Process Of Malignant Transformation Research Articles

Application of a Photothermal Microscope To Study the Process of Cutaneous Lesion Formation of Malignant Melanoma.

In this study, we applied a photothermal microscope to study the process of malignant melanoma formation. We analyzed benign papilloma tumors, their metastatic carcinomas, and metastatic melanoma on the preparation of mouse skin using a gray-level co-occurrence matrix (GLCM) method. Based on the analysis of nine GLCM parameters investigated, the characteristics during the degenerative and metastatic processes are clarified by the investigation. The determination of characteristic parameters corresponding to three processes before, during, and after the degeneration indicated that this investigation enables the detection of the malignant transformation and related processes.

Association of Methylenetetrahydrofolate Reductase (MTHFR) Polymorphism with Osteosarcoma in a Mexican Population.

The methylenetetrahydrofolate reductase (MTHFR) gene 677C➔T polymorphism is capable of altering folate metabolism and can modify certain neoplasia risk. Reports have suggested that folate can have an influence on bone development and so it is of interest to know if the MTHFR 677C➔T polymorphism is associated with the malignant transformation process of this tissue. The polymorphism was determined in 55 patients with osteosarcoma and in 180 healthy individuals. Compared with C/T+C/C genotypes, a 3.7-fold reduction in osteosarcoma probability is possible with the T/T genotype (OR 0.27, CI 95% 0.07-0.82). Undoubtedly, further studies, utilizing large samples and carried out on different populations, are necessary to confirm these results.

ZnO nanoparticles induce melanoma-like lesions via recruiting dermal dendritic cells in barrier-damaged skin in mice

ZnO nanoparticles (NPs) are used in skin treatments and cosmetics, the toxicity of long-term and continuous exposure to ZnO NPs is unknown. Mice with epidermal barrier dysfunction revealed melanoma-like lesions after continuous exposure to ZnO NPs. However, the effects of metallic NPs on the skin microenvironment and immune system remain poorly understood. Mice with epidermal barrier failure were given continuous exposure to ZnO NPs for 7 weeks. The malignant transformation of melanocytes was induced with ZnO NPs 2.5 μg/ml for 72 h exposure. The supernatant of the culture medium from dendritic cells after being exposed to 10 μg/ml ZnO NPs for 24 h was applied to melanocytes to explore the effect of recruitment of DCs. The expressure of ZnO NPs resulted in a tendency of malignant transformation of melanocytes, the recruitment of DCs induces this process by produce inflammatory factors such as TNF-α. These DC-produced inflammatory factors, which were induced by ZnO NP exposure, increased the production of matrix metalloproteinases in melanocytes and expedited the malignant transformation process. Our findings revealed that the disrupted cutaneous microenvironment by ZnO NPs penetrated directly promoted the malignant transformation of melanocytes, which process also indirectly enhanced by the TNF-αsecreted from the recruited DCs.

Secondary malignancy in a vulva cancer patient – HPV-induced field cancerization: A case report

Background: Human papillomavirus (HPV) infection is associated with oropharyngeal and anogenital cancers in men and women. Approximately 90% of all cervical cancers are attributed to high-risk HPV infections, and 60% of squamous cell carcinomas (SCC) of the vulva, vagina, anus, and penis are due to HPV infection. Case presentation: We present the case of a 26-year-old with retroviral disease managed for locally advanced vulva cancer on external beam radiotherapy followed by wide excision of the residual tumor and bilateral inguino femoral nodal dissection. She later presented with a history of foul-smelling vaginal discharge. A biopsy confirmed moderately differentiated squamous cell carcinoma of the cervix clinically and radiologically staged at 2B and 3B, respectively. She was scheduled to start chemotherapy with carboplatin and paclitaxel after blood transfusion due to anemia. Discussion: Field cancerization was coined by Slaughter et al. to describe the existence of generalized carcinogen-induced early genetic changes in the epithelium from which multiple independent lesions occur, leading to the development of multifocal tumors. In some cases, multiple contiguous tumor foci coalesce, hence the lateral spread of squamous cell cancers. It was also observed that normal-looking cells near malignant cells were histologically abnormal and therefore were part of the transformed cells in a particular tumor field and consequently were responsible for the occurrence of local tumor recurrences. Conclusion: Field cancerization is a well-known and well-documented process of malignant transformation. Several studies have confirmed the importance of this phenomenon in tumor development. Surveillance is the key to detecting early recurrence and secondary malignancies.

