Error-Corrected Deep Targeted Sequencing of Circulating Cell-Free DNA from Colorectal Cancer Patients for Sensitive Detection of Circulating Tumor DNA.

Circulating tumor DNA (ctDNA) is a promising biomarker, reflecting the presence of tumor cells. Sequencing-based detection of ctDNA at low tumor fractions is challenging due to the crude error rate of sequencing. To mitigate this challenge, we developed ultra-deep mutation-integrated sequencing (UMIseq), a fixed-panel deep targeted sequencing approach, which is universally applicable to all colorectal cancer (CRC) patients. UMIseq features UMI-mediated error correction, the exclusion of mutations related to clonal hematopoiesis, a panel of normal samples for error modeling, and signal integration from single-nucleotide variations, insertions, deletions, and phased mutations. UMIseq was trained and independently validated on pre-operative (pre-OP) plasma from CRC patients (n = 364) and healthy individuals (n = 61). UMIseq displayed an area under the curve surpassing 0.95 for allele frequencies (AFs) down to 0.05%. In the training cohort, the pre-OP detection rate reached 80% at 95% specificity, while it was 70% in the validation cohort. UMIseq enabled the detection of AFs down to 0.004%. To assess the potential for detection of residual disease, 26 post-operative plasma samples from stage III CRC patients were analyzed. From this we found that the detection of ctDNA was associated with recurrence. In conclusion, UMIseq demonstrated robust performance with high sensitivity and specificity, enabling the detection of ctDNA at low allele frequencies.

Age-related differences in cancer biology in older patients.

Aging impacts cancer development with incidence rising exponentially. Age-related genetic and epigenetic changes, along with the aging microenvironment, contribute to cancer development. In older individuals, tumours manifest a heightened mutational burden and distinct genetic changes which differ significantly from tumours observed in younger patients. The aging microenvironment accumulates senescent cells, altered matrix, and a dysregulated immune system. Age-related changes in the immune system fuel tumour development and treatment resistance. Understanding these processes is crucial for optimized treatment of older patients with cancer, as discussed in this review.

Geriatric screening and frailty intervention in older patients with cancer.

Frailty in older patients with cancer increases the risk of treatment related toxicity, mortality, physical decline, and quality of life. This review summarises various screening tools. Screening tools identifying frailty serve multiple purposes, providing awareness of health issues impacting oncologic treatment and prognosis and facilitating the delivery of a Comprehensive Geriatric Assessment (CGA). CGA is an overall health assessment and treatment targeting frailty. Providing CGA to older patients with cancer reduces the risk of toxicity and functional decline, increases treatment completion, and prevents loss of quality of life.

DNA methyltransferase inhibition promotes recruitment of myeloid-derived suppressor cells to the tumor microenvironment through induction of tumor cell-intrinsic interleukin-1.

DNA methyltransferase (DNMT) inhibitors are used for treatment of certain hematological malignancies and exert anti-cancer activity through diverse mechanisms, including reexpression of tumor suppressor genes and anti-viral responses triggered by expression of endogenous retroviruses. Despite advances in the pharmacokinetic properties of DNMT inhibitors, the efficacy of these drugs in solid cancers remains low. Here, we show in cell lines and clinical and experimental tumors across multiple cancer types that DNMT inhibition induces the expression of interleukin-1 (IL-1), a cytokine with proinflammatory and protumorigenic properties. Specifically, this tumor-intrinsic IL-1 expression modulates the chemokine landscape of tumors and leads to the recruitment of monocytic myeloid-derived suppressor cells to the tumor microenvironment, processes that can be blocked by IL-1 antagonists. Molecular analysis demonstrates complex patterns of IL-1 and interferon activation and crosstalk in response to DNMT inhibition, which depend on the integrity of IRF- and NF-κB-mediated antiviral pathways and may determine the outcome of DNMT-inhibitor treatment. Together, our results show that DNMT inhibitors may negatively affect the microenvironment of a large subset of tumors and suggest that co-treatment with IL-1 antagonists may be a favorable combination for these patients.

SSX addiction in melanoma propagates tumor growth and metastasis.

