROP-2 antibody (NY003) for immunoPET and SPECT imaging, as well as radioimmunotherapy (RIT) in TROP-2 (+)TNBC tumor-bearing model. Based on the camelid antibody, we developed a TROP-2 targeted recombinant antibody NY003. NY003 was conjugated with DFO and DTPA for 89Zr and 177Lu radiolabelling, respectively. The theranostic potential of [89Zr]Zr-DFO-NY003/[177Lu]Lu-DTPA-NY003 was evaluated through immunoPET, SPECT imaging, and RIT studies in the subcutaneous TROP-2 positive TNBC xenograft mice model. RESULTS: The high binding affinity of NY003 to TROP-2 was verified through ELISA. The radiochemical purity of [89Zr]Zr-DFO-NY003/[177Lu]Lu-DTPA-NY003 exceeded 95% and remained stable within 144h p.i. in vitro. ImmunoPET and SPECT imaging showed the specific accumulation of [89Zr]Zr-DFO-NY003/[177Lu]Lu-DTPA-NY003 in MDA-MB-231 tumors and gradually increased with the time tested, significantly higher than that in control groups (P < 0.05). The strongest anti-tumor efficacy was observed in the high-dose of [177Lu]Lu-DTPA-NY003 group, followed by the low-dose group, the tumor growth was significantly suppressed by [177Lu]Lu-DTPA-NY003, the tumor volumes of both high- and low-dose groups were smaller than the control groups (P < 0.05). Ex vivo biodistribution and histological staining verified the results of in vivo imaging and RIT studies. CONCLUSION: As a drug platform for radiotheranostics, 89Zr/177Lu-radiolabeled anti-TROP-2 antibody NY003 could not only non-invasively screen the potential beneficiaries for optimizing SG ADC treatment but also suppressed the growth of TROP-2 positive TNBC tumors, strongly supporting the theranostic potential of [89Zr]Zr-DFO-NY003/[177Lu]Lu-DTPA-NY003.