Abstract B093: Alcoholic chronic inflammation driven CREB mediates acinar-to-ductal reprogramming and promote neoplastic progression

Abstract Introduction: Alcoholic chronic pancreatitis (ACP) is a progressive fibroinflammatory disease of the pancreas often characterized by extensive acinar cell injury leading to acinar-to-ductal metaplasia (ADM). However, the impact of ADM associated with ACP on the acceleration of oncogenic mutant Kras (Kras*)-driven tumorigenesis remains poorly understood. In this study, we aimed to unravel the underlying mechanism by which ACP-induced dysfunction and with Kras*, leads to the development of irreversible ADM and premalignant lesions that establish a tumor-permissive microenvironment for the emergence of high-grade pancreatic intraepithelial neoplasia (PanINs). Methods: ACP mice model was developed in acinar cell-specific Ptf1aCreERTM/+, Ptf1aCreERTM/+; LSL-KrasG12D/+ (KC), and genetic ablation of cyclic AMP response element-binding protein 1 (CREB) in KC (KCC−/−) mice crossed with or without R26R-EYFP reporter mice, and these mice were fed with alcohol-enriched or regular diet along with repetitive caerulein administration. Lineage tracing studies and acinar explants were employed to investigate the fate of adult acinar cells. ACP-induced mice were subsequently euthanized either 3 days or 21 days after ACP induction, the pancreas was collected for immunohistochemical analysis and examined for ADM, PanINs, fibrosis, and inflammation. To gain insights into the molecular mechanisms; kinase array analysis, acinar cell explant culture, Western blot and qPCR-based studies were conducted. Additionally, single-cell RNA sequencing (scRNA-seq) was employed to investigate cell-specific transcriptomic changes focusing on distinct cellular compartments. Results: Lineage tracing studies showed that ACP-induced ADM stems from direct transdifferentiating adult acinar cells to a ductal phenotype in Kras* mice. ACP induction with Kras* cooperatively provided a sustained Kras - dependent oncogenic program in inflammation-induced metaplastic progenitor cells. The upregulation of CREB accompanied this process of malignant transformation. CREB activation persists even after ACP withdrawal in KC mice compared to Ptf1aCreERTM/+ mice without mutant Kras. Acinar-specific CREB ablation attenuated advanced PanIN lesion development, impeding tumor progression in Kras* mice. Additionally, it reduced inflammation-induced tissue injury and facilitated acinar cell recovery. ScRNA-seq analysis revealed gene enrichment favoring acinar cell homeostasis and downregulation of ductal gene signatures in KCC−/− mice, further emphasizing CREB's pivotal role in modulating these cellular processes. Conclusion: Our findings demonstrate that Kras* sustains an irreversible ADM and PanIN through continuous activation of CREB. Additionally, we have identified that CREB mediates an oncogenic transcriptional program that drives tumor progression in the context of inflammation-induced disease. Importantly, our study reveals that ACP synergistically cooperates with Kras*-driven activated CREB, promoting the progression of ADM toward high-grade PanINs. Citation Format: Siddharth Mehra, Supriya Srinivasan, Anna Bianchi, Austin Dosch, Samara Singh, Vanessa Garrido, Iago De Castro Silva, Varunkumar Krishnamoorthy, Sudhakar Jinka, Jashodeep Datta, Nipun B. Merchant, Nagaraj Nagathihalli. Alcoholic chronic inflammation driven CREB mediates acinar-to-ductal reprogramming and promote neoplastic progression [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B093.

Malignant Transformation of Normal Oral Tissue to Dysplasia and Early Oral Squamous Cell Carcinoma: An In Silico Transcriptomics Approach.

