Significance of CD44 expression in gastrointestinal stromal tumors in relation to disease progression and survival

Identification of Chemo and Radio-Resistant Sub-Population of Stem Cells in Human Cervical Cancer HeLa Cells

BACKGROUND

Cervical cancer ranks the second female malignancy after breast cancer. Cancer stem cells (CSCs) are hard to be eradicated, so can recur. We aim to isolate and characterize CSCs from HeLa cells.

METHODS

These cells express clusters of differentiation (CDs), 44 and 24, to be sorted by fluorescence-activated cell sorting (FACS).

RESULTS

CD44⁺CD24⁺ cells showed potential to form spheres, tumorigenicity, stemness genes and higher resistance to cisplatin, X-ray.

CONCLUSION

CD44⁺CD24⁺ HeLa cells hold characteristics of CSCs, in vitro, in vivo studies, suggesting that targeting may lead to screening of new anti-cancer therapies.

Paradoxical expression pattern of the epithelial mesenchymal transition-related biomarkers CD44, SLUG, N-cadherin and VSIG1/Glycoprotein A34 in gastrointestinal stromal tumors

AIM

To evaluate the immunohistochemical (IHC) expression of five biomarkers, commonly involved in epithelial mesenchymal/mesenchymal epithelial transition (EMT/MET), in gastrointestinal stromal tumors (GISTs).

METHODS

In 80 consecutive GISTs the IHC examinations were performed using the EMT-related antibodies E-cadherin, N-cadherin, SLUG, V-set and immunoglobulin domain containing 1 (VSIG1) and CD44.

RESULTS

The positivity rate was 88.75% for SLUG, 83.75% for VSIG1, 36.25% for CD44 and 10% for N-cadherin. No correlation was noted between the examined markers and clinicopathological parameters. Nuclear positivity for SLUG and VSIG1 was observed in all cases with distant metastasis. The extra-gastrointestinal stromal tumors (e-GISTs) expressed nuclear positivity for VSIG1 and SLUG, with infrequent positivity for N-cadherin and CD44. The low overall survival was mainly dependent on VSIG1 negativity (P = 0.01) and nuclear positivity for SLUG and/or CD44.

CONCLUSION

GIST aggressivity may be induced by nuclear up-regulation of SLUG and loss or cytoplasm-to-nuclear translocation of VSIG1. SLUG and VSIG1 may act as activated nuclear transcription factors. The CD44, but not N-cadherin, might also have an independent prognostic value in these tumors. The role of the EMT/MET-related transcription factors in the evolution of GISTs, should be revisited with a larger dataset. This is the first study exploring the IHC pattern of VSIG1 in GISTs.

Integrating miRNA and gene expression profiling analysis revealed regulatory networks in gastrointestinal stromal tumors

AIM

Currently, little is known about differences in miRNA expression between KIT/PDGFRA mutant and KIT/PDGFRA wild-type (WT)-SDH deficient gastrointestinal stromal tumors (GIST). This prompted us to perform an integrated multiple expression profile of miRNA and mRNA, constructing an original miRNA-mRNA regulatory network in KIT/PDGFRA WT-SDH deficient GIST patients.

PATIENTS & METHODS

Analyses were carried out on KIT/PDGFRA mutant versus KIT/PDGFRA WT-SDH deficient GIST. Genome-wide miRNA and gene-expression analysis were performed using Agilent Human miRNA microarray and Affimetrix array, respectively.

RESULTS

Three potential regulatory networks (IGF1R → miR-139-5p/miR-455/let-7b, cyclin-dependent kinase 6 (CDK6) → miR-139-5p/let-7b and CD44 → miR-330-3p) were identified.

CONCLUSION

The miR-139-5p, 455-5p and let-7b signature, in particular, may represent an important therapeutic target in KIT/PDGFRA WT-SDH deficient GIST, usually characterized by IGF1R overexpression.

Rapid and reliable detection of CD44 variants in gastric carcinoma using a nested reverse transcription-polymerase chain reaction

