Upregulation Of Epithelial-mesenchymal Transition Research Articles

ATF3 characterizes aggressive drug-tolerant persister cells in HGSOC

High-grade serous ovarian cancer (HGSOC) represents the most common and lethal subtype of ovarian cancer. Despite initial response to platinum-based standard therapy, patients commonly suffer from relapse that likely originates from drug-tolerant persister (DTP) cells. We generated isogenic clones of treatment-naïve and cisplatin-tolerant persister HGSOC cells. In addition, single-cell RNA sequencing of barcoded cells was performed in a xenograft model with HGSOC cell lines after platinum-based therapy. Published single-cell RNA-sequencing data from neo-adjuvant and non-treated HGSOC patients and patient data from TCGA were analyzed. DTP-derived cells exhibited morphological alterations and upregulation of epithelial-mesenchymal transition (EMT) markers. An aggressive subpopulation of DTP-derived cells showed high expression of the stress marker ATF3. Knockdown of ATF3 enhanced the sensitivity of aggressive DTP-derived cells to cisplatin-induced cell death, implying a role for ATF3 stress response in promoting a drug tolerant persister cell state. Furthermore, single cell lineage tracing to detect transcriptional changes in a HGSOC cell line-derived xenograft relapse model showed that cells derived from relapsed solid tumors express increased levels of EMT and multiple endoplasmic reticulum (ER) stress markers, including ATF3. Single cell RNA sequencing of epithelial cells from four HGSOC patients also identified a small cell population resembling DTP cells in all samples. Moreover, analysis of TCGA data from 259 HGSOC patients revealed a significant progression-free survival advantage for patients with low expression of the ATF3-associated partial EMT genes. These findings suggest that increased ATF3 expression together with partial EMT promote the development of aggressive DTP, and thereby relapse in HGSOC patients.

Transcriptomics and proteomics reveal distinct biology for lymph node metastases and tumour deposits in colorectal cancer.

Both lymph node metastases (LNMs) and tumour deposits (TDs) are included in colorectal cancer (CRC) staging, although knowledge regarding their biological background is lacking. This study aimed to compare the biology of these prognostic features, which is essential for a better understanding of their role in CRC spread. Spatially resolved transcriptomic analysis using digital spatial profiling was performed on TDs and LNMs from 10 CRC patients using 1,388 RNA targets, for the tumour cells and tumour microenvironment. Shotgun proteomics identified 5,578 proteins in 12 different patients. Differences in RNA and protein expression were analysed, and spatial deconvolution was performed. Image-based consensus molecular subtype (imCMS) analysis was performed on all TDs and LNMs included in the study. Transcriptome and proteome profiles identified distinct clusters for TDs and LNMs in both the tumour and tumour microenvironment segment, with upregulation of matrix remodelling, cell adhesion/motility, and epithelial-mesenchymal transition (EMT) in TDs (all p < 0.05). Spatial deconvolution showed a significantly increased abundance of fibroblasts, macrophages, and regulatory T-cells (p < 0.05) in TDs. Consistent with a higher fibroblast and EMT component, imCMS classified 62% of TDs as poor prognosis subtype CMS4 compared to 36% of LNMs (p < 0.05). Compared to LNMs, TDs have a more invasive state involving a distinct tumour microenvironment and upregulation of EMT, which are reflected in a more frequent histological classification of TDs as CMS4. These results emphasise the heterogeneity of locoregional spread and the fact that TDs should merit more attention both in future research and during staging. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Reduced proliferation of bone marrow MSC after allogeneic stem cell transplantation is associated with clinical outcome.

Engraftment and differentiation of donor hematopoietic stem cells is decisive for the clinical success of allogeneic stem cell transplantation (alloSCT) and depends on the recipient's bone marrow (BM) niche. A damaged niche contributes to poor graft function after alloSCT; however, the underlying mechanisms and the role of BM multipotent mesenchymal stromal cells (MSC) are ill-defined. Upon multivariate analysis in 732 individuals, we observed a reduced presence of proliferation-capable MSC in BM aspirates from patients (N= 196) who had undergone alloSCT. This was confirmed by paired analysis in 30 patients showing a higher frequency of samples with a lack of MSC presence post-alloSCT compared with pre-alloSCT. This reduced MSC presence was associated with reduced survival of patients after alloSCT and specifically with impaired graft function. Post-alloSCT MSC showed diminished invitro proliferation along with a transcriptional antiproliferative signature, upregulation of epithelial-mesenchymal transition and extracellular matrix pathways, and altered impact on cytokine release upon contact with hematopoietic cells. To avoid invitro culture bias, we isolated the CD146+/CD45-/HLA-DR- BM cell fraction, which comprised the entire MSC population. The post-alloSCT isolated native CD146+MSC showed a similar reduction in proliferation capacity and shared the same antiproliferative transcriptomic signature as for post-alloSCT colony-forming unit fibroblast-derived MSC. Taken together, our data show that alloSCT confers damage to the proliferative capacity of native MSC, which is associated with reduced patient survival after alloSCT and impaired engraftment of allogeneic hematopoiesis. These data represent the basis to elucidate mechanisms of BM niche reconstitution after alloSCT and its therapeutic manipulation.