Background: Oral squamous cell carcinoma (OSCC) is a prevalent and aggressive form of head and neck cancer, often diagnosed at advanced stages. Elucidating the molecular mechanisms involved in the malignant transformation from normal oral tissue to oral preinvasive lesions (OPL) and primary OSCC could facilitate early diagnosis and improve therapeutic strategies. Methods: Differentially expressed genes (DEGs) were identified from the GSE30784 dataset by comparing normal oral tissue, oral dysplasia, and primary OSCC samples. Cross-validation was performed using an independent RNA-seq dataset, GSE186775. Protein-protein interaction (PPI) network analysis, gene ontology annotation, and pathway enrichment analysis were conducted on the common DEGs. Hub genes were identified, and their prognostic significance was evaluated using survival analysis. Transcription factor (TF) enrichment analysis, cross-validation, and immunohistochemistry analyses were also performed. Results: A total of 226 proteins and 677 interactions were identified in the PPI network, with 34 hub genes, including FN1, SERPINE1, PLAUR, THBS1, and ITGA6. Pathways such as "Formation of the cornified envelope," "Keratinization," and "Developmental biology" were enriched. Overexpression of SERPINE1, PLAUR, THBS1, and ITGA6 correlated with poor prognosis, while upregulation of CALML5 and SPINK5 was associated with favorable outcomes. NFIB emerged as the most significant TF-regulating hub genes. Immunohistochemistry validated ITGA6 overexpression in primary OSCC. Cross-validation using the RNA-seq dataset supported the involvement of critical genes in the malignant transformation process. Conclusion: This study identified vital genes, pathways, and prognostic markers involved in the malignant transformation from normal oral tissue to OPL and primary OSCC, providing insights for early diagnosis and targeted therapy development. Cross-validation with an independent RNA-seq dataset and immunohistochemistry reinforced the findings, supporting the robustness of the identified molecular signatures.

Histone methyltransferases as a new target for the epigenetic action by vorinostat

Aberrant methylation and acetylation of histones are characteristic changes in the system of epigenetic regulation of gene expression accompanying the process of malignant transformation of the cell. Vorinostat is the epigenetic modulator that actively used in clinical oncology practice. The antitumor activity of vorinostat is considered to be associated with only with the inhibition of histone deacetylases. The effects of this drug on histone methylation have not been sufficiently studied. Using the HeLa TI test system, which allows evaluating the integral effect of epigenetically active compounds by activating the expression of the reporter gene GFP, and knockdown of genes by small interfering RNAs, we showed that the inhibitory effect of vorinostat is directed not only at HDAC1, but also at EZH2, SUV39H1, SUV39H2, SUV420H1. Using Western blotting, the ability of vorinostat to suppress the expression of enzymes EZH2, SUV39H1/2, SUV420H1 was confirmed and, in addition, its ability to inhibit the expression of enzymes SUV420H2 and DOT1L was revealed. The data obtained expand the understanding of the epigenetic effects of vorinostat and demonstrate the need for a large-scale analysis of its activity in relation to other epigenetic enzymes. A detailed understanding of the mechanism of epigenetic action of vorinostat will contribute to its more adequate use in the treatment of tumors with an aberrant epigenetic profile.

Molecular orchestra of microbiotic metabolites in the scenario of carcinogenesis

The mechanisms of carcinogenesis are extremely complex. Many players determine the scenario of malignant cell transformation, tumor growth and metastasis. In recent decades, more and more attention has been paid to the role of the symbiotic human microbiota in the regulation of metabolism and the functioning of the immune system of the host organism. Such a symbiosis of a macroorganism and its microorganisms was combined into the concept of a holoorganism. In the process of coevolution of the participants of the holoorganism, the ways of their interaction were formed, and the metabolites of the microbiota acquired a special role - signaling molecules and the main regulators of molecular interactions in the holoorganism. Being involved in the signaling pathways of the host, bacterial metabolites turned out to be obligatory participants in both physiological and pathological processes, including tumor growth. At the same time, the effects of signaling metabolites often have a multidirectional character, manifested in the impact both on the functions of the host cells and on the metabolic activity and composition of the microbiome. This review discusses the role of some microbiotic metabolites in the induction and prevention of the process of malignant transformation of cells in the host organism, as well as their influence on the effectiveness of anticancer therapy. We have tried to draw the reader’s attention to the role of some components of the molecular orchestra of microbial metabolites in the initiation and progression of tumor growth.

