Kensuke Sakai

High-Throughput Drug Screening of Clear Cell Ovarian Cancer Organoids Reveals Vulnerability to Proteasome Inhibitors and Dinaciclib and Identifies AGR2 as a Therapeutic Target

Abstract There are currently no effective treatments available for clear cell ovarian cancer (CCC). In this study, we aimed to identify effective drugs for CCC through high-throughput drug screening (HTDS) using ovarian cancer organoids and determine novel therapeutic targets based on the biological characteristics of CCC through omics analysis. An ovarian cancer organoid biobank was established, and HTDS was conducted using CCC organoids based on libraries of 361 and 4,560 compounds. The efficacy of the identified drugs was verified in in vitro and in vivo experiments using a patient-derived organoid xenograft mouse model. Transcriptome analysis was performed to identify genes related to the pathways targeted by the identified drugs in CCC and to assess their potential as therapeutic targets. Proteasome inhibitors and dinaciclib were extracted using HTDS and shown to inhibit tumorigenesis in vitro and in vivo. CCC, like multiple myeloma, exhibited activated endoplasmic reticulum (ER) stress and unfolded protein response (UPR), and treatment with proteasome inhibitors further enhanced ER stress and UPR, ultimately leading to cell death. Transcriptome analysis identified anterior gradient-2 (AGR2) as a key gene involved in UPR in CCC. CRISPR knockout of AGR2 suppressed cell proliferation, increased sensitivity to proteasome inhibitors, and reversed platinum resistance in CCC. AGR2 knockout also upregulated Schlafen 11, contributing to platinum sensitivity. ER stress and the UPR are activated in CCC, and proteasome inhibitors disrupt this balance, ultimately leading to cell death. AGR2 may serve as a potential therapeutic target in CCC. Significance: Proteasome inhibitors and dinaciclib are identified as effective drugs for CCC. CCC has a high basal UPR, and proteasome inhibition may disrupt this balance. AGR2 is involved in the UPR of CCC, and inhibiting AGR2 further enhances the UPR and confers platinum sensitivity, making it a potential therapeutic target.

Characteristics of endometrial cancer progressed to extrauterine lesions following fertility preserving medroxyprogesterone acetate therapy for young endometrial cancer patients

Medroxyprogesterone acetate (MPA) is an effective fertility-preserving treatment for early endometrial cancer and atypical endometrial hyperplasia (AEH), and rarely leads to the development of extrauterine lesions (ELs). We aimed to clarify the characteristics of patients who developed ELs post-MPA therapy. We analyzed the clinicopathological factors and prognoses of 319 patients with endometrioid carcinoma grade 1 (EMG1) and AEH treated with MPA at our institution. All patients underwent imaging before MPA treatment to rule out ELs. Seven patients (2.2%) with EMG1 showed EL after MPA treatment. Two patients developed EL during the initial treatment, 2 during repeated treatment, and 3 during follow-up. Two patients had peritoneal dissemination, 3 had regional lymph node metastasis, 1 had distant metastasis at the Virchow lymph node, and 1 had ovarian metastasis. ELs were diagnosed using imaging tests in 6 patients and elevated tumor markers in 3 (overlapping) patients. One patient was diagnosed with ELs pathologically after hysterectomy. Upon EL diagnosis, patients underwent standard treatment, including hysterectomy and chemotherapy, that was followed by a diagnosis of EMG1 for 5, EMG2 for 1, and EMG3 for 1 patient. One patient died 15 months after start of therapy and another died 119 months post-treatment initiation, while the others have been survived. Only 2.2% of all patients developed ELs post-MPA treatment, but some cases were fatal. It is essential to conduct imaging tests and screen for tumor markers during and after MPA treatment regularly and also when cancer progression is suspected.

A phase II trial evaluating the efficacy and safety of repeated high dose medroxyprogesterone acetate (MPA) therapy for patients with recurrent early-stage endometrial cancer or atypical endometrial hyperplasia: Japanese Gynecologic Oncology Group study (JGOG2051/KGOG2031, REMPA trial)

Fertility preserving therapy using medroxyprogesterone acetate (MPA) is an important option for young patients with endometrial cancer or atypical endometrial hyperplasia (AEH). However, the effectiveness and feasibility of repeated MPA therapy for patients with intrauterine recurrence following initial MPA therapy is controversial. Only a few single-institution retrospective studies have been conducted on repeated MPA therapy, therefore, multicenter prospective studies for repeated MPA therapy are highly needed. The aim of this study is to assess whether repeated MPA therapy is effective and feasible for patients with intrauterine recurrence following initial MPA therapy. This is a prospective, single-arm, a multicenter phase II trial on repeated MPA therapy for intrauterine recurrence following fertility-preserving therapy for AEH or stage IA (the International Federation of Gynecology and Obstetrics [FIGO] 2008) non-myoinvasive endometrioid carcinoma grade 1. Patients are treated with oral MPA (500-600 mg/day). Pathologically assessment via dilation and curettage will be performed every 2 months until complete response. The major inclusion criteria are 1) intrauterine recurrence of AEH or stage IA (FIGO 2008) endometrioid carcinoma grade 1 without myometrial invasion or extrauterine spread confirmed by imaging tests after complete remission with the previous MPA therapy. 2) The number of recurrences should be up to twice. 3) histologically diagnosed as AEH or endometrioid carcinoma grade 1, 4) 20-42 years of age, and 5) strong desire and consent for fertility-sparing treatment. The primary endpoint is 2-year recurrence-free survival rate. A total of 115 patients will be enrolled from multiple institutions in Japan and Korea within 4 years and followed up for 2 years. Japan Registry of Clinical Trials Identifier: jRCTs031200256.

