Margaret McLaughlin-drubin

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Papers by Margaret McLaughlin-drubin

Journal of Virology, Sep 1, 2008

The papillomavirus life cycle is intimately coupled to the differentiation state of the infected ... more The papillomavirus life cycle is intimately coupled to the differentiation state of the infected epithelium. Since papillomaviruses lack most of the rate-limiting enzymes required for genome synthesis, they need to uncouple keratinocyte differentiation from cell cycle arrest and maintain or reestablish a replication-competent state within terminally differentiated keratinocytes. The human papillomavirus (HPV) E7 protein appears to be a major determinant for this activity and induces aberrant S-phase entry through the inactivation of the retinoblastoma tumor suppressor and related pocket proteins. In addition, E7 can abrogate p21 and p27. Together, this leads to the activation of E2F1 to E2F5, enhanced expression of E2F-responsive genes, and increased cdk2 activity. E2F6 is a pRB-independent, noncanonical member of the E2F transcription factor family that acts as a transcriptional repressor. E2F6 expression is activated in S phase through an E2Fdependent mechanism and thus may provide a negative-feedback mechanism that slows down S-phase progression and/or exit in response to the activation of the other E2F transcription factors. Here, we show that lowand high-risk HPV E7 proteins, as well as simian virus 40 T antigen and adenovirus E1A, can associate with and inactivate the transcriptional repression activity of E2F6, thereby subverting a critical cellular defense mechanism. This may result in the extended S-phase competence of HPV-infected cells. E2F6 is a component of polycomb group complexes, which bind to silenced chromatin and are critical for the maintenance of cell fate. We show that E7-expressing cells show decreased staining for E2F6/polycomb complexes and that this is at least in part dependent on the association with E2F6.

AVI file - 1261KB, Representative 3D RENDERING HFK EETE.

AVI file - 970KB, Representative endogenous TPEF OPTICAL STACK HKcDR EETE.

PLOS Pathogens, Oct 2, 2017

Expression of E7 proteins encoded by carcinogenic, high-risk human papillomaviruses (HPVs) trigge... more Expression of E7 proteins encoded by carcinogenic, high-risk human papillomaviruses (HPVs) triggers increased expression of the histone H3 lysine 27 demethylase KDM6A. KDM6A expression is necessary for survival of high-risk HPV E7 expressing cells, including several cervical cancer lines. Here we show that increased KDM6A in response to high-risk HPV E7 expression causes epigenetic de-repression of the cell cycle and DNA replication inhibitor p21 CIP1 , and p21 CIP1 expression is necessary for survival of high-risk HPV E7 expressing cells. The requirement for KDM6A and p21 CIP1 expression for survival of highrisk HPV E7 expressing cells is based on p21 CIP1 's ability to inhibit DNA replication through PCNA binding. We show that ectopic expression of cellular replication factors can rescue the loss of cell viability in response to p21 CIP1 and KDM6A depletion. Moreover, we discovered that nucleoside supplementation will override the loss of cell viability in response to p21 CIP1 depletion, suggesting that p21 CIP1 depletion causes lethal replication stress. This model is further supported by increased double strand DNA breaks upon KDM6A or p21 CIP1 depletion and DNA combing experiments that show aberrant re-replication upon KDM6A or p21 CIP1 depletion in high-risk HPV E7 expressing cells. Therefore, KDM6A and p21 CIP1 expression are essential to curb E7 induced replication stress to levels that do not markedly interfere with cell viability.

AVI file - 1297KB, Representative 3D RENDERING E7 EETE.

AVI file - 1366KB, Representative 3D RENDERING E6E7 EETE.

AVI file - 1230KB, Representative 3D RENDERING HKcDR EETE.

AVI file - 1191KB, Representative endogenous TPEF OPTICAL STACK E6 EETE.

Keratin fluorescence identification: Identification of keratin positive and non-keratin positive ... more Keratin fluorescence identification: Identification of keratin positive and non-keratin positive pixels was based on linear discriminant analysis (LDA). Specifically, the average normalized fluorescence intensities from images acquired at the six different excitation and emission combinations were calculated for a training set of 2,296 user-specified regions from three independent C HFK and three independent 16E7 HFK EETEs. The C HFK and 16E7 HFK EETEs were chosen since those contained the most highly keratinized superficial layers as identified by H&E (Fig. 2) and involucrin/loricrin staining (Fig. S2). Based on the training set, a combination of five metrics was used to differentiate keratin from non-keratin fluorescence: the fluorescence intensity detected at 460 nm (755 nm excitation), its ratio to the fluorescence detected at 525nm (860 nm

AVI file - 1297KB, Representative endogenous TPEF OPTICAL STACK E7 EETE.

AVI file - 1119KB, Representative endogenous TPEF OPTICAL STACK E6E7 EETE.

AVI file - 1258KB, Representative 3D RENDERING E6 EETE.

AVI file - 1575KB, Representative endogenous TPEF OPTICAL STACK HFK EETE.

The Oncologist

Background FoundationOneCDx is approved in the US and Japan as a companion diagnostic test to ide... more Background FoundationOneCDx is approved in the US and Japan as a companion diagnostic test to identify patients with cancer who may benefit from treatment with 30 drug therapies in the US and 23 in Japan. Tumor profiling with FoundationOneCDx also detects genomic findings with evidence of clinical significance that may inform clinical care decisions beyond companion diagnostic claims. This observational study reports the breadth and impact of clinical decision insights from FoundationOneCDx solid tumor profiles. Materials and Methods Consecutive test result reports for patients with solid tumor diagnoses (n = 109 695) were retrospectively analyzed for clinically significant predictive, prognostic, and diagnostic genomic alterations and signatures, determined in accordance with professional guidelines. Interventional clinical trials with targeted therapies or immune checkpoint inhibitors were matched to tumor profiles based on evidence that the genomic finding may be an actionable, i...