Abstract B104: U18666A-induced cholesterol accumulation decreases tumor-derived exosomes load and modulates malignant transformation

Abstract Background: Tumor-derived exosomes (TDEs) play an important role in the horizontal transfer of oncogenic information from the tumor to other sites, where they regulate pre-metastatic niche formation, organotropism, migration, invasion and survival. Cellular cholesterol homeostasis emerges as an important factor for exosomal biogenesis and cellular release. In this study, we utilized U18666A to trigger cholesterol accumulation within late endosomes of MDA-MB231 cells and evaluated the ability of exosomes derived from both U18666A-treated and untreated cells to initiate malignant transformation in recipient human epithelial kidney (HEK293) cells. Methods: Exosomes were isolated and characterized from MDA-MB231 (untreated and U18666A-treated) and HEK293 cells. Cholesterol content of the cells and their associated exosomes were measured to confirm its accumulation following U18666A treatment. The effects of exosomes derived from untreated MDA-MB231 (UCE) and U18666A-treated MDA-MB231 (UTCE) cells on HEK293 cells were examined to determine their transforming potential. Results: Exosomes derived from MDA-MB231 cells induced proliferation, migration, malignant transformation and epithelial-mesenchymal transition (EMT) process in non-cancerous recipients’ cells. U18666A treatment led to accumulation of cholesterol within late endosomes and significantly reversed the EMT process in MDA-MB231 cells. It also reduced TAEs load from the cancer cells and rendered them less oncogenic which was evident from their inability to induce malignant transformation in the recipient HEK293 cells. Conclusion: Modulation of cholesterol homeostasis and disruption of cholesterol supply to aggressive cancer cells can be an attractive strategy for limiting TAEs release as well as their subsequent role in cancer progression and metastasis. Citation Format: Syed Sultan Beevi, Vinod Kumar Verma. U18666A-induced cholesterol accumulation decreases tumor-derived exosomes load and modulates malignant transformation [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B104.

Langerhans cell histiocytosis: current advances in molecular pathogenesis.

Langerhans cell histiocytosis (LCH) is a rare and clinically heterogeneous hematological disease characterized by the accumulation of mononuclear phagocytes in various tissues and organs. LCH is often characterized by activating mutations of the mitogen-activated protein kinase (MAPK) pathway with BRAFV600E being the most recurrent mutation. Although this discovery has greatly helped in understanding the disease and in developing better investigational tools, the process of malignant transformation and the cell of origin are still not fully understood. In this review, we focus on the newest updates regarding the molecular pathogenesis of LCH and novel suggested pathways with treatment potential.

Activation of immune evasion machinery is a part of the process of malignant transformation of human cells

Malignant transformation of human cells is associated with their re-programming which results in uncontrolled proliferation and in the same time biochemical activation of immunosuppressive pathways which form cancer immune evasion machinery. However, there is no conceptual understanding of whether immune evasion machinery pathways and expression of immune checkpoint proteins form a part of the process of malignant transformation or if they are triggered by T lymphocytes and natural killers (NK) attempting to attack cells which are undergoing or already underwent malignant transformation. To address this fundamental question, we performed experimental malignant transformation of BEAS-2B human bronchial epithelium cells and RC-124 non-malignant human kidney epithelial cells using bracken extracts containing carcinogenic alkaloid called ptaquiloside. This transformation led to a significant upregulation of cell proliferation velocity and in the same time led to a significant upregulation in expression of key immune checkpoint proteins – galectin-9, programmed death ligand 1 (PD-L1), indoleamine 2,3-dioxygenase (IDO1). Their increased expression levels were in line with upregulation of the levels and activities of HIF-1 transcription complex and transforming growth factor beta type 1 (TGF-β)-Smad3 signalling pathway. When co-cultured with T cells, transformed epithelial cells displayed much higher and more efficient immune evasion activity compared to original non-transformed cells. Therefore, this work resolved a very important scientific and clinical question and suggested that cancer immune evasion machinery is activated during malignant transformation of human cells regardless the presence of immune cells in microenvironment.

The relationship between cancer and biomechanics.

