Akira Yokoi

Mesothelial cells promote peritoneal invasion and metastasis of ascites-derived ovarian cancer cells through spheroid formation

Patients with epithelial ovarian cancer (EOC) are often diagnosed with peritoneal metastasis and ascites, the accumulation of intraperitoneal fluid containing nonmalignant cells. However, the interactions between EOC and nonmalignant cells before peritoneal metastasis remain unclear. To investigate this, whole EOC spheroids were observed using a multiphoton microscope, and their invasion ability was assessed. Mesothelial cells were identified as notable components of ascites through morphological assessment, immunohistochemical/immunofluorescence staining, and single-cell RNA sequencing analyses. Almost all EOC cells were spheroids, with 60% containing mesothelial cells. EOC cells quickly generate aggregated spheroids with mesothelial cells, and these aggregated cancer-mesothelial spheroids (ACMSs) invade collagen or mesothelial layers. Mesothelial cells forming ACMSs initiated the invasion. RNA sequencing analysis revealed marked RNA expression changes in mesothelial cells, whereas the changes in EOC cells were minor. Transforming growth factor–β1–stimulated mesothelial cells showed increased invadopodium formation along with fascin-1 up-regulation. These findings suggest that EOC cells alter mesothelial cells through ACMSs, thereby elucidating the rapid spread of EOC in the abdominal cavity.

Diagnostic Use of the Combination of CA72 ‐4 and Tumor Volume in Mucinous Ovarian Tumors

ABSTRACT Objective Mucinous ovarian cancer (MOC) is a rare epithelial ovarian cancer subtype with poor prognosis, particularly in advanced stages. Differentiating MOC from mucinous borderline ovarian tumor (MBT) remains clinically challenging, often leading to delayed or inadequate treatment. Accurate preoperative diagnosis is crucial for guiding surgical strategies and improving patient outcomes. This study evaluated preoperative clinical factors that can distinguish MOC from MBT. Methods We retrospectively analyzed 46 ovarian mucinous tumors diagnosed between 2017 and 2021, including 15 MOC and 31 MBT cases confirmed by histopathology. Patient age, tumor laterality, tumor size, tumor markers (CA125, CA19‐9, CA72‐4, CEA), and tumor volume were assessed. Tumor size was measured as the maximum magnetic resonance imaging diameter, whereas volume was calculated using three‐dimensional imaging. Statistical analyses included the Mann–Whitney U test and receiver operating characteristic curve analysis, with AUC as a measure of diagnostic accuracy. Results Among the tumor markers, CA72‐4 exhibited the highest diagnostic accuracy (area under the curve [AUC]: 0.834), with significantly higher levels in MOC than in MBT ( p  < 0.001). Tumor size alone was an unreliable discriminator (AUC: 0.42). The tumor volume tended to be larger in MBT than in MOC (median: 2 362 878 cm 3 vs. 1 262 436 cm 3 ; p  = 0.77). However, the combination of CA72‐4 and tumor volume improved the diagnostic performance (AUC: 0.875). Conclusion The combination of CA72‐4 levels and tumor volume enhances preoperative differentiation between MOC and MBT. This combined approach may optimize surgical planning and improve patient outcomes.

Differential Proteomics of Large Extracellular Vesicles in Ovarian Cancer

ABSTRACT Diverse extracellular vesicles (EVs) are present in all body fluids; however, knowledge of large EVs (lEVs) remains limited. Molecular EV profiles vary depending on EV size and the physiological circulatory system, even within the same patient. In this study, we aimed to characterize the proteomic profile of IEVs in ovarian cancer patients and identify lEV‐protein biomarkers. We collected tissue, serum, and ascites from patients with high‐grade serous ovarian cancer and concurrently separated small EVs (sEVs) and lEVs through sequential multistep centrifugation. Proteomic analysis of tissues and EVs revealed distinct EV profiles in serum and ascites, identifying 11 lEV‐specific proteins in serum and 14 in ascites that were absent in sEV. Of these, seven serum‐specific and 10 ascites‐specific proteins were further analyzed using transcriptomic databases, revealing candidate diagnostic and prognostic lEV‐protein biomarkers. Our findings underscore the importance of size‐based EV separation, as particle size influences biosynthetic mechanisms, in identifying lEV‐specific proteins with potential diagnostic and prognostic values. Summary This study underscores the importance of distinguishing extracellular vesicle (EV) subtypes and considering body fluid specificity in biomarker discovery. By isolating EVs based on size and stepwise separation and analyzing their proteomic profiles in ovarian cancer, we identified potential large EV (lEV)‐specific biomarkers that reflect disease pathology. These findings provide a foundation for lEV‐protein–based liquid biopsy approaches that could enhance the accuracy of early detection and patient stratification. Further validation in clinical settings may pave the way for more precise and personalized ovarian cancer diagnostics.

