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Supplementary Figures S1-S3 and Supplementary Table S1.

PDF file - 47K, Differentially methylated genes with beta values (3KT vs carcinogen exposed).

PDF file - 65K, Pathway analysis of differentially methylated genes.

DNA methylation is an early event in bronchial carcinogenesis and increased DNA methyltransferase (DNMT)1 protein expression is a crucial step in the oncogenic transformation of epithelia. Here, we investigate the role of class I histone deacetylases (HDAC) 1 to 3 in the stabilization of DNMT1 protein and as a potential therapeutic target for lung cancer chemoprevention. Long-term exposure of immortalized bronchial epithelial cells (HBEC-3KT) to low doses of tobacco-related carcinogens led to oncogenic transformation, increased HDAC expression, cell-cycle independent increased DNMT1 stability, and DNA hypermethylation. Overexpression of HDACs was associated with increased DNMT1 stability and knockdown of HDACs reduced DNMT1 protein levels and induced DNMT1 acetylation. This suggests a causal relationship among increased class I HDACs levels, upregulation of DNMT1 protein, and subsequent promoter hypermethylation. Targeting of class I HDACs with valproic acid (VPA) was associated with reduced HDAC expression and a profound reduction of DNMT1 protein level. Treatment of transformed bronchial epithelial cells with VPA resulted in reduced colony formation, demethylation of the aberrantly methylated SFRP2 promoter, and derepression of SFRP2 transcription. These data suggest that inhibition of HDAC activity may reverse or prevent carcinogen-induced transformation. Finally, immunohistochemistry on human lung cancer specimens revealed a significant increase in DNMT1, HDAC1, HDAC2, and HDAC3 expression, supporting our hypotheses that class I HDACs are mediators of DNMT1 stability. In summary, our study provides evidence for an important role of class I HDACs in controlling the stability of DNMT1 and suggests that HDAC inhibition could be an attractive approach for lung cancer chemoprevention. Cancer Prev Res; 7(3); 351–61. ©2014 AACR.

PDF file - 41K

Supplementary Data from Sox7 Is an Independent Checkpoint for β-Catenin Function in Prostate and Colon Epithelial Cells

The presence of somatic β-catenin mutations in some prostate cancers implies that aberrant WNT signaling is involved in the cancer development. Although β-catenin stability is regulated by a multicomponent destruction complex, mutational alterations of β-catenin or other components of the destruction complexes are rare in prostate tumors. Therefore, β-catenin may be regulated by another protein in the prostate. In fact, recent linkage and somatic deletion analyses in prostate cancers reveal a 1.4-Mb candidate tumor suppressor locus on 8p23.1, which includes the Sox7 gene. Here we show that Sox7 protein expression was indeed down-regulated in 47% (15 of 32) of prostate adenocarcinomas. In addition, Sox7 mRNA was down-regulated in 60% of snap-frozen tumors. This down-regulation was found to be due to tumor-specific promoter hypermethylation, which was present in 48% (10 of 21) of primary prostate tumors and 44% (11 of 25) of prostate cancer cell lines/xenografts. We discovered that Sox7 protein physically interacts with β-catenin and suppresses β-catenin–mediated transcription by depleting active β-catenin. Furthermore, in HCT116 colorectal cancer cell lines with Sox7 inactivation, ectopic Sox7 expression suppressed cell proliferation and inhibited transcription that was activated by an endogenous mutant β-catenin. Although nearly all colorectal cancers contain mutations in β-catenin or adenomatous polyposis coli/axin, epigenetic silencing of Sox7 was still observed. These data suggest that Sox7 is a tumor suppressor that functions as an independent checkpoint for β-catenin transcriptional activity. Inactivation of Sox7 could promote the development of a majority of colorectal tumors and approximately half of prostate tumors. (Mol Cancer Res 2008;6(9):1421–10)

