CD133 Expression as a Helicobacter pylori-independent Biomarker of Gastric Cancer Progression

A novel approach for transforming breast cancer stem cells into endothelial cells

Tumor vascular endothelial cells play a pivotal in the tumor microenvironment, influencing the proliferation, invasion, and metastasis of tumor progression. The present study investigated a novel method for inducing the transformation of breast cancer stem cells into endothelial cells, providing a cellular model investigating anti-angiogenic mechanisms in vitro. The breast cancer cell line MCF-7 was used, and the expression of CD133 was initially detected using flow cytometry. CD133+ breast cancer cells were purified using immunomagnetic bead sorting technology, yielding an MCF-7CD133+ subpopulation. The proliferation ability of these cells was assessed using an MTT assay, while their microsphere formation ability was evaluated using a microsphere formation assay. Post-transformation in an optimized endothelial cell culture medium, expression of endothelial cell markers CD31 and CD105 were detected using flow cytometry. Endothelial cell tube formation assays and DiI-labeled acetylated low-density lipoprotein (DiI-Ac-LDL) assays were employed to analyze the endothelial cell function of the MCF-7CD133+ cells. MDM2/CEN12 gene amplification was detected through fluorescence in situ hybridization (FISH). The MCF-7 breast cancer cell line exhibited 1.7±0.3% trace cells expressing the stem cell surface marker CD133. After anti-CD133 immunomagnetic bead sorting, MCF-7CD133+ and MCF-7CD133- subpopulation cells were obtained, with CD133 expression rates of 85.6±2.8 and 0.18±0.08%, respectively. MTT assay results demonstrated that, after 7 days, the proliferation rate of MCF-7CD133+ cells was significantly higher compared with MCF-7CD133- cells. MCF-7CD133+ subpopulation cells displayed strong stem cell characteristics, growing in suspension in serum-free media and forming tumor cell spheres. In contrast, MCF-7CD133- cells failed to form microspheres. After culturing cells in endothelial cell differentiation and maintenance media, the percentage of MCF-7CD133+ cells before and after endothelial cell culture was 0.3±0.16 and 81.4±8.37% for CD31+ cells and 0.2±0.08 and 83.8±7.24% for CD105+ cells, respectively. Vascular-like structure formation and Ac-LDL phagocytosis with red fluorescence in the tube formation assays confirmed endothelial cell function in the MCF-7CD133+ cells. FISH was used to verify MDM2/CEN12 gene amplification in the induced MCF-7CD133+ cells, indicating tumor cell characteristics. The modified endothelial cell transformation medium effectively induced differentiated tumor stem cells to express vascular endothelial cell markers and exhibit endothelial functions, ideal for in vitro anti-angiogenesis research.

Immunohistochemical Expression of CD90, CD133, and TPM1 in Relation to Gastric Cancer and H. pylori Association

BACKGROUND

Gastric cancer (GC) is the second most common cause of cancer-related death worldwide. Multiple malignancies overexpress CD90, making it a helpful diagnostic and prognostic marker. CD133 is suggested to be related to poor prognosis in GC. Tropomyosin-1 (TPM1) tumor-suppressor gene low expression may predict poor survival in GC. Our study aimed to investigate CD90, CD133, and TPM1 immunohistochemical expression in GC in relation to diagnosis, prognosis, and Helicobacter pylori (H. pylori) infection.

METHODS

144 paraffin blocks containing gastric cancerous (108 cases), and non-cancerous (36 cases) tissue were analyzed histopathologically for the type of lesion, grade, and stage of malignancy and by using an immunohistochemical assay for studying the expression of CD90, CD133, and TPM1. Data analysis was carried out using the Statistical Package for the Social Sciences (SPSS) version 20.0.

RESULTS

The obtained results showed a significantly higher expression of CD90 and CD133 while showing a significantly lower expression of TPM1 in malignant samples compared to benign ones. CD90 was significantly higher in grade-3, stage-3, and N3 (p<0.05), with no significant difference concerning positive and negative H. pylori samples. CD133 percentage and H-score were significantly higher in grade-2 and stage-4 tumors than in other grades and stages, while being insignificantly higher in N3 and H. pylori-positive cases. TPM1 expression levels were significantly downregulated in GC and H. pylori-positive cases (p<0.05). TPM1 downregulation was associated with grade progression, increased depth of invasion, and tumor node metastasis.

CONCLUSION

CD90, CD133, and TPM1 immunohistochemical expression in the gastric biopsy are related firmly to grades and stages of GC as well as H. pylori infection, so they could be of prognostic value. Further studies on a larger sample size are recommended.

The adenosine-A2a receptor regulates the radioresistance of gastric cancer via PI3K-AKT-mTOR pathway

BACKGROUND

Radiotherapy is a key strategy in gastric cancer (GC) treatment. However, radioresistance remains a serious concern. It is unclear whether the accumulation of adenosine A2a receptor (ADO-A2aR) is related to radioresistance in GC. In this study, the molecular role of ADO-A2aR in GC radioresistance was investigated.

