Expression of c-Kit and PDGFRα in epithelial ovarian tumors and tumor stroma

Characterization of stem cell and cancer stem cell populations in ovary and ovarian tumors

Background

Ovarian cancer is a complicated malady associated with cancer stem cells (CSCs) contributing to 238,700 estimated new cases and 151,900 deaths per year, worldwide. CSCs comprise a tiny fraction of tumor-bulk responsible for cancer recurrence and eventual mortality. CSCs or tumor initiating cells are responsible for self-renewal, differentiation and proliferative potential, tumor initiation capability, its progression, drug resistance and metastatic spread. Although several biomarkers are implicated in these processes, their distribution within the ovary and association with single cell type has neither been established nor demonstrated across ovarian tumor developmental stages. Therefore, precise identification, thorough characterization and effective targeted destruction of dormant and highly proliferating potent CSC populations is an immediate need.

Results

In view of this, distribution of various CSC (ALDH1/2, C-KIT, CD133, CD24 and CD44) and cell proliferation (KI67) specific markers in the ovarian surface epithelium (OSE) and cortex regions in normal ovary, and benign, borderline and high grade metastatic ovarian tumors by immuno-histochemistry and confocal microscopy was studied. We further confirmed their expression by RT-PCR analysis. Co-expression analysis of stem cell (OCT4, SSEA4) and CSC (ALDH1/2, CD44 and LGR5) markers with proliferation marker (KI67) in HG tumors revealed dual positive proliferating stem and CSCs, few non-proliferating stem/CSC (SSEA4⁺/KI67⁻ and ALDH1/2⁺/KI67⁻) and only KI67⁺ cells in cortex, signifying dynamic populations and interesting cellular hierarchy in cortex region. Smaller spherical (≤ 5 μm) and larger spindle/elliptical shaped (~ 10 μm) cell populations with high nucleo-cytoplasmic ratio were detected across all samples (including normal ovaries) but with variable distribution and characteristic stage-wise marker expression across different tumor stages.

Conclusions

Diverse stem and CSC populations expressing characteristic markers revealing distinct phenotypes (spherical ≤5 μm and spindle/elliptical ~ 10 μm) were distributed within different tumor stages studied signifying dynamic and probable functional hierarchy within these cell types. Involvement of extra-ovarian sites of origin of stem and CSCs requires rigorous evaluation. Quantitative analysis of potent CSC populations, their mechanisms and pathways for self-renewal, chemo-resistance, metastatic spread etc. with respect to various markers studied, will provide better insights and targets for developing effective therapeutics to prevent metastasis and eventually help improve patient mortality.

Electronic supplementary material

The online version of this article (10.1186/s13048-018-0439-3) contains supplementary material, which is available to authorized users.

Progression inference for somatic mutations in cancer

Computational methods were employed to determine progression inference of genomic alterations in commonly occurring cancers. Using cross-sectional TCGA data, we computed evolutionary trajectories involving selectivity relationships among pairs of gene-specific genomic alterations such as somatic mutations, deletions, amplifications, downregulation, and upregulation among the top 20 driver genes associated with each cancer. Results indicate that the majority of hierarchies involved TP53, PIK3CA, ERBB2, APC, KRAS, EGFR, IDH1, VHL, etc. Research into the order and accumulation of genomic alterations among cancer driver genes will ever-increase as the costs of nextgen sequencing subside, and personalized/precision medicine incorporates whole-genome scans into the diagnosis and treatment of cancer.

miR-140-5p inhibits ovarian cancer growth partially by repression of PDGFRA

Dysregulation of miRNAs is a common feature in human cancers, and miR-140-5p has been found to be down-regulated in cancer. However its role in ovarian cancer remains unclear. miR-140-5p was underexpressed in HCC tissues and cell lines compared with their normal controls. Additionally, PDGFRA was predicted the target gene of miR-140-5p. PDGFRA was inversely correlated with the expression of miR-140-5p in ovarian cancer cells. Importantly, we demonstrate that the over expression of miR-140-5p significantly inhibits ovarian cancer cell proliferation and induces apoptosis. Our results suggest the existence of a novel miR-140-5p-PDGFRA pathway and indicate that miR-140-5p acts as a tumor suppressor during ovarian carcinogenesis. These results may provide a promising alterative strategy for the therapeutic treatment of ovarian cancer.

