The CD44std and CD44v9 subpopulations in non-tumorigenic invasive SNU-423 cells present different features of cancer stem cells

Hepatocellular carcinoma (HCC) is a type of liver cancer, in which CD44 isoforms have been proposed as markers to identify cancer stem cells (CSCs). However, it is unclear what characteristics are associated with CSCs that exclusively express CD44 isoforms. The objective of the present study was to determine the expression of CD44 isoforms and their properties in CSCs. Analysis of transcriptomic data from HCC patient samples identified CD44v8-10 as a potential marker in HCC. In SNU-423 cells, CD44 expression was detected in over 99% of cells, and two CD44 isoforms, namely, CD44std and CD44v9, were identified in this cell line. CD44 subpopulations, including both CD44v9+ (CD44v9) and CD44v9- (CD44std) cells, were obtained by purification using a magnetic cell separation kit for human CD44v9+ cancer stem cells. CD44v9 cells showed greater potential for colony and spheroid formation, whereas CD44std cells demonstrated significant migration and invasion capabilities. These findings suggested that CD44std and CD44v9 may be used to identify features in CSC populations and provide insights into their roles in HCC.

Late recurrent gastric carcinoma 12 years after surgery with attenuation of CD44 variant 9 expression

BACKGROUND

Late recurrence of gastric cancer at 10 years post-gastrectomy is extremely rare, and the underlying mechanism remains unclear. We report a para-aortic lymph node metastasis case that recurred 12 years postoperatively.

CASE PRESENTATION

A 44-year-old woman pathologically diagnosed with moderately to poorly differentiated adenocarcinoma with pT2(SS)pN2cM0pStageIIIA according to the Japanese Classification of Gastric Carcinoma (the 13th Edition) underwent laparoscopic distal gastrectomy with D1 + lymph node dissection. She received adjuvant chemotherapy with tegafur-uracil (400 mg/day) for 2 years. At postoperative year (POY) 5, a swollen lymph node was detected in the No.16b1lat lymph node station. However, positron emission tomography (PET) revealed normal uptake, and the levels of tumor markers were within normal limits; hence, the possibility of metastasis was considered low, and the patient was placed under observation. At POY 12, computed tomography revealed an enlargement of the No.16b1lat lymph node station, and PET showed abnormal uptake. Endoscopic ultrasound-guided fine-needle aspiration revealed a moderately differentiated adenocarcinoma. Hence, a diagnosis of recurrence of gastric cancer was made. The patient underwent para-aortic nodal dissection (PAND) of No.16b1lat & int stations. Immunochemical staining results also suggested the recurrence of gastric cancer. However, the expression of CD44 variant 9 (CD44v9), a cancer stem cell marker for gastric adenocarcinoma, was attenuated in the recurrent lesions compared with that in the primary lesions. Postoperatively, she received chemotherapy with tegafur-gimeracil-oteracil (80 mg/day) for 1 year. Bone metastasis was observed at POY 4 after PAND, and the IHC analysis showed a HER2 score of 3 + in a needle biopsy specimen of bone metastasis. The expression of CD44v9 was slightly positive. The patient is being treated with chemotherapy with FOLFOX + trastuzumab.

CONCLUSIONS

A defense mechanism against reactive oxygen species has been reported as a mechanism causing recurrence of CD44v9-positive gastric cancer. Consequently, CD44v9-positive gastric cancer grows in metastatic organs, repeatedly self-renews, and proliferates to form recurrent lesions. In the present case, the degree of CD44v9 staining in recurrent lesions was suggested to be related to the recurrence time.

Expression of CD44 variant 9 induces chemoresistance of gastric cancer by controlling intracellular reactive oxygen spices accumulation

BACKGROUND

CD44 variant 9 (CD44v9) has been reported to suppress reactive oxygen spices (ROS) in association with antioxidant factors such as glutathione (GSH) and glutathione peroxidase 2 (GPx2), resulting in promoted tumor growth.