PDF file - 1302K, S1: Primary transcript qPCR indicates HDAC1 and 2 are regulated transcriptionally, HDAC3 is not. S2: Analysis of golden gate methylation array identifies 42/807 genes hypermethylated after long term carcinogen exposure. S3: Cycloheximide 2ug/ml final was added to cultures of 3kt or T31 cells for the indicated times (hours). Cycloheximide blocks the VPA induced degradation of DNMT1. S4: HEK293 cells transiently transfected with pDest51-V5tagged HDAC1, 2 demonstrates protective role of HDACs on DNMT1. % indicates percent fold change of DNMT1 expression over parental cell. S5: 3kt cells stably transfected with HDAC3 demonstrates protective role on DNMT1. % indicates percent fold change of DNMT1 expression over parental cell. S6: Overexpression of HDAC1 or HDAC3 do not increase cellular proliferation compared to empty vector control. S7: 6 tumor samples and matched resected histologically normal lungs were stained for PCNA. PCNA staining intensity is quantified by weighted index. S8: AKT phosphorylation (S473) was assessed with and without VPA exposure in several different passages of carcinogen exposure. VPA had no effect on AKT phosphorylation. S9: T31 wells were grown in triplicates in logarithmic phase and counted manually. VPA's effects on proliferation were assessed at 0.1 mM and 0.5 mM. No discernable effect of particularly the low dose of VPA on growth was observed. S10: carcinogen-transformed T31 cells were passaged for 28 days in the presence of VPA (0.5mM). Bisulfite sequencing of the RASSF1 locus was performed on cells derived from day 0 and day 28.

Purpose:Multiple myeloma is a malignancy of plasma cells. Extensive genetic and transcriptional characterization of myeloma has identified subtypes with prognostic and therapeutic implications. In contrast, relatively little is known about the myeloma epigenome.Experimental Design:CD138+CD38+ myeloma cells were isolated from fresh bone marrow aspirate or the same aspirate after freezing for 1–6 months. Gene expression and chromatin accessibility were compared between fresh and frozen samples by RNA sequencing (RNA-seq) and assay for transpose accessible chromatin sequencing (ATAC-seq). Chromatin accessible regions were used to identify regulatory RNA expression in more than 700 samples from newly diagnosed patients in the Multiple Myeloma Research Foundation CoMMpass trial (NCT01454297).Results:Gene expression and chromatin accessibility of cryopreserved myeloma recapitulated that of freshly isolated samples. ATAC-seq performed on a series of biobanked specimens identified thousands of chromatin accessible regions with hundreds being highly coordinated with gene expression. More than 4,700 of these chromatin accessible regions were transcribed in newly diagnosed myelomas from the CoMMpass trial. Regulatory element activity alone recapitulated myeloma gene expression subtypes, and in particular myeloma subtypes with immunoglobulin heavy chain translocations were defined by transcription of distal regulatory elements. Moreover, enhancer activity predicted oncogene expression implicating gene regulatory mechanisms in aggressive myeloma.Conclusions:These data demonstrate the feasibility of using biobanked specimens for retrospective studies of the myeloma epigenome and illustrate the unique enhancer landscapes of myeloma subtypes that are coupled to gene expression and disease progression.

Enrichment of transcription factor consensus binding motifs in regulatory elements predictive of gene expression associated with poor overall survival.

Correlation of regulatory element transcription and gene expression in CoMMpass specimens.

ATAC-seq data for Emory patients.

Correlation of chromatin accessibility and gene expression for the 5% most variably expressed genes.

Regulatory elements predictive of gene expression for genes prognostic of overall survival in CoMMpass.

Regulatory element transcription in newly diagnosed myelomas from CoMMpass.

Gene set enrichment analysis of transcribed regulatory elements in CoMMpass.

G9a and EZH2 are two histone methyltransferases commonly upregulated in several cancer types, yet the precise roles that these enzymes play cooperatively in cancer is unclear. We demonstrate here that frequent concurrent upregulation of both G9a and EZH2 occurs in several human tumors. These methyltransferases cooperatively repressed molecular pathways responsible for tumor cell death. In genetically distinct tumor subtypes, concomitant inhibition of G9a and EZH2 potently induced tumor cell death, highlighting the existence of tumor cell survival dependency at the epigenetic level. G9a and EZH2 synergistically repressed expression of genes involved in the induction of endoplasmic reticulum (ER) stress and the production of reactive oxygen species. IL24 was essential for the induction of tumor cell death and was identified as a common target of G9a and EZH2. Loss of function of G9a and EZH2 activated the IL24-ER stress axis and increased apoptosis in cancer cells while not affecting normal cells. These results indicate that G9a and EZH2 promotes the evasion of ER stress–mediated apoptosis by repressing IL24 transcription, therefore suggesting that their inhibition may represent a potential therapeutic strategy for solid cancers.Significance:These findings demonstrate a novel role for G9a and EZH2 histone methyltransferases in suppressing apoptosis, which can be targeted with small molecule inhibitors as a potential approach to improve solid cancer treatment.

