hymecromone and Ovarian-Neoplasms

CARM1 is often overexpressed in human cancers including in ovarian cancer. However, therapeutic approaches based on CARM1 expression remain to be an unmet need. Cancer cells exploit adaptive responses such as the endoplasmic reticulum (ER) stress response for their survival through activating pathways such as the IRE1α/XBP1s pathway. Here, we report that CARM1-expressing ovarian cancer cells are selectively sensitive to inhibition of the IRE1α/XBP1s pathway. CARM1 regulates XBP1s target gene expression and directly interacts with XBP1s during ER stress response. Inhibition of the IRE1α/XBP1s pathway was effective against ovarian cancer in a CARM1-dependent manner both in vitro and in vivo in orthotopic and patient-derived xenograft models. In addition, IRE1α inhibitor B-I09 synergizes with immune checkpoint blockade anti-PD1 antibody in an immunocompetent CARM1-expressing ovarian cancer model. Our data show that pharmacological inhibition of the IRE1α/XBP1s pathway alone or in combination with immune checkpoint blockade represents a therapeutic strategy for CARM1-expressing cancers.

Topics: Animals; Antibodies, Monoclonal; Base Sequence; Benzopyrans; Carcinoma, Ovarian Epithelial; Cell Line, Tumor; Endoplasmic Reticulum Stress; Endoribonucleases; Female; Gene Expression Regulation, Neoplastic; Humans; Hymecromone; Immune Checkpoint Inhibitors; Mice; Molecular Targeted Therapy; Ovarian Neoplasms; Programmed Cell Death 1 Receptor; Protein Binding; Protein Serine-Threonine Kinases; Protein-Arginine N-Methyltransferases; Signal Transduction; X-Box Binding Protein 1; Xenograft Model Antitumor Assays

Ovarian clear cell carcinomas often show a spherule-like mucoid stroma. In ascitic fluid, they form spheroids with a hollow acellular space. In spite of the absence of stromal cells, both the mucoid stroma and hollow spheroids contain abundant extracellular matrix, and one of the major components is hyaluronan. It has been suggested that tumor-derived hyaluronan plays a significant role in the formation of these structures. To clarify this, a hyaluronan inhibition assay was performed on HAC-2, a clear cell carcinoma cell line, in vitro. When hyaluronan synthesis was inhibited by 4-methylumbelliferone, HAC-2 failed to show the spherule-like accumulation of hyaluronan or hollow spheroids. Inhibition of hyaluronan synthesis was associated with the reduction of cell growth. Analysis of 28 archival ascites cytology specimens showed that clear cell carcinomas expressed hyaluronan more frequently than serous carcinomas (11 of 14 vs 3 of 14, respectively, P < 0.05). All of these facts indicate that tumor-derived hyaluronan is essential for the formation of the mucoid stroma or hollow spheroids, and that hyaluronan is also involved in the regulation of cell growth in ovarian clear cell carcinomas. The inhibition of hyaluronan synthesis could be a potential adjunctive therapy for refractory clear cell carcinomas outside the ovary.

Topics: Adenocarcinoma, Clear Cell; Adjuvants, Immunologic; Ascites; Cell Line, Tumor; Cystadenocarcinoma, Serous; Extracellular Matrix; Female; Humans; Hyaluronic Acid; Hymecromone; Ovarian Neoplasms

4-Methylumbelliferone (4-MU), a hyaluronan (HA) synthesis inhibitor, has antitumor activity in cancer cells. However, few studies have focused on its effects on ovarian cancer. The aim of this study was to investigate the effects of 4-MU on ovarian cancer and to elucidate its mechanism of action.. The HRA human ovarian serous adenocarcinoma cell line was used in this study. The effects of 4-MU on cell proliferation, migration, and invasion were determined by using in vitro assays as well as an in vivo rat peritoneal carcinomatosis model. The expression of HA synthase (HAS), CD44 HA receptor, vascular endothelial growth factor (VEGF), and thymidine phosphorylase (TP) mRNA in HRA cells was analyzed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR).. 4-MU administration inhibited the growth of peritoneal tumors and significantly prolonged survival. In vitro experiments showed that 4-MU inhibited HRA cell proliferation in a dose-dependent manner, while it did not affect HRA cell invasion and migration. 4-MU significantly decreased TP mRNA expression in HRA cells. On the other hand, since HAS2, CD44, and VEGF endogenous mRNA expression levels were very low in HRA cells, it was impossible to evaluate the effect of 4-MU treatment.. These results suggest that 4-MU exerts its antitumor effect on ovarian cancer through suppressing TP expression.

Topics: Animals; Antineoplastic Agents; Carcinoma; Cell Line, Tumor; Cell Movement; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Humans; Hymecromone; Neoplasm Invasiveness; Ovarian Neoplasms; Rats, Nude; Thymidine Phosphorylase; Xenograft Model Antitumor Assays

To investigate whether the activity of lysosomal enzymes is increased in the peritoneal fluid of patients with gynecologic cancers compared to activity in the peritoneal fluid from normal subjects and those with pelvic inflammatory disease, and fluid from benign ovarian cysts.. beta-glucuronidase, beta-galactosidase, and alpha-mannosidase activity was measured in the peritoneal fluid from patients with gynecologic cancer, pelvic inflammatory disease, and normal subjects, and fluid from benign ovarian cysts.. The mean+/-SD of beta-glucuronidase, beta-galactosidase, and alpha-mannosidase activity in the gynecologic cancers was 120+/-50 nmol, 203+/-86 nmol, and 240+/-119 nmol 4-methylumbelliferone/ml/h, respectively; in the normal control subjects it was 22+/-9 nmol, 46+/-10 nmol, and 80+/-23 nmol, respectively (P=0.00003, 0.0001, and 0.0001, respectively). The activity was increased even in cases without malignant cells in the peritoneal fluid. In pelvic inflammatory disease it was 148+/-82 nmol, 278+/-112 nmol, and 291+/-140 nmol, respectively. The activity in the fluid of the ovarian cysts was similar to that of the normal peritoneal fluid. There was a significant positive correlation between enzyme activity and stage of cancer, that was stronger for beta-glucuronidase (r=0.889, P=0.003).. The increased lysosomal enzyme activity in gynecologic cancers, without overlapping between patients and normal subjects or benign ovarian cyst fluid, indicates that such measurements might be applied for diagnostic purposes.

Topics: Adenocarcinoma; Adenocarcinoma, Clear Cell; Adenocarcinoma, Mucinous; alpha-Mannosidase; Ascitic Fluid; beta-Galactosidase; Case-Control Studies; Cystadenocarcinoma, Serous; Endometrial Neoplasms; Female; Glucuronidase; Humans; Hymecromone; Lysosomes; Neoplasms; Ovarian Cysts; Ovarian Neoplasms; Pelvic Inflammatory Disease