METHODS

CD44v9 and GPx2 expression were investigated by immunohistochemistry in resected specimens from 193 gastric cancer (GC) patients without preoperative chemotherapy and in pretreatment biopsy specimens from 29 GC patients with preoperative chemotherapy. We analyzed the relationship between CD44v9 expression and clinicopathological factors, prognosis, and pathological response to chemotherapy. In GC cell lines, we examined the relationship between CD44v9 expression and chemotherapeutic sensitivity.

RESULTS

In patients without preoperative chemotherapy, CD44v9 expression was significantly associated with depth of invasion, lymphatic permeation, vascular invasion, distant metastasis and GPx2 expression. In multivariate analysis, CD44v9 expression was an independent poor prognosis factor for overall survival and recurrence-free survival. In patients with preoperative chemotherapy, CD44v9 expression was significantly associated with worse pathological response and GPx2 expression. In GC cell lines, downregulation of CD44v9 expression enhanced chemotherapeutic sensitivity to 5-fluorouracil with changing GSH and ROS levels.

CONCLUSIONS

CD44v9-positive expression was associated with chemotherapeutic resistance by controlling intracellular accumulated ROS, suggesting that CD44v9 may be a predictive biomarker for chemotherapy in GC.

Trop2 is upregulated in the transition to dysplasia in the metaplastic gastric mucosa

Intestinal-type gastric adenocarcinoma arises in a field of pre-existing metaplasia. While biomarkers of cancer and metaplasia have been identified, the definition of dysplastic transition as a critical point in the evolution of cancer has remained obscure. We have evaluated Trop2 as a putative marker of the transition from metaplasia to dysplasia in the stomach in multiple mouse models of metaplasia induction and progression. In addition, TROP2 expression was evaluated in human samples by immunostaining tissue microarrays for metaplasia, dysplasia, and gastric cancer. Dysplastic mouse organoids were evaluated in vitro following shRNA knockdown of Trop2 expression. In mouse models, no Trop2 was observed in the normal corpus and Trop2 was not induced in acute models of metaplasia induction with either L635 or DMP-777. In Mist1-Kras mice, Trop2 expression was not observed in metaplasia at 1 month after Kras induction, but was observed in dysplastic glands at 3-4 months after Kras induction. In human tissues, no Trop2 was observed in normal corpus mucosa or SPEM, but Trop2 expression was observed in incomplete intestinal metaplasia, with significantly less expression in complete intestinal metaplasia. Trop2 expression was observed in all dysplastic and 84% of gastric cancer lesions, although expression levels were variable. Dysplastic mouse organoids from Mist1-Kras mice expressed Trop2 strongly. Knockdown of Trop2 with shRNA markedly reduced organoid growth and budding behavior, and induced the upregulation of apical villin expression. We conclude that Trop2 is upregulated in the transition to dysplasia in the stomach and promotes dysplastic cell behaviors. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

