Biology subjects

Takashima, M.

Publications and source records attributed to Takashima, M..

2 recordsLinked to original sources

bioRxiv2024

Priming versus propagating: distinct immune effects of an alpha- versus beta-particle emitting radiopharmaceutical when combined with immune checkpoint inhibition

Radiopharmaceutical therapy (RPT) enhances tumor response to immune checkpoint inhibitors (ICI) in preclinical models, but the effects of different radioisotopes have not been thoroughly compared. To evaluate mechanisms of response to RPT+ICI, we used NM600, an alkylphosphocholine selectively taken up by most tumors. Effects of 90Y-, 177Lu-, and 225Ac-NM600 + ICIs were compared in syngeneic murine models, B78 melanoma (poorly immunogenic) and MC38 colorectal cancer (immunogenic). 90Y-/177Lu-/or 225Ac-NM600 delivering 2 Gy mean tumor dose promoted tumor regression and improved survival when combined with ICIs in syngeneic mice bearing B78 or MC38 tumors. Regardless of the administered isotope, this combination was optimized with early ICI administration (days -3/0/3) relative to day 1 RPT. 90Y-NM600+ICI produced the greatest anti-tumor response for MC38, whereas high linear energy transfer (LET) alpha particle radiation from 225Ac-NM600+ICI was most effective against poorly immunogenic B78 tumors. Flow cytometry and single cell RNA and T cell receptor (TCR) sequencing illuminated distinct mechanisms of 90Y- or 177Lu-NM600 in promoting expansion of existing adaptive immunity and of 225Ac-NM600 in promoting immune priming when combined with ICI. Antitumor immune response can be achieved with appropriate application of - or {beta}- emitting RPT in combination with ICIs in diverse murine tumor models.

cancer biology↗

bioRxiv2022

Exocytotic dynamics of glucagon-like peptide-1 from enteroendocrine L cell line is regulated by actin polymerization

Stimulus-secretion coupling of glucagon-like peptide-1 (GLP-1) from enteroendocrine L cells is important for glucose homeostasis. Although intracellular second messengers including Ca2+ and cAMP, and cellular structures including actin cytoskeleton play roles in induction of exocytosis of GLP-1 granules, little is known about the specific part in the process of exocytosis in which they are involved. Here we explored the role of those molecules by live-cell imaging with mouse L cell line GLUTag cells, and used two stimuli: deoxycholic acid (DCA) and high K+. DCA increased both intracellular Ca2+ and cAMP levels, while high K+ only increased Ca2+. We next monitored a single exocytosis of GLP-1 granules and found that, during the first 10 minutes of stimulation, both stimuli mainly induced the exocytosis from the predocked granules with the plasma membrane before stimulation or granules immediately fused to the plasma membrane without docking. Furthermore, inhibition of actin polymerization suppressed the proportion of exocytosis by the predocked granules. These results suggest that the exocytotic process of GLP-1 granules is determined by interaction with F-actin upon the increase of either Ca2+ or cAMP. Summary statementExocytotic process of glucagon-like peptide-1 granules from a mouse enteroendocrine L cell line is regulated by actin polymerization immediately after elevation of intracellular Ca2+ or cAMP levels.

cell biology↗