Stromal p16 expression differentiates endometrial polyp from endometrial hyperplasia

Stromal p16 and SATB2 Expression Does Not Distinguish Atypical Polypoid Adenomyoma (APA) From its Benign Mimics

Atypical polypoid adenomyoma (APA) is a polypoid biphasic lesion of low malignant potential that arises in the lower uterine segment and uterine corpus. The diagnosis of APA is often challenging on biopsy and curettage specimens, and both benign and malignant processes need to be considered in the differential. Stromal expression of p16 and SATB2 have recently been shown to distinguish APA from myoinvasive endometrioid carcinoma. The authors hypothesized that p16 and SATB2 immunohistochemistry could also aid in the distinction of APA from benign adenomyomatous polyp and endometrioid adenomyoma. The study comprised 10 APAs, 7 adenomyomatous polyps, 11 endometrioid adenomyomas, and 10 myoinvasive endometrioid carcinomas. The majority of APAs showed moderate to strong, diffuse p16 and stromal expression. However, most adenomyomatous polyps and endometrioid adenomyomas also exhibited moderate to strong, focal to diffuse p16 stromal expression. SATB2 showed weak to moderate, focal to diffuse expression in the majority of APAs, adenomyomatous polyps and endometrioid adenomyomas. In contrast, p16 and SATB2 were negative to weak and focal in 90% of myoinvasive endometrioid carcinomas. Our findings demonstrate that p16 and SATB2 may be helpful in the differential diagnosis of myoinvasive endometrioid carcinoma and APA while not useful in separating APA from adenomyomatous polyp and endometrioid adenomyoma.

Senescent Stromal Cells in the Tumor Microenvironment: Victims or Accomplices?

Cellular senescence is a unique cellular state. Senescent cells enter a non-proliferative phase, and the cell cycle is arrested. However, senescence is essentially an active cellular phenotype, with senescent cells affecting themselves and neighboring cells via autocrine and paracrine patterns. A growing body of research suggests that the dysregulation of senescent stromal cells in the microenvironment is tightly associated with the development of a variety of complex cancers. The role of senescent stromal cells in impacting the cancer cell and tumor microenvironment has also attracted the attention of researchers. In this review, we summarize the generation of senescent stromal cells in the tumor microenvironment and their specific biological functions. By concluding the signaling pathways and regulatory mechanisms by which senescent stromal cells promote tumor progression, distant metastasis, immune infiltration, and therapy resistance, this paper suggests that senescent stromal cells may serve as potential targets for drug therapy, thus providing new clues for future related research.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosome Repairs Endometrial Epithelial Cells Injury Induced by Hypoxia via Regulating miR-663a/CDKN2A Axis

Aim

Thin endometrium remains a severe clinical challenge with no effective therapy to date. We aimed at exploring the role and molecular mechanism of human umbilical cord mesenchymal stem cell- (hucMSC-) derived exosomes (hucMSC-Ex) in repairing hypoxic injury of endometrial epithelial cells (EECs).

Methods

Exosomes were harvested from the conditioned medium of hucMSC and characterized using western blot, transmission electron microscopy (TEM), flow cytometry, and nanoparticle tracking analysis (NTA). EECs were subjected to hypoxic conditions before cocultured with hucMSC-Ex. Cell viability, apoptosis, and migration were determined with CCK-8, flow cytometry, and wound healing assay, respectively. Apoptosis/EMT-related proteins were detected by western blot. The miRNA profiling was determined by RNA sequencing. The expression of miR-663a and CDKN2A was measured by qRT-PCR. MiR-663a in EECs was overexpressed by transfecting with miR-663a mimics.

Results

Mesenchymal stem cells (MSCs) markers CD73, CD90, and CD106 were positively expressed in hucMSCs. Exosome isolated from hucMSC expressed CD63 and TSG101, and were 100-150 nm in diameter. HucMSC-Ex promoted cell proliferation inhibited by hypoxia. And hucMSC-Ex also inhibited hypoxia-induced apoptosis, migration, and EMT of EECs by upregulating the expression of Bcl-2 and E-cadherin and downregulating Bax and N-cadherin levels. Further, bioinformatics research found that hucMSC-Ex coculture can significantly upregulate the expression of miR-663a and decrease the expression of CDKN2A in hypoxia-induced EECs. Furthermore, miR-663a overexpression inhibited CDKN2A expression and increased the expression of Bcl-2 and E-cadherin in hypoxia-induced EECs.

