Search

Clinical data from diverse cancer types shows that the increased T cell infiltration in tumors correlates with improved patient prognosis. Acidic extracellular pH is a major attribute of the tumor microenvironment (TME) that promotes immune evasion and tumor progression. Therefore, antagonizing tumor acidity can be a powerful approach in cancer immunotherapy. Here, Pluronic F-127 is used as a NaHCO3 releasing carrier to focally alleviate extracellular tumor acidity. In a mouse tumor model, intratumoral treatment with pH modulating injectable gel (pHe-MIG) generates immune-favorable TME, as evidenced by the decrease of immune-suppressive cells and increase of tumor infiltrating CD8+T cells. The combination of pHe-MIG with immune checkpoint inhibitors, anti-PD-1 and anti-TIGIT antibodies, increases intratumoral T cell function, which leads to tumor clearance. Mechanistically, extracellular acidity was shown to upregulate co-inhibitory immune checkpoint receptors and inhibit mTOR signaling pathways in memory CD8+T cells, which impaired effector functions. Furthermore, an acidic pH environment increased the expression and engagement of TIGIT and its ligand CD155, which suggested that the extracellular pH can regulate the suppressive function of TIGIT pathway. Collectively, these findings suggest that pHe-MIG holds potential as a new TME modulator for effective immune checkpoint inhibitor therapies.

Intracellular protein delivery is a transformative tool for biologics research and medicine. Delivery into the cytosol allows proteins to diffuse throughout the cell and access subcellular organelles. Inefficient delivery caused by endosomal entrapment is often misidentified as cytosolic delivery. This inaccuracy muddles what should be a key checkpoint in assessing delivery efficiency. Green fluorescent protein (GFP) is a robust cargo small enough to passively diffuse from the cytosol into the nucleus. Fluorescence of GFP in the nucleus is a direct readout for cytosolic access and effective delivery. Here, we highlight recent examples from the literature for the accurate assessment of cytosolic protein delivery using GFP fluorescence in the cytosol and nucleus.

Ion-sensitive field-effect transistor (ISFET) as a biosensor facilitates a process of data-acquisition through label-free and real-time monitoring. Direct quantification of a biomarker in serum is challenging in ISFET biosensor since charged proteins in serum interfere transduction to electrical signals. Here, we report the fabrication of protein blocking layers (PBLs) with intended interfacial charges to minimize non-specific protein bindings on ISFET. Use of charged protein precursors enables to regulate the interfacial charge of PBLs, preserving their intrinsic electric features (neutral: hemoglobin, positively charged: lysozyme, negatively charged: BSA). The effect of this interfacial charge on the signal was demonstrated through PSMA (prostate cancer biomarker) sensing using a dual-gate ISFET biosensor. The neutral PBL showed the minimum noise compared to the negatively and positively charged PBLs, enabling the ISFET to exhibit the same detection range in untreated serum as with pre- or post-treatment (1 fg/ml to 100 ng/ml). The introduction of neutral PBLs to ISFET biosensors would allow the application of the ISFET biosensor as a point-of-care device.