Antitumor Efficacy of Dual Blockade with Encorafenib + Cetuximab in Combination with Chemotherapy in Human BRAFV600E-Mutant Colorectal Cancer.

Encorafenib + cetuximab (E+C) is an effective therapeutic option in chemorefractory BRAFV600E metastatic colorectal cancer (mCRC). However, there is a need to improve the efficacy of this molecular-targeted therapy and evaluate regimens suitable for untreated BRAFV600E in patients with mCRC. We performed a series of in vivo studies using BRAFV600E mCRC tumor xenografts. Mice were randomized to receive 5-fluoruracil (5-FU), irinotecan, or oxaliplatin regimens (FOLFIRI or FOLFOX), (E+C) or the combination. Patients received long-term treatment until disease progression, with deescalation strategies used to mimic maintenance therapy. Transcriptomic changes after progression on cytotoxic chemotherapy or targeted therapy were assessed. Antitumor activity of either FOLFIRI or E+C was better as first-line treatment as compared with second-line, with partial cross-resistance seen between a cytotoxic regimen and targeted therapy with an average 62% loss of efficacy for FOLFIRI after E+C and a 45% loss of efficacy of E+C after FOLFIRI (P < 0.001 for both). FOLFIRI-treated models had upregulation of epithelial-mesenchymal transition (EMT) and MAPK pathway activation, where E+C treated models had suppressed MAPK signaling. In contrast, with chemotherapy with E+C, EMT and MAPK signaling remained suppressed. FOLFOX or FOLFIRI, each in combination with E+C, were the most active first-line treatments as compared with E+C or to chemotherapy alone. Furthermore, FOLFOX in combination with E+C as first-line induction therapy, followed by E+C ± 5-FU as maintenance therapy, was the most effective strategy for long-term disease control. These results support the combination of cytotoxic chemotherapy and molecular-targeted therapy as a promising therapeutic approach in the first-line treatment of BRAFV600E mCRC.

Modeling bile duct ischemia and reoxygenation injury inhuman cholangiocyte organoids for screening of novel cholangio-protective agents.

Ischemia of the bile duct is a common feature in liver disease and transplantation, which represents a major cause of morbidity and mortality, especially after liver transplantation. Detailed knowledge of its pathogenesis remains incomplete due to the lack of appropriate invitro models. To recapitulate biliary damage induced by ischemia and reperfusion invitro, human intrahepatic cholangiocyte organoids (ICOs) were grown at low oxygen levels of 1% up to 72h, followed by re-oxygenation at normal levels. ICOs stressed by ischemia and subsequent re-oxygenation represented the dynamic change in biliary cell proliferation, upregulation of epithelial-mesenchymal transition (EMT)-associated markers, and the evocation of phase-dependent cell death programs similar to what is described in patients. Clinical-grade alpha-1 antitrypsin was identified as a potent inhibitor of both ischemia-induced apoptosis and necroptosis. These findings demonstrate that ICOs recapitulate ischemic cholangiopathy invitro and enable drug assessment studies for the discovery of new therapeutics for ischemic cholangiopathies. Dutch Digestive FoundationMLDS D16-26; TKI-LSH (Topconsortium Kennis en Innovatie-Life Sciences & Health) grant RELOAD, EMC-LSH19002; Medical Delta program "Regenerative Medicine 4D"; China Scholarship Council No. 201706230252.

