Tumor necrosis factor-alpha mRNA and protein in endometrial tumors: analysis by in situ hybridization and immunocytochemistry

TNFα signalling predicts poor prognosis of patients with endometrial cancer

Endometrial cancer (EC) is the most common gynaecologic tumour in the Western world. Previous studies have implicated an imbalance of oestrogens and progestogens in the development of most ECs, while the role of low-grade tissue inflammation remains largely unexplored. We investigated the impact of tumour necrosis factor alpha (TNFα), a central mediator of inflammation and spermatogenesis-associated protein 2 (SPATA2), a regulator of TNF receptor signalling, on clinical outcomes in EC. We evaluated TNFA and SPATA2 transcript levels in 239 EC patients and 25 non-malignant control tissues. Findings were validated in a cohort of 332 EC patients from The Cancer Genome Atlas (TCGA). Expression of TNFA and SPATA2 was increased in EC when compared with control tissues (P < 0.001). TNFA expression correlated with SPATA2 expression in non-malignant (P = 0.003, rS = 0.568) and EC tissue (P = 0.005, rS = 0.179). High TNFA and SPATA2 expression were associated with poor recurrence-free survival (RFS; P = 0.049 and P = 0.018) and disease-specific (P = 0.034 and P = 0.002) survival. Increased SPATA2 expression was also associated with decreased overall survival (OS; P = 0.013). In multivariate analysis, both TNFA and SPATA2 were predictors of clinical outcome. The impact of SPATA2 on RFS and OS could be validated in the TCGA cohort. Our study demonstrates that ECs exhibit a TNF signature which predicts clinical outcome. These findings indicate that TNF signalling modulates the course of EC, which could be therapeutically utilized in the future.

The clinical significance of inflammatory cytokines in primary cell culture in endometrial carcinoma

Endometrial cancer is the most common malignancy of the female genital tract, and the incidence and mortality rates from this disease are increasing. Although endometrial carcinoma has been regarded as a tissue-specific disease mediated by female sex steroid pathways, considerable evidence implicates a role for an inflammatory response in the development and propagation of endometrial cancer. We hypothesized that if specific patterns of cytokine expression were found to be predictive of adverse outcome, then selective receptor targeting may be a therapeutic option. This study was therefore undertaken to determine the relationship between cytokine production in primary cell culture and clinical outcome in endometrial adenocarcinoma. Fresh endometrial tissues were fractionated into epithelial and stromal fractions and cultured. After 6-7 days, supernatants were collected and cells enumerated. Batched aliquots were assayed using ELISA kits specific for CSF-1, GMCSF, G-CSF, TNF-α, IL-6, IL-8, and VEGF. Data were compared using ANOVA, Fisher's exact, and log rank tests. Increased epithelial VEGF production was observed more often in tumors with Type 2 variants (p = 0.039) and when GPR30 receptor expression was high (p = 0.038). Although increased stromal VEGF production was detected more often in grade 3 endometrioid tumors (p = 0.050), when EGFR expression was high (p = 0.003), and/or when ER/PR expression was low (p = 0.048), VEGF production did not correlated with overall survival (OS). Increased epithelial CSF-1 and TNF-α production, respectively, were observed more often in tumors with deep myometrial invasion (p = 0.014) and advanced stage (p = 0.018). Increased CSF-1 (89.5% vs. 42.9%, p = 0.032), TNF-α (88.9% vs. 42.9%, p = 0.032, and IL-6 (92.3% vs. 61.5%, p = 0.052) also correlated with low OS. In Cox multivariate models, CSF-1 was an independent predictor of low survival when stratified by grade (p = 0.046) and histology (p = 0.050), and TNF-α, when stratified by histology (p = 0.037). In this study, high CSF-1, TNF-α, and IL-6 production rates identified patients at greatest risk for death, and may signify patients likely to benefit from receptor-specific therapy.

