The cancer stem cell: evidence for its origin as an injured autoreactive T cell

Development and Validation of a Robust Pyroptosis-Related Signature for Predicting Prognosis and Immune Status in Patients with Colon Cancer

BACKGROUND

Pyroptosis has been confirmed as a type of inflammatory programmed cell death in recent years. However, the prognostic role of pyroptosis in colon cancer (CC) remains unclear.

METHODS

Dataset TCGA-COAD which came from the TCGA portal was taken as the training cohort. GSE17538 from the GEO database was treated as validation cohorts. Differential expression genes (DEGs) between normal and tumor tissues were confirmed. Patients were classified into two subgroups according to the expression characteristics of pyroptosis-related DEGs. The LASSO regression analysis was used to build the best prognostic signature, and its reliability was validated using Kaplan-Meier, ROC, PCA, and t-SNE analyses. And a nomogram based on the multivariate Cox analysis was developed. The enrichment analysis was performed in the GO and KEGG to investigate the potential mechanism. In addition, we explored the difference in the abundance of infiltrating immune cells and immune microenvironment between high- and low-risk groups. And we also predicted the association of common immune checkpoints with risk scores. Finally, we verified the expression of the pyroptosis-related hub gene at the protein level by immunohistochemistry.

RESULTS

A total of 23 pyroptosis-related DEGs were identified in the TCGA cohort. Patients were classified into two molecular clusters (MC) based on DEGs. Kaplan-Meier survival analysis indicated that patients with MC1 represented significantly poorer OS than patients with MC2. 13 overall survival- (OS-) related DEGs in MCs were used to construct the prognostic signature. Patients in the high-risk group exhibited poorer OS compared to those in the low-risk group. Combined with the clinical features, the risk score was found to be an independent prognostic factor of CC patients. The above results are verified in the external dataset GSE17538. A nomogram was established and showed excellent performance. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that the varied prognostic performance between high- and low-risk groups may be related to the immune response mediated by local inflammation. Further analysis showed that the high-risk group has stronger immune cell infiltration and lower tumor purity than the low-risk group. Through the correlation between risk score and immune checkpoint expression, T-cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) was predicted as a potential therapeutic target for the high-risk group.

CONCLUSION

The 13-gene signature was associated with OS, immune cells, tumor purity, and immune checkpoints in CC patients, and it could provide the basis for immunotherapy and predicting prognosis and help clinicians make decisions for individualized treatment.

Lung cancer stem cells-origin, characteristics and therapy

Cancer stem cells (CSCs) have gained an increasing attention recently in cancer research. CSCs have ability to generate new tumor through their stem cell properties, essentially self-renewal potential and differentiation into multiple cell lineages. Extensive evidences report that CSCs are resistant to many conventional therapies and mediate tumor recurrence. CSCs of lung cancer are well recognized by their specific markers such as CD133, CD44, ABCG2 and ALDH1A1 together with the CSC characteristics including spheroid and colony formation. Targeting these surface proteins with blocking antibodies and inhibition of ABC transporters and aldehyde dehydrogenase (ALDH) enzymes with small molecules may prove useful in inhibiting tumor progression. The Hh, Notch and Wnt pathways are key signaling cascades that govern cell fate during development and have been shown to be involved in CSCs in various solid tumors. Therapeutic approaches also target these signaling pathways in repressing the tumor progression. This review will focus on stem cell origins, role of signaling pathways, stem cell markers and therapeutic approaches specific to lung cancer.

Expression and prognostic significance of Oct4 and Nanog in neuroblastoma

Neuroblastoma is the most common extracranial solid tumor of children, accounting for an estimated 15% cancer-related deaths in this period. It has been hypothesized that drug resistance of cancer stem cells may be responsible for chemotherapy failure, sustained tumor growth, and recurrence in many solid tumors. In this study, we investigated the expression of Octamer-binding transcription factor 4 (Oct4) and Nanog, two stem cell markers, in 47 neuroblastic tumors by immunohistochemistry and correlated their expression by other prognostic factors especially with NMYC amplification using both fluorescent and chromogenic in situ hybridization methods. Twenty three cases (48.9%) showed Oct4 signals and eight cases (17%) showed Nanog expression. All Nanog positive tumors showed Oct4 expression. Seven cases (14.1%) had NMYC amplification. There was also no association between positive Oct4 and Nanog reactivity and tumor morphology, age, mitosis-karyorrhexis index, NMYC amplification, favorable or unfavorable histology, and risk groups (p > 0.05). Cancer stem cells hypothesis is a challenging issue and controversies exist about their significance. Although our study did not show strong association between prognostic factors and expression of stem cell markers, performing of further large-scale studies of various neuroblastic tumors with various stages is suggested.

Identification of cancer stem cells provides novel tumor models for drug discovery

Cancer stem cells (CSCs) have received considerable attention from the research community since they were first reported in human acute myeloid leukemia 15 years ago. Accumulating evidence suggests that CSCs are responsible for tumor initiation and progression, drug resistance, and metastasis in both liquid and solid tumors. These findings lead to the development of novel compounds targeting CSC populations that is becoming increasingly important for eradicating CSCs in heterogeneous tumor masses and to cure the cancer. Since 2003, we have participated in CSC studies and encountered crucial early events in the field. This article reviews the history of CSC biology, clarifies the term and its definition, and further addresses the issue of how to utilize CSCs in therapeutic target discovery and drug development based on our substantial experience.