Auto-inhibitory intramolecular S5/S6 interaction in the TRPV6 channel regulates breast cancer cell migration and invasion

TRPV6, a Ca-selective channel, is abundantly expressed in the placenta, intestine, kidney and bone marrow. TRPV6 is vital to Ca homeostasis and its defective expression or function is linked to transient neonatal hyperparathyroidism, Lowe syndrome/Dent disease, renal stone, osteoporosis and cancers. The fact that the molecular mechanism underlying the function and regulation of TRPV6 is still not well understood hampers, in particular, the understanding of how TRPV6 contributes to breast cancer development. By electrophysiology and Ca imaging in Xenopus oocytes and cancer cells, molecular biology and numerical simulation, here we reveal an intramolecular S5/S6 helix interaction in TRPV6 that is functionally autoinhibitory and is mediated by the R532:D620 bonding. Predicted pathogenic mutation R532Q within S5 disrupts the S5/S6 interaction leading to gain-of-function of the channel, which promotes breast cancer cell progression through strengthening of the TRPV6/PI3K interaction, activation of a PI3K/Akt/GSK-3β cascade, and up-regulation of epithelial-mesenchymal transition and anti-apoptosis.

DIPG-79. H3K27M INDUCES EPIGENETIC AND ONCOGENIC CHANGES THAT ARE PARTIALLY REVERSED BY SMALL MOLECULE AURORA KINASE B/C INHIBITION

Diffuse intrinsic pontine glioma (DIPG) is a fatal pediatric brain tumor with no curative treatments. Approximately 80% of DIPGs contain an H3K27M mutation. The implications of the mutation and how they may be targeted are not fully understood. We established an H3K27M effect-isolating model by transducing H3K27-wildtype lines (HSJD-GBM-001, normal human astrocytes) with lentiviral-packaged H3K27M. We characterized H3K27M-related changes through western blot, phenotypic assays, and RNA-seq. Drug screening of H3K27-wildtype and matched H3K27M-transduced lines was used to identify targets more effective with H3K27M present. Patient-derived pediatric glioblastoma and DIPG lines (BT-245, SU-DIPG-IV, HSJD-DIPG-007, SU-DIPG-XIII*, SF7761) were used for validation. We observed increased H3K27ac and decreased H3K27me3, as well as increased proliferative and migratory abilities, with the addition of H3K27M to H3K27-wildtype lines. RNA-seq showed downregulation of cell cycle regulation and upregulation of epithelial-mesenchymal transition. GSK1070916, an Aurora kinase B/C inhibitor, was isolated from a synthetic lethality screen with H3K27M. GSK1070916 showed strong efficacy in native H3K27M lines (IC50s=60nM-1250nM), superior to the Aurora kinase A inhibitor alisertib, to which all cell lines showed substantial resistance. Combination of both drugs was not synergistic. GSK1070916 treatment caused increased H3K27me3 and decreased H3S10ph and H3S28ph. GSK1070916 induced apoptosis and S-phase stall. The H3K27M mutation induces epigenetic, phenotypic, and cell cycle regulation changes resulting in relaxation of transcriptional controls and more aggressive growth. Aurora kinase B/C inhibition is a novel therapeutic modality for DIPG that appears capable of reversing some H3K27M-related epigenetic changes, inducing apoptosis, and repressing uncontrolled cellular division.

A pre-existing population of ZEB2+ quiescent cells with stemness and mesenchymal features dictate chemoresistance in colorectal cancer

BackgroundQuiescent/slow cycling cells have been identified in several tumors and correlated with therapy resistance. However, the features of chemoresistant populations and the molecular factors linking quiescence to chemoresistance are largely unknown.MethodsA population of chemoresistant quiescent/slow cycling cells was isolated through PKH26 staining (which allows to separate cells on the basis of their proliferation rate) from colorectal cancer (CRC) xenografts and subjected to global gene expression and pathway activation analyses. Factors expressed by the quiescent/slow cycling population were analyzed through lentiviral overexpression approaches for their ability to induce a dormant chemoresistant state both in vitro and in mouse xenografts. The correlation between quiescence-associated factors, CRC consensus molecular subtype and cancer prognosis was analyzed in large patient datasets.ResultsUntreated colorectal tumors contain a population of quiescent/slow cycling cells with stem cell features (quiescent cancer stem cells, QCSCs) characterized by a predetermined mesenchymal-like chemoresistant phenotype. QCSCs expressed increased levels of ZEB2, a transcription factor involved in stem cell plasticity and epithelial-mesenchymal transition (EMT), and of antiapototic factors pCRAF and pASK1. ZEB2 overexpression upregulated pCRAF/pASK1 levels resulting in increased chemoresistance, enrichment of cells with stemness/EMT traits and proliferative slowdown of tumor xenografts. In parallel, chemotherapy treatment of tumor xenografts induced the prevalence of QCSCs with a stemness/EMT phenotype and activation of the ZEB2/pCRAF/pASK1 axis, resulting in a chemotherapy-unresponsive state. In CRC patients, increased ZEB2 levels correlated with worse relapse-free survival and were strongly associated to the consensus molecular subtype 4 (CMS4) characterized by dismal prognosis, decreased proliferative rates and upregulation of EMT genes.ConclusionsThese results show that chemotherapy-naive tumors contain a cell population characterized by a coordinated program of chemoresistance, quiescence, stemness and EMT. Such population becomes prevalent upon drug treatment and is responsible for chemotherapy resistance, thus representing a key target for more effective therapeutic approaches.

