Yuichi Imai

T-LAK Cell-Originated Protein Kinase (TOPK) as a Prognostic Factor and a Potential Therapeutic Target in Ovarian Cancer.

Background: We aimed to clarify the clinical significance of TOPK (T-lymphokine–activated killer cell–originated protein kinase) expression in ovarian cancer and evaluate the possible effect of TOPK inhibitors, OTS514 and OTS964, on ovarian cancer cells. Methods: TOPK expression was examined by immunohistochemistry using 163 samples with epithelial ovarian cancer (EOC). TOPK protein level and FOXM1 transcriptional level in ovarian cancer cell lines were examined by Western blot and RT-PCR, respectively. Half-maximum inhibitory concentration (IC50) values against TOPK inhibitors were examined by the MTT assay. Using the peritoneal dissemination model of ES-2 ovarian cancer cells, we examined the in vivo efficacy of OTS514. In addition, the cytotoxic effect of OTS514 and OTS964 on 31 patient-derived primary ovarian cancer cells was examined. Results: TOPK was expressed very highly in 84 (52%) of 163 EOC tissues, and high TOPK expression was significantly associated with poor progression-free survival and overall survival in early-stage cases of EOC (P = 0.008 and 0.006, respectively). Both OTS514 and OTS964 showed significant growth-inhibitory effect on ovarian cancer cell lines with IC50 values of 3.0 to 46 nmol/L and 14 to 110 nmol/L, respectively. TOPK protein and transcriptional levels of FOXM1 were reduced by TOPK inhibitor treatment. Oral administration of OTS514 significantly elongated overall survival in the ES-2 abdominal dissemination xenograft model, compared with vehicle control (P < 0.001). Two drugs showed strong growth-inhibitory effect on primary ovarian cancer cells regardless of tumor sites or histological subtypes. Conclusions: Our results demonstrated the clinical significance of high TOPK expression and potential of TOPK inhibitors to treat ovarian cancer. Clin Cancer Res; 22(24); 6110–7. ©2016 AACR.

Clinical significance of T cell clonality and expression levels of immune-related genes in endometrial cancer

Immune microenvironment characterized by T cell clonality as well as expression signatures of immune-related genes in endometrial cancer tissues may play significant roles in clinical outcome of patients. We aimed to investigate the clinical significance of immune-related gene expression and TCR repertoire in endometrial cancer. Using total RNAs extracted from 32 endometrioid endometrial cancer cases, we performed quantitative real-time PCR to measure mRNA expression levels of immune-related genes including TRB, CD8, GZMA, HLA-A, CD11c and PD-L1. Higher mRNA expression levels of CD8 (P=0.039) and CD11c (P=0.046) in the 32 tissue samples were significantly associated with longer progression-free survival (PFS). Expression levels of CD8 (P<0.001) and CD11c (P=0.048) were also significantly associated with longer PFS in 540 cases in TCGA database. We also performed T cell receptor β (TCRβ) sequencing of tumor-infiltrating lymphocytes (TILs) on an Illumina MiSeq platform. To evaluate clonal expansion of TCRβ clonotypes, we adjusted the number of abundant TCRβ clonotypes by TRB mRNA expression levels and examined TCR clonality with the expression levels of immune-related genes and clinicopathological factors. The cases with high clonal T cell expansion along with high PD-L1 expression in cancer tissues was related to higher mRNA expression levels of CD8 (P<0.001), GZMA (P<0.001) and HLA-A (P=0.027), showed a significantly longer PFS (P=0.015), indicating a possibility that these parameters may serve as faborable prognostic factors. Considering clinical stage, mRNA expression of CD8 (P=0.037), GZMA (P=0.027) and HLA-A (P=0.022) was significantly higher in tumors at an early stage. Thus, we identified clinical and prognostic significance of immune microenvironment including the T cell clonality of TILs as well as PD-L1 and CD11c mRNA expression levels in endometrial cancer tissues.

The Risk of Ovarian Malignancy Algorithm (ROMA) as a Predictive Marker of Peritoneal Dissemination in Epithelial Ovarian Cancer Patients

Background: This study aimed to determine the efficacy of the risk of ovarian malignancy algorithm (ROMA), calculated using the carbohydrate antigen 125 (CA125) and human epididymis protein 4 (HE4) levels and the menopausal status, as a predictor of peritoneal dissemination in ovarian cancer. Methods: The CA125 and HE4 levels and the ROMA were compared between ovarian cancer patients (n = 122) with or without peritoneal dissemination. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated, and the results were compared with those of computed tomography (CT). Results: The CA125, HE4, and ROMA values differed significantly depending on the presence of peritoneal dissemination (p < 0.0001). The cut-off values were 181 U/ml for CA125, 161 pmol/ml for HE4, 44% for the ROMA (premenopausal), and 86% for the ROMA (postmenopausal). Among these markers, the ROMA (premenopausal) was the strongest predictor of peritoneal dissemination, with a specificity of 85.0% and a positive predictive value of 81.3%. In addition, the detection rates of small disseminations with less than 2 cm in diameter for the ROMA (93%) and HE4 (60%) were superior to that of CT (53%). Conclusions: The ROMA was a significant predictor of peritoneal dissemination and may be superior to CT for the detection of patients with small disseminations.