The onset, development, diagnosis, and treatment of cancer involve intricate interactions among various factors, spanning the realms of mechanics, physics, chemistry, and biology. Within our bodies, cells are subject to a variety of forces such as gravity, magnetism, tension, compression, shear stress, and biological static force/hydrostatic pressure. These forces are perceived by mechanoreceptors as mechanical signals, which are then transmitted to cells through a process known as mechanical transduction. During tumor development, invasion and metastasis, there are significant biomechanical influences on various aspects such as tumor angiogenesis, interactions between tumor cells and the extracellular matrix (ECM), interactions between tumor cells and other cells, and interactions between tumor cells and the circulatory system and vasculature. The tumor microenvironment comprises a complex interplay of cells, ECM and vasculature, with the ECM, comprising collagen, fibronectins, integrins, laminins and matrix metalloproteinases, acting as a critical mediator of mechanical properties and a key component within the mechanical signaling pathway. The vasculature exerts appropriate shear forces on tumor cells, enabling their escape from immune surveillance, facilitating their dissemination in the bloodstream, dictating the trajectory of circulating tumor cells (CTCs) and playing a pivotal role in regulating adhesion to the vessel wall. Tumor biomechanics plays a critical role in tumor progression and metastasis, as alterations in biomechanical properties throughout the malignant transformation process trigger a cascade of changes in cellular behavior and the tumor microenvironment, ultimately culminating in the malignant biological behavior of the tumor.

Ovarian Clear Cell Carcinoma: Genomic Characterization, Pathogenesis and Targeted Therapy.

Ovarian clear cell carcinomas (OCCCs) are a subtype of ovarian epithelial tumors that arise from the malignant transformation of endometriosis (EMs). These tumors have distinctive molecular features, high malignant potential, low sensitivity to conventional chemotherapy, and poor prognosis. The process and mechanism of malignant transformation from EMs to OCCCs remains elusive. Elucidation of the molecular pathogenesis and drug resistance mechanism of OCCCs is essential to guide the clinical management and basic research of this disease. This paper provides a comprehensive review of the mechanisms of malignant transformation, genomic characteristics, drug resistance and targeted therapy of OCCCs. The review aims to provide new insights for the clinical management of advanced OCCCs.

MOLECULAR PROFILING OF TEAR FLUIDS REVEALS SIGNATURES OF MALIGNANT TRANSFORMATION INTO ORAL CANCER

Objective We aimed to find biological signatures of malignant transformation using non-invasive liquid biopsy. Study Design Unstimulated tears from patients with OL (N=10), PVL (N=10), OSCC (n=14), and control patients (N=10) were collected, and submitted to discovery-based proteomics by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The data were analyzed by the software MaxQuant (proteomics), Byonics (N-glycoproteomics), and PEAKS database (post-translational modifications). Differential abundance between the groups was assessed by ANOVA following the Tukey test (p<0.05). We performed analyses of biologically processed enrichment, hierarchical clustering, and clinicopathologic correlation using Pearson correlation and linear regression (R²>0.5; p<0.05). Results We identified a panel of 24 proteins with differential abundance between the groups that present potential capacity to predict malignant transformation. The innate immune system was the main biological process correlated with these proteins. Clinicopathologic correlation analyses showed several associations, such as epithelial dysplasia, lymph node metastasis, and clinical stages of the disease. In addition, we identified several proteins that are druggable and may be useful as therapeutic targets. Conclusion Liquid biopsy from tear fluids may be a powerful non-invasive tool to provide insights into the process of malignant transformation into oral cancer, guiding early diagnosis and improving the prognosis. The São Paulo Research Foundation-FAPESP (18/19922-9). We aimed to find biological signatures of malignant transformation using non-invasive liquid biopsy. Unstimulated tears from patients with OL (N=10), PVL (N=10), OSCC (n=14), and control patients (N=10) were collected, and submitted to discovery-based proteomics by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The data were analyzed by the software MaxQuant (proteomics), Byonics (N-glycoproteomics), and PEAKS database (post-translational modifications). Differential abundance between the groups was assessed by ANOVA following the Tukey test (p<0.05). We performed analyses of biologically processed enrichment, hierarchical clustering, and clinicopathologic correlation using Pearson correlation and linear regression (R²>0.5; p<0.05). We identified a panel of 24 proteins with differential abundance between the groups that present potential capacity to predict malignant transformation. The innate immune system was the main biological process correlated with these proteins. Clinicopathologic correlation analyses showed several associations, such as epithelial dysplasia, lymph node metastasis, and clinical stages of the disease. In addition, we identified several proteins that are druggable and may be useful as therapeutic targets. Liquid biopsy from tear fluids may be a powerful non-invasive tool to provide insights into the process of malignant transformation into oral cancer, guiding early diagnosis and improving the prognosis.

