Cancer Stem Cell Markers Research Articles

Ex-vivo models of post-surgical residual disease in human glioblastoma

Background Glioblastoma is a highly infiltrative, currently incurable brain cancer. To date, translation of novel therapies for glioblastoma from the laboratory into clinical trials has relied heavily on in vitro cell culture and murine (subcutaneous and orthotopic) xenograft models using cells derived from the main bulk of patient tumours. However, it is the residual cells left-behind after surgery that are responsible for disease progression and death in the clinic. A lack of substantial improvements in patient survival for decades suggests commonly used murine xenograft models, a key step before clinical trials, do not reflect the biology of residual disease in patients. Methods To address this, we have developed the ‘Sheffield Protocol’ to generate ex vivo models that reflect both resected, and post-surgical residual disease from the same patient. The protocol leverages parallel derivation of inherently treatment-resistant glioblastoma stem cells (GSCs) from ‘core’ and distant ‘edge’ regions through careful macrodissection of a large en bloc specimen, such as from a partial lobectomy for tumour, followed by tissue dissociation and propagation in serum-free media. Opportunistic en bloc specimen use can liberate the most distant infiltrative cells feasibly accessible from living patients. Results We provide an example illustrating that resected and residual disease models represent spatially divergent tumour subpopulations harbouring distinct transcriptomic and cancer stem cell marker expression profiles. We also introduce the ‘Sheffield Living Biobank’ of glioma models (SLB) that incorporates over 150 GSC lines from 60+ patients, including 44+ resected and residual models, which are available for academic use via MTA. Conclusions These models provide a novel tool to reduce animal xenograft usage by improving candidate drug triage in early preclinical studies and directly replacing animal studies for some therapies that are post-Phase 1+ clinical trial for other cancers/conditions to, ultimately, deliver more effective treatments for post-surgical residual disease in glioblastoma.

Lymphocyte Antigen 6 Family Member D (LY6D) Affects Stem Cell Phenotype and Progression of Pancreatic Adenocarcinoma.

The membrane-bound protein lymphocyte antigen 6 family member D (LY6D), a marker of early B cell lineage is reportedly expressed in several human malignancies and has been implicated in cancer stemness. However, its expression and role in cancer stemness remain largely unexplored in pancreatic ductal adenocarcinoma (PDAC). The aim of this study was to clarify the role of LY6D in PDAC. We conducted functional analysis of LY6D to evaluate its impact on the malignant features of PDAC cells in vitro. Using our in-house developed stem cell separation technique, which isolates cells with low proteasome activity and CD44 v9 cell surface marker for cancer stem cells, we performed sphere formation and chemosensitivity tests and tumor formation assay in mice, through knockdown of LY6D expression. Immuno-histopathological analysis was also conducted to reveal the clinical significance of LY6D in PDAC. In vitro functional assays demonstrated that LY6D was critically involved in promoting the cancer malignant phenotype, including increased invasive ability, drug resistance, migration capacity, and cancer stemness. Immunohistopathological analysis revealed that high LY6D expression levels were associated with high recurrence rates and poorer prognosis in PDAC. Our study showed that LY6D is a novel prognostic indicator and plays a key role in regulation of cancer stemness in PDAC.

Oncogenic KRAS Mutations Confer a Unique Mechanotransduction Response to Peristalsis in Colorectal Cancer Cells.

