Features of lung cancer carcinogenesis involving cancer stem cells in COVID-19. Effects of photodynamic therapy in the treatment of cancer and COVID-19

1942P IL6 pre-treatment promotes chemosensitivity by eliminating quiescent cancer stem cells

Moving Forward in Human Mammary Stem Cell Biology and Breast Cancer Prognostication Using ALDH1

Cancer Stem Cell–Directed Therapies: Recent Data From the Laboratory and Clinic

The Sixteenth International Symposium of the Hiroshima Cancer Seminar (HCS) Foundation was held on October 22 2006 at the International Conference Center, Hiroshima. The symposium consisted of 10 special lectures and 23 free paper presentations for a poster session. About 230 people were present and actively discussed cancer stem cells. Prior to this symposium, an Open Lecture to the public by HCS and the Japan Society for Dying with Dignity was held on October 21 where Shigehito Yamawaki (Hiroshima University, Hiroshima) and Kazuko Hamanaka (Hamanaka Dermatological Clinic, Hiroshisma) spoke about Psycho-oncology and Breast Cancer to more than 260 people. Eiichi Tahara (Hiroshima Cancer Seminar Foundation), Chairman of the Organizing Committee of the Sixteenth International Symposium, and Chairman of the HCS Foundation, gave an opening address. Tahara introduced a brief background and the purpose of this series of symposia. Since the establishment of the HCS Foundation in 1992, annual international symposia are organized to create an opportunity for basic scientists and clinical researchers to exchange ideas for cancer research, cancer prevention and cancer therapy. This year, the organizing committee planned to explore the important issue of cancer stem cells. Stem cells have a critical role not only in the generation of new populations of normal cells but also in the development of tumors. The balance between self-renewal and differentiation is strictly regulated to maintain normal stem cell pools and to generate the required supply of fully differentiated cells. Recent evidence has suggested that a subset of cancer cells within the tumor, so-called cancer stem cells, may drive the growth and progression of the tumor. Eradication of cancer stem cells may be essential to a cure for cancer. Advances in our knowledge that regulate proliferation, self-renewal, survival and differentiation of cancer stem cells and normal stem cells may shed light on the mechanism that leads to cancer and perhaps improve cancer treatment. The participants will be able to profit by exchanging ideas and learning from the informative presentations and discussions, and will contribute to our understanding of stem cells in relation to cancer development and treatment.

Downregulation of miRNA-200c Links Breast Cancer Stem Cells with Normal Stem Cells

Reflection of stem cell therapy: An epilogue to the ‘Stem cells and the lung’ review series

Bone Marrow-Derived Cells Are Not the Origin of the Cancer Stem Cells in Ultraviolet-Induced Skin Cancer