Supplementary Data from Combined Inhibition of G9a and EZH2 Suppresses Tumor Growth via Synergistic Induction of IL24-Mediated Apoptosis

Supplementary Table 1 from A Multifactorial Signature of DNA Sequence and Polycomb Binding Predicts Aberrant CpG Island Methylation

Supplementary Figures 1-3 from A Multifactorial Signature of DNA Sequence and Polycomb Binding Predicts Aberrant CpG Island Methylation

Supplementary Figure 1 from The Tumor Suppressor LKB1 Regulates Lung Cancer Cell Polarity by Mediating cdc42 Recruitment and Activity

Supplementary Methods from Overexpression of MBD2 in Glioblastoma Maintains Epigenetic Silencing and Inhibits the Antiangiogenic Function of the Tumor Suppressor Gene BAI1

The tumor suppressor LKB1 is mutated in 30% of non–small cell lung cancer (NSCLC) tumors and cell lines and is proposed to be a key regulator of epithelial cell polarity; however, how LKB1 regulates cancer cell polarity is not known. The experiments described herein show for the first time that LKB1 is a dynamic, actin-associated protein that rapidly polarizes to the leading edge of motile cancer cells. LKB1 proves to be essential for NSCLC polarity, because LKB1 depletion results in classic cell polarity defects, such as aberrant Golgi positioning, reduced lamellipodia formation, and aberrant morphology. To probe how LKB1 regulates these events, we show that LKB1 colocalizes at the cellular leading edge with two key components of the polarity pathway — the small rho GTPase cdc42 and its downstream binding partner p21-activated kinase (PAK). Importantly, LKB1 functionality is required for cdc42 polarization to the leading edge, maintaining active cdc42 levels, and downstream PAK phosphorylation. To do this, LKB1 interacts only with active form of cdc42 and PAK, but not with inactive cdc42. Taken together, these results show that LKB1 is a critical mediator of the NSCLC polarity program in lung cancer cells through a novel LKB1-cdc42-PAK pathway. [Cancer Res 2008;68(3):740–8]

Supplementary Materials from A Multifactorial Signature of DNA Sequence and Polycomb Binding Predicts Aberrant CpG Island Methylation

Supplementary Figure 2 from The Tumor Suppressor LKB1 Regulates Lung Cancer Cell Polarity by Mediating cdc42 Recruitment and Activity

Supplementary Table 2 from A Multifactorial Signature of DNA Sequence and Polycomb Binding Predicts Aberrant CpG Island Methylation

Supplementary Figure 3 from The Tumor Suppressor LKB1 Regulates Lung Cancer Cell Polarity by Mediating cdc42 Recruitment and Activity

Supplementary Figure Legends 1-4 from The Tumor Suppressor LKB1 Regulates Lung Cancer Cell Polarity by Mediating cdc42 Recruitment and Activity

Supplementary Table 1, Figures 1-3 from LKB1 Is Necessary for Akt-Mediated Phosphorylation of Proapoptotic Proteins

Supplementary Table 4 from A Multifactorial Signature of DNA Sequence and Polycomb Binding Predicts Aberrant CpG Island Methylation

Supplementary Table 3 from A Multifactorial Signature of DNA Sequence and Polycomb Binding Predicts Aberrant CpG Island Methylation

LKB1 plays the role of tumor suppressor, opposite to Akt, by negatively regulating mammalian target of rapamycin through the activation of AMP-activated protein kinase and TSC signaling. We have discovered a novel, potentially oncogenic role for LKB1 as a supporter of Akt-mediated phosphorylation of proapoptotic proteins. We found that Akt activation led to increased phosphorylation of FoxO3a at Thr32 in LKB1 wild-type cells but not in LKB1-null cells. Depletion of LKB1 in the cells with wild-type LKB1 resulted in attenuation of that phosphorylation of FoxO3a by activated Akt, whereas the restoration of LKB1 function in LKB1-null cells reestablished Akt-mediated FoxO3a phosphorylation. On expanding our analysis to other Akt targets, using isogenic LKB1 knockdown cell line pairs and a phospho-specific antibody microarray, we observed that there was a requirement for LKB1 in the phosphorylation of other Akt downstream targets, including Ask1 (Ser83), Bad (Ser136), FoxO1 (Ser319), FoxO4 (Ser197), and glycogen synthase kinase 3β (GSK3β; Ser9). Because the phosphorylation of these sites by Akt suppresses apoptosis, the requirement of LKB1 suggests that LKB1 may have an antiapoptotic role in tumor cells with constitutively active Akt. Indeed, we found that the suppression of LKB1 expression led to apoptosis in three cell lines in which Akt is constitutively active but not in two cell lines without Akt activation. This observation may explain the lack of LKB1 somatic mutations in brain, breast, and colon cancers, where Akt is frequently activated due to mutations in phosphatidylinositol 3-kinase, PTEN, or Akt itself. [Cancer Res 2008;68(18):7270–7]