Colorectal cancer (CRC) tumors start as polyps on the inner lining of the colorectum, where they are exposed to the mechanics of peristalsis. Our previous work leveraged a custom-built peristalsis bioreactor to demonstrate that colonic peristalsis led to cancer stem cell enrichment in CRC cells. However, this malignant mechanotransductive response was confined to select CRC lines that harbored an oncogenic mutation in the KRAS gene. Here, we explored the involvement of activating KRAS mutations on peristalsis-associated mechanotransduction in CRC. Peristalsis enriched cancer stem cell marker LGR5 in KRAS mutant lines, in a Wnt-ligand-independent manner. Conversely, LGR5 enrichment in wild type KRAS lines exposed to peristalsis were minimal. LGR5 enrichment downstream of peristalsis translated to increased tumorigenicity in vivo. Differences in mechanotransduction was apparent via unbiased gene set enrichment analysis, where many unique pathways were enriched in wild type vs. mutant lines. Peristalsis also triggered β-catenin nuclear localization independent of Wnt-ligands, particularly in KRAS mutant lines. The involvement of KRAS was validated via gain and loss of function strategies. Peristalsis induced β-catenin activation and LGR5 enrichment depended on the activation of the MEK/ERK cascade. Taken together, our results demonstrated that oncogenic KRAS mutations conferred a unique peristalsis-associated mechanotransduction response to colorectal cancer cells, resulting in cancer stem cell enrichment and increased tumorigenicity. These mechanosensory connections can be leveraged in improving the sensitivity of emerging therapies that target oncogenic KRAS. Implications: Oncogenic KRAS empowers colorectal cancer cells to harness the mechanics of colonic peristalsis for malignant gain, independent of other cooperating signals. .

Expression of CD44 in Triple Negative Breast Cancer and its Correlation with Prognostic Parameters

Background: The study aims to evaluate CD44 expression as a cancer stem cell marker in Triple-negative breast cancer (TNBC) and its correlation with prognostic parameters. Evaluation of CD44 immunoexpression in TNBC is vital for understanding tumour aggressiveness and determining its prognostic value. Methods: A hospital based cross sectional study of 50 cases of primary triple negative breast cancer patients. The tissue sections were subjected to immunohistochemical examination using CD44 antigen marker. The proportion and intensity of CD44 immunostaining was assessed and correlation with prognostic markers such as histological grade, tumor size and nodal status. Results: CD44 expression was observed in 40% of the total cases with a statistically significant association with histological grade (p-value= 0.002). Higher CD44 expression was noticed with increasing tumour grade. However, no statistical significance was observed with respect to tumour size and nodal status. Conclusion: The study suggests that CD44 immunoexpression may serve as a surrogate marker of BCSCs and may hold prognostic value in TNBC patients. However, further studies on larger samples are required to fully understand its role.

Receptor for Hyaluronan Mediated Motility (RHAMM)/Hyaluronan Axis in Breast Cancer Chemoresistance

Background/Objectives: Receptor for hyaluronan-mediated motility (RHAMM) is a hyaluronan (HA) receptor, which exerts diverse biological functions in not only physiological but also pathological conditions in human malignancies, including breast cancer. Although chemoresistance is a significant clinical challenge in breast cancer, a possible contribution of RHAMM and hyaluronan to breast cancer chemoresistance has remained unclear. Methods: We immunolocalized RHAMM and HA in breast carcinoma tissues. Also, we utilized epirubicin-sensitive (parental) and rpirubicin-resistant (EPIR) breast cancer cell lines to explore the role of RHAMMM in breast cancer progression. Results: We found out that RHAMM and HA were cooperatively correlated with breast cancer aggressiveness and recurrence after chemotherapy. In vitro studies demonstrated that RHAMM was overexpressed in EPIR cells compared to parental cells. In addition, the knockdown of RHAMM significantly suppressed proliferation and migration of both parental and EPIR cells. On the other hand, the expression level of cancer stem cell marker CD44, which was overexpressed in M-EPIR (epirubicin-resistant MCF-7 subline) compared to MCF-7, was significantly suppressed by knockdown of RHAMM. In addition, the knockdown of RHAMM significantly altered the expression of N-cadherin and E-cadherin, leading to an epithelial phenotype. Conclusions: Aberrant RHAMM signaling were considered to cause chemoresistance related to cancer stemness and epithelial to mesenchymal transition, and increased cell proliferation and migration of both chemo-sensitive and chemo-resistant breast cancer cells.