Papillomaviruses and cancer: commonalities and differences in HPV carcinogenesis at different sites of the body.

Human papillomavirus (HPV) is associated with 5% of all cancers globally at a range of body sites, including cervix, anus, penis, vagina, vulva, and oropharynx. These cancers claim > 400,000 lives annually. The persistent infection of HPV and the function of viral oncogenes are the primary causes of HPV-related cancers. However, only some HPV-infected persons or infected lesions will progress to cancer, and the burden of HPV-associated cancer varies widely according to gender and the part of the body infected. The dissimilarity in infection rates at different sites can explain only a small part of the differences observed. Much responsibility likely sits with contributions of specific epithelial cells and the cellular microenvironment at infected sites to the process of malignant transformation, both of which affect the regulation of viral gene expression and the viral life cycle. By understanding the biology of these epithelial sites, better diagnosis/treatment/management of HPV-associated cancer and/or pre-cancer lesions will be provided.

Cholangiokines: undervalued modulators in the hepatic microenvironment.

The biliary epithelial cells, also known as cholangiocytes, line the intra- and extrahepatic bile ducts, forming a barrier between intra- and extra-ductal environments. Cholangiocytes are mostly known to modulate bile composition and transportation. In hepatobiliary diseases, bile duct injury leads to drastic alterations in cholangiocyte phenotypes and their release of soluble mediators, which can vary depending on the original insult and cellular states (quiescence, senescence, or proliferation). The cholangiocyte-secreted cytokines (also termed cholangiokines) drive ductular cell proliferation, portal inflammation and fibrosis, and carcinogenesis. Hence, despite the previous consensus that cholangiocytes are bystanders in liver diseases, their diverse secretome plays critical roles in modulating the intrahepatic microenvironment. This review summarizes recent insights into the cholangiokines under both physiological and pathological conditions, especially as they occur during liver injury-regeneration, inflammation, fibrosis and malignant transformation processes.

Inflammatory Cells Can Alter the Levels of H3K9ac and γH2AX in Dysplastic Cells and Favor Tumor Phenotype.

Oral potentially malignant disorders (OPMD) are clinical presentations that carry an increased risk of cancer development. Currently, epithelial dysplasia grade is based on architectural and cytological epithelial changes and is used to predict the malignant transformation of these lesions. However, predicting which OPMD will progress to a malignant tumor is very challenging. Inflammatory infiltrates can favor cancer development, and recent studies suggest that this association with OPMD lesions may be related to the etiology and/or aggressive clinical behavior of these lesions. Epigenetic changes such as histone modifications may mediate chronic inflammation and also favor tumor cells in immune resistance and evasion. This study aimed to evaluate the relationship between histone acetylation (H3K9ac) and DNA damage in the context of dysplastic lesions with prominent chronic inflammation. Immunofluorescence of "low-risk" and "high-risk" OPMD lesions (n = 24) and inflammatory fibrous hyperplasia (n = 10) as the control group was performed to assess histone acetylation levels and DNA damage through the phosphorylation of H2AX (γH2AX). Cell co-culture assays with PBMCs and oral keratinocyte cell lines (NOK-SI, DOK, and SCC-25) were performed to assess proliferation, adhesion, migration, and epithelial-mesenchymal transition (EMT). Oral dysplastic lesions showed a hypoacetylation of H3K9 and low levels of γH2AX compared to control. The contact of dysplastic oral keratinocytes with PBMCs favored EMT and the loss of cell-cell adhesion. On the other hand, p27 levels increased and cyclin E decreased in DOK, indicating cell cycle arrest. We conclude that the presence of chronic inflammation associated to dysplastic lesions is capable of promoting epigenetic alterations, which in turn can favor the process of malignant transformation.

