Investigator
Saitama Medical University
Evaluating the specific STAT3 inhibitor YHO-1701 in ovarian cancer cell lines and patient-derived cell models: efficacy, mechanisms, and therapeutic potential
Signal transducer and activator of transcription 3 (STAT3) plays key roles in regulating cancer cell proliferation, survival, and metastasis. We aimed to determine the effects of YHO-1701, an oral STAT3 inhibitor, in ovarian cancer (OC). We evaluated the impact of YHO-1701 on cell growth in patient-derived cells (PDCs) and OC cell lines using standard cell proliferation assays. Spheroid models derived from PDCs were assessed using three-dimensional (3D) cell viability assays. Antitumor activity was performed in SKOV3 xenograft mice treated orally administrated YHO-1701 with 20 mg/kg. Changes in STAT3 signaling were analyzed by western blotting. The molecular mechanisms of STAT3 inhibition were investigated by sequencing RNA and analyzing pathways in the SKOV3 using a small interfering RNA targeting STAT3 (STAT3 siRNA) and YHO-1701. YHO-1701 inhibited the growth of OC cell lines by preventing STAT3 dimerization and decreasing the expression of its downstream signaling molecule, survivin. The growth of PDCs and spheroids obtained from patients with primary and recurrent OCs was significantly inhibited. Antitumor effect was observed in the SKOV3 xenograft mice with YHO-1701. YHO-1701 induced apoptosis in OC cells. Additionally, p53 and/or MAPK signaling pathways were upregulated in SKOV3 cells incubated with YHO-1701 and in those with STAT3 siRNA. Our results showed that YHO-1701 suppressed cell growth in PDCs of OC, accompanied by survivin inhibition, and a decrease in the number of peritoneal metastasis in the mice by YHO-1701, compared with those treated with control. Therefore, YHO-1701 could be a promising candidate agent for treating OC.
Tumor-related mutations in cell-free DNA in pre-operative plasma as a prognostic indicator of recurrence in endometrial cancer
Circulating tumor DNA (ctDNA) has potential as a basis for understanding the molecular features of a tumor non-invasively and for use as a diagnostic, prognostic, and disease-monitoring marker. The aim of this study was to evaluate the clinical roles of ctDNA in patients with endometrial cancer. Since Somatic Tumor-related ctDNA detected in plasma before surgery was associated with poorer oncologic outcome on univariate analysis in patients with endometrial cancer harboring
High expression of maternal embryonic leucine-zipper kinase (MELK) impacts clinical outcomes in patients with ovarian cancer and its inhibition suppresses ovarian cancer cells growth ex vivo
Maternal embryonic leucine zipper kinase (MELK) is receiving an attention as a therapeutic target in various types of cancers. In this study, we aimed to evaluate the prognostic significance of Expression levels of MELK in 11 ovarian cancer cell lines were confirmed by western blotting. Inhibitory concentration of OTS167 was determined by colorimetric assay. We demonstrated MELK as both a prognostic marker and a therapeutic target for ovarian cancer using clinical ovarian cancer samples. MELK inhibition by OTS167 may be an effective approach to treat ovarian cancer patients.
Antitumor Effect of Farletuzumab Ecteribulin in Molecular Subtypes of Endometrial Cancer Patient-Derived Xenograft Models
Abstract Endometrial cancer represents a significant health burden globally, particularly in postmenopausal women. Current treatment options for advanced-stage endometrial cancer remain limited, emphasizing the need for novel therapeutic strategies. This study aimed to investigate farletuzumab ecteribulin (FZEC), an antibody–drug conjugate targeting folate receptor α (FRα), as a potential new therapeutic agent for endometrial cancer. We utilized a panel of 22 patient-derived xenograft (PDX) models, representing various histologic and molecular subtypes of endometrial cancer with different levels of FRα expression, to evaluate the antitumor effect of FZEC. FZEC was administered intravenously at doses of 5 and 12.5 mg/kg on day 0. Intratumoral accumulation of eribulin, the payload of FZEC, was visualized using phosphor-integrated dot imaging. FZEC demonstrated dose-dependent antitumor effects across the endometrial cancer–PDX panel. At 5 mg/kg, the FZEC efficacy was associated with FRα expression, with 100% of FRα 3+ models exhibiting tumor shrinkage compared with 33.3% of FRα-negative models. FZEC also demonstrated broad activity across both histologic and molecular subtypes. Intratumoral eribulin accumulation was highly correlated with antitumor effects, even in models with low FRα expression. Follow-up studies confirmed FRα-dependent antitumor effects while also indicating potential FRα-independent mechanisms of action. FZEC demonstrated a robust antitumor effect against the FRα-high endometrial cancer–PDX models with significant antitumor effects also observed, even in FRα-low or FRα-negative models. Notably, intratumoral eribulin accumulation exhibited a stronger correlation with efficacy than with FRα expression alone. These findings support further clinical development of FZEC for endometrial cancer treatment and highlight the complexity of the mechanisms of action of antibody–drug conjugates.
