Biology subjects

Whitehurst, A.

Publications and source records attributed to Whitehurst, A..

4 recordsLinked to original sources

bioRxiv2024

The Cancer Testis Antigen Testis Specific Serine Kinase 6 (TSSK6) is abnormally expressed in colorectal cancer and is essential for oncogenic behaviors

Cancer testis antigens (CTAs) are a collection of proteins whose expression is normally restricted to the gamete, but abnormally activated in a wide variety of tumors. The CTA, Testis specific serine kinase 6 (TSSK6), is essential for male fertility in mice. Functional relevance of TSSK6 to cancer, if any, has not previously been investigated. Here we find that TSSK6 is frequently anomalously expressed in colorectal cancer and patients with elevated TSSK6 expression have reduced relapse free survival. Depletion of TSSK6 from colorectal cancer cells attenuates anchorage independent growth, invasion and growth in vivo. Conversely, overexpression of TSSK6 enhances anchorage independence and invasion in vitro as well as in vivo tumor growth. Notably, ectopic expression of TSSK6 in semi-transformed human colonic epithelial cells is sufficient to confer anchorage independence and enhance invasion. In somatic cells, TSSK6 co-localizes with and enhances the formation of paxillin and tensin positive foci at the cell periphery, suggesting a function in focal adhesion formation. Importantly, TSSK6 kinase activity is essential to induce these tumorigenic behaviors. Our findings establish that TSSK6 exhibits oncogenic activity when abnormally expressed in colorectal cancer cells. Thus, TSSK6 is a previously unrecognized intervention target for therapy, which could exhibit an exceptionally broad therapeutic window.

cancer biology↗

bioRxiv2023

Efficient Multiplexing of Pollinator Metabarcodes Using Oxford Nanopore MinION Sequencing: Insights for Meadow Management from Floral Environmental DNA

Many pollinating species are experiencing declines globally, making effective, fast, and portable pollinator monitoring methods more important than ever before. Pollinators can leave DNA on the flowers they visit, and metabarcoding of these environmental DNA (eDNA) traces provides an opportunity to detect the presence of flower visitors. This study introduces an efficient, cost-effective workflow for utilizing DNA barcoding to monitor biodiversity through environmental DNA (eDNA) left on flowers from pollinators, employing the portable MinION and Nanopore sequencing. The developed method employs multiplexing with dual molecular tags on universal cytochrome oxidase 1 (COI) barcode primers. We used this approach to compare the arthropod diversity present in three meadows with different vegetation at three time points during the flowering season. The utility of eDNA metabarcoding in investigating pollinator biodiversity and interactions is highlighted through our results, revealing the presence and interactions of 65 species from 30 families. We multiplexed individual eDNA samples from hundreds of flowers and found plant-pollinator dynamics that showed differences in species richness between sampling times and meadow diversity. Comparative analyses with conventional methods showed eDNA metabarcodings ability to identify diverse species and ecological interactions compared to field sampling. While some DNA likely came from eggs or microscopic insects difficult to remove from flowers, traces of eDNA from various arthropods on multiple plant species confirmed the methods applicability, promising robust ecological monitoring and research potential in the wake of global pollinator declines. This is the first reported use of MinION based nanopore sequencing to detect arthropod species from eDNA samples collected from flowers using the described affordable multiplexing method.

ecology↗

bioRxiv2023

The Cancer Testes Antigen, HORMAD1, is a Tumor-Specific Replication Fork Protection Factor

Tumors frequently activate the expression of genes that are only otherwise required for meiosis. HORMAD1, which is essential for meiotic recombination in multiple species, is expressed in over 50% of human lung adenocarcinoma cells (LUAD). We previously found that HORMAD1 promotes DNA double strand break (DSB) repair in LUAD. Here, we report that HORMAD1 takes on an additional role in protecting genomic integrity. Specifically, we find HORMAD1 is critical for protecting stalled DNA replication forks in LUAD. Loss of HORMAD1 leads to nascent DNA degradation, an event which is mediated by the MRE11-DNA2-BLM pathway. Moreover, following exogenous induction of DNA replication stress, HORMAD1 deleted cells accumulate single stranded DNA (ssDNA). We find that these phenotypes are the result of a lack of RAD51 and BRCA2 loading onto stalled replication forks. Ultimately, loss of HORMAD1 leads to increased DSBs and chromosomal aberrations in response to replication stress. Collectively, our data support a model where HORMAD1 expression is selected to mitigate DNA replication stress, which would otherwise induce deleterious genomic instability.

cancer biology↗

bioRxiv2020

Sperm-specific COX6B2 Enhances Oxidative Phosphorylation, Proliferation, and Survival in Lung Adenocarcinoma

Cancer testis antigens (CTAs) are genes whose expression is normally restricted to the testis but anomalously activated in cancer. In sperm, a number of CTAs promote energy generation, however whether these proteins contribute to tumor cell metabolism is not understood. Here we describe COX6B2, a sperm-specific component of cytochrome c oxidase (complex IV). COX6B2 is frequently expressed in human lung adenocarcinoma (LUAD) and expression correlates with reduced survival time in patients. COX6B2, but not its somatic isoform COX6B1, enhances activity of complex IV, increasing mitochondrial oxidative phosphorylation (OXPHOS) and NAD+ generation. Consequently, COX6B2-expressing cells display a proliferative advantage, particularly in low oxygen conditions. Conversely, depletion of COX6B2 attenuates OXPHOS and collapses mitochondrial membrane potential leading to cell death or senescence. Furthermore, COX6B2 is both necessary and sufficient for growth of tumors in vivo. Our findings reveal a previously unappreciated, tumor specific metabolic pathway hijacked from one of the most ATP-intensive processes in the animal kingdom: sperm motility.

cancer biology↗