Prognostic significance of DNA quantification by flow cytometry in ovarian tumors

Autophagy modulating therapeutics inhibit ovarian cancer colony generation by polyploid giant cancer cells (PGCCs)

Background

Genomic instability and chemoresistance can arise in cancer due to a unique form of plasticity: that of polyploid giant cancer cells (PGCCs). These cells form under the stress of chemotherapy and have higher than diploid chromosome content. PGCCs are able to then repopulate tumors through an asymmetric daughter cell budding process. PGCCs have been observed in ovarian cancer histology, including the deadly and common form high-grade serous ovarian carcinoma (HGSC). We previously discovered that drugs which disrupt the cellular recycling process of autophagy are uniquely efficacious in pre-clinical HGSC models. While autophagy induction has been associated with PGCCs, it has never been previously investigated if autophagy modulation interacts with the PGCC life cycle and this form of tumor cell plasticity.

Methods

CAOV3 and OVCAR3 ovarian cancer cell lines were treated with carboplatin or docetaxel to induce PGCC formation. Microscopy was used to characterize and quantify PGCCs formed by chemotherapy. Two clinically available drugs that inhibit autophagy, hydroxychloroquine and nelfinavir, and a clinically available activator of autophagy, rapamycin, were employed to test the effect of these autophagy modulators on PGCC induction and subsequent colony formation from PGCCs. Crystal violet-stained colony formation assays were used to quantify the tumor-repopulating stage of the PGCC life cycle.

Results

Autophagy inhibitors did not prevent PGCC formation in OVCAR3 or CAOV3 cells. Rapamycin did not induce PGCC formation on its own nor did it exacerbate PGCC formation by chemotherapy. However, hydroxychloroquine prevented efficient colony formation in CAOV3 PGCCs induced by carboplatin (27% inhibition) or docetaxel (41% inhibition), as well as in OVCAR3 cells (95% and 77%, respectively). Nelfinavir similarly prevented colony formation in CAOV3 PGCCs induced by carboplatin (64% inhibition) or docetaxel (94% inhibition) as well as in OVCAR3 cells (89% and 80%, respectively). Rapamycin surprisingly also prevented PGCC colony outgrowth (52–84% inhibition).

Conclusions

While the autophagy previously observed to correlate with PGCC formation is unlikely necessary for PGCCs to form, autophagy modulating drugs severely impair the ability of HGSC PGCCs to form colonies. Clinical trials which utilize hydroxychloroquine, nelfinavir, and/or rapamycin after chemotherapy may be of future interest.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09503-6.

Prognostic significance of S-phase fractions in peritumoral invading zone analyzed by laser scanning cytometry in patients with high-grade glioma: A preliminary study

The predominant characteristic of malignant glioma is the presence of invading tumor cells in the peritumoral zone. Distinguishing between tumor cells and normal cells in a peritumoral lesion is challenging. Therefore, the aim of the present study was to investigate the cell-cycle phase measurements of fixed paraffin-embedded specimens from the peritumoral invading zone of high-grade gliomas using laser scanning cytometry. A total of 12 high-grade gliomas (2 anaplastic astrocytomas and 10 glioblastomas) were studied. The tumor core and peritumoral invading zone of each tumor specimen were investigated. Tissue sections (50 µm) from the paraffin blocks were deparaffinized, rehydrated and enzymatically disintegrated, and the cells in suspension were stained with propidium iodide and placed on microscope slides. A slight trend for an increased S-phase fraction in the peritumoral invading zone compared with the tumor core was observed (P=0.24). Additionally, there was a trend for a decrease in the overall survival time of patients with increasing peritumoral invading zone S-phase fraction (P=0.12). These data suggest that laser scanning cytometry is a powerful and clinically relevant tool for the objective analysis of the cell cycle in malignant gliomas.

Tetraploid cells from cytokinesis failure induce aneuploidy and spontaneous transformation of mouse ovarian surface epithelial cells

Most ovarian cancers originate from the ovarian surface epithelium and are characterized by aneuploid karyotypes. Aneuploidy, a consequence of chromosome instability, is an early event during the development of ovarian cancers. However, how aneuploid cells are evolved from normal diploid cells in ovarian cancers remains unknown. In the present study, cytogenetic analyses of a mouse syngeneic ovarian cancer model revealed that diploid mouse ovarian surface epithelial cells (MOSECs) experienced an intermediate tetraploid cell stage, before evolving to aneuploid (mainly near-tetraploid) cells. Using long-term live-cell imaging followed by fluorescence in situ hybridization (FISH), we demonstrated that tetraploid cells originally arose from cytokinesis failure of bipolar mitosis in diploid cells, and gave rise to aneuploid cells through chromosome mis-segregation during both bipolar and multipolar mitoses. Injection of the late passage aneuploid MOSECs resulted in tumor formation in C57BL/6 mice. Therefore, we reveal a pathway for the evolution of diploid to aneuploid MOSECs and elucidate a mechanism for the development of near-tetraploid ovarian cancer cells.