Atypical autoimmune polyglandular syndrome type 3 overlapped by chronic HCV infection resulting in carcinogenesis and fatal infection

The case of a woman with insulin-dependent diabetes mellitus, autoimmune thyroiditis, atrophic gastritis, pernicious anemia, and immunologic thrombocytopenic purpura consisting of autoimmune polyglandular syndrome type 3 associated with a history of gonadal failure is reported. Hepatitis C viral infection added xerophthalmia, lymphocytic sialadenitis, and exacerbation of idiopathic thrombocytopenic purpura. This unique disease constellation was complicated with splenic marginal zone lymphoma and gastric carcinoids. A lung infection, initially treated on an outpatient basis, proved fatal to the patient.

Target cells in graft-versus-host disease: implications for cancer therapy

Acute graft-versus-host disease (GVHD) conceptually may be divided into three evolutionary stages: allostimulation, effector cell homing to specific tissues, and cellular targeting and injury. Surprisingly, little is known regarding the targeting stage of GVHD. Recently, we have learned that epithelial target cell injury is mediated by specific subpopulations of effector T cells that may be identified based on Vbeta family expansion during allostimulation. Antibody probes specific for these Vbeta families have permitted precise identification of effector cell homing patterns. In squamous epithelium, allospecific T cells selectively home to basal cell layer subpopulations that express cytokeratin 15 (CK15) and that undergo target cell injury via apoptosis. Interestingly, these target cells coincide with basal layer subpopulations that have properties of epithelial stem cells and that normally express an apoptosis-resistant genomic profile. Accordingly, epithelial cell injury in GVHD appears to involve selective targeting of stem-cell subpopulations via conversion from an anti-apoptotic to a pro-apoptotic phenotype. Understanding of the mechanism(s) of this conversion could facilitate development of translationally relevant approaches to shielding target cells from injury in GVHD. Moreover, determination of how putative apoptosis-resistant stem cells may be rendered vulnerable to immune-mediated targeting has implications potentially relevant to more directed immunotherapeutic approaches focused at elimination of neoplastic (cancer) stem cells.

Cancer cell: using inflammation to invade the host

Background

Inflammation is increasingly recognized as an important component of tumorigenesis, although the mechanisms involved are not fully characterized. The invasive capacity of cancers is reflected in the classic metastatic cascade: tumor (T), node (N) and metastasis (M). However, this staging system for cancer would also have a tumoral biological significance.

Presentation of the hypothesis

To integrate the mechanisms that control the inflammatory response in the actual staging system of cancer. It is considered that in both processes of inflammation and cancer, three successive phenotypes are presented that represent the expression of trophic functional systems of increasing metabolic complexity for using oxygen.

Testing the hypothesis

While a malignant tumor develops it express phenotypes that also share the inflammatory response such as: an ischemic phenotype (anoxic-hypoxic), a leukocytic phenotype with anaerobic glycolysis and migration, and an angiogenic phenotype with hyperactivity of glycolytic enzymes, tumor proliferation and metastasis, and cachexia of the host. The increasing metabolic complexity of the tumor cell to use oxygen allows for it to be released, migrate and proliferate, thus creating structures of growing complexity.

Implication of the hypothesis

One aim of cancer gene therapy could be the induction of oxidative phosphorylation, the last metabolic step required by inflammation in order to differentiate the tissue that it produces.

Impact of tiny miRNAs on cancers

miRNAs are a class of small, ~22nt, non-coding RNAs that negatively regulate gene expression at the post-transcriptional level. They play profound and pervasive roles in manipulating gene expression involved in cell development, proliferation and apoptosis in various eukaryotes, which, in theory, could provide an access to many human diseases in theory. Recent evidence demonstrates that aberrant miRNA expression is a hallmark of tumor development, revealing that miRNA genes could function as potential oncogenes and repressors in the human body. miRNAs can affect tumorigenesis mainly by interrupting the cell cycle at the cellular level and by interacting with signaling, oncogenes and with the response to environmental factors at the molecular level. The established miRNA expression signature could be a potent tool to diagnose and treat human cancers in the future.

Cellular basis of cancer metastasis: A review of fundamentals and new advances

This review provides an introduction to fundamentals and new advances in cancer metastasis for general readers. The first segment includes topics such as cell adhesion, cell migration, proteases, inflammation, coagulation and site selection in metastasis. Then follows a discussion of an interesting report by Kaplan et al. [VEGFR1-positive haematopoietic bone marrow progenitors initiate the pre-metastatic niche. Nature 2005;438:820-7] that provides evidence for a role of VEGFR1+bone marrow cells in preparing pre-metastatic niches in specific organs that host the arrival and growth of metastatic cancer cells. The therapeutic implications of this study are explored.