Interferon-α Promotes the Expression of Cancer Stem Cell Markers in Oral Squamous Cell Carcinoma: Erratum

Interferon-α Promotes the Expression of Cancer Stem Cell Markers in Oral Squamous Cell Carcinoma: Erratum

8773 CD44 Variant Isoforms Expressed Within PAX7/SOX2-Positive Pituitary Neuroendocrine Tumors Attribute To Therapy Resistance And Recurrence Of Cushing’s Disease

Abstract Disclosure: J. Chakrabarti: None. J. Eschbacher: None. S. Mallick: None. E. Ferris: None. B. Hermes: None. A. Little: None. Y. Zavros: None. Background: Cushing’s disease (CD) is a serious rare endocrine disease caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary neuroendocrine tumor (PitNET) that subsequently stimulates the adrenal glands to overproduce cortisol. Approximately 56% of patients will experience disease recurrence during the 2 to 10-year follow-up period. Surgical failures and late recurrences of CD are common, and despite multiple treatments, biochemical control is achieved in only 50% of patients. Therefore, there is a need to advance targeted therapies that prevent recurrence and therapy resistance. The Cluster of Differentiation (CD) 44 transmembrane glycoprotein (CD44) is a prominent WNT signaling target, and deregulation of the Wnt pathway is associated with constitutively active βcatenin in SOX2-positive cells. Although a similar mechanism has been proposed in PitNETs, it has not been fully tested. The alternative mRNA splice variant, CD44v9 is expressed on cancer stem cells promotes resistance to ROS through the stabilization of the SLC7A11 (xCT) cystine glutamate transporter. Proteolytic cleavage of CD44 releases the CD44 intracellular domain which translocates to the nucleus activating cell stemness genes including SOX2. Although CD44 is a known cancer stem cell marker that plays multiple key roles including drug resistance and tumor cell invasiveness, the mechanisms underlying human PitNET tumorigenesis are unclear. Hypothesis: CD44 expressed on PAX7/SOX2-positive corticotroph PitNET cells define a cell population that attributes to therapy resistance and disease recurrence. Methods: CD patient PitNET tissues and matched PitNET-generated organoids (PitNETOs) were used for CosMx™ Spatial Molecular Imaging (SMI) and scRNAseq analyses respectively. Resistance to drug- and radiation-induced apoptosis was analyzed using PitNETOs generated. Results: SMI and scRNAseq data revealed a cell population co-expressing PAX7 and SOX2, CD44 and EpCAM that was abundant in invasive and silent corticotroph PitNET subtypes with Knosp grades 3-4. Invasive and silent corticotroph PitNETs also expressed an increased cell population of CD163+ macrophages, myofibroblast cancer associated fibroblasts (myCAFs), inflammatory CAFs. While cells isolated from the dura revealed growth of PitNETOs, adherent cells expressed increased proliferation (Ki67), and expression of somatostatin receptor subtype 2, cancer stem markers (CD44, SOX2, NESTIN, FUT4, PROM1), PAX7 progenitor cell population expressing stem cell markers NESTIN, SOX2, CD44 and EpCAM. Increased CD44/SLCA7A11 expression in CD44/PAX7/SOX2-positive PitNETOs rendered tumor cells resistant to radiation-induced apoptosis. Conclusions: Drugs targeting the CD44 variant isoforms may increase the efficacy of medical therapies and stereotactic radiosurgery to prevent residual and recurrent PitNETs in CD patients. Presentation: 6/3/2024

Targeting CREB-binding protein (CBP) abrogates colorectal cancer stemness through epigenetic regulation of C-MYC.