We have used hTERT (the catalytic component of telomerase) to immortalize a variety of human cell types (sometimes in combination with Cdk4 to bypass cell culture stress). Cell types immortalized include skin keratinocytes and fibroblasts, muscle satellite cells, breast epithelial and stromal cells, corneal epithelial cells and fibroblasts (keratocytes), and human colonic epithelial cells. In addition, we have immortalized human bronchial epithelial cells (HBEC) and have determined that these cells can terminally differentiate into both central and peripheral lung cell types. These immortalized HBECs have been used to study the molecular pathogenesis of lung cancer by stable “knock down” of TP53 and also by over-expression of C-myc and mutant K-rasV12. When these cells containing multiple genetic alterations are introduced into immunosuppressed mice, the experimentally transformed cells make tumors that represent several distinct histological types. This suggests that these immortalized and transformed HBECs have bronchiolar-alveolar stem-like characteristics that can differentiate into multiple lineages. Stem cells are defined by both their ability to make more stem cells (self renewal) and their ability to produce cells that can differentiate. Experimentally immortalized human bronchial epithelial cells fulfill this definition of normal stem cells by continuous self renewal and by retaining the capability of differentiating into several cell types. Since experimentally transformed cells make lung tumors representing several major lineages, this is also an indication that the HBECs are derived from a multi-potent lung stem cell. Similar to normal stem cells, cancer (initiating) stem cells also have the ability to self-renew as well as undergo differentiation to give rise to phenotypically diverse types of cancer cells. There is mounting evidence that these rare cancer stem cells may be multidrug resistant and responsible for tumor relapse and metastasis. Targeted cancer therapeutic approaches seek to identify pathways that are more tumor specific, resulting in fewer side-effects and that may produce long-term durable responses. Telomerase is a novel cancer therapeutic target since it is activated in the vast majority of human cancers and telomeres of almost all human tumor cells are maintained at short but stable lengths. In addition, telomerase is not expressed or is expressed at levels that do not fully maintain telomeres in normal tissues, and telomeres are generally longer in normal stem cells compared to cancer cells. This potentially provides a therapeutic advantage for targeting telomerase over approaches that affect both normal and cancer cells equally. We have previously reported that telomerase positive cancer cells that are experimentally induced to undergo quiescence, down regulate telomerase. As part of our anti-telomerase therapeutics program, we have addressed the following questions: Are putative cancer stem cell populations quiescent and do they have short or long telomeres? While the molecular characteristics of cancer stem cells are not completely defined and subject to some controversies, we have isolated and examined cells expressing these cancer stem cell putative markers reported for breast, brain, prostate, pancreas, and lung cancer. In each case we have observed that purified cancer stem cell populations are positive for telomerase activity, indicating they are not quiescent. In addition, a telomerase inhibitor currently being tested in clinical trials robustly inhibits the activity of telomerase in these sorted sub-populations of putative cancer stem cells as well as the mass population of cancer cells. Finally, we have observed that cancer stem cells have short telomeres in comparison to normal stem cells. These findings support the idea that there may be a therapeutic window of opportunity to target cancer stem cells by inhibiting telomerase, thus driving telomeres progressively shorter leading to cancer stem cell death, potentially without irreversible damage to normal stem cells. Cancer remains a major cause of death in spite of substantial progress towards understanding the molecular basis of many types of cancers. The discovery of new drugs is a high priority, and telomerase inhibitors have the potential to act by a novel mechanism that will provide new options for cancer therapy. A review of ongoing anti-telomerase clinical trials will be presented. In summary, telomerase inhibitors might not only directly limit or stop the growth of human tumors including cancer stem cells, but might also act in an additive or synergistic fashion with existing therapies to amplify their effectiveness. Citation Format: Jerry W. Shay. Role of telomerase in normal and neoplastic stem cells [abstract]. In: Proceedings of the AACR 101st Annual Meeting 2010; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr SY33-03

Photodynamic Therapy for Early Stage Central Type of Lung Cancer

This article is based on discussions of the lung cancer panel at the Hohenheim Consensus Meeting organized by the World Health Organization and the German Ministry of Health in November 1996. Panel members were international experts in the field of diet and cancer who discussed specific questions relating to lung cancer risk factors and prevention.

The emerging theory of cancer stem cells (CSC) postulates that cells in a tumor are hierarchically organized, so that only a subpopulation of cells has the capacity for sustaining tumor growth, and regenerating a heterogeneous tumor. Conceptually, CSC can be resistant to therapies that reduce tumor bulk, and therefore responsible for micrometastatic disease and local recurrence. The existence of CSC challenges the current paradigm of cancer treatment by implying that the fundamental test of most current therapies, i.e., their ability to reduce tumor size, may be inadequate unless it is ensured that the subpopulation of cells within a tumor with self-renewal properties is completely eradicated. Thus, their molecular definition is crucial to the development of innovative therapeutic strategies. Specific cell surface markers, analogous to those found in normal stem cells of the corresponding tissue, has proven useful for enrichment of CSC activity in several tissues. Viable human lung CSC have been isolated through their expression of CD133 or CD166 and within cell fractions characterized by intrinsic stem cell properties, such as high ALDH enzymatic activity or dye efflux (side population). CSC can be live-sorted based on these markers and xenotransplantated into immunodeficient mice, the current gold standard assay for identification of CSC. However, cell surface markers are very heterogeneous across lung cancer histological types and do little to functionally define the cells they label. We hypothesize that CSC can be functionally isolated and characterized using a pluripotency reporter. By definition, CSC resemble induced-pluripotent stem cells (iPS), in that they give rise to progeny that lack or have diminished capacity for self-renewal and reconstitution of the tumor bulk. iPS are generated from somatic cells through introduction of four key pluripotency genes: OCT4, SOX2, MYC, and KLF4, all of which are oncogenes (MYC, KLF4) or linked to tumorigenesis (OCT4, SOX2). Moreover, increased expression of OCT4, SOX2, and their downstream target, NANOG was reported in CSC defined by the cell surface marker CD44hi. Teratoma formation, the gold standard assay for adequate cell reprogramming, can occasionally produce teratocarcinomas, which have been proposed to arise from “partially reprogrammed” cells. Furthermore, increased expression of pluripotency genes is also associated with poor lung cancer prognosis. Here, we show that a subpopulation of cells with CSC properties can be isolated using a recently-developed lentivirus-based reporter that provides a readout of SOX2 and OCT4 activation. Reporter-positive cells represent ~8-20% cells in A549 and H460 lung cancer cells under regular growth conditions. Sorted reporter-positive cells form spheres with greater frequency than negative cells in media without serum, and show self-renewal properties through serial passage in matrigel. Reporter-positive cells show higher asymmetric cell division, repopulation, and tumor-initiating activity that can be sustained by passage in vivo. Importantly, the fraction of reporter-positive cells is increased after exposure to the chemotherapeutic agent cisplatin, consistent with the view that inefficient eradication of CSC may be responsible for tumor recurrence. We are currently investigating epigenetic mechanisms that may be responsible for functional heterogeneity and may provide a link between chromatin reprogramming and the CSC phenotype. We expect that characterizing the properties of CSC will reveal innovative strategies to therapeutically target them to treat lung cancer. Citation Format: Ana I. Robles, Brid M. Ryan, Krist Aploks, Binwu Tang, Lalage Wakefield, Curtis C. Harris. A pluripotency reporter defines lung cancer cells with tumor-initiating properties. [abstract]. In: Proceedings of the AACR-IASLC Joint Conference on Molecular Origins of Lung Cancer; 2014 Jan 6-9; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2014;20(2Suppl):Abstract nr A35.