CD44v9 Induces Stem Cell-Like Phenotypes in Human Cholangiocarcinoma

Background: Our previous study demonstrated an overexpression of CD44 variant 9 (CD44v9) in human cholangiocarcinoma (CCA) tissues that was associated with inflammation-related tumor development. However, the participation of CD44v9 in cholangiocarcinogenesis remains poorly understood. Therefore, in this study, we examined the potential roles of CD44v9 in CCA cells to understand the carcinogenic mechanism. Methods: Using normal cholangiocytes (MMNK1) and CCA cells (KKU213), the expression levels of CD44v9 and its related molecules were quantified through RT-qPCR and immunofluorescence (IF) staining. To evaluate its biological functions, we performed CD44v9 (exon 13) silencing using siRNA transfection, and assessed cell proliferation through MTT assay, cell migration and invasion by transwell technique, and carried out cell cycle analysis by flow cytometry. In vivo tumor growth was assessed by nude mouse xenografts, and histological and molecular changes were determined. Results: KKU213 exhibited higher protein expression levels of CD44v9 than those of MMNK1 through IF staining. RT-qPCR analysis revealed that the mRNA expression level of CD44v9 was predominantly elevated in CCA cells along with its neighboring exons such as variant 8 and 10, minimally affecting the standard form of CD44. CD44v9 silencing could regulate redox system in CCA cells by reducing the expression levels of SOD3 and cysteine transporter xCT. CD44v9 silencing suppressed the CCA cell proliferation by induction of apoptosis and cell cycle arrest. Migration and invasion were decreased in CD44v9 siRNA-treated CCA cells. CD44v9 downregulation inhibited CCA tumor growth in mouse xenografts. IF analysis demonstrated the histological changes in xenograft tissues such as an increase in connective tissues through collagen deposition and reduction of hyaluronic acid synthesis through CD44v9 silencing. CD44v9 knockdown in vitro and in vivo increased E-cadherin and reduced vimentin expression levels, resulting in reduction of epithelial-mesenchymal transition (EMT) process. Moreover, CD44v9 modulated Wnt10a and β-catenin in tumorigenesis. Conclusion: Our results indicate that CD44v9 plays a potential role in CCA development by the regulation of cell proliferation and redox balancing. CD44v9 silencing may suppress tumor growth, migration and invasion through EMT: a finding that could potentially be applied in the development of targeted cancer therapy.

Inhibiting xCT Improves 5-Fluorouracil Resistance of Gastric Cancer Induced by CD44 Variant 9 Expression

BACKGROUND/AIM

Cancer stem cells (CSCs) play a critical role in resistance to chemotherapy. CD44 is a cell surface marker of CSCs. CD44 variant 9 (CD44v9) interacts with a cystine-glutamate antiporter (xCT) and is an unfavorable predictive factor in gastric cancer. We investigated the impact of CD44v9 expression on 5-fluorouracil (5-FU) resistance and the efficacy of the xCT inhibitor, sulfasalazine (SASP), in improving drug resistance.

MATERIALS AND METHODS

The human gastric cancer cell line MKN28 was transfected with pRc/CMV plasmids encoding human CD44 or CD44v9, which were used for in vitro and in vivo experiments.

RESULTS

CD44v9 expression results in 5-FU resistance by increasing intracellular glutathione and suppressing the drug-induced production of reactive oxygen species (ROS). SASP improved the drug sensitivity of CD44v9-expressing cells.

CONCLUSION

Inhibition of xCT improved the clinical efficacy of chemotherapy against gastric cancer. CD44v9 expression can be a novel biomarker to predict resistance against 5-FU in gastric cancer.

Distinct metaplastic and inflammatory phenotypes in autoimmune and adenocarcinoma-associated chronic atrophic gastritis

BACKGROUND

Autoimmune gastritis (AIG) and adenocarcinoma-associated chronic atrophic gastritis (CAG) are both associated with oxyntic atrophy, but AIG patients demonstrate an increased risk of carcinoid tumors rather than the elevated risk of adenocarcinoma observed with CAG. We therefore sought to compare the characteristics of the metaplastic mucosa in AIG and CAG patients.

METHODS

We examined markers for metaplasia (spasmolytic polypeptide expressing metaplasia (SPEM) and intestinal metaplasia) as well as proliferation (Ki67) and immune cell populations (neutrophils, macrophages, and eosinophils) in gastric sections from 16 female patients with autoimmune thyroiditis and AIG and 17 patients with CAG associated with gastric adenocarcinoma.

RESULTS

Both AIG and CAG patients demonstrated prominent SPEM and intestinal metaplasia. However, AIG patients displayed significantly lower numbers of infiltrating macrophages and significantly reduced mucosal cell proliferation as compared to CAG patients.

CONCLUSIONS

These findings indicate that, while both AIG and CAG patients display prominent oxyntic atrophy and metaplasia, the AIG patients do not show proliferative metaplastic lineages that would predispose to adenocarcinoma.