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Supplementary Tables 1 and 2, Figures 1-9. Supplemental Table 1. H-score analysis for SPRY2 staining in 10 EGFRvIII-negative and 10 EGFRvIII-positive tumors. Supplemental Table 2. Upregulated genes shared by human GBMs expressing EGFRvIII and 9L.EGFRvIII rat tumors compared to wild-type EGFR human GBMs or 9L.EV rat tumors. Supplemental Figure 1. SPRY2 is efficiently knocked down by shRNA expression in GBM cell lines. Supplemental Figure 2. SPRY2 knockdown by a second non-overlapping shRNA reduces cellular proliferation, and SPRY2 knockdown by transient siRNA transfection reduces colony formation in soft agar in EGFRvIII-expressing cells. Supplemental Figure 3. SPRY2 knockdown increases cellular sensitivity to EGFR and c-MET co-inhibition. Supplemental Figure 4. SPRY2 knockdown promotes response to EGFR and c-MET coinhibition in GSC cells. Supplemental Figure 5. p38 and JNK control anchorage-independent growth and response to EGFR and c-MET co-inhibition. Supplemental Figure 6. shRNA-mediated knockdown of MKP-1 or MKP-5 reduces MKP-1 or MKP-5 mRNA level. Supplemental Figure 7. SPRY2 protein expression in kidney and cerebellum sections by immunohistochemical analysis. Supplemental Figure 8. SPRY2 correlates well with ERK phosphorylation in a panel of GBM cell lines. Supplemental Figure 9. TCGA GBM dataset analysis reveals that SPRY2 expression is associated with reduced patient survival.

Supplementary materials and methods for ALDEFLUOR assay and CD44 staining and data showing that patient-derived GSCs are enriched for ALDH+ cells and express CD44.

Supplemental tables include gene lists related to Figure 5, additional experimental data related to Figure S3I, and primers sequence. Table S1. Numbers of spheroids were counted for each cell dilution; Table S2. List of 20 genes that exhibit a significant change between control and FTO-overexpressing OVCAR5 cells in m6A peak levels, and abundance of the corresponding mRNA transcripta; Table S3. List of primers oligonucleotides; Table S4. Summary of the m6A-seq and RNA-seq; Table S5. List of top 50 hypo-methylation & down-regulated genes; Table S6: List of top 50 hypo-methylation &up-regulated genes.

Supplemental Methods and Material

Dose-response curves for MEC1 and MEC2 cells treated with fludarabine.

Supplementary Table S1, S2, S3, and S4

Supplementary Table S1 Clinical characteristics of two chronic lymphocytic leukemia patient datasets; Supplementary Table S2 Clinical characteristics of two lung cancer patient datasets; Supplementary Table S3 Clinical characteristics of the ALL dataset; Supplementary Table S4 Integrated function and pathway analysis on 248 experimentally validated targets of miR-155; Supplementary Table S5 Univariate and multivariate analyses of survival with patient characteristics and miR-155 and TP53 expression as categorical and continuous variables in different patient cohorts; Supplementary Table S6 Estimate of Cox model and multivariate Cox model, as well as the HR estimated based on the model for miR-155 high and TP53 low vs. miR-155 low and TP53 high.

Purpose: The oncogenic miR-155 is upregulated in many human cancers, and its expression is increased in more aggressive and therapy-resistant tumors, but the molecular mechanisms underlying miR-155-induced therapy resistance are not fully understood. The main objectives of this study were to determine the role of miR-155 in resistance to chemotherapy and to evaluate anti-miR-155 treatment to chemosensitize tumors.Experimental Design: We performed in vitro studies on cell lines to investigate the role of miR-155 in therapy resistance. To assess the effects of miR-155 inhibition on chemoresistance, we used an in vivo orthotopic lung cancer model of athymic nude mice, which we treated with anti-miR-155 alone or in combination with chemotherapy. To analyze the association of miR-155 expression and the combination of miR-155 and TP53 expression with cancer survival, we studied 956 patients with lung cancer, chronic lymphocytic leukemia, and acute lymphoblastic leukemia.Results: We demonstrate that miR-155 induces resistance to multiple chemotherapeutic agents in vitro, and that downregulation of miR-155 successfully resensitizes tumors to chemotherapy in vivo. We show that anti-miR-155-DOPC can be considered non-toxic in vivo. We further demonstrate that miR-155 and TP53 are linked in a negative feedback mechanism and that a combination of high expression of miR-155 and low expression of TP53 is significantly associated with shorter survival in lung cancer.Conclusions: Our findings support the existence of an miR-155/TP53 feedback loop, which is involved in resistance to chemotherapy and which can be specifically targeted to overcome drug resistance, an important cause of cancer-related death. Clin Cancer Res; 23(11); 2891–904. ©2016 AACR.