Development and Validation of Predictive Risk Scores for Ovarian Clear Cell Carcinoma: A Penalized Regression Model

ABSTRACT Background The precision management of ovarian clear cell carcinoma (OCCC) faces limitations due to the absence of personalized prognostic tools. This study aimed to establish predictive risk scores to enable effective stratification and tailored treatment of OCCC. Methods Retrospective data from 206 OCCC patients treated between 2004 and 2019 at two hospitals were analyzed. Penalized regression models were utilized to develop three risk scores based on preoperative laboratory results and intraoperative findings. These scores underwent internal and external validation. Results The median follow‐up periods were 65.7 and 44.0 months for the derivation and validation cohorts, respectively. In internal validation with the derivation cohort, all three risk scores effectively identified the high‐risk group for tumor recurrence. Upon validation with the external cohort, Risk Score 3, which incorporated variables selected in most cross‐validations by the penalized regression (Elastic Net), distinctly differentiated the high‐ and low‐risk groups ( p  = 0.03). Risk Score 2, consisting solely of preoperatively available variables, also demonstrated marginal significance ( p  = 0.08). Conclusion Our findings underscore the significance and utility of the developed risk scores in tailoring personalized treatments for patients with OCCC.

Spatial distribution of tumor‐resident macrophages as predictive biomarkers in endometrial cancer

Abstract Background To investigate the role of CD47 expression and its relationship with tumor‐resident macrophages, specifically at the tumor margin, in patients with type II endometrial cancer. This study aims to elucidate whether CD47 could serve as a prognostic marker and to understand the dynamics between CD47 and macrophages, which could inform new therapeutic strategies. Methods A retrospective cohort study was conducted involving 75 patients of type II endometrial. Immunohistochemical analysis was performed to assess CD47 expression and macrophage markers (CD68 and CD163). Results The study found no direct correlation between CD47 expression levels and overall survival ( p  = 0.32), challenging its role as an independent prognostic marker in type II endometrial cancer. The higher expression of CD47 had significantly less incidence of endometrioid carcinoma G3 ( p  = 0.047). The negative correlation between CD47 H‐score and the density of CD68‐positive macrophages at tumor margin was statistically significant ( p  = 0.049). A high density of CD68‐positive macrophages at the tumor margin but a low density of CD163‐positive macrophages at the tumor margin were associated with poorer prognosis ( p  = 0.036). Conclusions The complex interaction between CD47 and macrophages, particularly at the tumor margin, suggests new avenues for targeted therapy in type II endometrial cancer.

Real‐world data of poly (ADP‐ribose) polymerase inhibitor response in Japanese patients with ovarian cancer