METHODS

Colony formation assays were used to assess the role of ADO-A2aR on radioresistance. GC stem cell surface marker expression (including Nanog, OCT-4, SOX-2 and CD44) and PI3K/AKT/mTOR signaling pathway associated protein levels (including phosphorylated PI3K, phosphorylated AKT and phosphorylated mTOR) were determined via western blotting, flow cytometry and immunofluorescence. In addition, the role of ADO-A2aR on radioresistance was explored in vivo using murine xenograft models.

RESULTS

ADO-A2aR regulated GC cell stemness both in vitro and in vivo. This was shown to induce radioresistance in GC. ADO-A2aR was revealed to significantly induce cell cycle arrest and promote GC cell apoptosis. These activities were closely linked to activation of the PI3K/AKT/mTOR pathway.

CONCLUSION

This study identified that ADO enhances GC cell stemness via interaction with A2aR and subsequent activation of the PI3K/AKT/mTOR pathway. Ultimately, this resulted in radioresistance. A2aR is a potential target to improve GC radiosensitivity.

Emerging roles of CD133 in the treatment of gastric cancer, a novel stem cell biomarker and beyond

Gastric cancer (GC) is an aggressive disease with one of the highest mortality rates in the world. In the early stage, most patients are asymptomatic and early diagnosis is difficult. Recently, cancer stem cells (CSCs) have been highlighted as crucial emerging factors in the initiation or invasiveness of solid tumors. CD133, a CSC marker, is highly expressed in various tumors including gastric cancer. CD133-positive cells showed elevated malignant biological behaviors and CD133 upregulation is related to chemoresistance, cancer relapse, and poor prognosis. CD133 also plays an important role in the progression of tumors and metastasis. This review summarizes the current knowledge of the role of CD133 expression in GC and aims to contribute at identifying promising new strategies for treatment and management of gastric cancer.

Cancer Stem Cells-Origins and Biomarkers: Perspectives for Targeted Personalized Therapies

The use of biomarkers in diagnosis, therapy and prognosis has gained increasing interest over the last decades. In particular, the analysis of biomarkers in cancer patients within the pre- and post-therapeutic period is required to identify several types of cells, which carry a risk for a disease progression and subsequent post-therapeutic relapse. Cancer stem cells (CSCs) are a subpopulation of tumor cells that can drive tumor initiation and can cause relapses. At the time point of tumor initiation, CSCs originate from either differentiated cells or adult tissue resident stem cells. Due to their importance, several biomarkers that characterize CSCs have been identified and correlated to diagnosis, therapy and prognosis. However, CSCs have been shown to display a high plasticity, which changes their phenotypic and functional appearance. Such changes are induced by chemo- and radiotherapeutics as well as senescent tumor cells, which cause alterations in the tumor microenvironment. Induction of senescence causes tumor shrinkage by modulating an anti-tumorigenic environment in which tumor cells undergo growth arrest and immune cells are attracted. Besides these positive effects after therapy, senescence can also have negative effects displayed post-therapeutically. These unfavorable effects can directly promote cancer stemness by increasing CSC plasticity phenotypes, by activating stemness pathways in non-CSCs, as well as by promoting senescence escape and subsequent activation of stemness pathways. At the end, all these effects can lead to tumor relapse and metastasis. This review provides an overview of the most frequently used CSC markers and their implementation as biomarkers by focussing on deadliest solid (lung, stomach, liver, breast and colorectal cancers) and hematological (acute myeloid leukemia, chronic myeloid leukemia) cancers. Furthermore, it gives examples on how the CSC markers might be influenced by therapeutics, such as chemo- and radiotherapy, and the tumor microenvironment. It points out, that it is crucial to identify and monitor residual CSCs, senescent tumor cells, and the pro-tumorigenic senescence-associated secretory phenotype in a therapy follow-up using specific biomarkers. As a future perspective, a targeted immune-mediated strategy using chimeric antigen receptor based approaches for the removal of remaining chemotherapy-resistant cells as well as CSCs in a personalized therapeutic approach are discussed.

DYNC1I1 Promotes the Proliferation and Migration of Gastric Cancer by Up-Regulating IL-6 Expression

Gastric cancer is one of the top five malignant tumors worldwide. At present, the molecular mechanisms of gastric cancer progression are still not completely clear. Cytoplasmic dynein regulates intracellular transport and mitotic spindle localization, and its abnormal function is crucial for tumorigenesis, promotes tumor cell cycle progression, and tumor migration. DYNC1I1 is an important binding subunit of cytoplasmic dynein. However, studies on DYNC1I1 in tumors are currently limited. In the current study, we found that high DYNC1I1 expression in gastric cancer is associated with poor prognosis and is an independent prognostic factor. DYNC1I1 promoted the proliferation and migration of gastric cancer cells both in vitro and in vivo. DYNC1I1 also upregulated IL-6 expression by increasing NF-κB nuclear translocation. Collectively, these data revealed an important role for the DYNC1I1-driven IL-6/STAT pathway in gastric cancer proliferation and migration, suggesting that DYNC1I1 may be a potential therapeutic target for gastric cancer.