Atypical vessels in hysteroscopy: Usefulness in prediction of malignant diseases in patients treated with tamoxifen

AbstractAimTamoxifen (TAM) is widely used in adjuvant endocrine therapy for invasive breast cancer as a selective estrogen modulator, but this treatment has a risk of developing endometrial malignancy. However, hysteroscopic findings during or after TAM treatment are unclear. The aim of this study is to examine the association between hysteroscopic patterns and malignant histological findings during or after treatment with TAM.MethodsThe subjects were patients who received TAM after surgery for breast cancer and underwent hysteroscopy at our institution from January 2016 to December 2019. Clinicopathological factors and hysteroscopic findings were collected from medical records and investigated retrospectively. Histologically, atypical endometrial hyperplasia, endometrial cancer, and carcinosarcoma were classified as malignant diseases.ResultsA total of 26 patients were eligible for the study. Hysteroscopic findings included an irregular surface of the endometrium (n = 3, 11.5%), atypical vessels (n = 10, 38.5%), papillary structure (n = 3, 11.5%), and polypoid structure (n = 18, 69.2%). Histological examination revealed malignancy in six patients (23.0%). The percentage of atypical vessels in patients with malignancies was significantly higher than that in patients with a normal endometrium or benign lesion (100% vs. 20%, p = 0.0009). The sensitivity and specificity of atypical vessels in hysteroscopy for diagnosis of malignant diseases were 100% and 80%, respectively.ConclusionsHysteroscopic findings of atypical vessels may be useful for prediction of malignant diseases in patients treated with TAM.

Prognostic impact of peritoneal cytology on treating endometrial cancer using data from the Japan Society of Obstetrics and Gynecology cancer registry

The prognostic value and clinical usage of peritoneal cytology in endometrial cancer are uncertain. This study aimed to determine whether positive cytology is associated with the prognosis for endometrial cancer. A Japanese nationwide retrospective registry study was conducted between 2012 and 2019. Clinicopathological data were analyzed for patients who were registered in the Japan Society of Obstetrics and Gynecology (JSOG) gynecological tumor registry and underwent initial treatment for endometrial cancer. In total, 83,027 patients who met the inclusion criteria were identified. Data on peritoneal cytology status and overall survival (OS) were available for 74,984 and 36,995 patients, respectively. Positive peritoneal cytology was found in 11,536 (15.4%) patients. A higher proportion of patients who had positive peritoneal cytology were related to advanced stages, high-grade histology, deep myometrial invasion, lymph node (LN) metastasis, and poor risk of recurrence. After controlling for age, stage, myometrial invasion, LN metastasis, distant metastasis, and risk of recurrence, positive peritoneal cytology was associated with poor prognosis (p<0.001). Multivariate Cox regression analysis revealed that clinicopathological factors (i.e., age, International Federation of Gynecology and Obstetrics stage, histological type, myometrial invasion, LN metastasis, distant metastasis, and peritoneal cytology), including positive peritoneal cytology, were also significant prognostic factors for OS. Positive peritoneal cytology was a prognostic factor for endometrial cancer for the JSOG gynecological tumor registry.

A retrospective study for investigating the outcomes of endometrial cancer treated with radiotherapy

AbstractObjectiveTo clarify the role of radiotherapy for endometrial cancer.MethodsData were analyzed for 39 247 patients with endometrial cancer registered with the Gynecologic Cancer Registry of the Japan Society of Obstetrics and Gynecology from 2004 to 2011.ResultsThe rates of 5‐year overall survival (5y‐OS) in the radiotherapy and surgery groups were 53.6% and 94.5% in stage I or II, and 15.5% and 67.5% in stage III or IV, respectively. The prognosis in the radiotherapy group was significantly poorer than that in the surgery group. In multivariate analysis, age, advanced stage, histological type, risk of recurrence, and initial radiotherapy were independent prognostic factors. The rates of 5y‐OS with no adjuvant therapy, adjuvant chemotherapy, and adjuvant radiotherapy were 95.3%, 92.9%, and 87.1% for stage I or II, respectively, with significant differences among all groups (P &lt; 0.001), and 60.0%, 70.4%, and 55.5% for stage III or IV, respectively, with significant differences of adjuvant chemotherapy with no adjuvant therapy (P &lt; 0.001) and with adjuvant radiotherapy (P &lt; 0.001). In multivariate analysis, age, advanced stage, histological type, lymphadenectomy, and adjuvant radiotherapy were independent prognostic factors.ConclusionPatients treated with radiotherapy had a significantly poorer prognosis and the appropriate indication of radiotherapy for endometrial cancer requires further study.