Expression of multiple immune checkpoint molecules on T cells in malignant ascites from epithelial ovarian carcinoma

Expression of immune checkpoint molecules, including programmed cell death protein-1 (PD-1), has been reported on T cells in various types of cancer. However, the expression status of these molecules in the tumor microenvironment of epithelial ovarian cancer (EOC) has not yet been studied. A total of 54 cases of malignant ascites from patients with EOC were analyzed in the present study. The expression of PD-1, lymphocyte-activation gene-3 (LAG-3), T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) and B and T lymphocyte attenuator (BTLA) on cluster of differentiation (CD)4+ and CD8+ T cells in malignant EOC ascites were investigated using multicolor flow cytometric analysis. The expression of PD-L1 in tumor cells, PD-L2 in HLA-DR-positive cells and galectin-9 in ascitic fluid was also analyzed. In addition, cytokine profiling of ascitic fluid was performed to understand the immune microenvironment of EOC. PD-1, LAG-3 TIM-3, and BTLA were expressed on 65.8, 10.6, 4.3 and 37.6% of CD4+ T cells, and on 57.7, 5.0, 4.9 and 15.7% of CD8+ T cells, respectively. Programmed cell death protein-1 (PD-1), LAG-3 and BTLA were more frequently expressed on CD4+ compared with CD8+ T cells. The co-expression of immune checkpoints was further investigated and results indicated that 39 (72.2%) and 37 patients (68.5%) expressed multiple immune checkpoints on CD4+ T cells and CD8+ T cells, respectively. In addition, lower levels of TNF-α and interleukin-6 in ascitic fluid were significantly associated with multiple immune checkpoint expression on CD8+ T cells. The present findings indicated that multiple immune checkpoint molecules were expressed on T cells in the EOC tumor microenvironment and the results may suggest the significance of simultaneous blockade of immune checkpoints to control EOC.

The frequency of neoantigens per somatic mutation rather than overall mutational load or number of predicted neoantigens per se is a prognostic factor in ovarian clear cell carcinoma.

ABSTRACT Neoantigens derived from tumor-specific somatic mutations are excellent targets for anti-tumor immune responses. In ovarian clear cell carcinoma (OCCC), checkpoint blockade yields durable responses in a subset of patients. To approach the question of why only some patients respond, we first investigated neoantigen loads and immune signatures using exome sequencing and expression array data for 74 OCCC patients treated conventionally. Neither the number of missense mutations nor total predicted neoantigens assessed in the tumor correlated with clinical outcomes. However, the number of neoantigens per missense mutation (“neoAg frequency”) did correlate with clinical outcomes. Cox multivariate regression analysis demonstrated that low neoAg frequencies correlated with increased progression-free survival (PFS) and was an independent predictive factor for PFS in OCCC (p = 0.032), especially at stage I-II (p = 0.0045). Immunity-associated genes including those related to effector memory CD8 T cells were dominantly expressed in tumors with low neoAg frequencies in stage I-II patients, suggesting CD8 T cell-mediated elimination of immunogenic sub-clones expressing neoantigens (immunoediting) had occurred. In contrast, we observed decreased HLA-A, -B, and -C expression (p = 0.036, p = 0.026, and p = 0.030, respectively) as well as increased ratios of CTLA-4, PD-1, Tim-3, and LAG3 to CD8A expression (p = 0.0064, p = 0.017, p = 0.033 and p = 0.0136, respectively) in stage I-II tumors with high neoAg frequencies. Constrained anti-tumor immunity may thus result in limited immunoediting, and poor prognosis. Our results show that neoAg frequency in OCCC is an independent prognostic factor for clinical outcome and may become a potential candidate biomarker for immunomodulatory agent-based treatments.

A Phase 1 Dose-Escalation Study of Single-Agent Veliparib in Japanese Patients with Advanced Solid Tumors

Veliparib (ABT‐888) is a potent, orally bioavailable poly(ADP‐ribose) polymerase‐1 and ‐2 inhibitor. This phase 1 study evaluated the tolerability, pharmacokinetic profile, safety, and preliminary antitumor activity of single‐agent veliparib in Japanese patients with advanced solid tumors. Eligible patients were assigned to treatment with veliparib at 200 or 400 mg dose; veliparib was self‐administered orally twice daily on days 1–28 of 28‐day cycles. Dose escalation, following a 3 + 3 design, defined dose‐limiting toxicities, the maximum tolerated dose, and the recommended phase 2 dose. Sixteen patients were enrolled (median age, 59 years). Fourteen patients had high‐grade serous ovarian cancer, one had primary peritoneal cancer, and one had BRCA‐mutated breast cancer. The most frequent treatment‐emergent adverse events were nausea and vomiting (93.8% each), decreased appetite (62.5%), abdominal pain, diarrhea, and malaise (31.3% each). A grade ≥3 toxicity was observed in 50% of patients; one patient each in the 200 mg (n = 4) and 400 mg (n = 12) cohorts experienced serious adverse events. Dose‐limiting toxicities were observed for one patient at the 400 mg dose. No toxicities leading to death were reported. The recommended phase 2 dose was defined as 400 mg twice daily. The veliparib pharmacokinetic profile was consistent with that reported for the Western population. Two patients, both with ovarian cancer, had a RECIST partial response. Veliparib monotherapy showed manageable tolerability and safety profiles and a predictable pharmacokinetic profile at a 400 mg twice‐daily dose, and supports the inclusion of Japanese patients in the multinational phase 3 study (NCT02470585).