See related article in EMBO Molecular Medicine http://dx.doi.org/10.1002/emmm.201201516

The cancer stem cell (CSC) theory suggests that cancer is maintained by a subpopulation of cancer cells which possesses stem cell characteristics, including self renewal, tumor initiation and pluripotent differentiation abilities. A large series of CSC markers has been reported in various cancer types. CD133 is the most frequently used marker and has been applied to isolate cancer stem cells from cancers of the liver, brain, colon and lung, etc. CD44+/CD24-/low were used as CSC markers in breast cancers. CD34 and Sca-1 were used for identification of murine lung stem cells but Sca-1 is not expressed in human tissues. Expression of embryonic genes such as BMI1 and POU5F1 were found in CSC from different tissues and both proteins are key components in maintaining ‘stemness’ of embryonic stem (ES) cells and induced-pluripotent stem (iPS) cells. It still remains unclear whether additional markers are needed to detect lung CSC. To our knowledge, limited studies using CSC markers on a panel of non-small cell lung cancer (NSCLC) cell lines including those raised from Chinese lung cancer patients have been documented. This study aimed to examine the expression profiles of 6 CSC markers (CD24, CD34, CD44, CD133, BMI1 and POU5F1) in a panel of 10 NSCLC cell lines, 163 NSCLC tumor specimens, fetal lung, reactive and regenerating lung tissues. NSCLC cell lines showed expression of CSC markers at various frequencies that ranged from 0-99.7%, suggesting absence of a single universal marker. Six cell lines expressed CD44 while only HCC1833 expressed CD133. Expression of CD44 and CD133 were mutually exclusive. The CD133+ and CD44+ populations showed distinct properties from CD133- and CD44- cells, respectively. Both CD133+ and CD44+ expanded into tumor-spheroids in vitro in non-adherent medium but not CD133- and CD44- cells. CD44+ H1299 cells expressed ‘stemness’ markers including Oct4, Nanog and Sox2 by RT-PCR and immunofluorescence but were lost after induced-differentiation. The clonogenicity of CD44+ cells is significantly higher than CD44- cells and self-renewal ability was maintained after serial passages. CD44+ cells were cisplatin-resistant and initiated tumor formation in nude mice. The xenograft tumors showed poor differentiation that resembled the parental cell line. Freshly sorted tumor cells showed both CD44+ and CD44- populations, suggesting in vivo differentiation. Immunohistochemistry (IHC) results showed CD44 expression in epithelia of developing airways and regenerating lung. In lung cancers, CD44 expression was associated with squamous cell carcinoma (SCC) (P=0.046). When only 96 adenocarcinomas (AD) were included, CD44 expression was associated with non-smokers (P=0.024). Overall, CD44+cells in NSCLC are capable of tumor-initiation and possess stem cell characteristics. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-251.