Abstract 4742: Familial adenomatous polyposis epigenetic landscape as a precancer model of colorectal cancer

Abstract Aberrant shifts in DNA methylation have long been regarded as an early biomarker for cancer onset and progression. However, it is unclear when methylation aberrance starts and how it interacts with other epigenomic modifications. To address how epigenomic changes occur and interact during the transformation from normal healthy colon tissue to malignant colorectal cancer (CRC), we collected 51 samples from 15 familial adenomatous polyposis (FAP) and non-FAP colorectal cancer patients. We generated 30-70x of whole-genome enzymatic methylation sequencing (WGEM-seq) data via the novel Ultima Genomics ultra high-throughput sequencing platform. We observed hypermethylation and hypomethylation emerge early in the malignant transformation process in gene promoters and distal regulatory elements. We performed multifaceted analysis on methylation alterations with whole-genome sequencing (WGS), transposase accessibility (ATAC-seq), high-resolution chromatin accessibility (Tri-C), and gene expression (RNA-seq) data. Our multidimensional analysis demonstrates how collectively epigenomic alterations have affected gene expression throughout normal colon mucosa, benign and dysplasia polyps to adenocarcinoma. Epigenomic changes start as early as benign polyps, followed by other epigenomic shifts, including bivalent domains. Various epigenomic aberrances are associated with concomitant gene expression level changes. Our integrative analysis of multi-epigenomics data implicates collective and cumulative epigenomic instability in the early onset of colon carcinogenesis. Citation Format: Hayan Lee, Gat Krieger, Tyson Clark, Yizhou Zhu, Aziz Khan, Casey R. Hanson, Aaron Horning, Edward D. Esplin, Mohan Badu, Kristina Paul, Roxanne Chiu, Bahareh Bahmani, Stephanie Nevins, Annika K. Weimer, Ariel Jaimovich, Christina Curtis, William Greenleaf, James M. Ford, Doron Lipson, Zohar Shipony, Michael P. Snyder. Familial adenomatous polyposis epigenetic landscape as a precancer model of colorectal cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4742.

Mechanical profile of human keratinocytes expressing HPV-18 oncogenes

During tumorigenesis, the mechanical properties of cancer cells change markedly, with decreased stiffness often accompanying a more invasive phenotype. Less is known about the changes in mechanical parameters at intermediate stages in the process of malignant transformation. We have recently developed a pre-tumoral cell model by stably transducing the immortalized but non-tumorigenic human keratinocyte cell line HaCaT with the E5, E6 and E7 oncogenes from HPV-18, one of the leading causes of cervical cancer and other types of cancer worldwide. We have used atomic force microscopy (AFM) to measure cell stiffness and to obtain mechanical maps of parental HaCaT and HaCaT E5/E6/E7-18 cell lines. We observed a significant decrease in Young's modulus in HaCaT E5/E6/E7-18 cells measured by nanoindentation in the central region, as well as decreased cell rigidity in regions of cell-cell contact measured by Peakforce Quantitative Nanomechanical Mapping (PF-QNM). As a morphological correlate, HaCaT E5/E6/E7-18 cells displayed a significantly rounder cell shape than parental HaCaT cells. Our results therefore show that decreased stiffness with concomitant perturbations in cell shape are early mechanical and morphological changes during the process of malignant transformation.

Circular RNAs: New layer of complexity evading breast cancer heterogeneity.

Advances in high-throughput sequencing techniques and bioinformatic analysis have refuted the "junk" RNA hypothesis that was claimed against non-coding RNAs (ncRNAs). Circular RNAs (circRNAs); a class of single-stranded covalently closed loop RNA molecules have recently emerged as stable epigenetic regulators. Although the exact regulatory role of circRNAs is still to be clarified, it has been proven that circRNAs could exert their functions by interacting with other ncRNAs or proteins in their own physiologically authentic environment, regulating multiple cellular signaling pathways and other classes of ncRNAs. CircRNAs have also been reported to exhibit a tissue-specific expression and have been associated with the malignant transformation process of several hematological and solid malignancies. Along this line of reasoning, this review aims to highlight the importance of circRNAs in Breast Cancer (BC), which is ranked as the most prevalent malignancy among females. Notwithstanding the substantial efforts to develop a suitable anticancer therapeutic regimen against the heterogenous BC, inter- and intra-tumoral heterogeneity have resulted in an arduous challenge for drug development research, which in turn necessitates the investigation of other markers to be therapeutically targeted. Herein, the potential of circRNAs as possible diagnostic and prognostic biomarkers have been highlighted together with their possible application as novel therapeutic targets.