Differential expression of CD44v6 in metastases of intestinal and diffuse types of gastric carcinoma

CD44 In Sarcomas: A Comprehensive Review and Future Perspectives

It is widely accepted that the tumor microenvironment, particularly the extracellular matrix, plays an essential role in the development of tumors through the interaction with specific protein-membrane receptors. One of the most relevant proteins in this context is the transmembrane protein CD44. The role of CD44 in tumor progression, invasion, and metastasis has been well established in many cancers, although a comprehensive review concerning its role in sarcomas has not been published. CD44 is overexpressed in most sarcomas and several in vitro and in vivo experiments have shown a direct effect on tumor progression, dissemination, and drug resistance. Moreover, CD44 has been revealed as a useful marker for prognostic and diagnostic (CD44v6 isoform) in osteosarcoma. Besides, some innovative treatments such as HA-functionalized liposomes therapy have become an excellent CD44-mediated intracellular delivery system for osteosarcoma. Unfortunately, the reduced number of studies deciphering the prognostic/diagnostic value of CD44 in other sarcoma subgroups, neither than osteosarcoma, in addition to the low number of patients involved in those studies, have produced inconclusive results. In this review, we have gone through the information available on the role of CD44 in the development, maintenance, and progression of sarcomas, analyzing their implications at the prognostic, therapeutic, and mechanistic levels. Moreover, we illustrate how research involving the specific role of CD44 in the different sarcoma subgroups could suppose a chance to advance towards a more innovative perspective for novel therapies and future clinical trials.

Rapid Isolation of Gastric Adenocarcinoma Cancer Stem Cells as a Target for Autologous Dendritic Cell-Based Immunotherapy

BACKGROUND

Gastric cancer (GC) is a malignancy cause associated with a high death rate in the world. Cancer stem cells (CSCs) are a rare immortal subpopulation of cells within tumors with characteristics of the ability to self-renew, initiate tumor, and differentiate into defined progenies as well as and high resistance to conventional therapies.

OBJECTIVES

Despite the use of surgery and chemotherapy for GC therapy, there are no efficient therapeutic protocols for it to date. Therefore, rapid isolation of CSCs in order to therapeutic targets, especially immunotherapy is very important.

MATERIALS AND METHODS

Cancerous cell suspension isolated from patients with GC was cultured in the serum-free medium containing EGF, bFGF, LIF, and heparin under non-adherent culture conditions to generate spheres. Expression of mRNA level stemness transcription factors (OCT4, SOX2, SALL4, and Cripto-1), CD44 variable isoforms (CD44s, CD44v3, CD44v6, CD44V8-10) of spheroid-forming single cells compared with gastric normal tissue cells using real time PCR and molecules of CD44, CD54, and EpCAM as gastric CSC markers, and stemness factor Oct4 using flow cytometry, as well as tumorgenicity using subcutaneous injection of sphere-forming cells to nude mice were investigated.

RESULTS

Few cancerous cells isolated from patients with GC were able to generate three-dimensional spheroid colonies in the serum-free medium containing EGF, bFGF, LIF, and heparin under non-adherent culture conditions, and form xenograft tumors in immunodeficient nude mice after subcutaneous injection. Spheroid-forming single cells upregulated stemness transcription factors OCT4, SOX2, SALL4, and Cripto-1 that are associated with pluripotency and self-renewal and CD44 isoforms (CD44s, CD44v3, CD44v6, CD44V8-10) compared with gastric normal tissue cells. Finally, molecules of CD44, CD54, and EpCAM as gastric CSC markers and stemness factor Oct4 were expressed in sphere-forming cells.

CONCLUSION

We suggested that the sphere formation and tumorigenicity assays are two procedures, leading to the rapid isolation of cancer cells with certain stem-like properties in order to target CSCs using autologous dendritic cell therapy, especially in patients with advanced disease.

The Use of Normal Stem Cells and Cancer Stem Cells for Potential Anti-Cancer Therapeutic Strategy

BACKGROUND

Despite recent advance in conventional cancer therapies including surgery, radiotherapy, chemotherapy, and immunotherapy to reduce tumor size, unfortunately cancer mortality and metastatic cancer incidence remain high. Along with a deeper understanding of stem cell biology, cancer stem cell (CSC) is important in targeted cancer therapy. Herein, we review representative patents using not only normal stem cells as therapeutics themselves or delivery vehicles, but also CSCs as targets for anti-cancer strategy.