The present study aimed to establish a rapid and reliable method for detecting the expression of cluster of differentiation 44 variant (CD44v) in gastric carcinoma, and to investigate the significance of CD44v in gastric carcinoma. Using a nested reverse transcription-polymerase chain reaction (RT-PCR) technique, the expression of CD44v and CD44v8-10 was analyzed in gastric cancer tissues (128 cases), precancerous lesions (19 cases of atypical hyperplasia and 6 cases of intestinal metaplasia) and corresponding adjacent non-cancerous tissues (153 cases). The tumor and non-cancerous biopsy samples of 153 patients were analyzed using nested RT-PCR. All the PCR products included bands at 482 bp, demonstrating positive CD44 expression. By contrast, the CD44v band (>600 bp) was observed in 132/153 total tumor samples (86.3%), including 114/128 gastric cancer samples (89.1%), 16/19 atypical hyperplasia samples (84.2%) and 2/6 intestinal metaplasia samples (33.3%). However, 18/153 non-cancerous tissues samples (11.8%) exhibited a CD44v band. Thus, CD44v expression was significantly higher in gastric cancer tissues and precancerous lesions compared with that of adjacent non-cancerous tissues (P<0.05). Furthermore, there was a significant difference in CD44v8-10 expression detected between gastric cancer and adjacent non-cancerous tissue samples (P<0.05). Among the 25 patients with precancerous lesions, 8/19 atypical hyperplasia cases and 1/6 intestinal metaplasia cases were positive for CD44v8-10 expression. The difference in the CD44v8-10 expression rate among the various pathological types of gastric cancer (n=128) cases was not significant (P>0.05). Additionally, immunohistochemical analysis identified CD44v positivity (++) in 59/76 (77.6%) cases of gastric cancer and 5/12 (41.1%) cases of atypical hyperplasia. The CD44v and CD44v8-10 PCR products were confirmed by sequencing analysis. The results of the present study indicated that nested RT-PCR technology may be exploited as a method for gastric carcinoma diagnosis.

Anti-apoptotic effects of osteopontin through the up-regulation of Mcl-1 in gastrointestinal stromal tumors

Background

Osteopontin (OPN) is a secreted phosphoprotein expressed by neoplastic cells involved in the malignant potential and aggressive phenotypes of human malignancies, including gastrointestinal stromal tumors (GISTs). Our previous study showed that OPN can promote tumor cell proliferation in GISTs. In this series, we further aim to investigate the effect of OPN on apoptosis in GISTs.

Methods

The expression of apoptotic and anti-apoptotic proteins in response to OPN was evaluated. In vitro effects of OPN against apoptosis in GIST were also assessed. GIST specimens were also used for analyzing protein expression of specific apoptosis-related molecules and their clinicopathologic significance.

Results

Up-regulation of β-catenin and anti-apoptotic proteins Mcl-1 with concomitant suppression of apoptotic proteins in response to OPN was noted. A significant anti-apoptotic effect of OPN on imatinib-induced apoptosis was identified. Furthermore, Mcl-1 overexpression was significantly associated with OPN and β-catenin expression in tumor tissues, as well as worse survival clinically.

Conclusions

Our study identifies anti-apoptotic effects of OPN that, through β-catenin-mediated Mcl-1 up-regulation, significantly antagonized imatinib-induced apoptosis in GISTs. These results provide a potential rationale for therapeutic strategies targeting both OPN and Mcl-1 of the same anti-apoptotic signaling pathway, which may account for resistance to imatinib in GISTs.

Prognostic significance of PTEN, Ki-67 and CD44s expression patterns in gastrointestinal stromal tumors

AIM: To develop a prognostic approach for gastrointestinal stromal tumors (GISTs) using a cluster of indicators and follow-up information.

METHODS: One hundred and four GISTs that had not been subjected to targeted therapies were collected and classified by NIH risk assessment and anatomic location. By immunohistochemistry, the expressions of PTEN, Ki-67, CD44s matrix metalloproteinase (MMP)-9 and TIMP-1 were detected on tissue microarray. Univariate and multimarker survival analyses were performed and then a COX hazard proportion model was constructed to evaluate a cluster of predictors of GIST.

RESULTS: Our data showed small intestinal GIST are more aggressive than gastric GIST. The NIH risk assessment correlated with disease-free survival for either gastric GIST or small intestinal GIST. Immunohistochemical analysis revealed that Ki-67 labeling indexes (LIs) < 5% predicted higher disease-specific survival (DSS) in gastric and small intestinal GIST. CD44s positivity and PTEN LIs ≥ 50% correlated with higher DSS in gastric GIST. MMP-9 and TIMP-1 had no correlation with survival. Multimarker analysis revealed that the expression pattern of PTEN LIs ≥ 50% combined with Ki-67 LIs < 5% and CD44s positivity reliably predicted favorable outcomes for gastric GIST (P = 0.009), as did the combination of PTEN LIs ≥ 50% and Ki-67 LIs < 5% for small intestinal GIST (P = 0.011). Authors also found that high NIH risk grade was correlated with DSS in patients with gastric GIST and disease-free survival in patients with small intestinal GIST.

CONCLUSION: PTEN LIs ≥ 50%, Ki-67 LIs < 5% and CD44s positivity provides an accurate, favorable prognosis for gastric GIST. PTEN LIs ≥ 50% and Ki-67 LIs < 5% does the same for small intestinal GIST. Ki-67 LIs enhances the NIH assessment.

