New aspects of adjuvant therapy in endometrial cancer: Current standards and future directions

Ubiquitin C-Terminal Hydrolase L5 (UCHL5) Accelerates the Growth of Endometrial Cancer via Activating the Wnt/β-Catenin Signaling Pathway

Endometrial cancer (EC) is the most prevalent gynecological malignancy with high mortality. Chemotherapy plays a pivotal role both in an adjuvant setting and in exclusive treatment. However, current pharmacotherapies are limited and not ideal for improving the overall survival of EC patients. Thus, identification of the underlying molecular mechanisms responsible for initiation and progression of EC is imperative for developing novel therapeutic strategies. Ubiquitin C-terminal hydrolase L5 (UCHL5) has been found to aggravate tumor growth and metastasis in several different types of tumor models such as esophageal squamous cell carcinoma, hepatocellular carcinoma, and epithelial ovarian cancer. However, whether UCHL5 influences the growth of EC has not been elucidated. To expose the role of UCHL5 on EC, bioinformatics analysis was conducted, and it hinted that UCHL5 was overexpressed in EC tissues and associated with lower overall survival. Consistently, the overexpression of UCHL5 in EC tissues and cell lines was further confirmed by western blot (WB) and polymerase chain reaction (PCR) compared with non-tumor control. Lentivirus vectors carrying UCHL5 shRNA or CD sequences were used to reduce or overexpress the UCHL5 gene, respectively. Cell proliferation and cycle were facilitated, and cell apoptosis was decreased when the UCHL5 gene was overexpressed in EC cell lines. These results were opposite in UCHL5 knockdown EC cells. Additionally, the expression of β-catenin is positively related to UCHL5 levels and the tumorigenic effects of UCHL5 overexpression were reversed by the Wnt/β-catenin pathway inhibitor XAV939. Thus, Wnt/β-catenin pathway activation may be a partial mechanism responsible for the promoting effects of UCHL5 on EC growth. In conclusion, UCHL5 accelerated the growth of EC via the Wnt/β-catenin pathway and was expected to be an attractive target for EC treatment.

Wogonoside inhibits tumor growth and metastasis in endometrial cancer via ER stress-Hippo signaling axis

Wogonoside, a bioactive flavonoid component derived from Scutellaria baicalensis Georgi, has been reported to inhibit tumor growth in mice bearing various types of cancer cells such as breast cancer, lung cancer, and leukemia cells. However, whether wogonoside could inhibit tumor growth of endometrial cancer has not been elucidated. In this study, we explored the function of wogonoside on tumor growth and the underlying mechanism on endometrial cancer. Firstly, we investigated the effect of wogonoside on endometrial cancer cells and found that wogonoside could significantly decrease cell proliferation and metastasis. Mechanistically, wogonoside could aggravate the extent of ER stress and upregulate the phosphorylation level of Mammalian Ste20-like kinase 1, leading to the activation of the Hippo signaling pathway. Taken together, in vitro and in vivo data demonstrated that wogonoside could be a potent inducer of ER stress and could be further developed into a promising therapy for endometrial cancer.

Expression of CD133 in endometrial cancer cells and its implications

Cancer stem cells are an attractive therapeutic target for cancer. The present study examined stem cell characteristics of CD133+ cells isolated from endometrial cancer. Phenotypic characteristics, proliferation, migration, anchorage-independent growth, chemoresistance, gene expression profile and tumorigenicity of CD133+ tumor cells were assessed. Primary tumor exhibited immunoreactivity for CD133. Endometrial CD133+ tumor cells enhanced proliferation rate, colony formation, chemotaxis migration ability, and chemoresistance to cisplatin, paclitaxel, and doxorubicin than CD133- cells. CD133+ cells expressed more cancer stem cells markers such as EpCAM, aldehyde dehydrogenase 1 and insulin-like growth factor-1 receptor than CD133- cells. Moreover, CD133+ cells also increased expression of embryonic stem cell markers including oct4, nanog, sox2, and cmyc than CD133- cells. Finally, CD133+ tumor cells could generate xenograft but not CD133- tumor cells. CD133 and Ki67 were extensively expressed in the xenograft. In conclusion, endometrial CD133+ tumor cells displayed cancer stem cell characteristics and might represent a valuable tool for identifying endometrial cancer stem cells and hence a potential therapeutic target.