Establishing a comprehensive panel of patient-derived xenograft models for high-grade endometrial carcinoma: molecular subtypes, genetic alterations, and therapeutic target profiling
High-grade endometrial cancer (EC) has a poor prognosis, but molecular classification-based treatments present new therapeutic opportunities. Antibody-drug conjugates (ADC) emerge as promising tools, yet a deeper understanding of antigen dynamics, optimal therapeutic sequencing, and resistance mechanisms is essential. This study investigates the utility of patient-derived xenograft (PDX) models for EC as preclinical platforms, evaluating molecular subtypes and the ADC targets expression of patient and PDX tumors. We developed a comprehensive panel of molecularly characterized PDX models from patients with EC representing various histological types. Molecular subtypes and gene alterations were analyzed using sequencing and immunohistochemistry. ADC targets, including human epidermal growth factor receptor 2, trophoblast cell-surface antigen 2, B7-H4, folate receptor alpha, and cadherin-6, were profiled. Thirty-one EC-PDX models were successfully established, maintaining histological fidelity and 93.1 % molecular subtype consistency with the patient tumors. Notably, 80.6 % of the PDX models exhibited high expression (2+/3+) of at least one ADC target, and 54.8 % displayed high expression of multiple targets. Remarkably, 9.7 % showed high expression of all targets, with gene mutations also characterized. Meanwhile, patient tumors, 78.8 % showed high expression (2+/3+) of at least one ADC target, and 63.6 % showed high expression of multiple targets. The molecularly classified EC-PDX panel, enriched with detailed antigen profiles and genetic data, provides a robust platform for investigating novel ADC therapies and precision treatment strategies for high-grade EC.
Human epidermal growth factor receptor 3 expression in patients with epithelial ovarian cancer: a potential target for ovarian mucinous and clear cell carcinoma
Human epidermal growth factor receptor 3 (HER3), a tyrosine kinase belonging to the HER family, is a known target for cancer therapy; recently, an anti-HER3 antibody-drug conjugate (ADC) is developing. To understand HER3 expression in epithelial ovarian cancer (EOC), this study was conducted. We investigated the expression of HER3 in 202 patients with EOC using immunohistochemistry (IHC), and the association between HER3 expression, clinicopathological features, prognosis, and treatment timing. Of all the cases, 55.4% had a HER3 IHC score ≥ 1 + . In particular, 78.0% of the patients with clear cell carcinoma (CCC) and 87.9% of the patients with mucinous carcinoma (MC) had a HER3 IHC score ≥ 1 + . Regarding clinicopathological features, early disease stage, feasibility of primary debulking surgery, no residual tumor, and low CA125 levels were more frequently observed in patients with a HER3 IHC score ≥ 1 + . Furthermore, a HER3 no-expression showed a significant association with a relatively short progression-free survival (PFS). And, for patients with mucinous carcinoma, those with a HER3 IHC score ≥ 1 + had poorer PFS and overall survival than those with a HER3 no-expression (no statistically significant difference). In addition, we analyzed HER3 expression at primary tumor and recurrence tumor in same patients. Thus, we observed the HER3 IHC score tended to change from 0 to ≥ 1 + in recurrence cases compared with primary cases. These observations suggested that patients with MC, CCC and recurrence of all histological type may potentially benefit from future clinical trials of HER3-directed therapies.
Gut microbiome associated with PARP inhibitor efficacy in patients with ovarian cancer
To investigate an association between the gut microbiome and efficacy of poly(ADP-ribose) polymerase inhibitors (PARPi) in ovarian cancer. This study conducted fecal microbiome analysis (16S rRNA gene sequencing) and circulating tumor DNA (ctDNA) profiling for ovarian cancer patients who underwent PARPi maintenance therapy. Fecal and blood samples were collected at the baseline and the progressive disease (PD) or last follow-up. The relative abundance of gut microbes and progression-free survival (PFS) were analyzed using linear discriminant analysis of effect size and the Cox proportional hazard model according to Baseline samples were available from 23 High fecal composition of
Circulating Tumor DNA Study in Patients With Endometrial Cancer
The objective of this study is to identify a population at risk of early recurrence after oncologic resection surgery of a primary uterine tumor based on the detection of ctDNA