MiR-21 Promotes the Invasion and Metastasis of Gastric Cancer Cells by Activating Epithelial-Mesenchymal Transition

Background: Gastric cancer (GC) is one of the most common malignant tumors. It is likely to occur in lymph nodes and is prone to distant metastasis in its early stages, which portends a poor prognosis. Previous studies have shown that miRNA-21 was abnormally highly expressed and associated with early metastasis in GC, but the mechanism by which it regulates the invasion and metastasis of GC has not been elucidated. Methods: Epithelial-mesenchymal transition (EMT) is an important pathologic basis of tumor invasion and metastasis, and in this study, the relationship between miRNA-21 and EMT in GC invasion and metastasis was investigated using RT-qPCR, Western blot, and wound scratch and transwell assays. Results: We found that miRNA-21 expression in GC cell lines was higher than in a gastric mucosal epithelial cell line. After transfection with an miRNA-21 mimic, the upregulation of EMT was found to promote migration and invasion of MGC-803 cells. However, the downregulation of EMT was found to accompany the inhibition of invasion and migration of GC cells after downregulation of miRNA-21 expression due to the transfection of an miRNA-21 inhibitor. Conclusions: These findings suggest that miRNA-21 might promote the invasion and metastasis of GC by upregulating EMT.

Abstract 1044: PKC-ι and PKC-ζ are heavily responsible of up-regulating epithelial-mesenchymal transition (EMT) and activating Vimentin to facilitate cellular motility in prostate cancer cell lines

Abstract Prostate carcinoma is the most common cancer among men in terms of number of new cases reported each year. Approximately 26,000 deaths reported in 2018 in the United States and tumor metastasis is responsible for more than 90% of these deaths. Expression of Vimentin is a hallmark of metastatic mesenchymal prostate cancer cells which is initiated by EMT. Our previous studies show that atypical protein kinase C- iota (PKC-ι) and zeta (PKC-ζ) inhibition retards the activation of NF-κB pathway by diminishing NF-κB nuclei translocation {Apostolatos, A.H., et al. Int. J. Oncol. 53(5), (2018), 1836-1846 https://doi.org/10.3892/ijo.2018.4542}. The present study shows that siRNA knockdown of PKC-ι and PKC-ζ downregulate Snail1, PRRX1, Vimentin while upregulating E-cadherin thereby diminishes EMT. In-vitro migration and invasion assays for PC-3 and DU-145 prostate cancer cell lines demonstrated a significant reduction of cellular migration and invasion in PKC-ι and PKC-ζ knocked down samples. Immunoprecipitation experiments suggested direct association of Vimentin with PKC-ι and PKC-ζ separately. Laser stimulated confocal immunofluorescence and immuno-gold transmission electron microscopic techniques were used to further confirm the relationship of Vimentin with aPKCs. Real time qPCR was used to analyze the mRNA levels of targeted markers to further validate transcriptional downregulation of Vimentin which was observed in Westerns upon aPKC siRNA knockdown. Overall results showed stronger relationship between PKC-ι and Vimentin over PKC-ζ with Vimentin. Microscopic results also show PKC-ι concentrated along the cell membrane together with Vimentin in addition to the abundant distribution throughout the cell. In addition, our results suggest that both aPKCs target multiple activation sites (S33, S39 and S56) on Vimentin thereby playing a crucial role in the regulation of Vimentin dynamics which is essential for increased prostate cancer cell motility. We have used a novel PKC-ι specific inhibitor 5-amino-1-((1R,2S,3S,4R)-2,3-dihydroxy-4-methylcyclopentyl)-1H-imidazole-4-carboxamide (ICA-1S) to conduct in-vivo experiments on murine models. Excised tumors were analyzed for pathways observed in in-vitro experiments. Immunohistochemical and Western blot analysis on tumor samples confirmed the relationship of aPKCs with Vimentin. In addition, these samples will be analyzed for the miRNA expression upon PKC-ι inhibition. Overall results suggest that both aPKCs are essential in upregulation of EMT and for the activation of Vimentin to facilitate metastasis of prostate cancer cells. Finally, results suggest that PKC-ι and PKC-ζ can be effectively targeted using specific inhibitors to develop targeted therapeutics for metastatic prostate carcinoma. Citation Format: Wishrawana Sarathi Ratnayake, Christopher Apostolatos, Sloan Breedy, Robert Hill, Clare Dennison, Mildred Acevedo-Duncan. PKC-ι and PKC-ζ are heavily responsible of up-regulating epithelial-mesenchymal transition (EMT) and activating Vimentin to facilitate cellular motility in prostate cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1044.