METHODS

Relevant patent literatures published between 2005 and 2017 are discussed to present developmental status and experimental results on using normal stem cells and CSCs for cancer therapy and explore potential future directions in this field.

RESULTS

Stem cells have been considered as important element of regenerative therapy by promoting tissue regeneration. Particularly, there is a growing trend to use stem cells as a target drug-delivery system to reduce undesirable side effects in non-target tissues. Noteworthy, studies on CSC-specific markers for distinguishing CSCs from normal stem cells and mature cancer cells have been conducted as a selective anti-cancer therapy with few side effects. Many researchers have also reported the development of various substances with anticancer effects by targeting CSCs from cancer tissues.

CONCLUSION

There has been a continuing increase in the number of studies on therapeutic stem cells and CSC-specific markers for selective diagnosis and therapy of cancer. This review focuses on the current status in the use of normal stem cells and CSCs for targeted cancer therapy. Future direction is also proposed.

Isolation and identification of chemotherapy-enriched sphere-forming cells from a patient with gastric cancer

Gastric cancer (GC) is the third and fifth cause of cancer-associated mortality for men and women throughout the world, respectively. Despite the use of surgery and chemotherapy for GC therapy, there are no efficient therapeutic protocols for it to date. Cancer stem cells (CSCs) due to their pivotal role in tumor initiation, growth, progression, invasion, distant metastasis, recurrence and resistance to anticancer drugs are very appealing targets for cancer therapies. Here, we isolated and identified CSCs from a chemotherapy-treated patient. Small subpopulation of dissociated cells after tissue digestion formed spheroid colonies in serum-free media under the non-adherent condition. These spheroid colonies differentiated into epithelial like cells in serum-containing medium. Few sphere-forming cells carried CD44 and CD54 markers overexpressed DLL4 that is responsible for tumor growth and angiogenesis. Subcutaneous injections of sphere-forming cells in different passages conferred tumorigenicity in nude mice. Sphere-forming cells upregulated CD44 polymorphisms CD44v3, -v6, and -v8 -10, stemness factors OCT4, SOX2, SALL4 and Cripto-1, self-renewal molecules IHh, Wnt, β-catenin and BMI1, and epithelial mesenchymal transition (EMT) markers Twist1 and Snail1 in vitro and in vivo. Moreover, these cells similar to sphere-forming cells isolated from a chemotherapy-free patient expressed Oct-4 and β-catenin proteins. However, the Twist1 protein was only expressed by sphere-forming cells derived from the chemotherapy-treated patient. Thus, these cells have all the characteristics of stationary and migratory CSCs, including tumorigenicity, self-renewal, pluripotency, invasion and metastasis. Taken together, targeting chemotherapy-enriched CSCs as chemo-resistance cells observed in GC patients can provide more effective therapeutic strategies compared to untreated patients.

Prognostic Value of Cancer Stem Cell Markers CD44 and ALDH1/2 in Gastric Cancer Cases

Purpose:

To determine expression levels of CD44 and ALDH1/2, known cancer stem cell (CSC) markers, in stomach adenocarcinomas and assess relationships with clinicopathologic parameters and prognosis.

Methods:

Eighty patients diagnosed with gastric cancer between the years 2011-2015 were included in this study of clinicopathologic characteristics, postoperative prognostic indexes and stem cell marker CD44 and ALDH1/2 expression in paraffin-embedded tumour sections analyzed immunohistochemically. Clinicopathologic parameters were evaluated using the chi-square test and t-test. Survival analyses were conducted using Kaplan-Meier statistics.

Results:

We observed positive CD44 and ALDH1/2 staining in 45.0 % and 67.5% of tumour tissues, respectively, but not in normal gastric mucosa. Recurrence-free survival (RFS) was found to be shorter in cases with high levels of CD44 expression (p=0.004). Similarly, short RFS was observed in patients with high levels of CD44 and ALDH1/2 co-expression (p=0.004). Furthermore, tumour invasion depth was found to correlate with high CD44 and ALDH1/2 co-expression (p=0.028).

Conclusion:

The cancer stem cell markers CD44 and ALDH1/2 may indicate poor patient prognosis and play a role in tumour development and invasion.

