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C-MYC-dependent transcriptional inhibition of autophagy is implicated in Cisplatin sensitivity in HPV-positive Head and Neck Cancer

ABSTRACT: Autophagy is important for removal, degradation and recycling of damaged organelles, proteins, and lipids through the degradative action of lysosomes. In addition to its catabolic function, autophagy is important in cancer and viral-mediated tumorigenesis, including Human Papillomavirus (HPV) positive cancers. HPV infection is a major risk factor in a subset of Head and Neck Cancer (HNC), for which no targeted therapies are currently available. Herein, we assessed autophagy function in HPV-positive HNC. We showed that HPV-positive HNC cells presented a transcriptional and functional impairment of autophagic process compared to HPV-negative cells, which was reactivated by knocking-down HPV E6/E7 oncoproteins, the drivers of cellular transformation. We found that the oncoprotein c-MYC was stabilized and triggered in HPV-positive cell lines. This resulted in the reduced binding of the MiT/TFE transcription factors to their autophagy targets due to c-MYC competition. Thus, knock-down of c-MYC induced the upregulation of autophagic and lysosomal genes in HPV-positive HNC cells, as well as the increase of autophagic markers at the protein level. Moreover, HPV oncoprotein E7 upregulated the expression of the phosphatase inhibitor CIP2A, accounting for c-MYC upregulation and stability in HPV+ HNC cells. CIP2A mRNA expression negatively correlated with autophagy gene expression in tumor tissues from HNC patients, showing, for the first time, its implication in a transcriptional autophagic context. Both CIP2A and c-MYC knock-down, as well as pharmacological downregulation of c-MYC, resulted in increased resistance to Cisplatin treatment. Our results not only show a novel way by which HPV oncoproteins manipulate the host machinery, but also provide more insights on the role of autophagy in chemoresistance, with possible implications for targeted HPV-positive HNC therapy.

ORGANISM(S): Homo sapiens

PROVIDER: GSE235662 | GEO | 2023/11/08

REPOSITORIES: GEO

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Project description:Head and neck cancer (HNC) is the fifth most common malignancy worldwide with an annual mortality rate of 200,000. About 90% of HNC can be classified as head and neck squamous cell carcinomas (HNSCC), of which approximately 75% are attributed to alcohol and tobacco consumption and 25 are associated with human papillomavirus (HPV), predominantly HPV16. HPV-associated OPC have better prognosis and a more favorable response to therapy as compared to HPV-negative tumors. Viral oncoproteins are capable of transforming primary human keratinocytes from either genital or oral epithelia in vitro and most likely play the same role in vivo, by disrupting cell-cycle regulatory pathways leading to a genetic progression to ano-genital cancer and OPC. However, the precise mechanisms by which HPV mediates malignant transformation of keratinocytes in the upper digestive tract epithelia are not entirely clear. HPV E7-mediated inactivation of pRb results in overexpression of p16INK4A, which is commonly used as a clinical surrogate marker for HPV positivity/activity. However, high p16INK4A alone has insufficient sensitivity and specificity as a biomarker of HPV positivity in different mucosal sub-sites of HNC. Therefore, increasing emphasis is being placed on the assessment of viral load and E7 oncogene expression, resulting in further classification of HPV positive OPC as HPV-active and HPV-inactive. Differences in risk factors, age of presentation, clinical behavior and gene expression profiles indicate that HPV-positive and HPV-negative tumors develop via different molecular mechanisms and are biologically distinct. This study aimed to compare the gene expression profiles of HPV-active OPCs and normal benign uvula/tonsil tissues and determine what biological processes and pathways are affected in HPV-active tumors. ANALYSIS 5: Two-condition, one-color experiment: HPV-active oropharyngeal tumor samples and normal benign uvula/tonsil tissues. Biological replicates: 12 HPV active samples and 4 Normal samples.

Project description:Head and neck cancer (HNC) is the fifth most common malignancy worldwide with an annual mortality rate of 200,000. About 90% of HNC can be classified as head and neck squamous cell carcinomas (HNSCC), of which approximately 75% are attributed to alcohol and tobacco consumption and 25 are associated with human papillomavirus (HPV), predominantly HPV16. HPV-associated OPC have better prognosis and a more favorable response to therapy as compared to HPV-negative tumors. Viral oncoproteins are capable of transforming primary human keratinocytes from either genital or oral epithelia in vitro and most likely play the same role in vivo, by disrupting cell-cycle regulatory pathways leading to a genetic progression to ano-genital cancer and OPC. However, the precise mechanisms by which HPV mediates malignant transformation of keratinocytes in the upper digestive tract epithelia are not entirely clear. HPV E7-mediated inactivation of pRb results in overexpression of p16INK4A, which is commonly used as a clinical surrogate marker for HPV positivity/activity. However, high p16INK4A alone has insufficient sensitivity and specificity as a biomarker of HPV positivity in different mucosal sub-sites of HNC. Therefore, increasing emphasis is being placed on the assessment of viral load and E7 oncogene expression, resulting in further classification of HPV positive OPC as HPV-active and HPV-inactive. Differences in risk factors, age of presentation, clinical behavior and gene expression profiles indicate that HPV-positive and HPV-negative tumors develop via different molecular mechanisms and are biologically distinct. This study aimed to compare the gene expression profiles of HPV-negative and HPV-inactive OPCs from both African American and European American patients, and determine their biological and racial differences. ANALYSIS 4: Four-condition, one-color experiment: African American (AA) HPV-inactive, African American (AA) HPV-negative, European American (EA) HPV-inactive, European American (EA) HPV-negative oropharyngeal tumor samples. Biological replicates: 4 AA HPV Inactive samples, 8 AA HPV Negative samples, 4 EA HPV Inactive samples and 8 EA HPV Negative samples,

Project description:Approximately 25% of all head and neck cancers (HNC), and up to 60% of oropharyngeal cancers (OPC) are associated with human papillomavirus (HPV), predominantly HPV16. HPV-associated OPC have better prognosis and a more favorable response to therapy as compared to HPV-negative tumors. Viral oncoproteins are capable of transforming primary human keratinocytes from either genital or oral epithelia in vitro and most likely play the same role in vivo, by disrupting cell-cycle regulatory pathways leading to a genetic progression to ano-genital cancer and OPC. However, the precise mechanisms by which HPV mediates malignant transformation of keratinocytes in the upper digestive tract epithelia are not entirely clear. HPV E7-mediated inactivation of pRb results in overexpression of p16INK4A, which is commonly used as a clinical surrogate marker for HPV positivity/activity. However, high p16INK4A alone has insufficient sensitivity and specificity as a biomarker of HPV positivity in different mucosal sub-sites of HNC. Therefore, increasing emphasis is being placed on the assessment of viral load and E7 oncogene expression, resulting in further classification of HPV positive OPC as HPV-active and HPV-inactive. Differences in risk factors, age of presentation, clinical behavior and gene expression profiles indicate that HPV-positive and HPV-negative tumors develop via different molecular mechanisms and are biologically distinct. According to some reports, the rate of HPV-associated tumors is much lower in AA patients as compared to EA patients in United States. This study aimed to compare the gene expression profiles of HPV-active, -inactive and -negative OPCs from european american patients, and determine their biological differences. ANALYSIS 3: Three-condition, one-color experiment: HPV-active, HPV-inactive and HPV-negative oropharyngeal tumor samples from european american patients. Biological replicates: 8 HPV Negative Tumors. 4 HPV Inactive Tumors. 11 HPV Active Tumors.

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C-MYC-dependent transcriptional inhibition of autophagy is implicated in Cisplatin sensitivity in HPV-positive Head and Neck Cancer

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