7-Deoxynarciclasine shows promising antitumor efficacy by targeting Akt against hepatocellular carcinoma.

Akt is a promising therapeutic target for cancer treatment. In our study, we have identified that 7-deoxynarciclasine (7-DONCS) is a potential inhibitor of Akt, which results in the repression of multiple oncogenic processes in hepatocellular carcinoma (HCC). We have found that 7-DONCS suppresses the growth of HCC by inducing the apoptotic and autophagic capacities, as well as by inhibiting epithelial-mesenchymal transition (EMT) in vitro and in vivo. Pretreatment of cells with specific autophagy inhibitor (Bafilomycin A1) or knockdown of endogenous LC‐3B by siRNA strongly enhences 7‐DONCS‐regulated apoptosis and EMT. Consequently, we have found that 7-DONCS selectively inhibits phospho-Akt (Ser473), and subsequent molecular docking reveals that 7-DONCS directly binds to the C-terminal domain of Akt. Overexpressing Akt significantly blocks these effects via 7-DONCS in HCC cells. Furthermore, 7-DONCS, by targeting Akt, exhibits a promising therapeutic effect in orthotopic hepatocellular tumors. Finally, higher p-Akt expression is associated with poor prognosis, and higher level of Akt was positively correlated with the enrichment of both apoptosis and autophagy downregulation, and EMT upregulation in HCC patients. These studies suggest that 7-DONCS serves as an attractive drug candidate by targeting Akt for future HCC therapy.

Malignant ascites-derived exosomes promote peritoneal tumor cell dissemination and reveal a distinct miRNA signature in advanced gastric cancer.

Peritoneal dissemination (PD) is the most frequent metastasis with poor prognosis in patients with advanced gastric cancer (GC). However, the molecular mechanisms of PD remain poorly defined. Exosomes play a pivotal role in cancer progression. Thus, this study aims to investigate the effects of malignant ascites (MA)-derived exosomes from GC patients on tumor cells and to elucidate the underlying mechanism. In vitro and in vivo analysis showed that compared to exosome-depleted supernatants, exosomes from MA of GC patients promoted invasion of AGS cells by up-regulation of Epithelial-mesenchymal transition (EMT) signaling. In a mouse abdominal xenograft model, the median survival was shorter after MA-derived exosomes treatment than the control group (35.5 days versus 67 days, p = 0.0005). Moreover, 29 exosomal miRNAs from ascites were identified by high throughput sequencing among 8 paired GC patients before and after peritoneal chemotherapy and 3 individuals with non-malignant disease. In summary, MA-derived exosomes from patients with GC promote EMT signaling in GC cells and in mouse peritoneal tumor model. Differential exosomal miRNAs might be targeted therapeutically for inhibiting peritoneal metastasis, which provides new insights for the molecular mechanisms of PD in GC.

Identification of miR-200c and miR141-Mediated lncRNA-mRNA Crosstalks in Muscle-Invasive Bladder Cancer Subtypes.