MicroRNA-34 dysregulation in gastric cancer and gastric cancer stem cell

Gastric cancer is a major cause of cancer mortality worldwide, with a low survival rate for patients with advanced forms of the disease. Over the recent decades, the investigation of the pathophysiological mechanisms of tumourigenesis has opened promising avenues to understand some of the complexities of cancer treatment. However, tumour regeneration and metastasis impose great difficulty for gastric cancer cure. In recent years, cancer stem cells - a small subset of tumour cells in many cancers - have become a major focus of cancer research. Cancer stem cells are capable of self-renewal and are known to be responsible for tumour initiation, metastasis, therapy resistance and cancer recurrence. Recent studies have revealed the key role of microRNAs - small noncoding RNAs regulating gene expression - in these processes. MicroRNAs play crucial roles in the regulation of a wide range of biological processes in a post-transcriptional manner, though their expression is dysregulated in most malignancies, including gastric cancer. In this article, we review the consequences of aberrant expression of microRNA-34 in cancer and cancer stem cells, with a specific focus on the miR-34 dysregulation in gastric cancer and gastric cancer stem cells. We address the critical effects of the aberrant expression of miR-34 and its target genes in maintaining cancer stem cell properties. Information collection and discussion about the advancements in gastric cancer stem cells and microRNAs can be useful for providing novel insights into patient treatment.

Nomogram Incorporating CD44v6 and Clinicopathological Factors to Predict Lymph Node Metastasis for Early Gastric Cancer

Background

Treatment strategy for early gastric cancer depends on the probability of lymph node metastasis. The aim of this study is to develop a nomogram predicting lymph node metastasis in early gastric cancer using clinicopathological factors and biomarkers.

Methods

A literature review was performed to identify biomarkers related to lymph node metastasis in gastric cancer. Seven markers were selected and immunohistochemistry was performed in 336 early gastric cancer tissues. Based on the multivariable analysis, a prediction model including clinicopatholgical factors and biomarkers was developed, and benefit of adding biomarkers was evaluated using the area under the receiver operating curve and net reclassification improvement. Functional study in gastric cancer cell line was performed to evaluate mechanism of biomarker.

Results

Of the seven biomarkers studied, α1 catenin and CD44v6 were significantly associated with lymph node metastasis. A conventional prediction model, including tumor size, histological type, lymphatic blood vessel invasion, and depth of invasion, was developed. Then, a new prediction model including both clinicopathological factors and CD44v6 was developed. Net reclassification improvement analysis revealed a significant improvement of predictive performance by the addition of CD44v6, and a similar result was shown in the internal validation using bootstrapping. Prediction nomograms were then constructed based on these models. In the functional study, CD44v6 was revealed to affect cell proliferation, migration and invasion.

Conclusions

Overexpression of CD44v6 was a significant predictor of lymph node metastasis in early gastric cancer. The prediction nomograms incorporating CD44v6 can be useful to determine treatment plans in patients with early gastric cancer.

The Importance of CD44 as a Stem Cell Biomarker and Therapeutic Target in Cancer

CD44 is a cell surface HA-binding glycoprotein that is overexpressed to some extent by almost all tumors of epithelial origin and plays an important role in tumor initiation and metastasis. CD44 is a compelling marker for cancer stem cells of many solid malignancies. In addition, interaction of HA and CD44 promotes EGFR-mediated pathways, consequently leading to tumor cell growth, tumor cell migration, and chemotherapy resistance in solid cancers. Accumulating evidence indicates that major HA-CD44 signaling pathways involve a specific variant of CD44 isoforms; however, the particular variant almost certainly depends on the type of tumor cell and the stage of the cancer progression. Research to date suggests use of monoclonal antibodies against different CD44 variant isoforms and targeted inhibition of HA/CD44-mediated signaling combined with conventional radio/chemotherapy may be the most favorable therapeutic strategy for future treatments of advanced stage malignancies. Thus, this paper briefly focuses on the association of the major CD44 variant isoforms in cancer progression, the role of HA-CD44 interaction in oncogenic pathways, and strategies to target CD44-overexpressed tumor cells.