Human head and neck squamous cell carcinoma (HNSCC) is a highly malignant cancer associated with major morbidity and mortality. In this study, we determined that human HNSCC-derived HSC-3 cells contain a subpopulation of cancer stem cells (CSCs) characterized by high levels of CD44v3 and aldehyde dehydrogenase-1 (ALDH1) expression. These tumor cells also express several stem cell markers (the transcription factors Oct4, Sox2, and Nanog) and display the hallmark CSC properties of self-renewal/clonal formation and the ability to generate heterogeneous cell populations. Importantly, hyaluronan (HA) stimulates the CD44v3 (an HA receptor) interaction with Oct4-Sox2-Nanog leading to both a complex formation and the nuclear translocation of three CSC transcription factors. Further analysis reveals that microRNA-302 (miR-302) is controlled by an upstream promoter containing Oct4-Sox2-Nanog-binding sites, whereas chromatin immunoprecipitation (ChIP) assays demonstrate that stimulation of miR-302 expression by HA-CD44 is Oct4-Sox2-Nanog-dependent in HNSCC-specific CSCs. This process results in suppression of several epigenetic regulators (AOF1/AOF2 and DNMT1) and the up-regulation of several survival proteins (cIAP-1, cIAP-2, and XIAP) leading to self-renewal, clonal formation, and cisplatin resistance. These CSCs were transfected with a specific anti-miR-302 inhibitor to silence miR-302 expression and block its target functions. Our results demonstrate that the anti-miR-302 inhibitor not only enhances the expression of AOF1/AOF2 and DNMT1 but also abrogates the production of cIAP-1, cIAP-2, and XIAP and HA-CD44v3-mediated cancer stem cell functions. Taken together, these findings strongly support the contention that the HA-induced CD44v3 interaction with Oct4-Sox2-Nanog signaling plays a pivotal role in miR-302 production leading to AOF1/AOF2/DNMT1 down-regulation and survival of protein activation. All of these events are critically important for the acquisition of cancer stem cell properties, including self-renewal, clonal formation, and chemotherapy resistance in HA-CD44v3-activated head and neck cancer.

BackgroundLung cancer represents the most leading causes of cancer-related deaths worldwide, especially in Xuanwei in eastern Yunnan province, China. WD repeat and SOCS box containing protein (WSB) has been reported to participate in the carcinogenesis of lung cancer. However, there is no report about the role of WSB2 in the carcinogenesis and development of lung cancer in Xuanwei. Here, we investigated the functional role of WSB2 in Xuanwei lung cancer and uncovered its underlying molecular mechanisms.MethodsThe expression of WSB2 in lung cancer cell lines and tissues were measured using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Western blotting was used to determine the protein levels of WSB2, E-cadherin, N-cadherin, vimentin, c-Myc and β-catenin in lung cancer cells. Cell viability was detected using 3-(4,5-diethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-etrazolium, inner salt (MTS) assay. While cell apoptosis and cell cycle distribution were quantified using flow cytometry following indicated staining. The change of cell invasion ability was detected using Transwell assay. FH535 was employed to block Wnt/β-catenin pathway. A xenograft tumor model was applied to confirm the tumor properties of WSB2 in vivo.ResultsOur data showed that WSB2 was frequently up-regulated in Xuanwei lung cancer tissues and cells, when compared with paired non-cancerous tissues and normal lung epithelial cells. Knockdown of WSB2 notably reduced cell viability, cell invasion, epithelial-mesenchymal transition (EMT) process, while induced apoptotic cell death and cell cycle arrest of Xuanwei lung cancer cells. Moreover, in vivo findings also confirmed that WSB2 knockdown could effectively delay the growth of tumor. Mechanistic studies revealed that c-Myc and β-catenin were notably decreased at both protein and mRNA levels after knocking down of WSB2, while overexpression of WSB2 showed a contrary tendency. In addition, blocking Wnt/β-catenin pathway using FH535 rescued the cancer promoting effect mediated by overexpression of WSB2. Furthermore, WSB2 activated Wnt/β-catenin pathway and accelerated the progression of lung cancer.ConclusionsWSB2 promoted the progression of lung cancer in Xuanwei by triggering Wnt/β-catenin signaling pathway.