Aberrant expressions of c-KIT and DOG-1 in mucinous and nonmucinous colorectal carcinomas and relation to clinicopathologic features and prognosis

c-KIT and DOG-1 are 2 highly expressed proteins in gastrointestinal stromal tumors. Few studies had investigated c-KIT, but not DOG-1, expression in colorectal carcinoma (CRC). This study aims to investigate expressions of c-KIT and DOG-1 in colorectal mucinous carcinoma and nonmucinous carcinoma using manual tissue microarray technique. In this work, we studied tumor tissue specimens from 150 patients with colorectal mucinous (MA) and nonmucinous adenocarcinoma (NMA). High-density manual tissue microarrays were constructed using modified mechanical pencil tip technique, and immunohistochemistry for c-KIT and DOG-1 was done. We found that aberrant c-KIT expression was detected in 12 cases (8%); 6 cases (4%) showed strong expression. Aberrant DOG-1 expression was detected in 15 cases (10%); among them, only 4 cases (2.7%) showed strong expression. Nonmucinous adenocarcinoma showed a significantly high expression of c-KIT, but not DOG-1, than MA. Aberrant c-KIT and DOG-1 expressions were significantly unrelated but were associated with excessive microscopic abscess formation. Neither c-KIT nor DOG-1 expression showed a significant impact on disease-free survival or overall survival. In conclusion, aberrant c-KIT and DOG-1 expressions in CRC are rare events, either in NMA or MA. Nonmucinous adenocarcinoma showed a significantly higher expression of c-KIT, but not DOG-1, than MA. The expressions of both in CRC are significantly unrelated but are associated with microscopic abscess formation. Neither c-KIT nor DOG-1 expression showed a significant impact on disease-free survival or overall survival. So, c-KIT and DOG-1 immunostaining is not a cost-effective method of identifying patients with CRC who may benefit from treatment with tyrosine kinase inhibitors.

A panel of overexpressed proteins for prognosis in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a common cancer with poor prognosis. In order to identify useful biomarkers for accurately classifying prognostic risks for ESCC patients, we examined the expression of six proteins by immunohistochemistry (IHC) in 590 paraffin-embedded ESCC samples. The candidate proteins include p53, EGFR, c-KIT, TIMP1 and PI3K-p110α reported to be altered in ESCC tissues as well as another important component of PI3K, PI3K-p85α. Of the six proteins tested, p53, EGFR, c-KIT, TIMP1 and PI3K-p85α were detected with high expression in 43.0%, 36.6%, 55.9%, 70.7% and 57.1% of tumors, respectively. Significant associations were found between high expression of PI3K-p85α, EGFR and p53 and poor prognosis (P = 0.00111; 0.00001; 0.00426). Applying these three proteins as an IHC panel could divide patients into different subgroups (P<0.000001). Multivariate cox regression analysis indicated that the three-protein panel was an independent prognostic factor with very high statistical significance (HR = 2.090, 95% CI: 1.621–2.696, P = 0.00000001). The data suggest that the three-protein panel of PI3K-p85α, EGFR and p53 is an important candidate biomarker for the prognosis of patients with ESCC.

Establishment of an orthotopic transplantation tumor model in nude mice using a drug-resistant human ovarian cancer cell line with a high expression of c-Kit