Screening and Identification of a Phage Display Derived Peptide That Specifically Binds to the CD44 Protein Region Encoded by Variable Exons

CD44, especially the isoforms with variable exons (CD44v), is a promising biomarker for the detection of cancer. To develop a CD44v-specific probe, we screened a 7-mer phage peptide library against the CD44v3-v10 protein using an improved subtractive method. The consensus sequences with the highest frequency (designated CV-1) emerged after four rounds of panning. The binding affinity and specificity of the CV-1 phage and the synthesized peptide for the region of CD44 encoded by the variable exons were confirmed using enzyme-linked immunosorbent assay and competitive inhibition assays. Furthermore, the binding of the CV-1 probe to gastric cancer cells and tissues was validated using immunofluorescence and immunohistochemistry assays. CV-1 sensitively and specifically bound to CD44v on cancer cells and tissues. Thus, CV-1 has the potential to serve as a promising probe for cancer molecular imaging and target therapy.

Sequential expression of putative stem cell markers in gastric carcinogenesis

BACKGROUND

Gastric carcinogenesis has been well documented in the step-wise histopathological model, known as Correa pathway. Several biomarkers including CD44, Musashi-1 and CD133 have been reported as putative stem cell (PSC) markers.

METHODS

We investigated expression of PSC markers CD44, Musashi-1 and CD133 in relation to gastric carcinogenesis and prognosis and chemoresponse. Immunohistochemistry staining was performed in gastric cancer (GC) clinical specimens representing different steps of the Correa pathway. Gastric cancer samples taken before and after neoadjuvant chemotherapy with docetaxel, cisplatin and capecitabine (DCX) were also evaluated for PSC marker expression.

RESULTS

We showed that the expression of three PSC markers was significantly elevated in GC relative to normal gastric mucosa (P<0.001 for each marker). Precancerous lesions, including intestinal metaplasia and dysplasia, demonstrated increased expression of CD44 and Musashi-1. CD133 was predominantly expressed along the border between intramucosal carcinoma and connective tissue at later stages. High CD44 and CD133 expression showed prognostic value for worse patient survival (P=0.014 and P=0.019, respectively). A small number of tumours with high expression of CD44 and CD133 showed pathological response to DCX-based neoadjuvant chemotherapy.

CONCLUSION

CD44 and Musashi-1 are frequently expressed in both premalignant gastric lesions and invasive GC, whereas CD133 expression is restricted mainly to neoplastic tissues.

Expression of cell adhesion molecule CD44 in gastric adenocarcinoma and its prognostic importance

AIM: To evaluate the relation of cluster of differentiation 44 (CD44) expression with clinicopathological features of gastric adenocarcinoma, and also its effect on prognosis with an emphasis on the differences between intestinal and diffuse types.

METHODS: From 2000 to 2006, 100 patients with gastric adenocarcinoma, who had undergone total or subtotal gastrectomy without any prior treatment, were studied. Haematoxylin & eosin (HE) staining was used for histological evaluation, including the type (Lauren’s classification) and grading of the tumor. The expression of CD44 in the gastric adenocarcinoma mucosa and the adjacent mucosa were determined by immunohistochemistry. The survival analysis was obtained using the Kaplan-Meier test.

RESULTS: Of 100 patients, 74 (74%) patients were male. The tumors were categorized as intestinal type (78%) or diffuse type (22%). Sixty-five percent of patients were CD44-positive. CD44 expression was not detected in normal gastric mucosa. Rather, CD44 was more commonly expressed in the intestinal subtype (P = 0.002). A significant relation was seen between the grade of tumor and the expression of CD44 (P = 0.014). The survival analysis showed a poor prognosis of patients with CD44-positive tumors (P = 0.008); and this was more prominent in the intestinal (P = 0.001) rather than diffuse type.

CONCLUSION: Cell adhesion molecule CD44 is highly expressed in gastric adenocarcinoma. CD44 expression is correlated with a poor prognosis in patients with the intestinal type of gastric adenocarcinoma. CD44 can, therefore, be utilized as a prognostic marker for this group of patients.

Expression of tenascin-c and CD44 receptors in cardiac myxomas

BACKGROUND

Myxomas are the most frequent primary cardiac neoplasms. They have an abundant extracellular matrix rich in proteoglycans. Interactions between cells and matrix are very important in the development of tumors, but data about myxomas in this setting are scarce because of the rarity of such neoplasms. The expression of tenascin-c and hyaluran receptors in cardiac myxoma has never been investigated. Moreover, it is now well recognized that cells of cardiac myxoma differentiate along endothelial lines.

