Detection of circulating tumor cells in cervical cancer using a conditionally replicative adenovirus targeting telomerase-positive cells

Circulating tumor cells (CTC) are newly discovered biomarkers of cancers. Although many systems detect CTC, a gold standard has not yet been established. We analyzed CTC in uterine cervical cancer patients using an advanced version of conditionally replicative adenovirus targeting telomerase-positive cells, which was enabled to infect coxsackievirus-adenovirus receptor-negative cells and to reduce false-positive signals in myeloid cells. Blood samples from cervical cancer patients were hemolyzed and infected with the virus and then labeled with fluorescent anti-CD45 and anti-pan cytokeratin antibodies. GFP (+)/CD45 (-) cells were isolated and subjected to whole-genome amplification followed by polymerase chain reaction analysis of human papillomavirus (HPV) DNA. CTC were detected in 6 of 23 patients with cervical cancers (26.0%). Expression of CTC did not correlate with the stage of cancer or other clinicopathological factors. In 5 of the 6 CTC-positive cases, the same subtype of HPV DNA as that of the corresponding primary lesion was detected, indicating that the CTC originated from HPV-infected cancer cells. These CTC were all negative for cytokeratins. The CTC detected by our system were genetically confirmed. CTC derived from uterine cervical cancers had lost epithelial characteristics, indicating that epithelial marker-dependent systems do not have the capacity to detect these cells in cervical cancer patients.

FDG-PET-positive ovarian thecoma with GLUT5 expression: Five cases

Positron emission tomography (PET) with fluorodeoxyglucose F18 (¹⁸ F-FDG) is useful for detecting malignancies, but benign lesions occasionally have false-positive ¹⁸ F-FDG uptake. Here, we report the cases of five postmenopausal women with solid ovarian tumors suspected to be ovarian cancer on magnetic resonance imaging and ¹⁸ F-FDG uptake. Mean age of the five patients was 57 years (range, 53-65 years). Average early standardized uptake value (SUV) of ¹⁸ F-FDG was 5.76 (range, 2.2-12.0) and delayed SUV was 6.56 (range, 2.4-13.8). In all five patients, frozen section diagnosis at surgery was thecoma, and bilateral salpingo-oophorectomy was performed. On immunohistochemistry, immunoreactive glucose transporter 5 (GLUT5) expression was detected in thecoma tissues. This case shows that thecoma sometimes has positive ¹⁸ F-FDG uptake on positron emission tomography-computed tomography (PET-CT), indicating the need for caution regarding false-positive PET-CT in patients with benign solid ovarian tumor.

Tamoxifen-induced ovarian hyperstimulation during premenopausal hormonal therapy for breast cancer in Japanese women

Purpose

Tamoxifen is an anti-estrogenic drug that is widely used for endocrine-dependent breast cancer as adjuvant hormonal therapy, and its use has been reported to be frequently associated with high levels of serum estradiol. Since the population of premenopausal women receiving tamoxifen therapy is growing in Japan, we retrospectively analyzed the incidence of ovarian hyperstimulation by tamoxifen therapy in Japanese women.

Methods

Eleven patients who received surgical therapy for endocrine-dependent breast cancer and showed high values of serum estradiol during post-operative tamoxifen therapy were recruited in this study and evaluated by examining the serum concentration of follicular stimulating hormone (FSH) and follicular development.

Results

The mean age, serum concentrations of estradiol and FSH, and follicular diameter were 41.3 years old, 1015.8 pg/mL, 11.8 mIU/mL, and 3.47 cm, respectively. In 6 cases, multiple follicular development was observed, while the other cases showed single follicular development with a mean serum estradiol level of 848.6 pg/mL and follicular diameter of 4.46 cm. There was no significant difference in age or FSH concentration between the two groups. The mean periods from the start of the single administration of tamoxifen to the initial detection of a high estradiol concentration was 716.5 days.