The future therapy of endometrial cancer: microRNA's functionality, capability, and putative clinical application

PURPOSE

Endometrial cancer (EC) therapy is characterized by the heterogeneity of EC subtypes resulting in unclear clinical behavior as well as in unsatisfactory treatment options. The available biomarkers, such as cellular tumor antigen p53 (TP53), phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase and dual-specificity protein phosphatase (PTEN), and phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) genes alone might not be sufficient, and thus, new predictive and prognostic biomarkers are urgently required. The biomolecule class of microRNA represents a group of endogenously expressed regulatory factors primarily involved in control of pivotal cancer-related mechanisms including cell cycle, proliferation, apoptosis, and metastasis. Here, we review the current state of science regarding microRNA functionality in EC progression.

Immunohistochemical expression of cancer stem cell related markers CD44 and CD133 in endometrial cancer

The goal of this study was to detect the presence of cancer stem cell markers CD44 and CD133 in immunohistochemically stained samples of endometrial cancer and correlate their expression with clinicopathological variables to identify the impact of CD44 or CD133 expression on tumor behavior and endometrial carcinogenesis. Marker expression was analyzed in 62 endometrial cancer samples (57 endometrioid carcinoma and 5 carcinosarcoma) and 15 proliferative endometrium samples. We detected CD133 and CD44 expression in 87.09% and 79.03% respectively of the studied endometrial cancers, and the expression was significantly different from the normal group. CD44 expression decreased with myometrial invasive depth and lymph-vascular space invasion (LVSI), and these inverse relationships were significant (p=0.034, p=0.019, respectively). CD133 was more expressed by early stage tumor (FIGO I-II) compared with those having FIGO III to IV stage disease (p=0.021). The most notable conclusion of the present study is that CD44 and CD133 might participate in early-stage endometrial cancer carcinogenesis, and their overexpression may facilitate the early diagnosis of endometrial cancers. Analysis of our results supports the hypothesis that CD44 expression tends to decrease as the disease becomes invasive and progressive. So, we concluded that CD44 down-regulation might warn of a more aggressive course and may have a link with poorly prognosis carcinosarcomas. Further examination of the expression and function of CD44 and CD133 with a greater number of carcinosarcomas is warranted.

Examestane in advanced or recurrent endometrial carcinoma: a prospective phase II study by the Nordic Society of Gynecologic Oncology (NSGO)

BACKGROUND

We evaluated the efficacy and safety of the aromatase inhibitor exemestane in patients with advanced, persistent or recurrent endometrial carcinoma.

METHODS

We performed an open-label one-arm, two-stage, phase II study of 25 mg of oral exemestane in 51 patients with advanced (FIGO stage III-IV) or relapsed endometrioid endometrial cancer. Patients were stratified into subsets of estrogen receptor (ER) positive and ER negative patients.

RESULTS

Recruitment to the ER negative group was stopped prematurely after 12 patients due to slow accrual. In the ER positive patients, we observed an overall response rate of 10%, and a lack of progression after 6 months in 35% of the patients. No responses were registered in the ER negative patients, and all had progressive disease within 6 months. For the total group of patients, the median progression free survival (PFS) was 3.1 months (95% CI: 2.0-4.1). In the ER positive patients the median PFS was 3.8 months (95% CI: 0.7-6.9) and in the ER negative patients it was 2.6 months (95% CI: 2.1-3-1). In the ER positive patients the median overall survival (OS) time was 13.3 months (95% CI: 7.7-18.9), in the ER negative patients the corresponding numbers were 6.1 months (95% CI: 4.1-8.2). Treatment with exemestane was well tolerated.

CONCLUSION

Treatment of estrogen positive advanced or recurrent endometrial cancer with exemestane, an aromatase inhibitor, resulted in a response rate of 10% and lack of progression after 6 months in 35% of the patients.

TRIAL REGISTRATION

Trial identification number (Clinical Trials.gov): NCT01965080.Nordic Society of Gynecological Oncology: NSGO-EC-0302.EudraCT number: 2004-001103-35.

Adjuvant sequential chemoradiation therapy in high-risk endometrial cancer: results of a prospective, multicenter phase-II study of the NOGGO (North-Eastern German Society of Gynaecological Oncology)

PURPOSE

The management of high-risk endometrial cancer (HREC) remains controversial. We conducted a prospective multicenter phase-II clinical trial to evaluate an adjuvant chemotherapy (CT) with sequential radiotherapy (RT) in patients with HREC.