METHODS

We have analyzed left atrial myxomas from 13 consecutive patients (six male and seven female, surgically treated), via immunohistochemical methods for the expression of molecules also implicated in angiogenesis in normal and pathological conditions, like tenascin-c and hyaluran receptors CD44s, CD44v5 and CD44v6.

RESULTS

Our data suggest that tenascin-c and CD44s play a synergic and perhaps complementary role in development of cardiac myxomas. In particular, tenascin-c seems to promote aggregation of cells and differentiation in vascular structures, whereas CD44s receptors might be important for cellular motility. Cell proliferation rate in such tumors was very low (MIB-1 labeling index <1%) and uniform in all the areas of the neoplasms regardless of the presence of characteristic structures such as cords and rings of multinucleated cells or the expression of tenascin-c and CD44 receptors.

CONCLUSIONS

This study shows that cardiac myxomas express in the extracellular matrix tenascin-c and on the cellular membranes of neoplastic cells the hyaluran receptor CD44s. Such molecules take part in the mechanism of development of the myxomas and might be in the future the target of nonsurgical treatments.

A novel region of amplification at 11p12-13 in gastric cancer, revealed by representational difference analysis, is associated with overexpression of CD44v6, especially in early-onset gastric carcinomas

Diffuse-type gastric carcinomas (GCs) are often difficult to characterize because of contamination of tumor samples by surrounding normal tissue. As such, information regarding chromosomal aberrations in this subtype of GCs is limited. In this study, we used representational difference analysis to pinpoint genomic amplifications occurring in diffuse-type GCs. We found nine differential products from two novel regions of amplification in two tumors: one product mapped to 19p13.1 and eight mapped to a 1.8-Mb region in chromosomal segment 11p12-13. These amplifications were confirmed using Southern blot analysis and occurred in 3/16 and 6/15 diffuse-type GCs, respectively. CD44, a well characterized cellular adhesion molecule involved in several human malignancies, is encoded by a gene located within 200 kb of the 11p12-13 amplification fragments. We confirmed that overexpression of isoform CD44v6 was correlated with amplification at 11p12-13 in 11/12 diffuse-type GCs. Since diffuse-type GCs occur more frequently in early-onset gastric carcinomas (EOGCs, presented at 45 years of age or younger) than in "conventional" GCs, and the tumors carrying the original amplifications were EOGCs, we investigated overexpression of CD44v6 in 107 EOGCs and 88 conventional GCs using tissue microarrays. We found frequent CD44v6 overexpression in both tumor groups (76% and 57% respectively) and, interestingly, significantly more cases with overexpression of CD44v6 in EOGCs than in conventional GCs (P = 0.005), irrespective of histology. These findings provide further evidence for both the relevance of CD44 in GC and for distinct molecular characteristics of EOGCs when compared with those of GCs occurring at a later age.

CD44v6: a potential marker of malignant transformation in intestinal metaplasia of the stomach? An immunohistochemical study using tissue microarrays

OBJECTIVE

Intestinal metaplasia is a well-established risk factor in the development of stomach cancer. However, since the specificity is low it would be of great practical value to find a marker to separate cases of intestinal metaplasia into low and high risk for progression to dysplasia/carcinoma. So far this has not been achieved. CD44 is a cell surface molecule involved in cell-cell and cell-matrix interactions, and the spliced variant 6 has been shown to play a role in the progression of gastric carcinoma. The aim of this study was therefore to evaluate CD44v6 as a marker of increased cancer risk in intestinal metaplasia.

METHODS

The current study investigated immunohistochemical CD44v6 expression in biopsies of normal gastric mucosa (n = 154) and gastric mucosa with intestinal metaplasia (n = 127). A third group consisted of cancer gastrectomies (n = 117) in which both tumour and uninvolved mucosa was studied. Proximal (cardia) and distal (corpus/antrum) locations were noted in all cases.

RESULTS

There was a significant sequential increase in CD44v6 expression from normal mucosa and mucosa showing intestinal metaplasia to uninvolved mucosa adjacent to cancers without and with intestinal metaplasia to tumour. The most striking increase was from 'normal' to intestinal metaplastic mucosa adjacent to cancers. There were no differences between proximal and distal cases in any group.