Conclusions

These findings indicate that tamoxifen could stimulate the ovarian function even after 2-year treatment. Since single and multiple follicular developments with large sizes were observed, dual mechanisms through the inhibition of both negative and positive feedback to the hypothalamic-pituitary-axis can be proposed to explain the adverse effects of tamoxifen on ovarian function.

Dienogest, a synthetic progestin, down-regulates expression of CYP19A1 and inflammatory and neuroangiogenesis factors through progesterone receptor isoforms A and B in endometriotic cells

Dienogest (DNG) is a selective progesterone receptor (PR) agonist and oral administration of DNG is used for the treatment of endometriosis. DNG is considered to act on PR to down-regulate pathophysiological factors associated with endometriosis. PR exists as two major isoforms, PR-A and PR-B, and their physiological functions are mostly distinct. It was suggested that PR isoform expression patterns are altered in endometriosis, but it is unknown whether the pharmacological effects of DNG are exerted through PR-A, PR-B or both. In the present study, we investigated the pharmacological effects of DNG through these PR isoforms on the expression of CYP19A1 which encodes aromatase and inflammatory and neuroangiogenesis factors associated with the pain and progression of endometriosis. We used immortalized human endometriotic epithelial cell lines that specifically express PR-A or PR-B in a spheroid cell culture system, and treated them with DNG. We evaluated messenger RNA (mRNA) expression of CYP19A1, prostaglandin (PG)E2 synthase (cyclooxygenase (COX)-2 and microsomal PGE2 synthase (mPGES)-1), inflammatory cytokines (interleukin (IL)-6, IL-8, and monocyte chemoattractant protein (MCP)-1) and neuroangiogenesis factors (vascular endothelial growth factor (VEGF) and nerve growth factor (NGF)) using real-time polymerase chain reaction. In addition, PGE2 production was measured by enzyme immunoassay. We found that DNG down-regulated mRNA expression of CYP19A1, COX-2, mPGES-1, IL-6, IL-8, MCP-1, NGF and VEGF, and PGE2 production in human endometriotic epithelial cell lines that specifically express either PR-A or PR-B. These results demonstrate that DNG activates both PR-A and PR-B and down-regulates the expression of pathophysiological factors associated with pain and progression of endometriosis. Our results suggest that DNG exerts therapeutic efficacy against the pain and progression of endometriosis regardless of PR isoform expression patterns.

Abstract 205: Imatinib sensitizes endometrial cancer cells to cisplatin by targeting CD117-positive growth-competent cells

The use of molecular target therapy has not been established for endometrial cancer. The present study investigated the potential therapeutic strategy of targeting CD117-positive cancer cells as a novel molecular target therapy. FACS-sorted CD117+ cells isolated from endometrial cancer cell lines (Ishikawa or MFE280 cells) exhibited higher proliferative capacity in vitro and colony forming activity on soft agar, and decreased sensitivity to cisplatin, compared to CD117- cells. Immunohistochemical analyses with surgical specimens of endometrial cancers showed that high CD117 expression was tightly linked to advanced FIGO stages, myometrial invasion and histological grade, and was significantly associated with poor overall survival and relapse-free survival (Kaplan-Meier analysis; p<0.001, log-rank test). The Cox-regression hazard model identified high CD117 expression to be an independent prognostic factor for survival (p<0.05). In vitro assay confirmed that stem cell factor (SCF), a ligand of CD117, was produced specifically in CD117+ cells of endometrial cancer, and the colony-forming activity were abrogated by adding anti-SCF antibody, indicating an SCF-dependent growth property. Imatinib was confirmed to selectively target CD117+ cells in vitro, and synergistically enhanced the anti-tumor effect of low dose cisplatin in vivo, which showed only modest effects when used as a single use. These findings suggest that CD117 can be a marker of aggressive behavior of cells as well as an independent prognostic marker in endometrial cancer. Targeting of the SCF/CD117 axis by imatinib sensitized endometrial cancer cells to cisplatin, proposing a novel therapeutic strategy for this tumor type.