Conclusions

HucMSC-Ex promoted cell proliferation, inhibited cell apoptosis, migration, and EMT in hypoxia-induced EECs, thereby alleviating hypoxia-induced EECs injury, which may be related to its regulation of miR-663a/CDKN2A expression. Our study indicated that hucMSC-Ex might benefit for repairing thin endometrium.

Altered p16Ink4a, IL-1β, and Lamin b1 Protein Expression Suggest Cellular Senescence in Deep Endometriotic Lesions

Endometriosis causes immunological and cellular alterations. Endometriosis lesions have lower levels of lamin b1 than the endometrium. Moreover, high levels of pro-inflammatory markers are observed in the peritoneal fluid, follicular fluid, and serum in endometriosis lesions. Thus, we hypothesized that the accumulation of senescent cells in endometriosis tissues would facilitate endometriosis maintenance in an inflammatory microenvironment. To study senescent cell markers and the senescence-associated secretory phenotype (SASP) in endometriosis lesions, we conducted a cross-sectional study with 27 patients undergoing video laparoscopy for endometriosis resection and 19 patients without endometriosis. Endometriosis lesions were collected from patients with endometriosis, while eutopic endometrium was collected from patients both with and without endometriosis. Tissues were evaluated for senescence markers (p16Ink4a, lamin b1, and IL-1β) and interleukin concentrations. The expression of p16Ink4a increased in lesions compared to that in eutopic endometrium from endometriosis patients in the secretory phase. In the proliferative phase, lesions exhibited lower lamin b1 expression but higher IL-4 expression than the eutopic endometrium. Further, IL-1β levels were higher in the lesions than in the eutopic endometrium in both the secretory and proliferative phases. We believe that our findings may provide targets for better therapeutic interventions to alleviate the symptoms of endometriosis.

Breast Cancer and p16: Role in Proliferation, Malignant Transformation and Progression

The definition of new molecular biomarkers could provide a more reliable approach in predicting the prognosis of invasive breast cancers (IBC). The aim of this study is to analyze the expression of p16 protein in IBC, as well as its participation in malignant transformation. The study included 147 patients diagnosed with IBC. The presence of non-invasive lesions (NIL) was noted in each IBC and surrounding tissue. p16 expression was determined by reading the percentage of nuclear and/or cytoplasmic expression in epithelial cells of IBC and NIL, but also in stromal fibroblasts. Results showed that expression of p16 increases with the progression of cytological changes in the epithelium; it is significantly higher in IBC compared to NIL (p < 0.0005). Cytoplasmic p16 expression is more prevalent in IBC (76.6%), as opposed to nuclear staining, which is characteristic of most NIL (21.1%). There is a difference in p16 expression between different molecular subtypes of IBC (p = 0.025). In the group of p16 positive tumors, pronounced mononuclear infiltrates (p = 0.047) and increased expression of p16 in stromal fibroblasts (p = 0.044) were noted. In conclusion, p16 protein plays an important role in proliferation, malignant transformation, as well as in progression from NIL to IBC.

Patterns of SATB2 and p16 reactivity aid in the distinction of atypical polypoid adenomyoma from myoinvasive endometrioid carcinoma and benign adenomyomatous polyp on endometrial sampling

AIMS

Atypical polypoid adenomyoma (APAM) is an uncommon uterine lesion composed of complex endometrioid glands with frequent squamous morular metaplasia and fibromuscular stroma. On endometrial curettage, biopsy or polypectomy specimens, the admixture of endometrioid glands and smooth muscle raises the differential diagnosis of myoinvasive endometrioid carcinoma. Reproductive-age APAM patients may opt for fertility preservation, whereas myoinvasive carcinoma is treated surgically. One previous study reported an incidental finding that the stroma of APAM, in contrast to that of other polypoid lesions, was SATB2-positive. APAM has also been reported to show increased stromal p16 staining. We aimed to assess whether SATB2 and p16 are useful stains for the distinction of APAM from myoinvasive carcinoma and benign adenomyomatous polyps.

METHODS AND RESULTS

Cases of 'atypical polypoid adenomyoma' (n = 32), 'adenomyomatous polyp' (n = 39) and 'myoinvasive endometrioid carcinoma' (n = 30) were identified. Morphological features were assessed, along with the intensity and extent of SATB2 and p16 staining in the stromal component of each lesion. SATB2 expression was seen in the stromal components of 30 of 32 (94%) APAMs, versus none of 39 (0%) benign adenomyomatous polyps and five of 30 (17%) myoinvasive endometrioid carcinomas. Stromal p16 expression was seen in 31 of 31 (100%) APAMs, versus 20 of 39 (51%) benign adenomyomatous polyps and 12 of 30 (40%) myoinvasive endometrioid carcinomas.