Colorectal cancer (CRC) is a common cancer worldwide with an increasing annual incidence. Cancer stem cells (CSCs) play important roles in the occurrence, development, recurrence, and metastasis of CRC. The molecular mechanism regulating the development of colorectal CSCs remains unclear. The discovery of human induced pluripotent stem cells (hiPSCs) through somatic cell reprogramming has revolutionized the fields of stem cell biology and translational medicine. In the present study, we converted hiPSCs into cancer stem-like cells by culture with conditioned medium (CM) from CRC cells. These transformed cells, termed hiPSC-CSCs, displayed cancer stem-like properties, including a spheroid morphology and the expression of both pluripotency and CSC markers. HiPSC-CSCs showed tumorigenic and metastatic abilities in mouse models. The epithelial-mesenchymal transition phenotype was observed in hiPSC-CSCs, which promoted their migration and angiogenesis. Interestingly, upregulation of C-MYC was observed during the differentiation of hiPSC-CSCs. Mechanistically, CREB binding protein (CBP) bound to the C-MYC promoter, while histone deacetylase 1 and 3 (HDAC1/3) dissociated from the promoter, ultimately leading to an increase in histone acetylation and C-MYC transcriptional activation during the differentiation of hiPSC-CSCs. Pharmacological treatment with a CBP inhibitor or abrogation of CBP expression with a CRISPR/Cas9-based strategy reduced the stemness of hiPSC-CSCs. This study demonstrates for the first time that colorectal CSCs can be generated from hiPSCs. The upregulation of C-MYC via histone acetylation plays a crucial role during the conversion process. Inhibition of CBP is a potential strategy for attenuating the stemness of colorectal CSCs.

Pressure loading regulates the stemness of liver cancer stem cells via YAP/BMF signaling axis.

Cancer stem cells (CSCs) are considered the major cause of the occurrence, progression, chemoresistance/radioresistance, recurrence, and metastasis of cancer. Increased interstitial fluid pressure (IFP) is a key feature of solid tumors. Our previous study showed that the distribution of liver cancer stem cells (LCSCs) correlated with the mechanical heterogeneity within liver cancer tissues. However, the regulation of liver cancer's mechanical microenvironment on the LCSC stemness is not fully understood. Here, we employed a cellular pressure-loading device to investigate the effects of normal IFP (5 mmHg), as well as increased IFP (40 and 200 mmHg) on the stemness of LCSCs. Compared to the control LCSCs (exposure to 5 mmHg pressure loading), the LCSCs exposed to 40 mmHg pressure loading exhibited significantly upregulated expression of CSC markers (CD44, EpCAM, Nanog), enhanced sphere and colony formation capacities, and tumorigenic potential, whereas continuously increased pressure to 200 mmHg suppressed the LCSC characteristics. Mechanistically, pressure loading regulated Yes-associated protein (YAP) activity and Bcl-2 modifying factor (BMF) expression. YAP transcriptionally regulated BMF expression to affect the stemness of LCSCs. Knockdown of YAP and overexpression of BMF attenuated pressure-mediated stemness and tumorgenicity, while YAP-deficient and BMF-deletion recused pressure-dependent stemness on LCSCs, suggesting the involvement of YAP/BMF signaling axis in this process. Together, our findings provide a potential target for overcoming the stemness of CSCs and elucidate the significance of increased IFP in cancer progression.

Clinical significance and therapeutic implication of CD200 in pancreatic cancer

BackgroundCD200, a negative regulator of T cells as well as a marker for cancer stem cells, represents a significant prognostic factor and potential therapeutic target in certain cancers. However, its clinical significance remains unknown in pancreatic ductal adenocarcinoma (PDAC). MethodsCD200 was assessed in 220 resected PDAC patients who underwent surgery with or without neoadjuvant chemoradiotherapy (NACRT). We examined the clinicopathological outcomes associated with CD200 and further assessed its clinical implications regarding immunological and cancer stem cell properties. ResultsNACRT was associated with higher CD200 expression (66.4 % vs. 32.2 %, P < 0.001) compared to upfront surgery. CD200 was identified as an independent poor prognostic factor in NACRT (hazard ratio 1.90, 95 % confidence interval 1.12–3.23, P = 0.016), but not in upfront surgery patients. Post-recurrence survival was significantly worse in CD200+ patients compared to CD200- patients in the NACRT group, but there was no significant difference observed in the upfront surgery group. CD200 expression was correlated with significantly lower levels of CD4+, CD8+, and CD45RO+ tumor-infiltrating lymphocytes. Furthermore, the correlation of CD200 with pancreatic cancer stem cell markers CD44/CD24/ESA was stronger in irradiated human pancreatic cancer cells. ConclusionsOur data underscore novel roles for CD200 in immune evasion as well as therapy resistance in pancreatic cancer. CD200 may represent a novel poor prognostic predictive factor and potential therapeutic target for PDAC with NACRT.