Citation Format: Mitsuhiro Nakamura, Satoru Kyo, Xiuzhi Zhang, Masahiro Takakura, Yasunari Mizumoto, Yukiko Bono, Toshiyuki Sasagawa, Hiroshi Fujiwara. Imatinib sensitizes endometrial cancer cells to cisplatin by targeting CD117-positive growth-competent cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 205. doi:10.1158/1538-7445.AM2014-205

Concurrent estrogen action was essential for maximal progestin effect in oral contraceptives

OBJECTIVE

To investigate the impact of estrogen contained in oral contraceptives (OCs) on the action of progestin on ovarian endometrioma epithelial cells.

DESIGN

Experimental in vitro study and immunohistochemical analysis.

SETTING

University hospital.

PATIENT(S)

Patients who underwent surgery due to ovarian endometrioma.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Telomerase-immortalized epithelial cells derived from ovarian endometrioma were treated with norethindorone (NET; 80 nmol/L) or levonorgestrel (LNG; 20 nmol/L) with or without 17β-ethynylestradiol (EE; 0.6 nmol/L) for 96 hours, and the cell growth was monitored. Estrogen receptor (ER) α, progesterone receptor (PR) A, and PRB expressions in clinical samples of ovarian endometrioma epithelial cells were analyzed with the use of immunohistochemistry.

RESULT(S)

NET or LNG effectively suppressed cell growth, and addition of EE significantly enhanced the growth suppression. This EE-mediated enhancement of cell growth suppression was observed only in cells that expressed ERα and therefore was ERα dependent. Western blot analysis revealed that expression of PRB was significantly induced by the addition of EE. Immunohistochemical analysis confirmed that ERα expression and PRB expression are significantly correlated, indicating that progestin-sensitive cells with PRB expression are predisposed to react with estrogen stimulation.

CONCLUSION(S)

These findings suggest that EE contained in OCs plays a supportive role in progestin-induced growth inhibition of ovarian endometrioma epithelial cells. In the absence of estrogen priming, concurrent estrogen action was essential for rapid induction of PR to achieve maximal progestin effect.

Molecular characterization of CD133+ cancer stem-like cells in endometrial cancer

A small subset of cells with CD133 expression is thought to have increased chemoresistance and tumorigenicity, features of cancer stem cells (CSCs); the molecular mechanisms by which these properties arise remain unclear. We characterized CD133+ endometrial cancer cells based on microarray analyses of Ishikawa cells. Of the genes upregulated in CD133+ cells compared with CD133- cells, we noted several key factors involved in the aggressive behavior of cells, including ABCG2 and matrix metalloproteinase (MMP). Flow cytometric analyses identified a side-cell population (SP) with CSC features in Ishikawa cells, and they were found to be more enriched in CD133+ cells than CD133- cells. In particular, CD133+/SP cells exhibited higher proliferative and colony‑forming activity than CD133+/non-SP cells. Matrigel invasion assay revealed that CD133+ cells have enhanced invasive capacity with elevated MT1-MMP expression. siRNA‑based knockdown of MT1-MMP largely abolished the invasive capacity of CD133+ cells, but not CD133- cells due to low levels of constitutive MT1-MMP1 expression. These findings demonstrate that increased chemoresistance and tumorigenic potential of CD133+ cells are at least partly attributed to an enriched SP fraction as well as increased MMP-1 expression. These results will be of assistance in the establishment of molecular target therapy to CSCs in endometrial cancer.