Cancer/testis antigens are receiving attention as targets for cancer therapy due to their germ- and cancer cell-restricted expression. However, many of these antigens are inconsistently expressed among cancer types and individual tumors. Here, we show that members of the SSX cancer/testis antigen family comprise attractive targets in the majority of melanoma patients, as SSX is expressed in more than 90% of primary melanomas and metastases and plays a critical role in metastatic progression. Accordingly, SSX silencing in melanoma mouse xenograft models reduced tumor growth and completely abolished the formation of metastatic lesions in lungs and livers. Mechanistically, we demonstrate that silencing SSX in melanoma cells induces cell cycle S-phase stalling, leading to proliferative arrest and enhanced apoptosis, which elucidates the inhibitory effect of SSX loss on tumor growth and colonization capacity. Silencing SSX further compromised the capacity of melanoma cells to migrate and invade, influencing these cells' capability to spread and colonize. Taken together, these studies highlight SSX proteins as pivotal targets in melanoma with implications for blocking metastatic progression.

ZBED1 Regulates Genes Important for Multiple Biological Processes of the Placenta.

The transcription factor ZBED1 is highly expressed in trophoblast cells, but its functions in the processes of trophoblast and placental biology remain elusive. Here, we characterized the role of ZBED1 in trophoblast cell differentiation using an in vitro BeWo cell model. We demonstrate that ZBED1 is enhanced in its expression early after forskolin-induced differentiation of BeWo cells and regulates many of the genes that are differentially expressed as an effect of forskolin treatment. Specifically, genes encoding markers for the differentiation of cytotrophoblast into syncytiotrophoblast and factors essential for trophoblast cell fusion and invasion were negatively regulated by ZBED1, indicating that ZBED1 might be important for maintaining a steady pool of cytotrophoblast cells. In addition, ZBED1 affected genes involved in the regulation of trophoblast cell survival and apoptosis, in agreement with the observed increase in apoptosis upon knockdown of ZBED1 in forskolin-treated BeWo cells. In addition, genes implicated in the differentiation, recruitment, and function of innate immune cells by the placenta were affected by ZBED1, further suggesting a role for this protein in the regulation of maternal immune tolerance. In conclusion, our study implicates ZBED1 in major biological processes of placental biology.

Predictive value of geriatric oncology screening and geriatric assessment of older patients with cancer: A randomized clinical trial protocol (PROGNOSIS-RCT).

INTRODUCTION: Comprehensive geriatric assessment (CGA) has been shown to reduce frailty in older patients in general. In older patients with cancer, frailty affects quality of life (QoL), physical function, and survival. However, few studies have examined the effect of CGA as an additional intervention to antineoplastic treatment. This protocol presents a randomized controlled trial, which aims to evaluate the effects of CGA-based interventions in older patients with cancer and Geriatric 8 (G8) identified frailty. MATERIALS AND METHODS: This randomized controlled trial will include patients, age 70+ years, with solid malignancies and G8 frailty (G8 ≤ 14). Patients will be separated into two groups, with different primary endpoints, depending on palliative or curative antineoplastic treatment initiation, and subsequently randomized 1:1 to either CGA with corresponding interventions or standard of care, along with standardized antineoplastic treatment. A geriatrician led CGA with corresponding interventions and clinical follow-up will be conducted within one month of antineoplastic treatment initiation. The interdisciplinary CGA will cover multiple geriatric domains and employ a standard set of validated assessment tools. Primary endpoints will be physical decline measured with the 30-s Chair-Stand-Test at three months (palliative setting) and unplanned hospital admissions at six months (curative setting). Additional outcomes include QoL, treatment toxicity and adherence, occurrence of polypharmacy, potential drug interactions, potential inappropriate medications, and survival. The primary outcomes will be analyzed using a mixed model regression analysis (30-s chair stand test) and linear regression models (unplanned hospitalizations), with an intention to treat approach. Power calculations reveal the need to enroll 134 (palliative) and 188 (curative) patients. DISCUSSION: The present study will examine whether CGA, as an additional intervention to antineoplastic treatment, can improve endpoints valued by older patients with cancer. Inclusion began November 2020 and is ongoing, with 37 and 29 patients recruited April 15th, 2021. Registration:NCT04686851.

HMGA2 Supports Cancer Hallmarks in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that exhibits a high proliferation rate and early metastasis leading to a poor prognosis. HMGA2 is a DNA binding transcriptional regulator implicated in tumorigenesis. Here, we demonstrate that the HMGA2 promoter is demethylated in TNBC tumors, leading to increased expression of HMGA2 at both mRNA and protein levels. Importantly, high HMGA2 levels in TNBC tumors are correlated with poor prognosis. To detail the role of HMGA2 in TNBC development and progression, we studied its effect on core cancer phenotypes. Stable knockdown of HMGA2 in TNBC cells revealed that HMGA2 may support cell proliferation, cell migration and invasion. In addition, HMGA2 knockdown decreased cancer stem cell (CSC) features. Importantly, we found that silencing HMGA2 inhibited NF-kB signaling and lead to decreased expression of the downstream molecules IL-6 and IL-8 and reduced STAT3 pathway activation. Our results demonstrate that HMGA2 supports cancer hallmarks in TNBC and may represent a promising target for TNBC treatment.

