T-LAK cell-originated protein kinase (TOPK): an emerging target for cancer-specific therapeutics

‘Targeted’ or ‘biological’ cancer treatments rely on differential gene expression between normal tissue and cancer, and genetic changes that render tumour cells especially sensitive to the agent being applied. Problems exist with the application of many agents as a result of damage to local tissues, tumour evolution and treatment resistance, or through systemic toxicity. Hence, there is a therapeutic need to uncover specific clinical targets which enhance the efficacy of cancer treatment whilst minimising the risk to healthy tissues. T-LAK cell-originated protein kinase (TOPK) is a MAPKK-like kinase which plays a role in cell cycle regulation and mitotic progression. As a consequence, TOPK expression is minimal in differentiated cells, although its overexpression is a pathophysiological feature of many tumours. Hence, TOPK has garnered interest as a cancer-specific biomarker and biochemical target with the potential to enhance cancer therapy whilst causing minimal harm to normal tissues. Small molecule inhibitors of TOPK have produced encouraging results as a stand-alone treatment in vitro and in vivo, and are expected to advance into clinical trials in the near future. In this review, we present the current literature pertaining to TOPK as a potential clinical target and describe the progress made in uncovering its role in tumour development. Firstly, we describe the functional role of TOPK as a pro-oncogenic kinase, followed by a discussion of its potential as a target for the treatment of cancers with high-TOPK expression. Next, we provide an overview of the current preclinical progress in TOPK inhibitor discovery and development, with respect to future adaptation for clinical use

Comparative transcriptomics reveals commonalities and differences in the genetic underpinnings of a floral dimorphism

Distyly, a floral dimorphism associated with heteromorphic self-incompatibility and controlled by the S-locus supergene, evolved independently multiple times. Comparative analyses of the first transcriptome atlas for the main distyly model, Primula veris, with other distylous species produced the following findings. A set of 53 constitutively expressed genes in P. veris did not include any of the housekeeping genes commonly used to normalize gene expression in qPCR experiments. The S-locus gene CYP$^{T}$ acquired its role in controlling style elongation via a change in expression profile. Comparison of genes differentially expressed between floral morphs revealed that brassinosteroids and auxin are the main hormones controlling style elongation in P. veris and Fagopyrum esculentum, respectively. Furthermore, shared biochemical pathways might underlie the expression of distyly in the distantly related P. veris, F. esculentum and Turnera subulata, suggesting a degree of correspondence between evolutionary convergence at phenotypic and molecular levels. Finally, we provide the first evidence supporting the previously proposed hypothesis that distyly supergenes of distantly related species evolved via the recruitment of genes related to the phytochrome-interacting factor (PIF) signaling network. To conclude, this is the first study that discovered homologous genes involved in the control of distyly in distantly related taxa

Tropospheric Ozone In A Mountain Forest Area: Spatial Distribution And Its Relation With Meteorology And Emission Sources

Biological injuries to forest ecosystems in two lateral valleys of Valtellina (Italy) have been studied. The selected areas are characterized by different forest novel decline symptoms and ozone concentration levels. Analyses of meteorological and air quality data collected by fixed and mobile stations located in the two valleys are presented. Ozone concentration has been measured both by passive samplers and continues analyzers and the ozone vertical gradient in one valley has been determined. In order to investigate the relation between emission sources, ambient ozone levels and plant biological injuries, a modeling research project has been started. As preliminary results the wind field obtained by the application of two diagnostic meteorological models, MINERVE and CALMET, and the computation of the biogenic emissions are presented. Some examples of spatial distribution and temporal trend of the most important pollutants emitted by plants are discussed

An 89Zr-HDL PET Tracer Monitors Response to a CSF1R Inhibitor

The immune function within the tumor microenvironment has become a prominent therapeutic target, with tumor-associated macrophages (TAMs) playing a critical role in immune suppression. We propose an 89Zr-labeled high-density lipoprotein (89Zr-HDL) nanotracer as a means of monitoring response to immunotherapy. Methods: Female MMTV-PyMT mice were treated with pexidartinib, a colony-stimulating factor 1 receptor (CSF1R) inhibitor, to reduce TAM density. The accumulation of 89Zr-HDL within the tumor was assessed using PET/CT imaging and autoradiography, whereas TAM burden was determined using immunofluorescence. Results: A significant reduction in 89Zr-HDL accumulation was observed in PET/CT images, with 2.9% ± 0.3% and 3.7% ± 0.2% injected dose/g for the pexidartinib- and vehicle-treated mice, respectively. This reduction was corroborated ex vivo and correlated with decreased TAM density. Conclusion: These results support the potential use of 89Zr-HDL nanoparticles as a PET tracer to quickly monitor the response to CSF1R inhibitors and other therapeutic strategies targeting TAMs.We thank the Small Animal Imaging Core, the Radiochemistry and Molecular Imaging Probes Core, and the Molecular Cytology Core at Memorial Sloan Kettering Cancer Center. This work was supported by National Institutes of Health grants R01 CA204441, P30 CA008748 and R01 CA220234. The authors thank the Tow Foundation and Memorial Sloan Kettering Cancer Center's Center for Molecular Imaging & Nanotechnology (CMINT), the Imaging and Radiation Sciences Program and the MSK Molecularly Targeted Intraoperative Imaging Fund.S

