Canonical and noncanonical Wnt pathways: a comparison between endometrial cancer type I and atrophic endometrium in Brazil

Association of Membranous WNT-1 and Nuclear mTOR with Endometrial Cancer Grade

Endometrial cancer remains a common cancer affecting the female reproductive system. There is still a need for more efficient ways of determining the degree of malignancy and optimizing treatment. WNT and mTOR are components of signaling pathways within tumor cells, and dysfunction of either protein is associated with the pathogenesis of neoplasms. Therefore, the aim of our study was to assess the impact of subcellular WNT-1 and mTOR levels on the clinical course of endometrial cancer. WNT-1 and mTOR levels in the plasma membrane, nucleus, and cytoplasm were evaluated using immunohistochemical staining in a group of 64 patients with endometrial cancer of grades 1-3 and FIGO stages I-IV. We discovered that the levels of WNT-1 and mTOR expression in the cellular compartments were associated with tumor grade and staging. Membranous WNT-1 was negatively associated, whereas cytoplasmic WNT-1 and nuclear mTOR were positively associated with higher grading of endometrial cancer. Furthermore, nuclear mTOR was positively associated with FIGO stages IB-IV. To conclude, we found that the assessment of WNT-1 in the cell membrane may be useful for exclusion of grade 3 neoplasms, whereas cytoplasmic WNT-1 and nuclear mTOR may be used as indicators for confirmation of grade 3 neoplasms.

Cancer chemoprevention through Frizzled receptors and EMT

Frizzled (FZD) transmembrane receptors are well known for their role in β-catenin signaling and development and now understanding of their role in the context of cancer is growing. FZDs are often associated with the process of epithelial to mesenchymal transition (EMT) through β-catenin, but some also influence EMT through non-canonical pathways. With ten different FZDs, there is a wide range of activity from oncogenic to tumor suppressive depending on the tissue context. Alterations in FZD signaling can occur during development of premalignant lesions, supporting their potential as targets of chemoprevention agents. Agonizing or antagonizing FZD activity may affect EMT, which is a key process in lesion progression often targeted by chemoprevention agents. Recent studies identified a specific FZD as important for activity of an EMT inhibiting chemopreventive agent and other studies have highlighted the previously unrecognized potential for targeting small molecules to FZD receptors. This work demonstrates the value of investigating FZDs in chemoprevention and here we provide a review of FZDs in cancer EMT and their potential as chemoprevention targets.

Changes in the expression of Notch and Wnt signalling molecules in human endometrial cancer

Background

Endometrial cancer is the  sixth most frequent type of cancer among women worldwide. Type  I adenocarcinomas account for 80-85% of endometrial cancer cases and sometimes require more aggressive treatment than the remaining part of this group. Therefore, molecular markers to stratify adenocarcinomas are needed.

Materials and methods

In this study, we analysed Notch and Wnt signalling in human endometrial cancer cases to evaluate these pathway elements as potential biomarkers for type  I endometrial cancer. Endometrial samples were obtained from 47 women undergoing surgery for stage I-IV endometrial cancer in the National Cancer Institute (Vilnius, Lithuania) in 2015-2016. The expression at the mRNA level of signalling molecules genes (NOTCH1, NOTCH2, NOTCH3, NOTCH4, JAG1, JAG2, DLL1, HES1, AXIN2 and CTNNB1) was analysed by the quantitative real-time polymerase chain reaction. Relative expression of NOTCH1, NOTCH4, HES1 and β-catenin proteins in endometrioid adenocarcinoma was evaluated by the Western blot method.

Results

The  expression level of Notch receptors, ligands, and the target gene, as well as CTNNB1 and AXIN2, was reduced in stage I endometrioid adenocarcinoma if compared to the adjacent non-tumour tissue. The expression of all receptors, ligands, and target molecules was reduced in adenocarcinomas of later stages. The statistically significant correlations between transcript amounts of Notch receptors and ligands were found. There was a statistically significant difference in the  gene expression of Notch signalling pathway components between different tumour differentiation grade samples. A positive correlation between mRNA and protein the expression level of NOTCH1, NOTCH4, HES1 was determined in stage I samples.

Conclusions

Analysis of 47 human endometrial cancer samples revealeda reduction in the transcript levels of Notch and Wnt signalling molecule compared to the adjacent non-tumour tissue. These results suggest tumour suppressor function of Notch and Wnt signalling in human endometrial cancer. More detailed research on these signalling pathways should reveal their importance as potential biomarkers.

Role of WNT5A receptors FZD5 and RYK in prostate cancer cells

Prostate cancer is the most common malignancy in men and has a high propensity to metastasize to bone. WNT5A has recently been implicated in the progression of prostate cancer, however, the receptors that mediate its effects remain unknown. Here, we identified Wnt receptors that are highly expressed in prostate cancer and investigated which of these receptors mediate the anti-tumor effects of WNT5A in prostate cancer in vitro.