Meta-Analysis of Prognostic Significance of Cancer Stem Cell Markers in Oral Squamous Cell Carcinoma.

Researchers have shown significant interest in cancer stem cells in recent years. CD44, CD24, CD133, and ALDH serve as indicators of cancer stem cell-like cells in Oral Squamous Cell Carcinoma. However, the prognostic significance of these Cancer Stem Cell markers in Squamous Cell Carcinoma is still debated. This study employed meta-analysis to evaluate the prognostic significance of cancer stem cells about Oral Squamous Cell Carcinoma. CD44, CD133, CD24, and ALDH markers were analyzed in 19 retrospective studies to determine their relationship with prognosis and clinicopathological parameters. Risk ratios (RRs) and odds ratios (ORs) were calculated for 3-years survival rates and clinicopathological parameters, respectively, using a fixed-effects model. The finding of our study based on extracted survival rates showed that cancer stem cell markers, CD133 expression was related with the poor prognosis (RR= 1.62 ,95% CI = 1.08-2.44, P= 0.02). ALDH expression significantly correlated with lymph node metastasis (OR= 4.13, 95% Cl= 1.88-9.10, P<0.001) and clinical staging (OR= 2.26, 95% CI= 1.05-4.88, P= 0.04). The findings indicate that CSC markers could be used to predict oral cancer prognosis. Our study contributes to the literature on survival outcomes of Oral Squamous Cell Carcinoma. These findings offer a structure for the advancement of cancer treatments that specifically target cancer stem cells. Conducting additional studies with a broader group of patients will help confirm the role of cancer stem cells as dependable predictors of prognosis.

Significance of CD70, VEGF, and CD90 Immunohistochemical Expression in Colorectal Cancer.

Colorectal cancer is the 4th most reported reason for cancer death worldwide. It is a complex and multifaceted disease with diverse histopathological manifestations. CD70 is present on activated immune cells and is upregulated in patients who have finished adjuvant therapy. VEGF controls angiogenesis and demonstrates immuno-regulatory characteristics that inhibit the anticancer activity of immune cells. CD90 is an extracellular cancer stem cell marker and regulates apoptosis, cell migration, and T cell activation. to elucidate the prognostic potential of a combined immunohistochemical assessment of CD70, VEGF, and CD90 biomarkers in colorectal cancer tissues. Our study is a retrospective study done on 70 paraffin blocks (45 colorectal carcinoma cases and 11 adenomas, along with 14 cases of colitis serving as controls) were subjected to conventional Hematoxylin and Eosin stain for routine histopathological assessment and immunohistochemical staining for CD70, VEGF and CD90. Our investigation focused on evaluating the expression of CD70, VEGF, and CD90 in various colorectal tissues, including colitis, adenomas, and adenocarcinomas, as well as different grades of adenocarcinoma tissues, different stages of tumor invasiveness, and lymph node status. Our research revealed distinctive expression patterns of CD70, VEGF, and CD90 across different stages and grades of colorectal cancer. our research signifies the potential clinical utility of the CD70, VEGF, and CD90 triad as prognostic markers in colorectal cancer. The combined analysis of these markers emerged as a potent prognostic tool, offering valuable insights into disease progression. Our research showed that epithelial CD90 is the most sensitive marker for both tumor stage and lymph node status. CD70 and VEGF showed a statistically significant relation with lymph node status only and not with tumor stage.

A live single-cell reporter system reveals drug-induced plasticity of a cancer stem cell-like population in cholangiocarcinoma.