Basal and luminal subtypes of muscle-invasive bladder cancer (MIBC) have distinct molecular profiles and heterogeneous clinical behaviors. The interactions between mRNAs and lncRNAs, which might be regulated by miRNAs, have crucial roles in many cancers. However, the miRNA-dependent crosstalk between lncRNA and mRNA in specific MIBC subtypes still remains unclear. In this study, we first classified MIBC into two conservative subtypes using miRNA, mRNA and lncRNA expression data derived from The Cancer Genome Atlas. Then we investigated subtype-related biological pathways and evaluated the subtype classification performance using Decision Trees, Random Forest and eXtreme Gradient Boosting (XGBoost). At last, we explored potential miRNA-mediated lncRNA-mRNA crosstalks based on co-expression analysis. Our results show that: (1) the luminal subtype is primarily characterized by upregulation of metabolism-related pathways while the basal subtype is predominantly characterized by upregulation of epithelial-mesenchymal transition, metastasis, and immune system process-related pathways; (2) the XGBoost prediction model is consistently robust for classification of the molecular subtypes of MIBC across four datasets (The area under the ROC curve > 0.9); (3) the expression levels of the molecules in the miR-200c and miR141-mediated lncRNA-mRNA crosstalks differ considerably between the two subtypes and have close relationships with the prognosis of MIBC. The miR-200c and miR-141-dependent mRNA-lncRNA crosstalks might be of great significance in tumorigenesis and tumor progression and may serve as the novel prognostic predictors and classification markers of MIBC subtypes.

Abstract 3177: KITENIN leads to resistance against temozolomide through enhancement of cancer stemness factors in mouse glioma model

Abstract Background: Recently, a new research spotlighted the role of KITENIN (KAI1 COOH-terminal interacting tetraspanin) on glioma invasiveness and progression, associated with the up-regulation of EMT (epithelial-mesenchymal transition) and cancer stemness markers. In this study, furthermore, it is investigated whether KITENIN leads to resistance against TMZ through enhancement of cancer stemness factors using mouse glioma model. Materials and Methods: TMZ-resistant T98G cell line (T98G/TR) was developed. EMT and cancer stemness markers and KITENIN expression were assessed by Western blotting and qRT-PCR. With KITENIN modulated U251 (knockdown) and GL261 (overexpression) cells, cell viability and apoptotic cell death factors after TMZ treatment were evaluated. Biological role of KITENIN on TMZ-resistance was investigated using magnetic resonance imaging (MRI) and immunofluorescence analysis for tumor sections of orthotopic glioma model. Using human glioma samples and primary cells, the mechanistic link between KITENIN and cancer stemness factors was confirmed. Results: T98G/TR cells showed increased expression of the KITENIN and EMT and cancer stemness factors. Also, In vitro assays revealed that KITENIN knockdown inhibited cell viability against TMZ treatment, whereas KITENIN overexpression promoted their viability, via apoptotic cell death pathway. In orthotopic glioma models, mice implanted with KITENIN-overexpressed cells showed resistance to TMZ on MRI and histopathological examination. The expression of KITENIN/ALDH1 or KITENIN/CD44 were co-localized and significantly higher in tumor sections of mouse transplanted with KITENIN-overexpressed cells than in tumor sections of mouse transplanted with control cells. Genetic down-regulation of KITENIN for KITENIN-overexpressed cell line and primary glioma cells led decreased expression of ALDH1 and CD44. In human glioma samples, high expression of KITENIN was closely related with high expression of ALDH1. Conclusion: KITENIN affects TMZ-resistance in malignant gliomas through induction of ALDH1 and CD44. Therefore, it could be suggested that KITENIN is therapeutic target to overcome TMZ-resistance of malignant gliomas. Citation Format: Kyung-Hwa Lee, Eun-Jung Ahn, Shin Jung, Jae-Hyuk Lee, Kyung-Keun Kim, Kyung-Sub Moon. KITENIN leads to resistance against temozolomide through enhancement of cancer stemness factors in mouse glioma model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3177. doi:10.1158/1538-7445.AM2017-3177

Poor-prognosis nasopharyngeal carcinoma as defined by a molecularly distinct subgroup and prediction by a miRNA expression signature.