TOPK as a novel determinant of radiosensitivity

Radiotherapy is the use of ionising radiation to induce localised DNA damage to cancerous tissues, leading to cell death and disease control. In order to maximise tumour growth control and to limit damage of the healthy surrounding tissues and the consequent side effects for the patient, molecular determinants of tumour radioresistance are investigated as potential clinical targets. A high-throughput siRNA colony formation assay screen in HeLa cervical carcinoma cells previously published by our laboratory identified modulators of radiosensitivity. From the list CSF1R, EPHB2, GAK and TOPK, were selected and validated. TOPK (T-LAK cell-originated protein kinase, also known as PDZ-binding kinase, PBK) was selected for further investigation because it is overexpressed in most malignancies but not in normal tissues, apart from testis and placenta. Knockdown of TOPK was shown to induce radiosensitisation in a panel of cancer cell lines with no significant effects on normal cells. A role for TOPK in the cell cycle response to ionising radiation (IR) was discovered in HCT116 colorectal cancer cells, with alterations in the G1/S and G2/M checkpoints. Furthermore, immunoprecipitation experiments identified a physical interaction between TOPK and CDKN1A (p21) at 8 hours after IR. Apoptosis and the number of multinucleated cells were significantly increased in TOPK depleted cells exposed to IR, suggesting the possibility of aberrant mitosis and mitotic catastrophe in these cells. High TOPK expression in early breast cancer patients was shown to be associated with poor recurrence-free survival. In addition, immunohistochemistry (IHC) analysis on samples from prostate cancer patients identified a strong correlation between high levels of TOPK and poor clinical response to radiotherapy. In order to facilitate future in vivo experiments, an HCT116 shRNA stable knockdown cell line was developed and two commercially available TOPK inhibitors were tested and optimised. Taken together, these data suggest that TOPK is a molecular determinant of radiosensitivity with a great potential for future clinical applications.</p

Comparative transcriptomics reveals commonalities and differences in the genetic underpinnings of a floral dimorphism

Abstract Distyly, a floral dimorphism associated with heteromorphic self-incompatibility and controlled by the S-locus supergene, evolved independently multiple times. Comparative analyses of the first transcriptome atlas for the main distyly model, Primula veris, with other distylous species produced the following findings. A set of 53 constitutively expressed genes in P. veris did not include any of the housekeeping genes commonly used to normalize gene expression in qPCR experiments. The S-locus gene CYP T acquired its role in controlling style elongation via a change in expression profile. Comparison of genes differentially expressed between floral morphs revealed that brassinosteroids and auxin are the main hormones controlling style elongation in P. veris and Fagopyrum esculentum, respectively. Furthermore, shared biochemical pathways might underlie the expression of distyly in the distantly related P. veris, F. esculentum and Turnera subulata, suggesting a degree of correspondence between evolutionary convergence at phenotypic and molecular levels. Finally, we provide the first evidence supporting the previously proposed hypothesis that distyly supergenes of distantly related species evolved via the recruitment of genes related to the phytochrome-interacting factor (PIF) signaling network. To conclude, this is the first study that discovered homologous genes involved in the control of distyly in distantly related taxa

Comparative Genomics Elucidates the Origin of a Supergene Controlling Floral Heteromorphism