Imatinib sensitizes endometrial cancer cells to cisplatin by targeting CD117-positive growth-competent cells

The use of molecular target therapy has not been established for endometrial cancer. The present study investigated the potential therapeutic strategy of targeting CD117-positive cancer cells as a novel molecular target therapy. FACS-sorted CD117(+) cells isolated from endometrial cancer cell lines (Ishikawa or MFE280 cells) exhibited higher proliferative capacity in vitro and colony forming activity on soft agar, and decreased sensitivity to cisplatin, compared to CD117(-) cells. Immunohistochemical analyses with surgical specimens of endometrial cancers showed that high CD117 expression was tightly linked to advanced FIGO stages, myometrial invasion and histological grade, and was significantly associated with poor overall survival and relapse-free survival (Kaplan-Meier analysis; p<0.001, log-rank test). The Cox-regression hazard model identified high CD117 expression to be an independent prognostic factor for survival (p<0.05). In vitro assay confirmed that stem cell factor (SCF), a ligand of CD117, was produced specifically in CD117(+) cells of endometrial cancer, and the colony-forming activity were abrogated by adding anti-SCF antibody, indicating an SCF-dependent growth property. Imatinib was confirmed to selectively target CD117(+) cells in vitro, and synergistically enhanced the anti-tumor effect of low dose cisplatin in vivo, which showed only modest effects when used as a single use. These findings suggest that CD117 can be a marker of aggressive behavior of cells as well as an independent prognostic marker in endometrial cancer. Targeting of the SCF/CD117 axis by imatinib sensitized endometrial cancer cells to cisplatin, proposing a novel therapeutic strategy for this tumor type.

Abstract 4892: Hypoxia enhances tumor vascularization by endothelial differentiation of endometrial cancer stem cells

Emerging evidence has shown that a small subpopulation of cancer cells plays critical roles in tumorigenesis, establishing the cancer stem cells (CSCs) theory. CSCs have properties of tumorigenesis, self-renewal and multilineage differentiation. Previous our study demonstrated that CD133+ enodometrial cancer cells showed tumorigenic and self-renewal ability, suggesting that CD133 was a potential CSC marker in endometrial cancer. In this study, we focused on multilineage differentiation and investigated an ability of endothelial differentiation in endometrial CSCs. Immunohistochemistry of subcutaneous xenografts showed that human endometrial tumors contained human vessels labeled by human-specific anti-CD31 and vWF antibodies. Endothelial tube formation assay (in vitro angiogenesis) revealed that isolated CD133+ endometrial cancer cells could show tube formation while CD133- cells could not. CD133+ cells expressed CD31 and VEGFR-1 higher than CD133- cells. In some cell types of endometrial cancer cells, flow cytometric analysis showed expression of CD31 was high ratio under hypoxia compared to normoxia. Furthermore, in vitro angiogenesis assay demonstrated hypoxic condition could promote and keep tube formation in CD133+ cells, but not CD133- cells. These results suggest that CSCs have potential of endothelial differentiation and hypoxia enhances endothelial differentiation of CSCs. These findings shed light on the establishment of new target therapy for endometrial cancer.

Citation Format: Mitsuhiro Nakamura, Xiuzhi Zhang, Masahiro Takakura, Yoshiko Maida, Yasunari Mizumoto, Yukiko Bono, Toshiyuki Sasagawa, Satoru Kyo. Hypoxia enhances tumor vascularization by endothelial differentiation of endometrial cancer stem cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4892. doi:10.1158/1538-7445.AM2013-4892

Abstract 5199: Tumor vascularization by endothelial differentiation of endometrial cancer stem cells