METHODS

Patients with HREC from 8 institutions in Germany were enrolled. After surgery, patients received four cycles of paclitaxel 175 mg/m² (P) and carboplatin AUC5 (C) (d1, q21d) and subsequent external pelvic radiation therapy (1.8 Gy/d, d1-5) at a total dose of 45 Gy with vaginal brachytherapy (3 × 5 Gy). Quality of life (QoL) was assessed using the EORTC-QLQ-C30 questionnaire. Primary endpoints were tolerability, toxicity and QoL. Progression-free survival (PFS) was defined as secondary endpoint.

RESULTS

Thirty-five patients were enrolled from 2004 through 2008. Median follow-up was 24 months (range 3-24 months). All patients received 4 cycles of P and C and completed RT. Overall, grade 3/4 haematological toxicity was 25.6 %. Three cycles were delayed because of leukopenia. Grade 3/4 non-haematologic toxicities were rare (≤3 %). No overall change in QoL occurred during treatment. Two-year median PFS and OS rates were both 75.8 %.

CONCLUSIONS

Adjuvant combination CT with P + C and sequential RT is well tolerated and a feasible regimen in patients with HREC. Subsequent phase-III trials are warranted.

Survival of endometrial cancer patients in Germany in the early 21st century: a period analysis by age, histology, and stage

Background

Population-based studies on endometrial cancer providing survival estimates by age, histology, and stage have been sparse. We aimed to derive most up-to-date and detailed survival estimates for endometrial cancer patients in Germany.

Methods

We used a pooled German national dataset including data from 11 cancer registries covering a population of 33 million people. 30,906 patients diagnosed with endometrial cancer in 1997-2006 were included. Period analysis was performed to calculate 5-year relative survival (RS) in 2002-2006. Trends in survival between 2002 and 2006 were examined using model-based period analysis. Age-adjustment was performed using five age groups (15-44, 45-54, 55-64, 65-74, and 75+ years).

Results

Overall, age-adjusted 5-year relative survival in 2002-2006 was 81%. A moderate age gradient was observed, with 5-year RS decreasing from 90% in the age group 15-49 years to 75% in the age group 70+ years. Furthermore prognosis varied strongly by histologic subtypes and stage, with age-adjusted 5-year RS ranging from 43% (for sarcoma) to 94% (for squamous metaplasia), and reaching 91% for localized, 51% for regional, and 20% for distant stage. Except for age group 65-74 years, no significant improvement in survival was seen during the recent 5-year period under investigation.

Conclusion

In this comprehensive population-based survival analysis of patients with endometrial cancer from Germany, prognosis of endometrial cancer moderately varied by age, and strongly varied by histology and stage. While prognosis is rather good overall, further improvement in 5-year relative survival of endometrial cancer patients has been stagnating in the early 21^st century.

Hormonal therapy in advanced or recurrent endometrial cancer

BACKGROUND

Endometrial cancer is a cancer of the lining of the womb and worldwide is the seventh most common cancer in women. Treatment with hormones is thought to be beneficial in patients with endometrial cancer.

OBJECTIVES

To assess the indications, effectiveness and safety of hormone therapy for advanced or recurrent epithelial endometrial cancer.

SEARCH STRATEGY

We searched the Cochrane Gynaecological Cancer Group Trials Register, MEDLINE, EMBASE up to May 2009 and and CENTRAL (Issue 2, 2009). We also searched registers of clinical trials, abstracts of scientific meetings, reference lists of included studies, and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that studied hormonal therapy in adult women diagnosed with advanced or recurrent endometrial cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted data and assessed risk of bias. Comparisons were restricted to single-trial analyses so we did not synthesise data in meta-analyses.

MAIN RESULTS

We found six trials (542 participants) that met our inclusion criteria. These trials assessed the effectiveness of hormonal therapy in women with advanced or recurrent endometrial cancer as a single agent, as part of combination therapy and as low versus high dose. All comparisons were restricted to single-trial analyses, where we found no evidence that hormonal therapy as a single agent or as a combination treatment prolonged overall or five-year disease-free survival of women with advanced or recurrent endometrial cancer. However, low-dose hormonal therapy may have had a benefit in terms of overall and progression-free survival (PFS) compared to high-dose hormonal therapy (HR 1.31, 95% CI 1.04 to 1.66 and HR 1.35, 95% CI 1.07 to 1.71 for overall and PFS, respectively).