Cancer stem cells (CSC) play an important role in carcinogenesis and are acknowledged to be responsible for chemoresistance in cholangiocarcinoma (CCA). Studying CCA CSC has been challenging, due to lack of consensus CSC markers, and to their plastic nature. Since dual expression of the core pluripotent factors SOX2/OCT4 has been shown to correlate with poor outcome in CCA patients, we selected the SOX2/OCT4 activating short half-life GFP-based live reporter (SORE6-dsCopGFP) to study CSC dynamics at the single-cell level. Transduction of five human CCA cell lines resulted in the expression of 1.8-13.1% GFP-positive (SORE6POS) cells. By live imaging, we found that SORE6POS CCA cells possess self-renewal capacity and that they can be induced to differentiate. Significantly, the SORE6POS cells were highly tumorigenic, both in vitro and in vivo, thus implicating the characteristics of primary CSCs. When we then analyzed for selected CSC-related markers, we found that the majority of both CD133+/CD44+, and CD133+/LGR5+ CCA cells were SORE6POS cells. Exposing transduced cells to standard CCA chemotherapy revealed higher growth rate inhibition at 50% (GR50s) for SORE6POS cells compared to GFP-negative (SORE6NEG) ones indicating that these CSC-like cells were more resistant to the treatment. Moreover, the chemotherapy induced SORE6POS from SORE6NEG cells, while retaining the existing SORE6POS population. Finally, treatment of transduced cells with CDK4/6 inhibitors in vitro for 3 days resulted in a lowered CSC number in the culture. Thus, applying a live reporter system allowed us to elucidate the stem cell diversity and drug-induced plasticity of CCA CSCs. These findings have clear implications for future management of such patients.

Exploring the Role and Pathophysiological Significance of Aldehyde Dehydrogenase 1B1 (ALDH1B1) in Human Lung Adenocarcinoma

Aldehyde dehydrogenases (ALDHs) constitute a diverse superfamily of NAD(P)+-dependent enzymes pivotal in oxidizing endogenous and exogenous aldehydes to carboxylic acids. Beyond metabolic roles, ALDHs participate in essential biological processes, including differentiation, embryogenesis and the DNA damage response, while also serving as markers for cancer stem cells (CSCs). Aldehyde dehydrogenase 1B1 (ALDH1B1) is a mitochondrial enzyme involved in the detoxification of lipid peroxidation by-products and metabolism of various aldehyde substrates. This study examines the potential role of ALDH1B1 in human lung adenocarcinoma and its association with the CSC phenotype. To this end, we utilized the lung adenocarcinoma cell line A549, engineered to stably express the human ALDH1B1 protein tagged with green fluorescent protein (GFP). Overexpression of ALDH1B1 led to notable changes in cell morphology, proliferation rate and clonogenic efficiency. Furthermore, ALDH1B1-overexpressing A549 cells exhibited enhanced resistance to the chemotherapeutic agents etoposide and cisplatin. Additionally, ALDH1B1 overexpression correlated with increased migratory potential and epithelial–mesenchymal transition (EMT), mediated by the upregulation of transcription factors such as SNAI2, ZEB2 and TWIST1, alongside the downregulation of E-cadherin. Moreover, Spearman’s rank correlation coefficient analysis using data from 507 publicly available lung adenocarcinoma clinical samples revealed a significant correlation between ALDH1B1 and various molecules implicated in CSC-related signaling pathways, including Wnt, Notch, hypoxia, Hedgehog, retinoic acid, Hippo, NF-κΒ, TGF-β, PI3K/PTEN-AKT and glycolysis/gluconeogenesis. These findings provide insights into the role of ALDH1B1 in lung tumor progression and its relation to the lung CSC phenotype, thereby offering potential therapeutic targets in the clinical management of lung adenocarcinoma.