AbstractBackgroundPoly (ADP‐ribose) polymerase (PARP) inhibitors have been increasingly used in the treatment of ovarian cancer, with BRCA positivity and homologous recombination deficiency (HRD) being common biomarkers used for predicting their efficacy. However, given the limitations of these biomarkers, new ones need to be explored.MethodsThis retrospective study included 181 ovarian cancer patients who received olaparib or niraparib at two independent hospitals in Japan between May 2018 and December 2022. Clinical information and blood sampling data were collected. Patient characteristics, treatment history, and predictability of treatment duration based on blood data before treatment initiation were examined.ResultsHigh‐grade serous carcinoma, BRCA positivity, HRD, and maintenance therapy after recurrence treatment were observed more frequently in the olaparib group than in the niraparib group. The most common reasons for treatment interruption were anemia, fatigue, and nausea in the olaparib group and thrombocytopenia in the niraparib group. Regarding response to olaparib treatment, complete response to the most recent treatment, maintenance therapy after the first chemotherapy, high‐grade serous carcinoma, and germline BRCA positivity were observed significantly more frequently among responders than among non‐responders. Furthermore, neutrophil counts were significantly higher among responders than among non‐responders.ConclusionsInflammation‐related blood data, such as neutrophil count, obtained at the initial pre‐treatment visit might serve as potential predictors for prolonged olaparib treatment. While this study offers valuable insights into potential indicators for prolonged olaparib treatment, it underscores the need for more expansive research to strengthen our understanding of PARP inhibitors and optimize treatment strategies in ovarian cancer.

Spatial exosome analysis using cellulose nanofiber sheets reveals the location heterogeneity of extracellular vesicles

AbstractExtracellular vesicles (EVs), including exosomes, are recognized as promising functional targets involved in disease mechanisms. However, the intravital heterogeneity of EVs remains unclear, and the general limitation for analyzing EVs is the need for a certain volume of biofluids. Here, we present cellulose nanofiber (CNF) sheets to resolve these issues. We show that CNF sheets capture and preserve EVs from ~10 μL of biofluid and enable the analysis of bioactive molecules inside EVs. By attaching CNF sheets to moistened organs, we collect EVs in trace amounts of ascites, which is sufficient to perform small RNA sequence analyses. In an ovarian cancer mouse model, we demonstrate that CNF sheets enable the detection of cancer-associated miRNAs from the very early phase when mice did not have apparent ascites, and that EVs from different locations have unique miRNA profiles. By performing CNF sheet analyses in patients, we identify further location-based differences in EV miRNA profiles, with profiles reflecting disease conditions. We conduct spatial exosome analyses using CNF sheets to reveal that ascites EVs from cancer patients exhibit location-dependent heterogeneity. This technique could provide insights into EV biology and suggests a clinical strategy contributing to cancer diagnosis, staging evaluation, and therapy planning.

Downregulation of Chromosome 19 miRNA Cluster and the Tumor‐Suppressive Role of miR ‐517a‐3p in Choriocarcinoma

ABSTRACT Choriocarcinoma is a rare gynecologic malignancy. MicroRNAs, which are noncoding RNAs approximately 22 nucleotides in length, are known to regulate gene expression and play important roles in various cancers; however, their functions in choriocarcinoma remain largely unknown. This study aimed to identify disease‐specific microRNAs involved in choriocarcinoma development. Eleven cases of choriocarcinoma and five cases of complete hydatidiform mole treated at our institution were analyzed. Total RNA was extracted from trophoblast cells in formalin‐fixed, paraffin‐embedded specimens using laser capture microdissection, and microRNA sequencing was performed. The analysis revealed that 87 microRNAs were significantly upregulated, whereas 28 were downregulated in choriocarcinoma compared to complete hydatidiform mole. Notably, 13 of the 28 downregulated microRNAs belonged to the chromosome 19 microRNA cluster. In vitro experiments demonstrated that overexpression of miR‐517a‐3p, a representative member of this cluster, significantly suppressed cell proliferation, migration, and invasion in JEG‐3 and BeWo cell lines. Further transcriptome sequencing and computational analysis identified SRSF1 as a target gene of miR‐517a‐3p, which was validated by dual‐luciferase reporter assays. Knockdown of SRSF1 also led to significant reductions in proliferation, migration, and invasion, supporting its functional relevance. Immunohistochemical analysis confirmed that SRSF1 protein was highly expressed in choriocarcinoma tissues compared to complete hydatidiform mole. These findings indicate that downregulation of the chromosome 19 microRNA cluster is a characteristic feature of choriocarcinoma and that miR‐517a‐3p functions as a tumor suppressor by directly regulating SRSF1 expression.

