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Background: Hyperthermia can play a synergistic role with chemotherapy in combination therapy. Although the association between caspase activation, apoptosis, and pyroptosis have been published for both cisplatin (CDDP) and hyperthermia therapies independently, the interactions between these molecular pathways in combination therapy are unknown. The present study aimed to investigate the possible interactions between caspase 8 activation, apoptosis, and pyroptosis in combination therapy., Methods: Cells were treated with CDDP (15 µg/ml), followed by hyperthermia at optimized temperature (42.5 °C) in water-bath. After combination therapy, cell viability was analyzed by CCK-8, and cell death was analyzed by Annexin-V-FITC/PI and caspases activation. Immuno-staining and co-immuno-precipitation were used to examine the interaction between p62 and caspase-8. Pyroptosis was investigated by western blotting and transmission electron microscopy. E3 ligase Cullin 3 was knockdown by siRNA. In addition, caspase-8 activation was modulated by CRISPR-Cas9 gene-editing or pharmacological inhibition., Results: Combination therapy promoted K63-linked polyubiquitination of caspase-8 and cellular accumulation of caspase-8. In turn, polyubiquitinated caspase-8 interacted with p62 and led to the activation of caspase-3. Knockdown of the E3 ligase Cullin 3 by siRNA reduced caspase-8 polyubiquitination and activation. In addition, combination therapy induced release of the pore-forming N-terminus from gasdermins and promoted pyroptosis along with caspase-8 accumulation and activation. Knockdown of caspase-8 by CRISPR/Cas9 based gene editing reduced the sensitivity of tumor cells to apoptosis and pyroptosis., Conclusions: Our study presented a novel mechanism in which hyperthermia synergized with chemotherapy in promoting apoptosis and pyroptosis in a caspase-8 dependent manner.

Quantum dots (QDs) have favorable physical and photochemical properties. In this work, we used QDs fluorescent nanoprobes to follow the migration of inflammatory cells from local tissue to draining lymph node in inflammation resolution. Electric pulse stimulation was used to establish inflammation model in mouse tibialis anterior. QDs injected to inflammatory tissue were found to aggregate and endocytosed by inflammatory cells. While in the draining lymph node, QDs mainly distributed in the T cell area. TEM and confocal observation showed that most of QDs in the draining lymph node were located in the endosomes of monocytes/macrophages. Our work shows that QDs can be used as fluorescent probes to follow migration of cells especially phagocytic cells. Thus QDs may be explored in application in immunology research.

Micro/nano-particle drug delivery systems are being developed for improving therapeutic effects. However, most studies can only evaluate the delivery properties by indirectly measuring the pharmacokinetic changes of the drugs. It had been difficult to directly assay the drug carrier status and distribution in vivo. We described here a method using intravital microscopy to visualize individual drug carriers traveling through blood vessels. The transportation and extravasation process of these particles were monitored. The in vivo distribution patterns were also confirmed by fluorescence microscopy studies of the various tissue samples.