CONCLUSIONS

Patchy to diffuse SATB2 and block-type p16 staining of fibromuscular stroma separating atypical endometrioid glands is more consistent with APAM than with myoinvasive endometrioid carcinoma. These stains are potentially useful adjuncts to careful morphological evaluation of endometrial biopsies/curettings.

Decreased number of p16-positive senescent cells in human endometrium as a marker of miscarriage

PURPOSE

The aim of this study was to evaluate whether the number of p16-positive cells in the functional layer of the endometrium could be a useful biomarker to identify women with recurrent implantation failure (RIF) undergoing in vitro fertilization (IVF) at risk of miscarriage.

METHODS

Immunohistochemical staining was performed in 311 endometrial biopsies taken during mid-luteal phase using antibody against p16^INK4A. The percentage of p16-positive cells was determined in luminal, glandular and stromal endometrial cells. After embryo transfer, women were divided into the following groups: unsuccessful embryo implantation (n = 151), miscarriage (n = 66) and live birth (n = 94). The percentage of p16-positive cells in all endometrial compartments was compared among these groups.

RESULTS

We found that the percentages of p16-positive glandular and luminal epithelial endometrial cells were significantly higher in patients with live births compared to women with miscarriage (9.3% vs. 2.9%, P < 0.001; and 35.2% vs. 11.7%, P = 0.001, respectively). This tendency was not confirmed in thе stroma. The cut-off values with p16-positive luminal cells lower than 12.5% and p16-positive glandular cells lower than 3.2% could be predictive factors for miscarriage (AUC 0.80 and 0.79; sensitivity 71.3% and 74.5%; specificity 74.2% and 71.2%, respectively).

CONCLUSION

A decreased number of senescent p16-positive cells could be involved in the implantation failures and aetiology of recurrent miscarriage. Women with history of RIF with reduced populations of p16-positive cells in the endometrial glandular and luminal epithelium may be at greater risk for unsuccessful implantation and miscarriage. The percentage of p16-positive luminal epithelial cells may be clinically useful as a biomarker of miscarriage.

Phenotyping of immune and endometrial epithelial cells in endometrial carcinomas revealed by single-cell RNA sequencing

Tumors are complex ecosystems harboring multiple cell types which might play a critical role in tumor progression and treatment response. The endometrial epithelial cell identities and immune microenvironment of endometrial carcinoma (ECC) are poorly characterized. In this study, a cellular map of endometrial carcinoma was generated by profiling 30,780 cells isolated from tumor and paratumor tissues from five patients using single-cell RNA sequencing. 7 cell types in lymphocytes, 7 types in myeloid cells and 3 types in endometrial epithelial cells were identified. Distinct CD8⁺ T cell states and different monocyte-macrophage populations were discovered, among which exhausted CD8⁺ T cells and macrophages were preferentially enriched in tumor. Both CD8⁺ T cells and macrophages comport with continuous activation model. Gene expression patterns examination and gene ontology enrichment analysis of endometrial epithelial cells revealed 3 subtypes: stem-like cells, secretory glandular cells and ciliated cells. Overall, our study presents a view of endometrial carcinoma at single-cell resolution that reveals the characteristics of endometrial epithelial cells in the endometrium, and provides a cellular landscape of the tumor immune microenvironment.

Depleted lamin B1: a possible marker of the involvement of senescence in endometriosis?

PROPOSE

Endometriosis is a benign disease characterized by implantation and the growth of endometrial tissue outside the uterine cavity and it shares similarities with cancer. Lamin B1, p16 and p21 play a role on cell cycle regulation, development, cell repair and its activities are related to cancers. Considering the similarities between endometriosis and cancer, the aim of the present cross-sectional study is to detect p16, p21 and Lamin B1 in the ectopic endometrium of patients with endometriosis (n = 8) with eutopic (n = 8) and control endometrium (n = 8) and relate them to the maintenance and development of endometriosis.

METHODS

Biopsies were obtained from both eutopic and ectopic, from deep infiltrating lesions, endometrium frozen and used for immunofluorescent (p16) or immunohistochemistry procedures (p16, p21, lamin B1).

RESULTS

Detected higher lamin B1 in the eutopic endometrium when compared with ectopic endometrium, with no differences between endometriosis tissue with control endometrium. Similar presence of p16 in all groups of patients and no p21 detection was observed.