Long-term oncological outcomes of ovarian serous carcinomas with psammoma bodies: a novel insight into the molecular pathogenesis of ovarian epithelial carcinoma

A two-tier system in which ovarian epithelial carcinomas are subdivided into type I and type II tumors has been proposed on the basis of recent molecular pathogenesis findings. Type I tumors, unrelated to tumor protein p53 (TP53) mutations, show favorable prognosis in a slow step-wise process, whereas type II tumors, related to TP53 mutations, contribute to poor prognosis. Ovarian serous carcinomas with excessive psammoma bodies behave like type I tumors. However, their etiology and prognostic significance remain obscure. The objective of the present study was to evaluate the characteristic features and potential relevance of psammoma bodies to the clinical outcome of 44 patients with serous carcinomas with long-term follow-up. The 5- and 10-year survival rates were significantly different between the serous carcinomas with less than 5% area of psammoma bodies and those at least 5% area (P < 0.01). All tumors with at least 5% area were both diploid and immunohistochemically negative for TP53 mutations. All patients with these tumors, including eight with International Federation of Gynecology and Obstetrics (FIGO) stages III or IV disease, survived more than 5 years and their 10-year survival rate was 76%. In multivariate analysis using clinical parameters, the apparent existence of psammoma bodies was an indication to view serous carcinomas as type I tumors with long-term survival. Our results suggested that the formation of psammoma bodies is associated with increased apoptotic tumor cell death related to normal TP53 function. The pathological findings of psammoma bodies might contribute to the consideration of pathogenesis and to the development of prognostic prediction rules for serous carcinomas.

A population-based 5-year cohort study including all cases of epithelial ovarian cancer in western Sweden: 10-year survival and prognostic factors

Epithelial ovarian cancer (EOC) is the major gynecologic cancer mortality cause in Sweden. The aim of the present study was to investigate the long-term survival and prognostic factors of a complete population-based 5-year cohort of 682 patients with invasive EOC in western Sweden (population around 1.6 million). Data relating to residual tumor after surgery, FIGO stage, grade, histopathologic subtype, ploidy status, adjuvant chemotherapy (the prepaclitaxel period), and disease state (recurrence and death) were reported to a quality register in a prospectively kept database and were controlled against the Swedish National Cancer Registry for completeness. The median follow-up durations for the prospectively collected data in the Cox analysis and for the survival analysis that was made for all patients were 81 months (range, 52-109 months) and 11.7 years (range, 8.7-14.1 years), respectively. No patient was lost to follow-up. The relative 10-year survival rate was 38.4% (95% confidence interval, 34.5%-42.8%). The median relative survival time was 4.3 years (95% confidence interval, 3.6%-5.2%). In the univariate Cox regression analysis, prognostic significances for age, stage, residual tumor, histopathologic subtype of serous cystadenocarcinoma, grade, CA-125, and ploidy status were seen. In the multivariate analysis, age, stage, residual tumor after surgery, and postoperative CA-125 were of prognostic significance. In conclusion, 4 major prognostic factors were found for EOC in this population-based cohort study that also presents nearly accurate long-term survival owing to the nonselective nature and completeness regarding patients and follow-up of the study.

Clinical and pathological predictive factors in women with adult-type granulosa cell tumor of the ovary

Granulosa cell tumor (GCT) is a rare neoplasm hallmarked by a very indolent course and late recurrences. Although numerous clinical and pathological parameters have been implicated as prognostic factors for GCT, their role remains controversial. We performed a retrospective study at our institution where we identified 48 patients with GCT from our tumor registry. Demographic and clinical course information was recorded from the medical record. Twenty of 48 formalin-fixed, paraffin-embedded blocks were retrieved from archived specimens. Pathological parameters such as nuclear atypia, mitotic count, Ki-67 index using immunohistochemistry, and quantitative DNA ploidy were performed. DNA aneuploidy by quantitative method was associated with patients' overall survival. The degree of nuclear atypia, mitotic count, Ki-67 index, and DNA aneuploidy was not predictive of tumor recurrence. Multi-institutional collaboration is imperative to create a comprehensive national database for investigation into ways that may better indicate prognosis in these patients.