G9a and EZH2 are two histone methyltransferases commonly upregulated in several cancer types, yet the precise roles that these enzymes play cooperatively in cancer is unclear. We demonstrate here that frequent concurrent upregulation of both G9a and EZH2 occurs in several human tumors. These methyltransferases cooperatively repressed molecular pathways responsible for tumor cell death. In genetically distinct tumor subtypes, concomitant inhibition of G9a and EZH2 potently induced tumor cell death, highlighting the existence of tumor cell survival dependency at the epigenetic level. G9a and EZH2 synergistically repressed expression of genes involved in the induction of endoplasmic reticulum (ER) stress and the production of reactive oxygen species. IL24 was essential for the induction of tumor cell death and was identified as a common target of G9a and EZH2. Loss of function of G9a and EZH2 activated the IL24-ER stress axis and increased apoptosis in cancer cells while not affecting normal cells. These results indicate that G9a and EZH2 promotes the evasion of ER stress–mediated apoptosis by repressing IL24 transcription, therefore suggesting that their inhibition may represent a potential therapeutic strategy for solid cancers. Significance: These findings demonstrate a novel role for G9a and EZH2 histone methyltransferases in suppressing apoptosis, which can be targeted with small molecule inhibitors as a potential approach to improve solid cancer treatment.

A variety of organisms have been shown to have altered physiology or developed pathology due to gene transfer, but mammals have never been shown to do so. Here, we show that circulating tumor DNA (ct) can promote cell-specific horizontal gene transfer (HGT) between human cancer cells and explain the mechanisms behind this phenomenon. Once ctDNA enters the host cell, it migrates to the nucleus and integrates into the cell’s genome, thereby transferring its genetic information. We determine that retrotransposons of the ERVL, SINE, and LINE families are necessary for cell targeting and the integration of ctDNA into host DNA. Using chemically synthesized retrotransposons, we found that AluSp and MER11C reproduced multiple myeloma’s (MM) ctDNA’s cell targeting and integration into MM cells. We also discovered that ctDNA might, as a result of HGT, influence the treatment response of multiple myeloma and pancreatic cancer models. Overall, this is the first study to show that retrotransposon-directed HGT can promote genetic material transfer in cancer. There is, however, a broader impact of our findings than just cancer since cell-free DNA has also been found in physiological and other pathological conditions as well. Furthermore, with the discovery of transposons-mediated tissue-specific targeting, a new avenue for the delivery of genes and therapies will emerge.

Purpose: Multiple myeloma is a malignancy of plasma cells. Extensive genetic and transcriptional characterization of myeloma has identified subtypes with prognostic and therapeutic implications. In contrast, relatively little is known about the myeloma epigenome. Experimental Design: CD138+CD38+ myeloma cells were isolated from fresh bone marrow aspirate or the same aspirate after freezing for 1–6 months. Gene expression and chromatin accessibility were compared between fresh and frozen samples by RNA sequencing (RNA-seq) and assay for transpose accessible chromatin sequencing (ATAC-seq). Chromatin accessible regions were used to identify regulatory RNA expression in more than 700 samples from newly diagnosed patients in the Multiple Myeloma Research Foundation CoMMpass trial (NCT01454297). Results: Gene expression and chromatin accessibility of cryopreserved myeloma recapitulated that of freshly isolated samples. ATAC-seq performed on a series of biobanked specimens identified thousands of chromatin accessible regions with hundreds being highly coordinated with gene expression. More than 4,700 of these chromatin accessible regions were transcribed in newly diagnosed myelomas from the CoMMpass trial. Regulatory element activity alone recapitulated myeloma gene expression subtypes, and in particular myeloma subtypes with immunoglobulin heavy chain translocations were defined by transcription of distal regulatory elements. Moreover, enhancer activity predicted oncogene expression implicating gene regulatory mechanisms in aggressive myeloma. Conclusions: These data demonstrate the feasibility of using biobanked specimens for retrospective studies of the myeloma epigenome and illustrate the unique enhancer landscapes of myeloma subtypes that are coupled to gene expression and disease progression.