Supergenes are nonrecombining genomic regions ensuring the coinheritance of multiple, coadapted genes. Despite the importance of supergenes in adaptation, little is known on how they originate. A classic example of supergene is the S locus controlling heterostyly, a floral heteromorphism occurring in 28 angiosperm families. In Primula, heterostyly is characterized by the cooccurrence of two complementary, self-incompatible floral morphs and is controlled by five genes clustered in the hemizygous, ca. 300-kb S locus. Here, we present the first chromosome-scale genome assembly of any heterostylous species, that of Primula veris (cowslip). By leveraging the high contiguity of the P. veris assembly and comparative genomic analyses, we demonstrated that the S-locus evolved via multiple, asynchronous gene duplications and independent gene translocations. Furthermore, we discovered a new whole-genome duplication in Ericales that is specific to the Primula lineage. We also propose a mechanism for the origin of S-locus hemizygosity via nonhomologous recombination involving the newly discovered two pairs of CFB genes flanking the S locus. Finally, we detected only weak signatures of degeneration in the S locus, as predicted for hemizygous supergenes. The present study provides a useful resource for future research addressing key questions on the evolution of supergenes in general and the S locus in particular: How do supergenes arise? What is the role of genome architecture in the evolution of complex adaptations? Is the molecular architecture of heterostyly supergenes across angiosperms similar to that of Primula

[18F]PARPi Imaging Is Not Affected by HPV Status In Vitro

Background. Human papillomavirus- (HPV-) associated oropharyngeal squamous cell carcinomas (OPSCCs) are clinically and pathologically distinct from HPV-negative tumors. Here, we explore whether HPV affects functional biomarkers, including γH2AX, RAD51, and PARP1. Moreover, the role of [18F]PARPi as a broadly applicable imaging tool for head and neck carcinomas is investigated. Methods. HPV-positive and HPV-negative cell lines were used to evaluate the γH2AX, RAD51, and PARP1 expression with immunoblotting and immunofluorescence. Effects of external beam ionizing radiation were investigated in vitro, and survival was investigated via colony-formation assay. [18F]PARPi uptake experiments were performed on HPV-negative and HPV-positive cell lines to quantify PARP1 expression. PARP1 IHC and γH2AX foci were quantified using patient-derived oropharyngeal tumor specimens. Results. Differences in DNA repair were detected, showing higher RAD51 and γH2AX expression in HPV-positive cell lines. Clonogenic assays confirm HPV-positive cell lines to be significantly more radiosensitive. PARP1 expression levels were similar, irrespective of HPV status. Consequently, [18F]PARPi uptake assays demonstrated that this tracer is internalized in cell lines independently from their HPV status. Conclusion. The HPV status, often used clinically to stratify patients, did not affect PARP1 levels, suggesting that PARP imaging can be performed in both HPV-positive and HPV-negative patients. This study confirms that the PET imaging agent [18F]PARPi could serve as a general clinical tool for oropharyngeal cancer patients

Smartphone epifluorescence microscopy for cellular imaging of fresh tissue in low-resource settings

Disease diagnosis in low-resource settings can be challenging due to the lack of equipment and trained personnel required for histologic analysis. In this paper, we have developed a smartphone-based epifluorescence microscope (SeFM) for imaging fresh tissues at sub-cellular resolution. SeFM provides similar resolution and field of view (FOV) as those used during histologic analysis. The SeFM device achieved the lateral resolution of 0.57 gm and provided microscopy images over a sample area larger than 500 gin. The material cost was low, approximately $3,000. Preliminary images of human pancreatic tumor specimens clearly visualized cellular details. Quantitative analysis showed that using an excess dose of a chemotherapy drug significantly reduced the tumor-specific fluorescence signal, confirming the specificity of the drug and the detection potential of SeFM. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing AgreementOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The anti-malarial drug atovaquone potentiates platinum-mediated cancer cell death by increasing oxidative stress

Platinum chemotherapies are highly effective cytotoxic agents but often induce resistance when used as monotherapies. Combinatorial strategies limit this risk and provide effective treatment options for many cancers. Here, we repurpose atovaquone (ATQ), a well-tolerated & FDA-approved anti-malarial agent by demonstrating that it potentiates cancer cell death of a subset of platinums. We show that ATQ in combination with carboplatin or cisplatin induces striking and repeatable concentration- and time-dependent cell death sensitization in vitro across a variety of cancer cell lines. ATQ induces mitochondrial reactive oxygen species (mROS), depleting intracellular glutathione (GSH) pools in a concentration-dependent manner. The superoxide dismutase mimetic MnTBAP rescues ATQ-induced mROS production and pre-loading cells with the GSH prodrug N-acetyl cysteine (NAC) abrogates the sensitization. Together, these findings implicate ATQ-induced oxidative stress as key mediator of the sensitizing effect. At physiologically achievable concentrations, ATQ and carboplatin furthermore synergistically delay the growth of three-dimensional avascular spheroids. Clinically, ATQ is a safe and specific inhibitor of the electron transport chain (ETC) and is concurrently being repurposed as a candidate tumor hypoxia modifier. Together, these findings suggest that ATQ is deserving of further study as a candidate platinum sensitizing agent