Defining traits of platinum-tolerant cancer cells could expose new treatment vulnerabilities. Here, new markers associated with platinum-tolerant cells and tumors were identified using in vitro and in vivo ovarian cancer models treated repetitively with carboplatin and validated in human specimens. Platinum-tolerant cells and tumors were enriched in ALDH+ cells, formed more spheroids, and expressed increased levels of stemness-related transcription factors compared with parental cells. Additionally, platinum-tolerant cells and tumors exhibited expression of the Wnt receptor Frizzled-7 (FZD7). Knockdown of FZD7 improved sensitivity to platinum, decreased spheroid formation, and delayed tumor initiation. The molecular signature distinguishing FZD7+ from FZD7− cells included epithelial-to-mesenchymal (EMT), stemness, and oxidative phosphorylation-enriched gene sets. Overexpression of FZD7 activated the oncogenic factor Tp63, driving upregulation of glutathione metabolism pathways, including glutathione peroxidase 4 (GPX4), which protected cells from chemotherapy-induced oxidative stress. FZD7+ platinum-tolerant ovarian cancer cells were more sensitive and underwent ferroptosis after treatment with GPX4 inhibitors. FZD7, Tp63, and glutathione metabolism gene sets were strongly correlated in the ovarian cancer Tumor Cancer Genome Atlas (TCGA) database and in residual human ovarian cancer specimens after chemotherapy. These results support the existence of a platinum-tolerant cell population with partial cancer stem cell features, characterized by FZD7 expression and dependent on the FZD7–β-catenin–Tp63–GPX4 pathway for survival. The findings reveal a novel therapeutic vulnerability of platinum-tolerant cancer cells and provide new insight into a potential “persister cancer cell” phenotype.Significance:Frizzled-7 marks platinum-tolerant cancer cells harboring stemness features and altered glutathione metabolism that depend on GPX4 for survival and are highly susceptible to ferroptosis.

Clinical correlation of miR-155 expression with survival in leukemia. Kaplan-Meier survival analysis for patients expressing high levels of miR-155 vs. low levels of miR-155 in two CLL cohorts, CLL - NEJM (A) and CLL - Italy (B), and in one ALL cohort, ALL - MDACC (C).

N6-Methyladenosine (m6A) is the most abundant modification of mammalian mRNAs. RNA methylation fine tunes RNA stability and translation, altering cell fate. The fat mass- and obesity-associated protein (FTO) is an m6A demethylase with oncogenic properties in leukemia. Here, we show that FTO expression is suppressed in ovarian tumors and cancer stem cells (CSC). FTO inhibited the self-renewal of ovarian CSC and suppressed tumorigenesis in vivo, both of which required FTO demethylase activity. Integrative RNA sequencing and m6A mapping analysis revealed significant transcriptomic changes associated with FTO overexpression and m6A loss involving stem cell signaling, RNA transcription, and mRNA splicing pathways. By reducing m6A levels at the 3′UTR and the mRNA stability of two phosphodiesterase genes (PDE1C and PDE4B), FTO augmented second messenger 3′, 5′-cyclic adenosine monophosphate (cAMP) signaling and suppressed stemness features of ovarian cancer cells. Our results reveal a previously unappreciated tumor suppressor function of FTO in ovarian CSC mediated through inhibition of cAMP signaling.Significance:A new tumor suppressor function of the RNA demethylase FTO implicates m6A RNA modifications in the regulation of cyclic AMP signaling involved in stemness and tumor initiation.