The resistance of ovarian cancer to platinum-based chemotherapy is a critical issue in the clinical setting. The present study aimed to establish animal models to replicate this clinical condition, as well as to investigate the resistance mechanisms of ovarian cancer. A cisplatin (DDP)-resistant human ovarian cancer cell line, SKOV3/DDP, was screened, validated and injected subcutaneously into the neck of female nude mice. Following tumor establishment, the tumor was collected and cut into small sections, which were subsequently implanted into the ovaries of other nude mice. The growth of the orthotopic tumors was observed and the tumor-bearing mice were sacrificed and dissected. The orthotopic and metastatic tumor tissues were collected, sectioned, stained with hematoxylin and eosin and analyzed. In the present study, 16 nude mice underwent orthotopic transplantation surgery and a tumor model was successfully established in 14/16 of the mice, with an in situ tumor formation rate of 87.5%. Following euthanasia, a laparotomy demonstrated the tumor formation at the site of transplantation, as well as varying degrees of metastasis to additional organs and tissues. Therefore, the present study successfully established an orthotopic tumor transplantation model in nude mice using a c-Kit-positive DDP-resistant human ovarian cancer cell line. This model may represent a useful tool for investigating the resistance mechanism of ovarian cancer, as well as evaluating the efficacy of therapeutic strategies.

Expression and significance of transforming growth factor-β1 in epithelial ovarian cancer and its extracellular matrix

The aim of the present study was to investigate the expression and significance of transforming growth factor-β1 (TGF-β1) in the cytoplasm and extracellular matrix (ECM) of epithelial ovarian cancer cells. The expression of TGF-β1 protein was detected in paraffin-embedded sections of 25 normal ovarian epithelial tissues, 10 benign epithelial cysts and 72 epithelial ovarian cancer specimens, using the Strept Avidin Biotin Peroxidase Complex immunohistochemistry method. In addition, the expression of TGF-β1 mRNA in normal fibroblasts (NFs) and ovarian cancer-associated fibroblasts (CAFs) was assessed using semi-quantitative polymerase chain reaction (PCR). TGF-β1 protein was expressed in the cytoplasm and ECM, and no significant difference was identified between normal and benign ovarian tissues (P>0.05). However, the cytosolic expression of TGF-β1 declined gradually between the benign ovarian tumor and epithelial ovarian cancer, while its expression in the ECM significantly increased (P<0.05). The expression of TGF-β1 in the cytoplasm and ECM in epithelial ovarian cancer was found to negatively correlate with tumor differentiation, however, it was positively associated with the clinical stages. The positive rates of TGF-β1 in the cytoplasm and ECM between ovarian cancers in clinical stages I–II and III–IV were significantly different (P<0.05). Furthermore, the PCR data indicated that the relative expression of TGF-β1 mRNA in ovarian CAFs (1.0270±0.0539) was significantly higher than that in NFs (0.7131±0.0186). Therefore, the expression of TGF-β1 was identified to be associated with the development and progression of epithelial ovarian cancer, and the high expression of TGF-β1 in the ECM may be associated with the invasion and metastasis of ovarian cancer.

CD117 expression in operable oesophageal squamous cell carcinomas predicts worse clinical outcome

Aims

To investigate the aberrant expression of CD117 in oesophageal squamous cell carcinoma (SCC) and its prognostic significance.

Methods and results

Immunohistochemical staining for CD117 was performed on tissue microarray and routine tissue sections from 157 oesophageal SCC patients and 10 normal oesophageal epithelia adjacent to tumour. The positive rate of CD117 expression was 29.9% in oesophageal SCC tissues, whereas no CD117 expression was detected in the 10 normal oesophageal epithelia. CD117 expression was significantly associated with T stage (P < 0.001), distant metastasis (P = 0.015), lymph node metastasis (P = 0.019), and clinical stage (P = 0.021). Progression-free survival in the patients with CD117-positive tumours was shorter than that in the patients with CD117-negative tumours (P = 0.010). In univariate analyses, CD117 expression was the most significant factor for overall survival of oesophageal SCC patients (P < 0.001), followed by lymph node metastasis (P = 0.001), T stage (P = 0.002), clinical stage (P = 0.006), distant metastasis (P = 0.020), and histological grade (P = 0.027). Multivariate analyses verified that CD117 expression was an independent prognostic marker for oesophageal SCC patients (P = 0.002). In addition, CD117 expression predicted poorer survival in patients without distant metastases.

Conclusions

CD117 expression in operable oesophageal SCC may be a valuable prognostic marker, and detection of its expression in clinical samples may be useful in defining a subclass of oesophageal SCCs with extremely poor clinical outcome, which may require a specially targeted treatment modality.