Activating KRAS mutations and functional loss of members of the SWI/SNF complex, including ARID1A, are found together in the primary liver tumor cholangiocarcinoma (CC). How these mutations cooperate to promote CC has not been established. Using murine models of hepatocyte and biliary-specific lineage tracing, we show that Kras and Arid1a mutations drive the formation of CC and tumor precursors from the biliary compartment, which are accelerated by liver inflammation. Using cultured cells, we find that Arid1a loss causes cellular proliferation, escape from cell-cycle control, senescence, and widespread changes in chromatin structure. Notably, we show that the biliary proliferative response elicited by Kras/Arid1a cooperation and tissue injury in CC is caused by failed engagement of the TGF-β-Smad4 tumor suppressor pathway. We thus identify an ARID1A-TGF-β-Smad4 axis as essential in limiting the biliary epithelial response to oncogenic insults, while its loss leads to biliary pre-neoplasia and CC.

Background Intratumoral heterogeneity is defined by subpopulations with varying genotypes and phenotypes. Specialized, highly invasive leader cells and less invasive follower cells are phenotypically distinct subpopulations that cooperate during collective cancer invasion. Because leader cells are a rare subpopulation that would be missed by bulk sequencing, a novel image-guided genomics platform was used to precisely select this subpopulation. This study identified a novel leader cell mutation signature and tested its ability to predict prognosis in non-small cell lung cancer (NSCLC) patient cohorts. Methods Spatiotemporal genomic and cellular analysis was used to isolate and perform RNA sequencing on leader and follower populations from the H1299 NSCLC cell line, and it revealed a leader-specific mutation cluster on chromosome 16q. Genomic data from patients with lung squamous cell carcinoma (LUSC; n = 475) and lung adenocarcinoma (LUAD; n = 501) from The Cancer Genome Atlas were stratified by 16q mutation cluster (16qMC) status (16qMC+ vs 16qMC-) and compared for overall survival (OS), progression-free survival (PFS), and gene set enrichment analysis (GSEA). Results Poorer OS, poorer PFS, or both were found across all stages and among early-stage patients with 16qMC+ tumors within the LUSC and LUAD cohorts. GSEA revealed 16qMC+ tumors to be enriched for the expression of metastasis- and survival-associated gene sets. Conclusions This represents the first leader cell mutation signature identified in patients and has the potential to better stratify high-risk NSCLC and ultimately improve patient outcomes.

Despite highly advanced diagnosis and treatment strategies, breast cancer patient outcomes vary extensively, even among individuals with the same diagnosis. Thus, a better understanding of the unique molecular characteristics that underlie tumor trajectories and responses to therapy remains a central goal. We report that chromatin patterns represent an important characteristic, capable of stratifying tumor identity and progression. We find that patterns of chromatin accessibility can be classified into 3 major groups, representing Basal-like tumors, hormone receptor (HR)-expressing tumors, and invasive lobular Luminal-A tumors. Major chromatin differences occur throughout the genome at motifs for the transcription factor FOXA1 in HR-positive tumors, and motifs for SOX9 in Basal-like tumors. A large portion of lobular Luminal-A tumors display a chromatin signature defined by accessibility at FOXA1 binding motifs, distinguishing them from others within this subtype. Expression of the histone chaperone ANP32E is inversely correlated with tumor progression and chromatin accessibility at FOXA1 binding sites. Tumors with high levels of ANP32E exhibit an immune response and proliferative gene expression signature, whereas tumors with low ANP32E levels appear programmed for differentiation. Our results indicate that ANP32E may function through chromatin state regulation to control breast cancer differentiation and tumor plasticity.