Clinical proteomics identified ATP-dependent RNA helicase DDX39 as a novel biomarker to predict poor prognosis of patients with gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal malignancy of the gastrointestinal tract, comprising a wide spectrum from a curable disorder to highly malignant disease. GIST is characterized by tyrosine kinase mutations, and molecular targeting therapies against these abnormal enzymes require prognostic biomarkers. To identify candidate prognostic biomarkers, we examined proteomic features corresponding to metastasis after surgery. Using two-dimensional difference gel electrophoresis with a large format gel, we compared the primary tumor tissues of GIST patients free of metastasis for two years after surgery (eight cases) with those of patients who developed metastasis within one year after surgery (nine cases). We found the intensities of 38 protein spots to differ significantly between the two groups. Mass spectrometric protein identification revealed that these corresponded to 25 unique genes. Immunohistochemical validation demonstrated ATP-dependent RNA helicase DDX39 to be significantly associated with metastasis and poor clinical outcomes in a group of 72 GIST patients. In conclusion, we have established a novel prognostic utility of ATP-dependent RNA helicase DDX39 in GIST.ATP-dependent RNA helicase DDX39, a novel biomarker for GIST likely to be associated with metastatic disease, can identify patients likely to benefit from new therapeutic strategies such as tyrosine kinase inhibitors.

Identification of CD44+CD24+ gastric cancer stem cells

OBJECTIVE

Purification and characterization of cancer stem cells (CSCs) can lead to the identification of targets for therapeutic interventions of cancer. With regard to gastric cancer, studies have not yet defined and characterized CSCs.

METHODS

The expression of the cell surface markers CD44 and CD24 was examined in gastric cell lines AGS and gastric cancer tissues from five patients with fluorescence-activated cell sorting analysis (FACS). The tumorigenic properties, self-renewal, and differentiated progeny in the two distinct cell populations CD44+CD24+ and CD44-CD24- were identified in vivo serial transplantation and in vitro culture. Real-time RT-PCR was used to assess the expression of sonic hedgehog (SHH), patched 1 (PTCH1), and GLI3 signaling molecules in CD44+CD24+ and CD44-CD24- cells.

RESULTS

As few as 200 CD44+CD24+ cells injected in NOD-SCID mice were able to generate tumors in 50% of mice (6 of 12), while tumors did not form in mice until at least 10,000 CD44-CD24- cells were injected, where only one of 12 mice formed a tumor, further verifying that CD44+CD24+ gastric cancer cells have the capacity to both self-renew and produce differentiated progeny. Moreover, SHH, PTCH1, and GLI3 mRNA expression increased significantly in the CD44+CD24+ subpopulation when compared with the CD44-CD24- subpopulation.

CONCLUSIONS

These studies strongly suggest that the CD44+CD24+ subpopulation of human gastric cancer cell lines, AGS, is gastric cancer stem cells.

Clinical implication and mitotic effect of CD44 cleavage in relation to osteopontin/CD44 interaction and dysregulated cell cycle protein in gastrointestinal stromal tumor

BACKGROUND

CD44 and osteopontin (OPN) are functionally related molecules that, alone or in combination, play miscellaneous biological and pathophysiologic roles. CD44 cleavage, one unique feature of CD44, occurs in human cancers, but its function remains unclear. This study aimed to assess the clinicopathologic significance and mechanism of CD44 cleavage in gastrointestinal stromal tumor (GIST) with respect to OPN and OPN/CD44 interaction.

MATERIALS AND METHODS

CD44 cleavage was evaluated by immunoblotting in 31 primary GIST tumor specimens with paired normal tissues. OPN/CD44 interaction was examined by in situ proximity ligation assay. The associations of CD44 cleavage activity with clinicopathologic parameters, cyclin D1 expression, beta-catenin expression, OPN expression, and OPN/CD44 interaction were analyzed.

RESULTS

CD44 cleavage activity was demonstrated in 87.1% of GIST, in contrast to its absence in normal tissues. Increased CD44 cleavage activity was significantly associated with enhanced mitosis by multivariate analysis, in addition to being related to tumor size, recurrence, high-risk status, and poor survival by univariate analysis. Mitosis was significantly higher in GIST with increased CD44 cleavage activity, which also positively correlated with tumor-specific beta-catenin and cyclin D1 overexpression, indicating a mitotic effect through aberrant cell cycle. Both OPN and OPN/CD44 interactions were significantly associated with CD44 cleavage.

CONCLUSION

Our study demonstrates the clinicopathological significance of CD44 cleavage in GIST. There is a significantly increased mitosis associated with CD44 cleavage in relation to OPN/CD44 interaction and dysregulated cell cycle in GIST.