CONCLUSION

These findings strongly suggest that CD44v6 expression is a late phenomenon in the transformation of intestinal metaplasia to dysplasia/cancer. It may therefore be a useful marker of cancer risk in patients with intestinal metaplasia.

Effect of P-selectin monoclonal antibody on metastasis of gastric cancer and immune function

AIM: To investigate the effect of cell adhesion molecule P-selectin monoclonal antibody (Mab) on metastasis and immune function of mice orthototopically implanted with human gastric cancer tissue.

METHODS: SCID mice were implanted orthotopically with SGC-7901 human gastric carcinoma tissue. Starting from day 3 after operation, animals were given intravenously PBS or P-selectin Mab (100 μg/injection) (for both normal mice and tumor-implanted mice with tumors), twice weekly for 3 wk. Two animals in each group were sacrificed randomly at the 1st, 2nd, 4th week and 6th week. While T cell and B cell transformation indices were determined with the ³H TdR infiltration method, the NK cell activity was detected by the LDH release method.

RESULTS: The metastatic rate in the P-selectin Mab treated group was lower than that in the PBS treated group (with tumors). The NK activity of normal mice increased over time. The immune functions (T, B cell function, NK activity) of the tumor group in the 6th week were significantly lower than those in the 4th week, but the change was attenuated by P-selectin Mab.

CONCLUSION: P-selectin Mab could suppress the metastasis of gastric cancer with no adverse effect on host immune function.

The role of the CD44/ezrin complex in cancer metastasis

CD44 is a cell adhesion molecule that was traditionally known as 'homing receptor'. This molecule is known to interact with the ezrin family (ERM family) members and form a complex that plays diverse roles within both normal and abnormal cells, particularly cancer cells. CD44 and ezrin and their respective complex have properties suggesting that they may be important in the process of tumour-endothelium interactions, cell migrations, cell adhesion, tumour progression and metastasis. This article reviews the role of CD44, ezrin family and the CD44/ezrin complex in cancer cells and their clinical impact in patients with cancer.

Biopsy of a biopsy: validation of immunoprofiling in gastric cancer biopsy tissue microarrays

AIMS

Tissue microarrays offer an efficient way of examining a large number of tumour cases on a single glass slide. A major concern, however, is tumour heterogeneity. Also, the use of tissue microarrays in biopsy material is unexplored. The purpose of the present study was to assess the possibility and validity of arraying three 0.6-mm cores per case in endoscopic gastric cancer biopsies for immunophenotyping.

METHODS AND RESULTS

Thirty-eight cases were studied with immunohistochemical staining for p53, CD44v6 and vascular endothelial growth factor. Full tissue sections were compared with triple core-tissue microarrays. Thirty-six cases contained three cores with tumour, one case contained two cores with tumour and one case contained only a single core with viable tumour and was excluded. Three further cores had been lost from three separate cases on the sections for immunohistochemistry. kappa values for whole-sections versus tissue microarrays ranged between 0.77 and 0.94. p53 immunohistochemical staining (interpretation as + or -) yielded the best result with only 1/37 mismatches, whereas CD44v6 (graded both for intensity and extent) showed 3/37 mismatches. The small depth of tissue in cores from biopsies necessitates all cores being arrayed flush with the face of the recipient wax block for maximizing the number of sections available. Compared with the first section over 30 additional 4- micro m sections were available before the first case (with one core left) had to be excluded and 80 sections before half the tissue cores were lost.

CONCLUSIONS

It is impracticable to array more than 120-150 cores per block. Tissue microarray with three cores per case is feasible and valid for studying biopsy material.