Extensive in vitro analyses revealed that the WNT5A receptors FZD5 and RYK mediate the anti-tumor effects of WNT5A on prostate cancer cells. Knock-down of FZD5 completely abrogated the anti-proliferative effect of WNT5A in PC3 cells. In contrast, knock-down of RYK and FZD8 did not rescue the inhibition of proliferation after WNT5A overexpression. In contrast, RYK knock-down inhibited the pro-apoptotic effect of WNT5A in PC3 cells by 60%, whereas the knock-down of either FZD5 or FZD8 further stimulated apoptosis after WNT5A overexpression (by 33% and 234%, respectively). Surface plasmon resonance analysis indicated that WNT5A has a 30% stronger binding response to FZD5 than to RYK. Further investigations using a tissue microarray revealed that expression of RYK is increased in advanced prostate cancer tumor stages, but is not associated with survival of prostate cancer patients. In contrast, patients with low local FZD5 expression, in particular in combination with low WNT5A expression, showed a longer disease-specific survival.

In conclusion, WNT5A/FZD5 and WNT5A/RYK signaling are both involved in mediating the pro-apoptotic and anti-proliferative effects of WNT5A in prostate cancer.

Molecular cues on obesity signals, tumor markers and endometrial cancer

Tumor markers are important tools for early diagnosis, prognosis, therapy response and endometrial cancer monitoring. A large number of molecular and pathologic markers have been described in types I and II endometrial cancers, which has served to define the main oncogenic, epidemiological, genetic, clinical and histopathological features. Ongoing attempts to stratify biological markers of endometrial cancer are presented. However, data on changes in tumor marker profiles in obesity-related endometrial cancer are scarce. Obesity is a pandemic in Western countries that has an important impact on endometrial cancers, albeit through not very well-defined mechanisms. Although endometrial cancer is more common in Caucasian women, higher mortality is found in African Americans who also show higher incidence of obesity. Here, we describe how obesity signals (estrogen, leptin, leptin induced-molecules, Notch; cytokines and growth factors) could affect endometrial cancer. Leptin signaling and its crosstalk may be associated to the more aggressive and poor prognosis type II endometrial cancer, which affects more postmenopausal and African-American women. In this regard, studies on expression of novel molecular markers (Notch, interleukin-1 and leptin crosstalk outcome) may provide essential clues for detection, prevention, treatment and prognosis.

Wnt signalling in gynaecological cancers: A future target for personalised medicine?

The three major gynaecological cancers, ovarian, uterine and cervical, contribute a significant burden to global cancer mortality, and affect women in both developed and developing countries. However, unlike other cancer types that have seen rapid advances and incorporation of targeted treatments in recent years, personalised medicine is not yet a reality in the treatment of gynaecological cancers. Advances in sequencing technology and international collaborations and initiatives such as The Cancer Genome Atlas are now revealing the molecular basis of these cancers, and highlighting key signalling pathways involved. One pathway which plays a role in all three cancer types, is the Wnt signalling pathway. This complex developmental pathway is altered in most human malignancies, and members of this pathway, particularly the recently linked ROR receptor tyrosine kinases may be attractive future therapeutic targets. This review provides an up-to-date summary of research into Wnt signalling and ovarian, uterine and cervical cancers, and discusses the potential of the Wnt pathway as a future target for personalised medicine in gynaecological cancers.

Down-regulated expression of Notch signaling molecules in human endometrial cancer

Notch signaling pathway is a highly conserved developmental pathway, which plays an important role in the regulation of cellular proliferation, differentiation and apoptosis. Deregulation of Notch pathway has been connected with the carcinogenesis in a variety of cancers. In this study, we investigated the expression of Notch receptors (NOTCH1, NOTCH2, NOTCH3 and NOTCH4), ligands (JAG1, JAG2 and DLL1) and target gene HES1. Fifty paired samples of endometrial cancer and adjacent nontumor endometrial tissue from endometrial cancer patients were analyzed by quantitative PCR. The mRNA levels of all investigated molecules were lower in endometrial cancer compared to adjacent nontumor tissue. The expression of NOTCH1, NOTCH4 and DLL1 in IB stage adenocarcinoma was significantly lower (P < 0.05) than the expression in IA stage adenocarcinoma. Significant correlations were found between mRNA expression levels of Notch target gene HES1 and several Notch signaling molecules: NOTCH1, NOTCH3, DLL1 (P < 0.001) and NOTCH2, JAG2 (P < 0.05). This supports the notion that Notch pathway can function as tumor suppressor in human endometrial cancer.