Evidence for existence of cancer stem cells (CSCs) has been reported in several malignant tumors. CSCs have properties of self-renewal, tumorigenesis and multilineage differentiation. Many studies about CSCs have focused on self-renewal, tumorigenesis. However, it is unclear about multilineage differentiation. Our previous study showed CD133 was a CSC marker and a critical prognostic marker in endometrial cancer. In that study, we demonstrated that CD133+ cells were capable of generating both CD133+ and CD133- cells, whereas CD133 cells did not generate CD133+ cells, indicating that CD133+ CSCs have a differential ability. The present study investigated endothelial differentiation of endometrial cancer cells. We have established endometrial cancer cells from normal human endometrial epithelial cells by introduction of HPV16 E6/E7, hTERT and K-ras genes (EM-E6/E7/hTERT/K-ras cells). Histological findings of tumors formed from EM-E6/E7/hTERT/K-ras cells showed that tumors were composed of solid and vascular regions. Vascular regions were stained human-specific anti-CD31 antibody, suggesting that EM-E6/E7/hTERT/K-Ras cells are capable of differentiating to endothelial cells. Subcutaneous xenografts from clinical samples in endometrial cancer also demonstrated that human endometrial tumors contained human vessels labeled by human-specific anti-CD31 antibody. Endothelial tube formation assay (in vitro angiogenesis) revealed that isolated CD133+ endometrial cancer cells could show tube formation while CD133- cells could not, indicating that CD133+ endometrial cancer cells had an ability of endothelial differentiation. Furthermore, western blot analysis showed high expression of VEGFR1 in CD133+ cells. We demonstrated a new function of CSCs in endometrial cancer cells. These findings shed light on the establishment of new target therapy to endometrial cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5199. doi:1538-7445.AM2012-5199

Creation of immortalised epithelial cells from ovarian endometrioma

Background:

Epithelial cells of endometriotic tissues are difficult to propagate in vitro as experimental material is scarce owing to their limited life span. However, there is an increasing concern regarding their malignant transformation in ovaries. The present study sought to generate their stable culture system.

Methods and results:

Purified epithelial cells isolated from ovarian endometriomas using microscopic manipulation were successfully immortalised by combinatorial transfection of human cyclinD1, cdk4 and human telomerase reverse transcriptase (hTERT) genes, whereas the introduction of hTERT alone, or together with cdk4, was insufficient for immortalisation, leading to cellular senescence. We confirmed stable cytokeratin expression in the immortalised cells, proving their epithelial origin. These cells expressed progesterone receptor B and showed significant growth inhibition by various progestins. Oestrogen receptor (ER) expression was detected in these cells, albeit at low levels. Additional overexpression of ERα generated stable cells with oestrogen-dependent growth activation. Soft-agar colony formation assay and nude mice xenograft experiments demonstrated that these cells, even those with additional inactivation of p53, did not have transformed phenotypes.

Conclusion:

We for the first time generated immortalised epithelial cells from ovarian endometrioma that retained sex steroid responsiveness. These cells are invaluable tools not only for the consistent in vitro work but also for the study of molecular pathogenesis or carcinogenesis of endometriosis.

Abstract 3411: Analysis of gene profile and identification of molecular targets in endometrial cancer stem cells

Background; Cancer stem cells (CSCs) have been known to be the major source of tumor propagation and might be an attractive therapeutic target. Our previous study showed that CD133+ Ishikawa and MFE 280 endometrial cancer cells have the ability of tumorigenicity, self-renewal and differentiation capacity in vitro and in vivo, while CD133- cells did not. Furthermore, CD133+ cells showed more resistance to cisplatin- or paclitaxel-induced cytotoxicity than CD133- cells. These results indicate that CD133 is the CSC maker in endometrial cancer cells. In the present study, we sought to analyze gene profile and identify molecular targets in endometrial cancer stem cells. Methods; We examined microarray analysis to investigate the molecules essential for the CSCs characteristics by 3D-Gene chip (TORAY). Results; Microarray analysis of total 25,000 genes showed that about 500 genes were highly expressed in CD133+ cells, compared to CD133- cells. The ALDH1 gene was up-regulated in CD133+ cells, in accordance with the previous reported expression of ALDH1 on breast and colorectal CSCs. We also found out the elevated expression of ABC transporter genes, ABCG2, ABCG3, ABCG4, ABCG8, ABCC8 and ABCC9. It is well known that cells expressing those genes are resistant to chemotherapeutic agents and associated with side population (SP). Fluorescence activated cell sorter analysis demonstrated that the ratio of SP fraction in CD133+ Ishikawa cells is slightly higher than in CD133- Ishikawa cells (0.8% vs 0.6%). Isolated SP/CD133+ cells ells showed more extensive proliferation and tumorigenicity, compared with non-SP/CD133+, SP/CD133- and non-SP/CD133- cells. Finally, we focused on high expression of MMP14 (MT1-MMP) gene in CD133+ cells. Invasion assay revealed that CD133+ Ishikawa and MFE 280 cells have more invasive property than CD133- Ishikawa and MFE 280 cells. The inhibition of MT1-MMP gene by siRNA significantly reduced the invasive ability of CD133+ cells. These results suggest that MT1-MMP is one of the critical molecules that generate biological features of CSC and may be a potential therapeutic target in endometrial cancer. Conclusions; We demonstrated that SP/CD133+ cells might be more defined CSCs in endometrial cancer and identified important molecules essential for characterizing endometrial CSCs in which MT1-MMP plays critical roles in generating biological features of CSCs in this tumor type. These findings shed light on establishment of molecular target therapy in endometrial cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3411. doi:10.1158/1538-7445.AM2011-3411