Expression of the chrXq27.3 miRNA cluster in recurrent ovarian clear cell carcinoma and its impact on cisplatin resistance

AbstractOvarian clear cell carcinoma (OCCC) is a histological subtype of epithelial ovarian cancer and exhibits dismal prognosis due to chemoresistance. Moreover, only few effective therapeutic options exist for patients with recurrent OCCC, and an understanding of its molecular characteristics is essential for the development of novel therapeutic approaches. In the present study, we investigated unique MicroRNAs (miRNA) profiles in recurrent/metastatic OCCC and the role of miRNAs in cisplatin resistance. Comprehensive miRNA sequencing revealed that expression of several miRNAs, including miR-508-3p, miR-509-3p, miR-509-3-5p, and miR-514a-3p was remarkably less in recurrent cancer tissues when compared with that in paired primary cancer tissues. These miRNAs are located in the chrXq27.3 region on the genome. Moreover, its expression was negative in omental metastases in two patients with advanced OCCC. In vitro analyses revealed that overexpression of miR-509-3p and miR-509-3-5p reversed cisplatin resistance and yes-associated protein 1 (YAP1) was partially responsible for the resistance. Immunohistochemistry revealed that YAP1 expression was inversely correlated with the chrXq27.3 miRNA cluster expression. In conclusion, these findings suggest that alteration of the chrXq27.3 miRNA cluster could play a critical role in chemoresistance and miRNAs in the cluster and their target genes can be potential therapeutic targets.

Adjuvant taxane plus platinum chemotherapy for stage I ovarian clear cell carcinoma with complete surgical staging: are more than three cycles necessary?

Previous studies on adjuvant chemotherapy for patients with ovarian clear cell carcinoma (OCCC) have included a limited number of Asian patients with surgical stage I OCCC, despite differences in OCCC survival by race and stage. The aim of this study was to estimate the survival effect of the number of cycles of adjuvant taxane plus carboplatin chemotherapy in Asian patients with surgical stage I OCCC. We retrospectively identified 227 patients with surgical stage I OCCC at 14 institutions from 1995 to 2017. Kaplan-Meier analysis and Cox proportional hazard regression with inverse probability of treatment weighting (IPTW) adjustment were performed to evaluate overall survival (OS) and recurrence-free survival (RFS) in patients receiving ≤ 3 and 4-6 cycles of taxane plus platinum adjuvant chemotherapy. Eighty-nine and 138 patients received ≤ 3 and 4-6 cycles of adjuvant chemotherapy, respectively. There was no between-group difference in OS or RFS with or without IPTW adjustment. In Cox proportional hazards analysis, 4-6 cycles of adjuvant chemotherapy were not associated with improved OS (HR 1.090; 95% CI 0.518-2.291; p = 0.821) or RFS (HR 1.144; 95% CI 0.619-2.114; p = 0.669) compared to ≤ 3 cycles, even with IPTW adjustment. Subgroup analysis in different substages of stage I OCCC showed that the number of cycles of adjuvant chemotherapy had no impact on OS or RFS. Three or fewer cycles of taxane plus carboplatin chemotherapy may be a reasonable treatment regime for patients with surgical staging I OCCC.

Survival benefits of retroperitoneal lymphadenectomy for optimally-resected advanced ovarian high-grade serous carcinoma: a multi-institutional retrospective study

The survival benefits of retroperitoneal lymphadenectomy (RLNA) for epithelial ovarian cancer (EOC) remain controversial because clinical behaviors differ among subtypes. The purpose of the present study was to clarify whether RLNA increases the survival rate of advanced high-grade serous carcinoma (HGSC). This was a retrospective cohort analysis of 3,227 patients with EOC treated between 1986 and 2017 at 14 institutions. Among them, 335 patients with stage IIB-IV HGSC who underwent optimal cytoreduction (residual tumor of <1 cm) were included. Patients were divided into the RLNA group (n=170) and non-RLNA group (n=165). All pathological slides were assessed based on a central pathological review. Oncologic outcomes were compared between the two groups in the original and weighted cohorts adjusted with the inverse probability of treatment weighting. The median observation period was 49.8 (0.5-241.5) months. Overall, 219 (65%) out of 335 patients had recurrence or progression, while 146 (44%) died of the disease. In the original cohort, RLNA was a significant prognostic factor for longer progression-free survival (PFS) (hazard ratio [HR]=0.741; 95% confidence interval [CI]=0.558-0.985) and overall survival (OS) (HR=0.652; 95% CI=0.459-0.927). In the weighted cohort in which all variables were well balanced as standardized differences decreased, RLNA was also a significant prognostic factor for more favorable oncologic outcomes (PFS, adjusted HR=0.742; 95% CI=0.613-0.899) and OS, adjusted HR=0.620; 95% CI=0.488-0.787). The present study demonstrated that RLNA for stage III-IV HGSC with no residual tumor after primary debulking surgery contributed to better oncologic outcomes.