Predictive Value of Geriatric Oncology Screening and Geriatric Assessment in Older Patients with Solid Cancers: Protocol for a Danish prospective cohort study (PROGNOSIS-G8).

INTRODUCTION: Older patients with cancer constitute a heterogeneous group with varying degrees of frailty; therefore, geriatric assessment with initial geriatric oncology screening is recommended. The Geriatric 8 (G8) and the modified Geriatric 8 (mG8) are promising screening tools with high accuracy and an association with survival. However, evidence is sparse regarding patient-centered outcomes. This protocol describes a study, which aims to address the predictive and prognostic value of the G8 and mG8, with quality of life (QoL) as the primary outcome. MATERIALS AND METHODS: In this single-center prospective cohort study, patients, age ≥70 years with solid malignancies, will be screened with the G8 and mG8 prior to receiving 1st line antineoplastic treatment. Patients will contribute medical record data including; cancer type, Charlson comorbidity index score, performance status, and treatment intent, type, and dosage, at baseline. Patients will complete QoL questionnaires (EORTC QLQ-C30 and ELD-14) at baseline, 3, 6, 9, and 12-months follow-up. Two functional measurements (the 30-s chair stand test and the handgrip strength test) will be conducted at baseline to assess the added predictive and prognostic value. At 12 months follow-up, initially administered treatment and treatment adherence will be recorded and assessed with generalized linear models, while overall survival and cancer-specific survival will be assessed using survival analysis models with time-varying covariates. The relationship between frailty (G8 ≤ 14, mG8 ≥ 6) and QoL within 12 months will be examined using mixed regression models. DISCUSSION: Geriatric oncology screening may identify a subgroup of older patients with frailty, at risk of experiencing diminishing QoL and poor treatment adherence. With the proposed screening program, patients who require treatment modification and additional support to maintain their QoL may be identified. It is our hope, that these insights may facilitate the formation of national guidelines for the treatment of older patients with cancer. Registration:NCT04644874.

Human DREF/ZBED1 is a nuclear protein widely expressed in multiple cell types derived from all three primary germ layers.

Drosophila DNA replication-related element binding factor (DREF) is a transcription regulatory factor that binds the promoters of many genes involved in replication and cell proliferation and is required for normal cell cycle progression. Human DREF/zinc finger BED domain-containing protein 1 (ZBED1), an orthologue of Drosophila DREF, also has DNA binding activity, but its cellular functions remain largely uncharacterized. Herein, we show that ZBED1 is a chromatin-associated nuclear protein with a wide expression profile in human tissues from all three primary germ layers. For instance, ZBED1 was expressed in mesodermal-derived epithelial cells of the reproductive system and urinary tract, in endodermal-derived epithelial cells throughout the gastrointestinal tract, and in epidermal epithelium from the ectoderm. ZBED1 was also expressed in connective tissue and smooth muscle cells of multiple organs. To investigate whether ZBED1 is implicated in cell proliferation, similar to Drosophila DREF, we compared the tissue distribution of ZBED1 to that of the proliferation marker Ki-67. ZBED1 and Ki-67 were co-expressed in many epithelial tissues, but ZBED1 expression extended widely beyond that of Ki-67-positive cells. In other tissues, ZBED1 expression was more restricted than Ki-67 expression. These results suggest that ZBED1 is not a cell proliferation-associated factor such as Drosophila DREF, and our study adds to the cumulative understanding of the functions of ZBED1 in human cells and tissues.

Epigenetic Reprogramming of Pericentromeric Satellite DNA in Premalignant and Malignant Lesions.