6056 Background: Nasopharyngeal carcinoma (NPC) is a highly invasive and metastatic cancer, with diverse molecular characteristics and clinical outcomes. Our aim in this study is to dissect the molecular heterogeneity of NPC, followed by construction of a prognostic model for prediction of distant metastasis. Methods: For molecular subtyping of NPC using miRNA expression data, we selected 86 stage II (AJCC 7th Edition) NPC patients from GSE32960 as training cohort. The remaining 226 NPC patients from GSE32960 and 246 NPC patients from GSE70970 were used as two validation cohorts. Consensus clustering was employed for unsupervised classification of the training cohort. Classifier was built using support vector machine (SVM), and was validated in the two validation cohorts. Univariate and multivariate Cox regression analyses were employed for feature selection and constructing a prognostic model for predicting high-risk distant metastasis, respectively. Results: We identified three NPC subtypes (NPC1, 2, and 3) that are molecularly distinct and clinically relevant. NPC1 (~45%) is enriched for cell cycle related pathways, and patients classified to NPC1 have an intermediate survival; NPC3 (~19%) is enriched for immune related pathways, and has good clinical outcomes. More importantly, NPC2 (~36%) is associated with poor prognosis, and is characterized by upregulation of epithelial-mesenchymal transition (EMT). Out of the total 25 differentially expressed miRNAs in NPC2, miR-142, miR-26a, miR-141 and let-7i have significant prognostic power (p &lt; 0.05), as determined by univariate Cox regression analysis. For identification of high-risk distant metastasis, we built a multivariate Cox regression model using the selected 4 miRNAs. Our model can robustly stratify NPC patients into high- and low- risk groups both in GSE32960 (HR 3.1, 95% CI 1.8-5.4, p = 1.2e-05) and GSE70970 (HR 2.2, 95% CI 1.1-4.5, p = 0.022) cohorts. Conclusions: We proposed for the first time that NPC can be stratified into three subtypes. Using a panel of 4 miRNAs, we established a prognostic model that can robustly stratify NPC patients into high- and low- risk groups of distant metastasis.

Somatic polyploidy is associated with the upregulation of c-MYC interacting genes and EMT-like signature.

The dependence of cancer on overexpressed c-MYC and its predisposition for polyploidy represents a double puzzle. We address this conundrum by cross-species transcription analysis of c-MYC interacting genes in polyploid vs. diploid tissues and cells, including human vs. mouse heart, mouse vs. human liver and purified 4n vs. 2n mouse decidua cells. Gene-by-gene transcriptome comparison and principal component analysis indicated that c-MYC interactants are significantly overrepresented among ploidy-associated genes. Protein interaction networks and gene module analysis revealed that the most upregulated genes relate to growth, stress response, proliferation, stemness and unicellularity, as well as to the pathways of cancer supported by MAPK and RAS coordinated pathways. A surprising feature was the up-regulation of epithelial-mesenchymal transition (EMT) modules embodied by the N-cadherin pathway and EMT regulators from SNAIL and TWIST families. Metabolic pathway analysis also revealed the EMT-linked features, such as global proteome remodeling, oxidative stress, DNA repair and Warburg-like energy metabolism. Genes associated with apoptosis, immunity, energy demand and tumour suppression were mostly down-regulated. Noteworthy, despite the association between polyploidy and ample features of cancer, polyploidy does not trigger it. Possibly it occurs because normal polyploidy does not go that far in embryonalisation and linked genome destabilisation. In general, the analysis of polyploid transcriptome explained the evolutionary relation of c-MYC and polyploidy to cancer.

H-Prune is associated with poor prognosis and epithelial-mesenchymal transition in patients with colorectal liver metastases.

The prognosis of patients with colorectal liver metastases (CRLM) remains low despite advances in chemotherapy and surgery. The expression of h-prune (human homolog of Drosophila prune protein; HGNC13420), an exopolyphosphatase, is correlated with progression and aggressiveness in several cancers and promotes migration and invasion. We investigated the role of h-prune in CRLM. To investigate the role of h-prune, immunohistochemical analysis for h-prune was performed in 87 surgically resected specimens of CRLM obtained between 2001 and 2009 at the Hiroshima University Hospital. Immunohistochemical analysis revealed positive staining for h-prune in 24 (28%) cases. The overall survival rate was significantly lower in h-prune-positive cases than in h-prune-negative cases (p = 0.003). Multivariate analysis showed that h-prune positivity was the only independent factor related to poor overall survival of patients after curative hepatectomy of CRLM. In vitro and in vivo, h-prune-knocked-down and h-prune-overexpressing cells were analyzed. In vitro, h-prune was associated with increased cell motility and upregulation of epithelial-mesenchymal transition (EMT) markers. In a mouse model, h-prune was associated with invasion of the tumor and distant metastases. In summary, h-prune expression is a useful marker to identify high-risk patients for resectable colorectal liver metastasis. h-Prune expression is necessary for cancer cell motility and EMT and is associated with liver and lung metastasis in colorectal cancer cells. h-Prune could be a new prognostic marker and molecular target for CRLM.