Association between polymorphism of the tumor necrosis factor alpha-308 gene promoter and colon cancer in the Chinese population

Tumor necrosis factor (TNF) is a type of cytokine that inhibits tumorigenesis. Several studies have assessed the relationship between the polymorphism of TNF-alpha 308G/A and the susceptibility to colon cancer; however, the results have been controversial. A case-control study was carried out to investigate whether TNF-alpha 308G/A gene polymorphism was associated with the risk of colon cancer in a group of 180 cases and 180 controls from Heilongjiang, China. DNA was isolated from peripheral blood, and gene polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism. Results of our study showed that colon cancer cases had a significantly higher frequency of TNF-alpha 308AA genotype (odds ratio=9.42, 95% confidence interval=1.18, 75.15; p=0.03) than controls. When stratified by the tumor location, tumor size, growth pattern, differentiation, and stage of colon cancer, no statistically significant results was observed. The present study demonstrated that TNF-alpha 308AA genotype was associated with a higher risk of colon cancer in the Chinese population. Confirmation of these findings in other populations is required.

Endometrial cancer invasion depends on cancer-derived tumor necrosis factor-alpha and stromal derived hepatocyte growth factor

Cancer invasion is an outcome of interactions of the cancer and the host cell. It is now becoming increasingly clear that ovarian hormones have a huge influence on such intercommunications in various types of cancers. Estrogen is known to aggravate the aggressiveness of the endometrial cancer whereas progesterone seems to act as a negative factor. Insight into the mode of ovarian hormonal actions could come from the studies of its regulation of the paracrine interactions between the endometrial cancer and the normal stromal cells during the cancer invasion. In this context, we report here that estrogen promotes the endometrial cancer invasion by inducing humoral interactions between the cancer and the stromal cells, i.e., estrogen stimulates tumor necrosis factor-alpha expression from the endometrial cancer cells, which, in turn, induces the stromal expression of hepatocyte growth factor (HGF), conferring the enhanced NK4 (HGF-antagonist/angiogenesis inhibitor)-sensitive invasion characteristic of the endometrial cancer cells. Additionally, we demonstrate a close correlation of the invasion of endometrial cancer cells with the expression and dimerization of integrin alpha(v)beta(5) as well as the activation of focal adhesion kinase as the consequences of paracrine interactions. Thus, understanding of paracrine interactions of cancer cells with host stromal cells can yield new insight into the architecture and function of cancer invasion and metastasis, leading to a development of a new cancer therapeutic intervention.

Regulation of contractility of cultured human endometrial stromal cells by tumor necrosis factor-alpha

OBJECTIVE

The aim of this study is to evaluate the involvement of tumor necrosis factor (TNF)-alpha in endometrial tissue remodeling during the perimenstrual period.

STUDY DESIGN

Human endometrial stromal cells (ESCs) were isolated from eight premenopausal patients in the late secretory phase. The effects of TNF-alpha on the contractility of cultured ESCs were investigated by collagen gel contraction assay. The effects of TNF-alpha on the proliferation of ESCs were also assessed by a modified methylthiazoletetrazolium assay.

RESULTS

TNF-alpha significantly upregulated the collagen gel contractility of ESCs in a dose-dependent manner. TNF-alpha did not affect ESC proliferation.

CONCLUSION

The results suggest that TNF-alpha may promote endometrial tissue repair by stimulating the contraction of the extracellular matrix by ESCs. By regulating ESC function during the perimenstrual period, TNF-alpha may be involved in the physiological tissue remodeling of the cyclic endometrium.

Evaluation of the associations between the single nucleotide polymorphisms of the promoter region of the tumor necrosis factor-alpha gene and nasopharyngeal carcinoma

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is a pro-inflammatory cytokine and may act as an endogenous tumor promoter. Single nucleotide polymorphisms (SNPs) of the TNF-alpha gene promoter region have been found to be associated with certain cancers. We conducted a case-control study to evaluate the association between these SNPs and nasopharyngeal carcinoma (NPC).

METHODS

We used polymerase chain reaction followed by restriction fragment length polymorphism analysis to determine the -308 TNF-alpha promoter genotypes of 89 NPC patients and 360 healthy controls. In 23 NPC patients and 50 controls, we determined the sequence from -1065 to -101 nucleotides of the TNF-alpha gene promoter region to detect SNPs.