Expression of CD44v5 and -v6 in Barrett's carcinoma is not increased compared to that in nondysplastic Barrett's mucosa

Barrett's adenocarcinoma currently shows the highest increase in the incidence of all malignant tumors. Reliable molecular markers to identify Barrett's patients at risk are still missing. Our own results demonstrate that the expression of CD44v6 correlates with the development of dysplasia in colorectal neoplasms. Therefore, we examined the expression of CD44 variants v5 and v6 in normal esophageal mucosa, non-dysplastic Barrett's mucosa, and Barrett's carcinoma. mRNA from biopsy specimens of patients with Barrett's esophagus (n = 19) or Barrett's carcinoma (n = 15) and patients without esophageal diseases (controls; n = 9) were extracted and used as templates for cDNA synthesis. CD44 variants were detected by RT-PCR with primers hybridizing with CD44 sequences up- and downstream of variable exons. CD44v6 expression was found in 36 of 56 biopsy specimens (64%) of non-dysplastic Barrett's mucosa, in 100% of squamous epithelium, and in none of the gastric mucosa specimens. Eleven of 15 specimens (73%) of Barrett's carcinoma tested positive for v6 expression. The identification of v5 expression did not give additional information. There was no correlation between CD44v5 or -v6 expression and staging or grading of the tumors. Expression of CD44v5 and -v6 seems to be independent of the development of cancer in Barrett's mucosa.

Expression of CD44 and its variant isoform v3 has no prognostic value in gastric cancer

AIMS

To study the controversial role of transmembrane glycoprotein CD44 as a moderator of tumour spread and as a prognostic factor in gastric cancer.

METHODS AND RESULTS

The expression of all CD44 forms and that with exon v3 was assessed in 198 stage I-IV gastric adenocarcinomas using immunohistochemistry. CD44 expression was found in 72% and CD44v3 in 55% of the cases. The intensity of CD44 expression was associated with the level of invasion and with hyaluronan expression, while the frequency of CD44 positive cells was not significantly related to any of the clinical or histological features of the tumours. CD44v3 expression failed to show any association with the clinical or histological variables examined. Neither total CD44 nor CD44v3 expression affected survival. The most important prognostic factors in this cohort were the level of invasion, lymph node status, tumour size and vascular or perineural invasion.

CONCLUSIONS

Changes in CD44 or CD44v3 expression level do not predict tumour spread or patient survival in gastric cancer.

Effects of photodynamic therapy on adhesion molecules and metastasis

Photodynamic therapy (PDT) induces among numerous cell targets membrane damage and alteration in cancer cell adhesiveness, an important parameter in cancer metastasis. We have previously shown that hematoporphyrin derivative (HPD)-PDT decreases cancer cell adhesiveness to endothelial cells in vitro and that it reduces the metastatic potential of cells injected into rats. The present study analyzes the influence of PDT in vivo on the metastatic potential of cancers cells and in vitro on the expression of molecules involved in adhesion and in the metastatic process. Photofrin and benzoporphyrin derivative monoacid ring A (BPD) have been evaluated on two colon cancer cell lines obtained from the same cancer [progressive (PROb) and regressive (REGb)] with different metastatic properties. Studies of BPD and Photofrin toxicity and phototoxicity are performed by colorimetric MTT assay on PROb and REGb cells to determine the PDT doses inducing around 25% cell death. Flow cytometry is then used to determine adhesion-molecule expression at the cell surface. ICAM-I, MHC-I, CD44V6 and its lectins (àHt1.3, PNA, SNA and UEA) are studied using cells treated either with BPD (50 ng/ml, 457 nm light, 10 J/cm2) or Photofrin (0.5 microgram/ml, 514 nm light, 25 J/cm2). Changes of metastatic patterns of PROb cells have been assessed by the subcutaneous injection of non-lethally treated BPD or Photofrin cells and counting lung metastases. First, we confirm the metastatic potential reduction induced by PDT with respectively a 71 or 96% decrease of the mean number of metastases (as compared with controls) for PROb cells treated with 50 ng/ml BPD and 10 or 20 J/cm2 irradiation. Concerning Photofrin-PDT-treated cells, we find respectively a 90 or 97% decrease (as compared with controls) of the mean number of metastases for PROb cells treated with 0.5 microgram/ml Photofrin and 25 or 50 J/cm2 irradiation. Then, we observe that CD44V6, its lectins (àHt1.3, PNA, SNA) and MHC-I are significantly decreased (compared with the other molecules tested) in PROb and REGb cells after both BPD and Photofrin PDT treatment. These modifications in adhesion-molecule expression, particularly of CD44V6, can thus account only for part of the decrease in the metastatic potential of PDT-treated cancer cells. Changes in adhesion-molecule expression induced by PDT are only transient, implying that the rate of metastatic reduction is probably not linked simply to these changes.