In vivo orthotopic lung cancer model for the role of miR-155 in chemoresistance. (A) Injection and treatment schedule for CDDP (green arrows) and anti-miR negative control (NC) or anti-miR-155 liposomal nanoparticles (red stars) for four different treatment groups: mice that were injected with A549-LVEV cells and untreated (group 1), injected with A549-LVEV cells and treated with anti-miR-NC and CDDP (group 2), injected with A549-155LV cells and treated with anti-miR-NC and CDDP (group 3), and injected with A549-155LV cells and treated with anti-miR-155 and CDDP (group 4). (B) Representative pictures of dissected mice belonging to each of the treatment groups described in panel A of this Figure. Tumor nodules are marked by dotted white circles. (C-D) Graphs of the primary tumor size (C) and aggregate mass of nodules in mediastinum (D) of the four treatment groups mentioned above. (E) In situ hybridization for miR-155 for each of the four treatment groups mentioned above. (F) Immunohistochemical analysis for Ki-67 (proliferation) and CD31 (angiogenesis), as well as the TUNEL assay (apoptosis) and TP53 immunostaining for each of the four treatment groups mentioned above.

Clinical correlation of miR-155 and TP53 expression with survival in the lung adenocarcinoma - TCGA dataset when distinguishing between TP53 wild-type and TP53 mutated samples. (A-B) Kaplan-Meier survival analysis for patients expressing high levels of miR-155 vs. low levels of miR-155 in samples that express wild-typeTP53 or harbor TP53 mutations that do not affect TP53 function (A), and in samples expressing mutated TP53 that affects TP53 function (B). (C-D) Kaplan-Meier survival analysis for patients expressing high levels of miR-155 and low levels of TP53 vs. low levels of miR-155 and high levels of TP53 in samples that express wild-type TP53 or harbor TP53 mutations that do not affect TP53 function (C), and in samples expressing mutated TP53 that affects TP53 function (D).

Additional experimental results supporting the main figures are included. Figure S1. Expression of key RNA methylation regulators in OC; Figure S2. Flow cytometry analysis for ALDH and CD133 in single cell suspensions derived from human ovarian tumors; Figure S3. FTO overexpression in OC cells; Figure S4. FTO overexpression decreases spheroid formation ability of OC cells dissociated from xenografts; Figure S5. m6A activity and tumor initiation capacity; Figure S6. Gene sets enriched in FTO vs. control OC cells; Figure S7. Expression of PDE4B and PDE1C in FTO overexpressed OC cells; Figure S8. The Genome Browser visualizes the predicted motif binding sites for proteins (IGF2BP2 and IGF2BP3) on the input sequence; Figure S9. Effects of phosphodiesterase inhibitors on stemness features are dependent on FTO; Figure S10. Quality control for RNA-seq; Figure S11. Quality control for MeRIP-seq

Detailed information regarding materials and methods are included in this file.

Purpose: Aberrant DNA methylation, now recognized as a contributing factor to neoplasia, often shows definitive gene/sequence preferences unique to specific cancer types. Correspondingly, distinct combinations of methylated loci can function as biomarkers for numerous clinical correlates of ovarian and other cancers.Experimental Design: We used a microarray approach to identify methylated loci prognostic for reduced progression-free survival (PFS) in advanced ovarian cancer patients. Two data set classification algorithms, Significance Analysis of Microarray and Prediction Analysis of Microarray, successfully identified 220 candidate PFS-discriminatory methylated loci. Of those, 112 were found capable of predicting PFS with 95% accuracy, by Prediction Analysis of Microarray, using an independent set of 40 advanced ovarian tumors (from 20 short-PFS and 20 long-PFS patients, respectively). Additionally, we showed the use of these predictive loci using two bioinformatics machine-learning algorithms, Support Vector Machine and Multilayer Perceptron.Conclusion: In this report, we show that highly prognostic DNA methylation biomarkers can be successfully identified and characterized, using previously unused, rigorous classifying algorithms. Such ovarian cancer biomarkers represent a promising approach for the assessment and management of this devastating disease.

Supplementary Figures S1, S2, S3, S4, S5, S6, S7 and S8

Alterations in histones, chromatin-related proteins, and DNA methylation contribute to transcriptional silencing in cancer, but the sequence of these molecular events is not well understood. Here we demonstrate that on disruption of estrogen receptor (ER) α signaling by small interfering RNA, polycomb repressors and histone deacetylases are recruited to initiate stable repression of the progesterone receptor (PR) gene, a known ERα target, in breast cancer cells. The event is accompanied by acquired DNA methylation of the PR promoter, leaving a stable mark that can be inherited by cancer cell progeny. Reestablishing ERα signaling alone was not sufficient to reactivate the PR gene; reactivation of the PR gene also requires DNA demethylation. Methylation microarray analysis further showed that progressive DNA methylation occurs in multiple ERα targets in breast cancer genomes. The results imply, for the first time, the significance of epigenetic regulation on ERα target genes, providing new direction for research in this classical signaling pathway.