Significance of Concurrent Chemoradiotherapy as Primary Treatment in Patients with Metastatic Cervical Cancer

(1) This study investigated the prognostic impact of tumor size in patients with metastatic cervical cancer. (2) Methods: Seventy-three cervical cancer patients in our institute were stratified into two groups based on distant metastasis: para-aortic lymph node metastasis alone (IIIC2) or spread to distant visceral organs with or without para-aortic lymph node metastasis (IVB) to identify primary tumor size and concurrent chemoradiotherapy. (3) Results: The overall survival (OS) for patients with a tumor &gt;6.9 cm in size was significantly poorer than that for patients with a tumor ≤6.9 cm in the IVB group (p = 0.0028); the corresponding five-year OS rates in patients with a tumor ≤6.9 and &gt;6.9 cm were 53.3% and 13.4%, respectively. In the multivariate analysis, tumor size and primary treatment were significantly associated with survival in metastatic cervical cancer. (4) Conclusions: Tumor size ≤6.9 cm and concurrent chemoradiotherapy as the primary treatment were favorable prognostic factors for patients with metastatic cervical cancer.

Overcoming platinum-resistant ovarian cancer targeting the activated JAK-STAT pathways via extracellular vesicles

Abstract Platinum-resistant ovarian cancer (PROC) is a clinically severe unresolved issue, and it remains unclearly defined by molecular biology. Extracellular vesicles (EVs) play an essential role in cell-to-cell communication in the tumor microenvironment. This study aimed to investigate the molecular mechanisms of PROC, focusing on the unique ascites environment of ovarian cancer. Multi-transcriptome analyses using clinical samples revealed that PROC exhibited an activated Janus kinase (JAK)/signal transducer and activator of transcription pathway with high JAK1 expression in cancer cells. Immunohistochemistry for patient tissues confirmed the negative association between JAK1 expression and platinum response. JAK inhibitors were effective in PROC cell lines and cell- and patient-derived xenograft models, as well as synergistic with platinum. Furthermore, small RNA sequencing indicated that activated peritoneal mesothelial cell-derived EVs enriched in miR135a-5p increased JAK expression and platinum resistance in cancer cells. Collectively, EVs in ascites regulated platinum sensitivity in ovarian cancer cells, and JAK targeting therapeutic strategy overcomes PROC.

Single‐Nucleus RNA Sequencing and Spatial Transcriptomics for Squamous Cell Carcinoma Arising From Ovarian Mature Teratoma

ABSTRACTSquamous cell carcinoma arising from mature teratoma (SCC‐MT) is a rare ovarian malignancy. The detailed molecular pathology of SCC‐MT is not well understood. Moreover, the prognosis of the patients remains poor because no standard treatment has been established. In this study, we performed single‐nucleus RNA sequencing and spatial transcriptomics using clinical SCC‐MT samples to identify novel therapeutic candidates. snRNA‐seq revealed three epithelial cell clusters, of which one was significantly associated with epidermis and keratinocyte development. Moreover, spatial transcriptomics revealed that the epithelial‐mesenchymal transition was significantly inhibited, and the MYC and E2F targets were significantly activated in cancer spots on specimen sections. We focused on KLF5, which was one of the upregulated genes in cancer cells, and performed a functional analysis using NOSCC‐1, a cell line derived from an SCC‐MT. KLF5 downregulation significantly decreased cell proliferation and increased apoptosis. Furthermore, we previously identified miR‐145‐5p as a downregulated miRNA in SCC‐MT. We demonstrated that miR‐145‐5p overexpression attenuated cell proliferation and decreased KLF5 expression. In conclusion, through multi‐omics analyses, we identified unique gene expression profiles of SCC‐MT and determined a role for KLF5 in SCC‐MT development. Therefore, KLF5‐related factors may be novel therapeutic targets, and further studies are needed to improve the diagnosis and treatment of SCC‐MT.