RESULTS

In comparison with the controls, the NPC patients had higher proportions of men and carriage of IgA antibodies against the capsid antigen of Epstein-Barr virus, but had a similar carrier rate of the -308A allele (odds ratio [OR], 1.2; 95% confidence interval [CI], 0.7-2.0). The carriage of the -308A allele was not associated with the occurrence of NPC in comparison with -308G homozygosity. We also found no significant differences in the distributions of allelic variants of the -1031, -863, -857, and -806 loci of the TNF-alpha promoter region, but observed a lower carrier rate of the novel -806T allele in the NPC patients (OR, 0.3; 95% Cl, 0.0-2.9).

CONCLUSION

Allelic variants of the TNF-alpha promoter gene may not be used as biomarkers of susceptibility to NPC. The role of the -806T allele needs to be studied further.

Apoptosis and apoptosis-related factors Bcl-2, Bax, tumor necrosis factor-alpha, and NF-kappaB in human endometrial hyperplasia and carcinoma

BACKGROUND

Apoptosis controls cell homeostasis in the endometrium during normal menstrual cycles, and morphologic studies have suggested its association with the development of endometrial carcinoma. Apoptosis is regulated by several genes, especially those of the Bcl-2 gene family, but their significance in endometrial pathologies is not well understood.

METHODS

To study the role and regulation of apoptosis in endometrial hyperplasia and carcinoma, human endometrial specimens were analyzed using in situ 3'-end labeling of apoptotic cells and in situ hybridization and immunohistochemistry of apoptosis-related factors.

RESULTS

Apoptosis was scarce in normal proliferating endometrium as well as in simplex, complex, and atypical hyperplasia and was low in Grade I adenocarcinoma. In Grade II adenocarcinoma a significant increase in the rate of apoptosis was observed. Apoptosis decreased in Grade III adenocarcinoma, but it was still higher than in normal or hyperplastic endometrium. Bcl-2 and Bax were expressed in normal and hyperplastic endometrium, and the Bcl-2/Bax ratio was lower in endometrial carcinoma. Tumor necrosis factor-alpha was expressed in normal endometrium and simplex and complex hyperplasia, but it was down-regulated in atypical hyperplasia and endometrial carcinoma. The transcription factor NF-kappaB was present in proliferating endometrium and in endometrial hyperplasia, but its expression was lower in carcinoma.

CONCLUSIONS

In endometrial proliferation and hyperplasia a low rate of apoptosis is present. In Grade I carcinoma the rate of apoptosis is decreased, but the rate is subsequently increased in advanced carcinoma. The decrease in the rate of apoptosis in Grade III adenocarcinoma may reflect loss of control of cell homeostasis, decreased differentiation, and increased malignancy.

CD8+ T cells in human uterine endometrial lymphoid aggregates: evidence for accumulation of cells by trafficking

Lymphoid aggregates (LA) develop during the proliferative phase of the menstrual cycle in the human uterine endometrium (EM). They contain mostly CD8+ T cells and B cells. As these LA are absent immediately following menses, they may arise by division of cells resident in the EM, or by division of a limited number of precursor cells that traffic into the EM during the early proliferative phase of the menstrual cycle. Alternatively, they may arise by the continuous trafficking of cells into the EM throughout the proliferative phase of the menstrual cycle. In this study we investigated the distribution and frequency of CD8+ T cells in the aggregates using expression of Vbeta2 or Vbeta8 as markers of clonality and Ki-67 as a marker of dividing cells. Confocal microscopic analysis of endometrial tissues showed the random distribution of CD8+ T cells within aggregates within the same sample and in aggregates from different samples. Furthermore, comparisons of the distribution of Vbeta2 and Vb8 with expected values predicted from Poisson distribution values were not significantly different, suggesting that CD8+ T cells do not arise by division from single precursors. A low level of T-cell division within LAs was confirmed by positive staining for Ki-67. Dividing T cells were randomly dispersed throughout the LA and the frequency of dividing cells did not vary greatly between aggregates within the same tissue. Nearest-neighbour analysis of dividing cells showed no statistically significant deviations from a random distribution. Taken together, these results suggest that LA develop during the menstrual cycle largely by the trafficking of cells to nucleation sites within the EM, rather than by division of a limited number of precursor cells.