ID: 33: CCL4 can promote bone metastasis of a murine breast cancer cell line, by interacting CCR5-expressing non-tumor cells in bone marrow

From a murine breast cancer cell line, 4T1, we established a subclone, 4T1.3, which can metastasize to bone upon orthotopic injection into mammary fat pad. 4T1.3 cells proliferated in vitro and in vivo at the primarily injected site, mammary fat pad, with a similar growth rate as the parental cells. Moreover, 4T1.3 cells migrated to bone with a comparable speed as the parental cells, when injected intravenously. However, 4T1.3 cells survived better than the parental cells when injected directly into osseous tissues. 4T1.3 clone exhibited increased expression of cancer stem cell markers, CD44 and CD24, with upregulation of epithelial-mesenchymal transition (EMT) markers. Microarray analysis revealed an enhanced mRNA expression of chemokine, CCL4, by 4T1.3 clone. On the contrary, 4T1.3 clone did not express CCR5, a specific receptor for CCL4. CCL4 shRNA transfection had few effects on the expression of cancer stem cell markers and EMT markers, but reduced its tumorigenicity in bone when injected directly into osseous tissues. Moreover, tumor formation was attenuated in mice deficient in CCR5, compared with wild-type mice upon intra-osseous inoculation of 4T1.3. Thus, tumor cell-derived CCL4 can interact with CCR5-expressing non-tumor cells to gain a growth advantage in bone marrow.

KITENIN promotes glioma invasiveness and progression, associated with the induction of EMT and stemness markers

KITENIN (KAI1 COOH-terminal interacting tetraspanin) promotes tumor invasion and metastasis in various cancers. This study assessed the association between KITENIN expression and advanced glioma grade in patients. In vitro assays revealed that KITENIN knockdown inhibited the invasion and migration of glioma cells, whereas KITENIN overexpression promoted their invasion and migration. In orthotopic mouse tumor models, mice transplanted with KITENIN-transfected glioma cells had significantly shorter survival than mice transplanted with mock-transfected cells. Patients with low KITENIN expression showed a significantly longer progression-free survival than patients with high KITENIN expression. KITENIN induced the expression of the epithelial-mesenchymal transition (EMT) markers (N-cadherin, ZEB1, ZEB2, SNAIL and SLUG) as well as the glioma stemness markers (CD133, ALDH1 and EPH-B1). Taken together, these findings showed that high levels of KITENIN increased glioma invasiveness and progression, associated with the up-regulation of EMT and stemness markers.

Failure of anti tumor-derived endothelial cell immunotherapy depends on augmentation of tumor hypoxia

We have previously demonstrated that Tenascin-C (TNC)(+) human neuroblastoma (NB) cells transdifferentiate into tumor-derived endothelial cells (TDEC), which have been detected both in primary tumors and in tumors formed by human NB cell lines in immunodeficient mice. TDEC are genetically unstable and may favor tumor progression, suggesting that their elimination could reduce tumor growth and dissemination. So far, TDEC have never been targeted by antibody-mediated immunotherapy in any of the tumor models investigated. To address this issue, immunodeficient mice carrying orthotopic NB formed by the HTLA-230 human cell line were treated with TDEC-targeting cytotoxic human (h)CD31, that spares host-derived endothelial cells, or isotype-matched mAbs. hCD31 mAb treatment did not affect survival of NB-bearing mice, but increased significantly hypoxia in tumor microenvironment, where apoptotic and proliferating TDEC coexisted, indicating the occurrence of vascular remodeling. Tumor cells from hCD31 mAb treated mice showed i) up-regulation of epithelial-mesenchymal transition (EMT)-related and vascular mimicry (VM)-related gene expression, ii) expression of endothelial (i.e. CD31 and VE-cadherin) and EMT-associated (i.e. Twist-1, N-cadherin and TNC) immunophenotypic markers, and iii) up-regulation of high mobility group box-1 (HMGB-1) expression. In vitro experiments with two NB cell lines showed that hypoxia was the common driver of all the above phenomena and that human recombinant HMGB-1 amplified EMT and TDEC trans-differentiation. In conclusion, TDEC targeting with hCD31 mAb increases tumor hypoxia, setting the stage for the occurrence of EMT and of new waves of TDEC trans-differentiation. These adaptive responses to the changes induced by immunotherapy in the tumor microenvironment allow tumor cells to escape from the effects of hCD31 mAb.