BackgroundMedulloblastoma (MB) is the most common malignant pediatric brain tumor that originates in the cerebellum and brainstem. Frequent somatic mutations and deregulated expression of epigenetic regulators in MB highlight the substantial role of epigenetic alterations. 5-hydroxymethylcytosine (5hmC) is a highly abundant cytosine modification in the developing cerebellum and is regulated by ten-eleven translocation (TET) enzymes.ResultsWe investigate the alterations of 5hmC and TET enzymes in MB and their significance to cerebellar cancer formation. We show total abundance of 5hmC is reduced in MB, but identify significant enrichment of MB-specific 5hmC marks at regulatory regions of genes implicated in stem-like properties and Nanog-binding motifs. While TET1 and TET2 levels are high in MBs, only knockout ofTet1in the smoothened (SmoA1)mouse model attenuates uncontrolled proliferation, leading to a favorable prognosis. The pharmacologicalTet1inhibition reduces cell viability andplatelet-derived growth factorsignaling pathway-associated genes.ConclusionsThese results together suggest a potential key role of 5hmC and indicate an oncogenic nature for TET1 in MB tumorigenesis, suggesting it as a potential therapeutic target for MBs.

Multiple myeloma is a malignancy of antibody-secreting plasma cells. Most patients benefit from current therapies, however, 20% of patients relapse or die within two years and are deemed high risk. Here we analyze structural variants from 795 newly-diagnosed patients as part of the CoMMpass study. We report translocations involving the immunoglobulin lambda (IgL) locus are present in 10% of patients, and indicative of poor prognosis. This is particularly true for IgL-MYC translocations, which coincide with focal amplifications of enhancers at both loci. Importantly, 78% of IgL-MYC translocations co-occur with hyperdiploid disease, a marker of standard risk, suggesting that IgL-MYC-translocated myeloma is being misclassified. Patients with IgL-translocations fail to benefit from IMiDs, which target IKZF1, a transcription factor that binds the IgL enhancer at some of the highest levels in the myeloma epigenome. These data implicate IgL translocation as a driver of poor prognosis which may be due to IMiD resistance., Multiple myeloma is frequently characterised by translocation of genes next to the immunoglobulin heavy chain locus. In this study, the authors sequence a large cohort of high risk myeloma samples and find translocations of cMyc to the immunoglobulin heavy chain locus and this is associated with poor prognosis.

Advanced prostate cancer (PCa) often develops bone metastasis, for which therapies are very limited and the underlying mechanisms are poorly understood. We report that bone-borne TGF-β induces the acetylation of transcription factor KLF5 in PCa bone metastases, and acetylated KLF5 (Ac-KLF5) causes osteoclastogenesis and bone metastatic lesions by activating CXCR4, which leads to IL-11 secretion, and stimulating SHH/IL-6 paracrine signaling. While essential for maintaining the mesenchymal phenotype and tumorigenicity, Ac-KLF5 also causes resistance to docetaxel in tumors and bone metastases, which is overcome by targeting CXCR4 with FDA-approved plerixafor. Establishing a mechanism for bone metastasis and chemoresistance in PCa, these findings provide a rationale for treating chemoresistant bone metastasis of PCa with inhibitors of Ac-KLF5/CXCR4 signaling., The therapies for bone metastatic prostate cancer are limited and the underlying mechanisms are unclear. Here, the authors show that bone derived TGF-β induces acetylation of KLF5 (Ac-KLF5), and Ac-KLF5 promotes prostate cancer bone metastasis and resistance to docetaxel by upregulating CXCR4.

Introduction Older patients with myeloid neoplasms (MN) receiving outpatient chemotherapy are at risk of experiencing treatment-related toxicities such as functional decline. A mobile health (mHealth) exercise intervention may ameliorate these toxicities. This qualitative study aimed to inform the design of a mHealth exercise intervention for this population. Methods This was a qualitative study of thirteen patients aged ≥60 years receiving hypomethylating agents for MN. EXCAP©® is a home-based walking and progressive resistance exercise program. We combined EXCAP©® with a mobile app; the combination (GO-EXCAP Mobile App) has not been previously tested. A brief verbal description about the intervention was provided to the participants but they did not perform it. Participants were interviewed and inductive thematic analysis was used to analyze the data. Results Mean age was 71.6 (SD 8.5). Three themes were identified: 1) Perceptions of the intervention feasibility, 2) Ways to leverage the app to deliver the exercise intervention, and 3) Personalized exercise goals. Walking and resistance exercises were perceived to be feasible. Patients were comfortable initiating the intervention in cycle 2 of chemotherapy, with exercise increments occurring from week 2–4 of the cycle. Ways to leverage the app to deliver EXCAP©® include 1) Video feature for exercise demonstration and interactions, and 2) Exercise data and symptom surveys to be communicated to the exercise physiologist and primary oncology team. Preservation of existing function and activity was an important goal to participants. Conclusions Our findings provide insights about the preferences of older adults with MN for a mHealth exercise intervention.