Comparison of methods for cancer stem cell detection in prognosis of early stages NSCLC

BackgroundDespite advances in diagnosis and treatment in lung cancer, therapies still fail to improve patient management due to resistance mechanisms and relapses. As Cancer stem cells (CSCs) directly contribute to tumor growth and therapeutic resistance, their clinical detection represents a major challenge. However specific and additional CSC markers lack. Thus, our aim was to achieve selective detection of CSCs with specific glycan patterns and assess the CSCs burden to predict the risk of relapse in NSCLC tumors.MethodsThe lung CSCs detection and sorting with a lectin MIX were assessed and compared to CD133 in vitro. Then, its putative role as CSC biomarker was evaluated in vivo and its clinical significance on 221 NSCLC patients.ResultsWe showed a significant CSCs enrichment in the MIX+ sorted fraction compared to CD133+ cells and confirmed its high tumorigenic capacity. The MIX prognostic value on the overall survival from early stages patients was validated suggesting its potential for detecting CSCs directly linked to tumor aggressiveness.ConclusionThe MIX could be more relevant for detecting and sorting CSCs than CD133. Moreover, its prognosis value could enable clinicians to better classify early-stage patients at high risk of relapse in order to tailor therapeutic decisions.

Tumour stemness and poor clinical outcomes in haemochromatosis patients with hepatocellular carcinoma

AimsPatients with haemochromatosis (HFE) are known to have an increased risk of developing hepatocellular carcinoma (HCC). Available data are conflicting on whether such patients have poorer prognosis, and there is...

Cancer Stem Cell Marker CD147 Expression in Erosive Oral Lichen Planus Compared to Moderately and Severely Dysplastic Leukoplakia

Oral lichen planus is a frequent, chronic autoimmune disease that affects the oral mucosa and is characterized as an oral potentially malignant disorder. The aim of our study is to examine the presence of CSCs bearing CD147 (a marker related to local inflammation and associated with various cancers) through immunohistochemistry in oral lichen planus (OLP) compared to oral leukoplakia (OL) and healthy tissues. These findings could contribute to clinical practice by providing a marker for the prognostic assessment of OLP lesions with regards to their potentially malignant nature. The study sample consisted of paraffin-embedded oral mucosa specimens from the archives of the Department of Oral Medicine/Pathology, School of Dentistry, Aristotle University of Thessaloniki, Greece during the period 2009–2019. The study sample contained 24 cases of OLP (14 erosive and 10 reticular) and 30 cases of oral leukoplakia, which were compared to 5 normal oral epithelium samples derived from healthy epithelium adjacent to fibromas from other cases. Cell membrane staining of CD147 was observed mostly in the basal and parabasal cell layer. The statistically significantly higher expression of CD147 in the erosive lichen planus subgroup than in the moderately and severely dysplastic leukoplakia subgroup (p = 0.01) constituted the most important finding of this study. The characteristic expression of CD147 in erosive OLP suggests the presence of epithelial cells with CSC characteristics, but its lower expression in oral leukoplakias suggests a more intense relation of the CD147 marker with inflammation rather than with oral dysplastic progression.

Abstract B080: A porcine model of pancreatic ductal adenocarcinoma for human scale translational cancer research

Abstract Pancreatic ductal adenocarcinoma (PDAC) remains a highly fatal form of cancer, requiring urgent advancements in diagnostic and therapeutic strategies. Although PDAC mouse models have been crucial in advancing our comprehension of the disease, they present some limitations in replicating key human PDAC aspects. In this study, we present the development of the first large animal model of pancreatic cancer via Cre activatable mutations in the endogenous KRAS and TP53 genes 1,2. In order to activate these mutations in the pancreas, two Cre driver pig lines expressing Cre recombinase from PTF1A 3 and PDX1 were created. Crossing both Cre lines with pigs carrying latent KRAS G12D and TP53 R167H alleles produced double (KC) and triple (KPC) genetically modified animals. Pathological analyses revealed the presence of inter- and intralobular fibrosis with multifocal acinar-to-ductal metaplasia (ADM), some low-grade PanINs, dysplasia, inflammation and duct obstruction in most of the KPC pigs between 3 to 6 months of age. Interestingly, the majority of these pigs already exhibited local metastasis in the lymph nodes, suggesting that the metastatic potential is established early in the tumorigenic process. Age-matched KC pigs exhibited mainly ADM with dysplasia. Flow cytometry and RNA expression analyses of the established pancreatic tumour primary cells revealed a pronounced epithelial-to-mesenchymal transition (EMT). Moreover, both bulk tumour samples and primary tumour cells showed high expression of the pancreatic cancer stem cell marker CD44, with differential expression of its isoforms, including the major isoform and variants 6 and 9. In addition, histological and molecular analyses revealed notable similarities between pig and human PDAC, including molecular subtypes, neuronal invasion and loss of acinar identity. These findings highlight the unique advantage of the pig PDAC model, that allows longitudinal and multi-regional tumour sampling in the absence of any therapeutic interventions. This makes it a valuable tool for developing new diagnostic and therapeutic approaches that can greatly improve patient outcomes in the long run.