Supplementary Table 1 from Loss of Estrogen Receptor Signaling Triggers Epigenetic Silencing of Downstream Targets in Breast Cancer

Supplementary Tables 3-9 from Single-Nucleotide Polymorphisms Inside MicroRNA Target Sites Influence Tumor Susceptibility

Supplementary Table 2 from Single-Nucleotide Polymorphisms Inside MicroRNA Target Sites Influence Tumor Susceptibility

Supplementary Table 1 from Single-Nucleotide Polymorphisms Inside MicroRNA Target Sites Influence Tumor Susceptibility

Supplementary Table Legends 1-9, Figures 1-4, Methods from Single-Nucleotide Polymorphisms Inside MicroRNA Target Sites Influence Tumor Susceptibility

Defining traits of platinum-tolerant cancer cells could expose new treatment vulnerabilities. Here, new markers associated with platinum-tolerant cells and tumors were identified using in vitro and in vivo ovarian cancer models treated repetitively with carboplatin and validated in human specimens. Platinum-tolerant cells and tumors were enriched in ALDH+ cells, formed more spheroids, and expressed increased levels of stemness-related transcription factors compared with parental cells. Additionally, platinum-tolerant cells and tumors exhibited expression of the Wnt receptor Frizzled-7 (FZD7). Knockdown of FZD7 improved sensitivity to platinum, decreased spheroid formation, and delayed tumor initiation. The molecular signature distinguishing FZD7+ from FZD7− cells included epithelial-to-mesenchymal (EMT), stemness, and oxidative phosphorylation-enriched gene sets. Overexpression of FZD7 activated the oncogenic factor Tp63, driving upregulation of glutathione metabolism pathways, including glutathione peroxidase 4 (GPX4), which protected cells from chemotherapy-induced oxidative stress. FZD7+ platinum-tolerant ovarian cancer cells were more sensitive and underwent ferroptosis after treatment with GPX4 inhibitors. FZD7, Tp63, and glutathione metabolism gene sets were strongly correlated in the ovarian cancer Tumor Cancer Genome Atlas (TCGA) database and in residual human ovarian cancer specimens after chemotherapy. These results support the existence of a platinum-tolerant cell population with partial cancer stem cell features, characterized by FZD7 expression and dependent on the FZD7–β-catenin–Tp63–GPX4 pathway for survival. The findings reveal a novel therapeutic vulnerability of platinum-tolerant cancer cells and provide new insight into a potential “persister cancer cell” phenotype.Significance:Frizzled-7 marks platinum-tolerant cancer cells harboring stemness features and altered glutathione metabolism that depend on GPX4 for survival and are highly susceptible to ferroptosis.

N6-Methyladenosine (m6A) is the most abundant modification of mammalian mRNAs. RNA methylation fine tunes RNA stability and translation, altering cell fate. The fat mass- and obesity-associated protein (FTO) is an m6A demethylase with oncogenic properties in leukemia. Here, we show that FTO expression is suppressed in ovarian tumors and cancer stem cells (CSC). FTO inhibited the self-renewal of ovarian CSC and suppressed tumorigenesis in vivo, both of which required FTO demethylase activity. Integrative RNA sequencing and m6A mapping analysis revealed significant transcriptomic changes associated with FTO overexpression and m6A loss involving stem cell signaling, RNA transcription, and mRNA splicing pathways. By reducing m6A levels at the 3′UTR and the mRNA stability of two phosphodiesterase genes (PDE1C and PDE4B), FTO augmented second messenger 3′, 5′-cyclic adenosine monophosphate (cAMP) signaling and suppressed stemness features of ovarian cancer cells. Our results reveal a previously unappreciated tumor suppressor function of FTO in ovarian CSC mediated through inhibition of cAMP signaling. Significance: A new tumor suppressor function of the RNA demethylase FTO implicates m6A RNA modifications in the regulation of cyclic AMP signaling involved in stemness and tumor initiation.