Circulating serum miRNAs predict response to platinum chemotherapy in high‐grade serous ovarian cancer

Abstract Background Platinum chemotherapy is the cornerstone of treatment for high‐grade serous ovarian cancer (HGSOC); however, validated biomarkers that can accurately predict platinum response are lacking. Based on their roles in the underlying pathophysiology, circulating microRNAs are potential, noninvasive biomarkers in cancer. In the present study, we aimed to evaluate the circulating miRNA profiles of patients with HGSOC and to assess their potential utility as biomarkers to predict platinum response. Methods Pretreatment serum samples collected from patients who received platinum chemotherapy for Stage III–IV HGSOC between 2008 and 2016 were analyzed using miRNA microarray. LASSO logistic regression analysis was used to construct predictive models for treatment‐free interval of platinum (TFIp). Results The median follow‐up was 54.6 (range, 3.5–144.1) months. The comprehensive analysis of 2588 miRNAs was performed in serum samples of 153 eligible patients, and predictive models were constructed using a combination of circulating miRNAs with an area under the receiver operating characteristic curve of 0.944 for TFIp &gt;1 month, 0.637 for TFIp ≥6 months, 0.705 for TFIp ≥12 months, and 0.938 for TFIp ≥36 months. Each predictive model provided a significant TFIp classification ( p  = 0.001 in TFIp &gt;1 month, p  = 0.013 in TFIp ≥6 months, p  &lt; 0.001 in TFIp ≥12 months, and p  &lt; 0.001 in TFIp ≥36 months). Conclusion Circulating miRNA profiles has potential utility in predicting platinum response in patients with HGSOC and can aid clinicians in choosing appropriate treatment strategies.

In‐Tumor CRISPR ‐Cas9 Knockout Screening and Novel Therapy Development for Malignant Transformation of Ovarian Teratoma

ABSTRACT Malignant transformation of mature cystic teratoma (MTMCT) of the ovary is a rare but aggressive malignancy for which no standardized chemotherapy or effective targeted therapies currently exist. To identify therapeutic vulnerabilities in MTMCT, we performed a genome‐wide CRISPR‐Cas9 knockout screen using the MTMCT‐derived NOSCC1 cell line. Two parallel selective pressures were applied: in vivo tumorigenicity in immunodeficient mice and cisplatin exposure in vitro. From this screen, 67 negatively selected genes were identified, among which SOD1 and NDUFB4 emerged as top candidates based on high basal expression levels and clinical relevance. Integration with spatial transcriptomic data from three independent MTMCT patient tumors further supported the prioritization of these targets. SOD1 was selected for further investigation due to the availability of known pharmacological inhibitors. Both siRNA‐mediated knockdown and small‐molecule inhibition of SOD1 using LCS‐1 significantly suppressed MTMCT cell proliferation in vitro by inducing oxidative stress and impairing cell cycle progression. This antiproliferative effect was reversed by co‐treatment with N ‐acetylcysteine, a reactive oxygen species scavenger. In vivo validation using patient‐derived xenograft models demonstrated that oral administration of LCS‐1 led to significant tumor growth suppression and increased expression of apoptotic and DNA damage markers, including cleaved caspase‐3 and γH2AX. These findings establish SOD1 as a critical vulnerability in MTMCT and provide preclinical evidence supporting redox modulation as a therapeutic strategy for this highly chemoresistant and understudied ovarian cancer subtype. Our integrative approach combining functional genomics, spatial transcriptomics, and pharmacologic validation offers a framework for the discovery of novel targets in rare gynecologic malignancies.