Repression of repetitive DNA is important for maintaining genomic stability, but is often perturbed in cancer. For instance, the megabase satellite domain at chromosome 1q12 is a common site of genetic rearrangements, such as translocations and deletions. Polycomb-group proteins can be observed as large subnuclear domains called polycomb bodies, the composition and cellular function of which has remained elusive. This study demonstrates that polycomb bodies are canonical subunits of the multiprotein polycomb repressive complex 1 deposited on 1q12 pericentromeric satellite DNA, which are normally maintained as constitutive heterochromatin by other mechanisms. Furthermore, the data reveal that polycomb bodies are exclusive to premalignant and malignant cells, being absent in normal cells. For instance, polycomb bodies are present in melanocytic cells of nevi and conserved in primary and metastatic melanomas. Deposition of polycomb on the 1q12 satellite DNA in melanoma development correlated with reduced DNA methylation levels. In agreement with this, inhibition of DNA methyltransferases, with the hypomethylating agent guadecitabine (SGI-110), was sufficient for polycomb body formation on pericentromeric satellites in primary melanocytes. This suggests that polycomb bodies form in cancer cells with global DNA demethylation to control the stability of pericentromeric satellite DNA. These results reveal a novel epigenetic perturbation specific to premalignant and malignant cells that may be used as an early diagnostic marker for detection of precancerous changes and a new therapeutic entry point.Implications: Pericentromeric satellite DNA is epigenetically reprogrammed into polycomb bodies as a premalignant event with implications for transcriptional activity and genomic stability. Mol Cancer Res; 16(3); 417-27. ©2018 AACR.

HIF2α contributes to antiestrogen resistance via positive bilateral crosstalk with EGFR in breast cancer cells.

The majority of breast cancers express estrogen receptor α (ERα), and most patients with ERα-positive breast cancer benefit from antiestrogen therapy. The ERα-modulator tamoxifen and ERα-downregulator fulvestrant are commonly employed antiestrogens. Antiestrogen resistance remains a clinical challenge, with few effective treatments available for patients with antiestrogen-resistant breast cancer. Hypoxia, which is intrinsic to most tumors, promotes aggressive disease, with the hypoxia-inducible transcription factors HIF1 and HIF2 regulating cellular responses to hypoxia. Here, we show that the ERα-expressing breast cancer cells MCF-7, CAMA-1, and T47D are less sensitive to antiestrogens when hypoxic. Furthermore, protein and mRNA levels of HIF2α/HIF2A were increased in a panel of antiestrogen-resistant cells, and antiestrogen-exposure further increased HIF2α expression. Ectopic expression of HIF2α in MCF-7 cells significantly decreased sensitivity to antiestrogens, further implicating HIF2α in antiestrogen resistance. EGFR is known to contribute to antiestrogen resistance: we further show that HIF2α drives hypoxic induction of EGFR and that EGFR induces HIF2α expression. Downregulation or inhibition of EGFR led to decreased HIF2α levels. This positive and bilateral HIF2-EGFR regulatory crosstalk promotes antiestrogen resistance and, where intrinsic hypoxic resistance exists, therapy itself may exacerbate the problem. Finally, inhibition of HIFs by FM19G11 restores antiestrogen sensitivity in resistant cells. Targeting HIF2 may be useful for counteracting antiestrogen resistance in the clinic.

The role of GAGE cancer/testis antigen in metastasis: the jury is still out.

BACKGROUND: GAGE cancer/testis antigens are frequently expressed in various types of malignancies and represent attractive targets for immunotherapy, however their role in cancer initiation and progression has remained elusive. GAGE proteins are expressed in normal cells during early development with migratory and invasive properties and were found to be upregulated in cancer cells with metastasizing potential in a gastric cancer model. METHODS: We have addressed the direct role of GAGE proteins in supporting metastasis using an isogenic metastasis model of human cancer, consisting of 4 isogenic cell lines, which are equally tumorigenic in immunodeficient mice, but differ with their ability to generate metastases in the lungs and lymph nodes. RESULTS: Although GAGE proteins were strongly upregulated in the highly metastatic clone (CL16) compared to non-metastatic (NM2C5), weakly metastatic (M4A4) and moderately metastatic clones (LM3), stable downregulation of GAGE expression did not affect the ability of CL16 cells to establish primary tumors and form metastasis in the lungs of immunodeficient mice. CONCLUSIONS: These results suggest that GAGE proteins per se do not support metastasis and that further studies are needed to clarify the contribution of GAGE proteins to the metastatic potential of different types of cancer cells.

SSX2 is a novel DNA-binding protein that antagonizes polycomb group body formation and gene repression.

Polycomb group (PcG) complexes regulate cellular identity through epigenetic programming of chromatin. Here, we show that SSX2, a germline-specific protein ectopically expressed in melanoma and other types of human cancers, is a chromatin-associated protein that antagonizes BMI1 and EZH2 PcG body formation and derepresses PcG target genes. SSX2 further negatively regulates the level of the PcG-associated histone mark H3K27me3 in melanoma cells, and there is a clear inverse correlation between SSX2/3 expression and H3K27me3 in spermatogenesis. However, SSX2 does not affect the overall composition and stability of PcG complexes, and there is no direct concordance between SSX2 and BMI1/H3K27me3 presence at regulated genes. This suggests that SSX2 antagonizes PcG function through an indirect mechanism, such as modulation of chromatin structure. SSX2 binds double-stranded DNA in a sequence non-specific manner in agreement with the observed widespread association with chromatin. Our results implicate SSX2 in regulation of chromatin structure and function.