A monoclonal antibody recognizing CD98 on human embryonic stem cells shows anti-tumor activity in hepatocellular carcinoma xenografts

CD98, also known as SLC3A2, is a multifunctional cell surface molecule consisting of amino acid transporters. CD98 is ubiquitously expressed in many types of tissues, but expressed at higher levels in cancerous tissues than in normal tissues. CD98 is also upregulated in most hepatocellular carcinoma (HCC) patients; however, the function of CD98 in HCC cells has been little studied. In this study, we generated a panel of monoclonal antibodies (MAbs) against surface proteins on human embryonic stem cells (hESCs). NPB15, one of the MAbs, bound to hESCs and various cancer cells, including HCC cells and non-small cell lung carcinoma (NSCLC) cells, but not to peripheral blood mononuclear cells (PBMCs) and primary hepatocytes. Immunoprecipitation and mass spectrometry identified the target antigen of NPB15 as CD98. CD98 depletion decreased cell proliferation, clonogenic survival, and migration and induced apoptosis in HCC cells. In addition, CD98 depletion decreased the expression of cancer stem cell (CSC) markers in HCC cells. In tumorsphere cultures, the expression of CD98 interacting with NPB15 was significantly increased, as were known CSC markers. After cell sorting by NPB15, cells with high expression of CD98 (CD98-high) showed higher clonogenic survival than cells with low expression of CD98 (CD98-low) in HCC cells, suggesting CD98 as a potential CSC marker on HCC cells. The chimeric version of NPB15 was able to induce antibody-dependent cellular cytotoxicity (ADCC) against HCC cells in vitro. NPB15 injection showed antitumor activity in an HCC xenograft mouse model. The results suggest that NPB15 may be developed as a therapeutic antibody for HCC patients.

Extracellular vesicles regulate metastable phenotypes of lymphangioleiomyomatosis cells via shuttling ATP synthesis to pseudopodia and activation of integrin adhesion complexes.

Pulmonary lymphangioleiomyomatosis (LAM) is metastatic sarcoma but mechanisms regulating LAM metastasis are unknown. Extracellular vesicle (EV) regulate cancer metastasis but their roles in LAM have not yet been investigated. Here, we report that EV biogenesis is increased in LAM and LAM EV cargo is enriched with lung tropic integrins, metalloproteinases, and cancer stem cell markers. LAM-EV increase LAM cell migration and invasion via the ITGα6/β1-c-Src-FAK-AKT axis. Metastable (hybrid) phenotypes of LAM metastasizing cells, pivotal for metastasis, are regulated by EV from primary tumor or metastasizing LAM cells via shuttling ATP synthesis to cell pseudopodia or activation of integrin adhesion complex, respectively. In mouse models of LAM, LAM-EV increase lung metastatic burden through mechanisms involving lung extracellular matrix remodeling. Collectively, these data provide evidence for the role of EV in promoting LAM lung metastasis and identify novel EV-dependent mechanisms regulating metastable phenotypes of tumor cells. Clinical impact of research is that it establishes LAM pathway as novel target for LAM therapy.