CONCLUSION

We observed reduced detection of lamin B1 in the ectopic endometrium raising the possibility that the presence of senescent cells might be contributing to the maintenance and progression of endometriosis by apoptosis resistance and peritoneal stress inherent of the disease.

Stromal p16 expression is significantly increased in malignant ovarian neoplasms

Alterations in p16 protein expression have been reported to be associated with tumor development and progression. However, p16 expression status in the peritumoral stroma has been rarely investigated. We investigated the stromal p16 expression in ovarian neoplasms using immunohistochemistry, and differences in the expression status depending on the degree of malignancy and histological type were analyzed. This study included 24, 21, and 46 cases of benign, borderline, and malignant ovarian lesions, respectively, of which 29, 25, and 32 cases were serous, mucinous, and endometriosis-associated lesions. Most benign lesions showed negative or weak expression, whereas borderline lesions showed focal, moderate expression. Malignant lesions showed markedly elevated stromal p16 expression compared with benign or borderline lesions. There were significant differences in stromal p16 expression between benign and borderline lesions (P < 0.001) and between borderline and malignant lesions (P < 0.001). These significances remained when analysis was performed based on lesion classification as serous, mucinous, and endometriosis-associated. In contrast, differences in stromal p16 expression among the histological types were not significant. Stromal p16 expression in ovarian neoplasms was absent or weak in benign and focal, moderate in borderline lesions, whereas malignant lesions exhibited diffuse, moderate-to-strong p16 immunoreactivity. Our observations suggest that stromal p16 expression is involved in the development of ovarian carcinoma. Further studies are necessary to confirm our preliminary results.

Stromal p16 expression is significantly increased in endometrial carcinoma

p16 is a negative regulator of cell proliferation and is considered a tumor suppressor protein. Alterations in p16 protein expression are associated with tumor development and progression. However, the p16 expression status in the peritumoral stroma has not been investigated in the endometrium. Therefore, we evaluated stromal p16 expression in different types of endometrial lesions using immunohistochemistry. Differences in the p16 expression status according to the degree of malignancy and histological type were analyzed. This study included 62, 26, and 36 cases of benign, precancerous, and malignant endometrial lesions, respectively. Most benign lesions showed negative or weak expression, whereas precancerous lesions showed a variable degree of staining proportion and intensity. Atypical hyperplasia/endometrial intraepithelial neoplasia (AH/EIN) and serous endometrial intraepithelial carcinoma (SEIC) had significantly higher stromal p16 expression levels than benign lesions. Endometrioid carcinoma (EC), serous carcinoma (SC), and carcinosarcoma showed significantly elevated stromal p16 expression levels compared with benign and precancerous lesions. In addition, there were significant differences in stromal p16 expression between AH/EIN and SEIC and between EC and SC. In contrast, differences in stromal p16 expression among nonpathological endometrium, atrophic endometrium, endometrial polyp, and hyperplasia without atypia were not statistically significant. Our observations suggest that stromal p16 expression is involved in the development and progression of endometrial carcinoma, and raise the possibility that p16 overexpression in the peritumoral stroma is associated with aggressive oncogenic behavior of endometrial SC.

Forkhead-box A1 induces cell senescence in endometrial cancer by regulating p16INK4a

We previously identified FOXA1 as a tumor-suppressor in EC cells. In the present study, we sought to delineate the different roles of FOXA1 associated with cell senescence and further investigated the correlation between FOXA1 and p16INK4a in the progression of EC. Using reverse transcription-quantitative PCR (RT-qPCR), we found that FOXA1 expression was significantly downregulated in EC cells compared to that in normal endometrial cells. Functionally, senescence‑associated β-galactosidase staining, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clonogenic and Transwell assays showed that in addition to acting as a pioneer factor, FOXA1 was significantly upregulated in senescent EC cells. Furthermore, restoration of FOXA1 expression triggered multiple steps of cellular senescence in EC cells and activated p16INK4a expression. All of these findings indicate that FOXA1 promotes cell senescence in EC by interaction with p16INK4a, possibly via the AKT pathway. Notably, a selective PI3K inhibitor raised the possibility that FOXA1‑induced senescence is associated with the AKT pathway in EC cells. Collectively, the present study provides a conceivable molecular mechanism by which cell senescence acts as the barrier to EC, and is regulated by FOXA1-induced p16INK4a expression. This may be a newly identified regulatory mechanism of cell senescence in EC.