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Biology subjects

Meeks, L.

Publications and source records attributed to Meeks, L..

2 recordsLinked to original sources

Exosome-like biogenesis from the Golgi releases extracellular vesicles lacking conventional tetraspanins that mediate immune evasion in cancer

Immunotherapy has improved survival across multiple malignancies but remains largely ineffective in solid cancers such as lung, breast, and pancreatic cancer. A key driver of resistance is the immunosuppressive tumor microenvironment (TME). Although numerous mediators of TME immunosuppression have been identified, therapeutic targeting has provided limited clinical benefit. Tumor-derived extracellular vesicles (EVs) have recently emerged as contributors to resistance, yet their mechanisms remain unclear. We developed human non-small cell lung cancer models to investigate EV-mediated immunosuppression. We identified a distinct Golgi-derived EV subpopulation that potently suppress T cell function and tumor infiltration. These EVs express the trans-Golgi network marker TGOLN2, and exhibit minimal levels of canonical EV markers. TGOLN2 overexpression drives this suppressive phenotype. Clinically, elevated TGOLN2 associates with poor survival and correlate with an immunosuppressive TME signature across more than 20 cancer types, including NSCLC. Collectively, this work defines a previously unrecognized mechanism of TGOLN2-driven, EV-mediated immunosuppression. Statement of SignificanceWe revealed TGOLN2 overexpression as a new immune evasion mechanism that mediates T cell suppression through increased secretion of a Golgi-derived extracellular vesicle (EV) subpopulation. These findings redefine current paradigms of EV biology and nominate TGOLN2 as a potential biomarker and therapeutic target in immunosuppressive cancers.

cell biology↗

AMPK activation restores salivary function following radiation treatment

Head and neck cancers represent a significant portion of cancer diagnoses, with head and neck cancer incidence increasing in some parts of the world. Typical treatment of early-stage head and neck cancers includes either surgery or radiotherapy; however, advanced cases often require surgery followed by radiation and chemotherapy. Salivary gland damage following radiotherapy leads to severe and chronic hypofunction with decreased salivary output, xerostomia, impaired ability to chew and swallow, increased risk of developing oral mucositis, and malnutrition. There is currently no standard of care for radiation-induced salivary gland dysfunction and treatment is often limited to palliative treatment that provides only temporary relief. AMP-activated protein kinase (AMPK) is an enzyme that activates catabolic processes and has been shown to influence the cell cycle, proliferation, and autophagy. In the present study, we found that radiation (IR) treatment decreases tissue levels of phosphorylated AMPK following radiation and decreases intracellular NAD+ and AMP while increasing intracellular ATP. Further, expression of Sirtuin-1 (SIRT1) and nicotinamide phosphoribosyl transferase (NAMPT) were lower five days following IR. Treatment with AMPK activators, AICAR and metformin, attenuated compensatory proliferation (days 6, 7 and 30) following IR, and reversed chronic (day 30) salivary gland dysfunction post-IR. Additionally, treatment with metformin or AICAR increased markers of apical/basolateral polarity (phosphorylated aPKC{zeta}T560 positive area) and differentiation (amylase positive area) within irradiated parotid glands to levels similar to untreated controls. Taken together, these data suggest that AMPK may be a novel therapeutic target for treatment of radiation-induced salivary damage.

molecular biology↗