Activation of NF-kappaB is a novel target of KRAS-induced endometrial carcinogenesis

PURPOSE

Although the KRAS mutation is one of critical genetic alterations in endometrial carcinogenesis, the downstream targets are not known.

EXPERIMENTAL DESIGN

In this study, we investigated the molecular targets of KRAS signals, using tumorigenic cells with oncogenic KRAS mutation established from telomerase reverse transcriptase (TERT)-immortalized endometrial epithelial cells.

RESULTS

We first confirmed that the RAF-ERK pathway, but not the PI3K-Akt pathway, was activated in KRAS tumorigenic cells. However, the introduction of constitutively active MAP/ERK kinase into immortalized cells to mimic RAF-ERK activation failed to obtain tumorigenic phenotypes, indicating the existence of other carcinogenic pathways triggered by KRAS. Recent evidence suggestive of linkage with KRAS signals prompted us to examine the involvement of NF-κB in endometrial carcinogenesis. We found that the DNA-binding activity of NF-κB was markedly elevated in KRAS tumorigenic cells compared with TERT-immortalized cells. Furthermore, the ability of NF-κB to activate the target gene promoters significantly increased in KRAS tumorigenic cells. Introduction of a mutant IκB that is resistant to degradation and thereby enhances the inhibitory effect on NF-κB largely abrogated the transformed phenotypes of KRAS tumorigenic cells. Thus, oncogenic KRAS signals contributed to the tumorigenic phenotypes of endometrial cells by activating the transcription function of NF-κB.

CONCLUSIONS

These findings clearly show that NF-κB activation is a novel target of oncogenic KRAS in endometrial carcinogenesis, implying the potential utility of NF-κB inhibitors for endometrial cancer chemoprevention, especially with KRAS mutation.

A reliable method for culture of dissociated mouse cerebellar cells enriched for Purkinje neurons

The cerebellar Purkinje neuron (PN) serves as an important model in studies of neuronal development in the mammalian central nervous system. Dissociated PN preparations maintained in an in-vitro environment with simplified cellular and biochemical conditions can facilitate molecular analyses of neuronal development. Here we describe a reliable method to prepare dissociated cultures of mouse cerebellar neurons maintained with a serum-free, Dulbecco's modified Eagle's medium/F-12 nutrient-based medium, which facilitates PN survival and dendritic differentiation. The survival of mouse PNs in this culture was maximized when cerebellar cells were (1) taken from prenatal animals, (2) dissociated with papain, and (3) seeded at a density of 5 000 000 cells/ml or higher. Dissociated PNs prepared by our method from mice of embryonic day 18 (E 18) reproduced several morphological and electrophysiological changes seen in intact postnatal rodents with similar time-courses. Therefore, our culture method offers a useful model for investigating molecular mechanisms underlying postnatal neuronal development.