Tissue microarrays in non-small-cell lung cancer: reliability of immunohistochemically-determined biomarkers.

BACKGROUND: The reliability of immunohistochemically-determined biomarkers using tissue microarrays (TMAs) of clinical specimens has long been open to question. Heterogeneity related to tumor biology might compromise determination of accurate biomarker expression in tumors, especially in small core biopsies. We evaluated the reliability of immunohistochemical staining scoring in small core biopsies using 11 biomarkers in non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: Four 1-mm tumor cores from 178 NSCLCs, 2 representing peripheral areas close to the border of normal lung tissue and 2 representing central areas, were examined. The biomarkers analyzed included p63, p40, cytokeratin 1/5/10/14, cytokeratin 7, thyroid transcription factor-1, napsin A, cyclin-D1, p53, Ki-67, integrin beta-1, and thymidylate synthase. RESULTS: Using a random intercept logistic regression model, immunohistochemical marker expression of TMAs had a moderate to high reliability measured using the intraclass correlation coefficient (0.67-0.99) between cores within the same tumor. Reliability was dependent on the selected biomarker, with lineage-specific biomarkers being less heterogeneously expressed than functional biomarkers. Expressions of most biomarkers showed no significant difference between central versus peripheral tumor cores. CONCLUSION: Our results demonstrated that biomarkers involved in clinical tumor classification (cell lineage markers) of NSCLC can be adequately assessed using 1 or 2 biopsy samples. However, the optimal number of cores required for biomarkers with functional properties varied from 1 to > 4 cores. The results indicate that the optimal number of biopsies required to compensate for potential biomarker heterogeneity should be determined individually for each biomarker used in clinical settings.

Quantitative proteomics of primary tumors with varying metastatic capabilities using stable isotope-labeled proteins of multiple histogenic origins.

The development of metastasis is a complex, multistep process that remains poorly defined. To identify proteins involved in the colonization phase of the metastatic process, we compared the proteome of tumors derived from inoculation of a panel of isogenic human cancer cell lines with different metastatic capabilities into the mammary fat pad of immunodeficient mice. Using a protein standard generated by SILAC-labeling, a total of 675 proteins were identified and 30 were differentially expressed between at least two of the tumors. The protein standard contained the proteomes of seven cell lines from multiple histogenic origins and displayed superior features compared to standard super-SILAC. The expression of some proteins correlated with metastatic capabilities, such as myosin-9 (nonmuscle myosin II A) and L-lactate dehydrogenase A, while the expression of elongation factor tu correlated inversely to metastatic capabilities. The expression of these proteins was biochemically validated, and expression of myosin-9 in clinical breast cancer samples was further shown to be altered in primary tumors versus corresponding lymph node metastasis. Our study demonstrates an improved strategy for quantitative comparison of an unlimited number of tumor tissues, and provides novel insights into key proteins associated with the colonization phase of metastasis formation.

Cancer-germline antigen vaccines and epigenetic enhancers: future strategies for cancer treatment.

IMPORTANCE OF THE FIELD: Immunotherapy holds great potential for disseminated cancer, and cancer-germline (CG) antigens are among the most promising tumor targets. They are widely expressed in different cancer types and are essentially tumor-specific, since their expression in normal tissues is largely restricted to immune-privileged sites. Although the therapeutic potential of these antigens may be compromised by their highly heterogeneous expression in many tumors and low frequency in some cancers, recent developments suggest that tumor-cell-selective enhancement of CG antigen gene expression can be achieved using epigenetic modifiers. AREAS COVERED IN THIS REVIEW: We provide an overview of the potential of CG antigens as targets for cancer immunotherapy, including advantages and disadvantages. We also discuss the current state of development of CG antigen vaccines, and the potential synergistic effect of combining CG antigen immunotherapeutic strategies with epigenetic modifiers. WHAT THE READER WILL GAIN: The reader will gain an overview of the past, present and future role of CG antigens in cancer immunotherapy. TAKE HOME MESSAGE: Chemoimmunotherapy using epigenetic drugs and CG antigen vaccines may be a useful approach for treating cancer.