Prognostic Biomarker of Fertility‐Preserving Hormonal Therapy Based on Multigene Panel Testing for Endometrial Cancer

ABSTRACT In this study, we identified prognostic biomarkers that predict treatment outcome in patients receiving fertility‐preserving high‐dose medroxyprogesterone acetate (MPA) therapy through comprehensive multigene panel testing. A total of 38 patients (20 atypical endometrial hyperplasia and 18 stage IA G1 without myometrial invasion) who received first‐line MPA therapy were enrolled. Genomic DNA was extracted from formalin‐fixed paraffin‐embedded samples, and PleSSision‐Rapid multigene panel testing was performed. Of the 38 patients, 31 (82%) achieved complete response (CR), 2 (5%) had stable disease (SD), and 5 (13%) had progressive disease (PD) following initial treatment. The median duration to achieve tumor disappearance was 7 months (range: 4–14 months). Following initial treatment, 25 of 32 patients (78%) experienced recurrence, with a median recurrence‐free survival (RFS) of 21 months (range: 2–84 months). The most frequently observed actionable gene mutations were PTEN (68.4%), CTNNB1 (55.2%), and PIK3CA (33.3%). Patients harboring PTEN mutations in EMG1 required a significantly longer duration to achieve tumor disappearance ( p  = 0.011). In addition, the presence of PIK3CA mutations in AEH was significantly associated with shorter RFS ( p  = 0.048). Molecular classification identified 34 patients (89%) with no specific molecular profile (NSMP), 1 patient (3%) with POLE mutation, and 3 patients (8%) with deficient mismatch repair (d‐MMR). Most patients undergoing MPA therapy were classified as having NSMP. Genetic alterations, specifically mutations in PTEN and PIK3CA , were significantly associated with treatment outcomes, highlighting their potential as prognostic biomarkers.

Efficacy and safety of olaparib maintenance monotherapy for Japanese patients with platinum-sensitive relapsed ovarian, fallopian tube, and primary peritoneal cancer

Olaparib maintenance therapy for platinum-sensitive relapsed ovarian cancer has been approved in Japan since April 2018. Here, we report the experience administering this therapy in our hospital, with the aim of evaluating efficacy and safety in the Japanese population. The study included 52 patients with platinum-sensitive relapsed ovarian, fallopian tube, and primary peritoneal cancer. All patients started olaparib at a dose of 300 mg twice daily. Information about treatment efficacy and adverse effects was collected retrospectively from medical records. Median age was 58 years old (range: 33-80), and 82.7% of the patients were diagnosed with high-grade serous carcinoma. Sixteen patients (30.8%) possessed the BRCA1/2 pathogenic variant (15 germline and 1 tissue), 3 (5.8%) possessed variants of unknown significance (2 germline and 1 tissue), 16 (30.8%) possessed wild type, and 17 (32.7%) were not analyzed. Median progression-free survival was 15.3 months (95% CI 9.0-21.6). Patients with BRCA1/2 pathogenic variants showed significantly longer PFS than patients with wild-type BRCA1/2 (p = 0.007). Disease progression caused 34 cases to discontinue olaparib. Eighteen (34.6%) individuals exhibited ≥ grade 3 anemia, although they recovered in response to appropriate management. One patient discontinued olaparib because of prolonged renal dysfunction. Another patient presented with grade 3 fatigue, but recovered after 2 weeks of interruption and continued olaparib treatment. Olaparib maintenance therapy for platinum-sensitive recurrent ovarian cancer in the Japanese population is sufficiently safe and no less effective than reports from previous studies.

Clinical availability and characteristics of multigene panel testing for recurrent/advanced gynecologic cancer

Japan's health insurance covers multigene panel testing. This study aimed to determine the potential availability and utility of gene panel testing clinically in gynecologic oncology. We analyzed the characteristics of patients with gynecologic cancer who underwent gene panel testing using FoundationOne Out of 102 patients analyzed, 32, 18, 43, 8, and 1 had cervical, endometrial, ovarian cancers, sarcoma, and vaginal cancer, respectively. Druggable gene alteration was found in 70 patients (68.6%; 21 with cervical cancer, 15 with endometrial cancer, 28 with ovarian cancer, 5 with sarcoma, and 1 with other). The most common druggable gene alteration was PIK3CA mutation (n = 21), followed by PTEN mutation (n = 12) and high tumor mutation burden (TMB-H) (n = 11). TMB-H was detected in 5 patients with cervical cancer, 5 with endometrial cancer, and 1 with endometrial stromal sarcoma. Eleven patients (10.8%) received molecularly targeted therapy according to their gene aberrations. Gene panel testing was mostly performed when the second-line treatment was ineffective. Of all 102 patients, 60 did not have recommended treatment, and 15 died or had worsened conditions before obtaining the test results. Through multigene panel testing, although many patients had druggable gene alterations, 10.8% of them received the recommended treatment. TMB-H was mainly observed in cervical/endometrial cancer, suggesting its potential as a therapeutic biomarker of immune checkpoint inhibitors. Furthermore, patients' prognosis and performance status should be considered before performing the test.