An inverse relation between the expression of tumor necrosis factor alpha (TNF-alpha) and TNF-alpha receptor in human endometrium

PROBLEM

To determine whether the expression of tumor necrosis factor (TNF-alpha) correlates with TNF-alpha receptor expression in human endometrium.

METHOD OF STUDY

A multiprimer synthetic cDNA standard template containing complimentary sequences for several cytokines including TNF-alpha and TNF-alpha receptor type 2 was constructed and used in quantitative reverse transcription polymerase chain reaction (Q-RT-PCR).

RESULTS

Endometrium from proliferative phase of the menstrual cycle expresses higher levels of TNF-alpha mRNA (2.35 +/- 0.2 x 10(5) copies/microg of total cellular RNA) than secretory phase ([1.3 +/- 0.08 x 10(5) copies] P < 0.05), with a significant reduction during menses (1.2 +/- 0.1 x 10(4) copies) and postmenopausal period (8.1 +/- 1.6 x 10(4) copies [P < 0.05]). In contrast, TNF-alpha type 1 receptor mRNA expression was higher in endometrium from the secretory phase (6.6 +/- 0.6 x 10(7) copies) compared to the menses (5.1 +/- 0.5 x 10(6) copies), proliferative phase (1.9 +/- 0.1 x 10(6) copies) and postmenopausal period (5.8 +/- 0.7 x 10(4) copies [P < 0.05]). Comparatively, TNF-alpha receptor type 2 is expressed 10 to 100 fold higher in the endometrium than TNF-alpha (P < 0.05).

CONCLUSION

The data confirm that human endometrium expresses TNF-alpha; and provide the first evidence that TNF-alpha expression is inversely related to TNF-alpha type 1 receptor expression during the menstrual cycle. Such an inverse relation between TNF-alpha and TNF-alpha receptor expression may provide a regulatory mechanism necessary to overcome the detrimental effect of high levels of TNF-alpha on various endometrial cell types.

Expression of vascular permeability factor (vascular endothelial growth factor) and its receptors in endometrial carcinoma

BACKGROUND

Solid tumors, including endometrial carcinomas, must induce a vascular stroma to grow beyond a minimal size. The mechanisms responsible for angiogenesis in endometrial carcinoma, however, are not well defined. Vascular permeability factor (VPF), also known as vascular endothelial growth factor (VEGF), is a multifunctional cytokine that is an important regulator of tumor angiogenesis. We evaluated VPF/VEGF mRNA and protein expression, as well as VPF/VEGF receptor mRNA expression, in endometrial carcinoma.

METHODS

Fourteen examples of endometrial carcinoma were evaluated by in situ hybridization; in 7 cases, benign atrophic endometrium from the same patient was also examined. Histologic sections were subjected to in situ hybridization using 35S-labeled riboprobes specific for VPF/VEGF and, in a subset of cases, riboprobes specific for the VPF/VEGF receptors flt-1 and KDR. In addition, ten examples of endometrial carcinoma were evaluated for VPE/VEGF protein expression by immunohistochemistry.

RESULTS

All 14 examples of endometrial carcinoma studied by in situ hybridization exhibited focal strong VPF/VEGF mRNA expression by tumor cells. In addition, the endothelial cells of surrounding microvessels strongly expressed flt-1 and KDR mRNAs in all ten cases examined. In contrast, no strong expression of VPF/VEGF, flt-1, or KDR mRNA was observed in the seven examples of benign atrophic endometrium studied. All ten cases of endometrial carcinoma studied by immunohistochemistry exhibited strong VPF/VEGF protein expression by tumor cells.

CONCLUSIONS

These observations suggest that VPF/VEGF is an important angiogenic factor in endometrial carcinoma.