AUTHORS' CONCLUSIONS

We found insufficient evidence that hormonal treatment in any form, dose or as part of combination therapy improves the survival of patients with advanced or recurrent endometrial cancer. However, a large number of patients would be needed to demonstrate an effect on survival and none of the included RCTs had a sufficient number of patients to demonstrate a significant difference. In the absence of a proven survival advantage and the heterogeneity of patient populations, the decision to use any type of hormonal therapy should be individualised and with the intent to palliate the disease. It is debatable whether outcomes such as quality of life, treatment response or palliative measures such as relieving symptoms should take preference over overall and PFS as the major objectives of future trials.

Systematic pelvic and aortic lymphadenectomy in intermediate and high-risk endometrial cancer: lymph-node mapping and identification of predictive factors for lymph-node status

OBJECTIVE

To systematically assess the metastatic pattern of intermediate- and high-risk endometrial cancer in pelvic and para-aortic lymph-nodes and to evaluate risk factors for lymph-node metastases.

STUDY DESIGN

Between 01/2005 and 01/2009 62 consecutive patients with intermediate- and high-risk endometrial cancer who underwent a systematic surgical staging including pelvic and para-aortic lymphadenectomy were enrolled into this study. Patients' characteristics, histological findings, lymph-node localization and involvement, surgical morbidity and relapse data were analyzed. Univariate analysis was performed to define risk factors for lymph-node metastasis.

RESULTS

Of the 13 patients (21%) with positive lymph-nodes (N1), 8 (61.5%) had both pelvic and para-aortic lymph-nodes affected, 2 (15.4%) only para-aortic and 3 (23%) only pelvic lymph-node metastases. Overall, 54% of the N1-patients had positive lymph-nodes above the inferior mesenteric artery (IMA) to the level of the renal veins. Univariate analysis revealed lymph vascular space invasion (p-value: <0.001), vascular-space-invasion (p-value: <0.001) and incomplete tumor resection (p-value: 0.008) as significant risk factors for N1-status. Overall and progression-free survival was not significantly different between N1- and N0-patients.

CONCLUSIONS

Since the proportion of N1-endometrial cancer patients with positive para-aortic lymph-nodes is, at 76%, considerably high, and more than half of them have affected lymph-nodes above the IMA-level, lymphadenectomy for endometrial cancer should be extended up to the renal veins, when indicated. The therapeutic impact of systematic lymphadenectomy on overall and progression-free survival has still to be evaluated in future prospective randomized studies.

Cells with characteristics of cancer stem/progenitor cells express the CD133 antigen in human endometrial tumors

PURPOSE

Cancer stem cells represent an attractive therapeutic target for tumor eradication. The present study aimed to determine whether CD133 expression may identify cells with characteristics of cancer stem/progenitor cells in human endometrial tumors.

EXPERIMENTAL DESIGN

We analyzed 113 tumor samples for CD133/1 expression by flow cytometry, immunohistochemistry, and semiquantitative reverse transcription-PCR. CD133(+) cells were isolated and used to assess phenotypic characteristics, self-renewal capacity, ability to maintain CD133 expression and form sphere-like structures in long-term cultures, sensitivity to chemotherapeutic agents, gene expression profile, and ability to initiate tumors in NOD/SCID mice.

RESULTS

Primary tumor samples exhibited a variable degree of immunoreactivity for CD133/1, ranging from 1.3% to 62.6%, but stained negatively for other endothelial and stem cell-associated markers. Isolated CD133(+) cells expanded up to 4.6-fold in serum-replenished cultures and coexpressed the GalNAcalpha1-O-Ser/Thr MUC-1 glycoform, a well-characterized tumor-associated antigen. Dissociated bulk tumors formed sphere-like structures; cells grown as tumor spheres maintained CD133 expression and could be propagated for up to 12 weeks. CD133(+) cells purified from endometrioid adenocarcinomas were resistant to cisplatin-induced and paclitaxel-induced cytotoxicity and expressed a peculiar gene signature consisting of high levels of matrix metalloproteases, interleukin-8, CD44, and CXCR4. When serially transplanted into NOD/SCID mice, CD133(+) cells were capable of initiating tumor formation and recapitulating the phenotype of the original tumor.

CONCLUSIONS

CD133 is expressed by human endometrial cancers and might represent a valuable tool to identify cells with cancer stem cell characteristics.