A novel EGFR-tyrosine kinase inhibitor (TKI), osimertinib, has marked efficacy in patients with EGFR-mutated lung cancer. However, some patients show intrinsic resistance and an insufficient response to osimertinib. This study showed that osimertinib stimulated AXL by inhibiting a negative feedback loop. Activated AXL was associated with EGFR and HER3 in maintaining cell survival and inducing the emergence of cells tolerant to osimertinib. AXL inhibition reduced the viability of EGFR-mutated lung cancer cells overexpressing AXL that were exposed to osimertinib. The addition of an AXL inhibitor during either the initial or tolerant phases reduced tumor size and delayed tumor re-growth compared to osimertinib alone. AXL was highly expressed in clinical specimens of EGFR-mutated lung cancers and its high expression was associated with a low response rate to EGFR-TKI. These results indicated pivotal roles for AXL and its inhibition in the intrinsic resistance to osimertinib and the emergence of osimertinib-tolerant cells.

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Inflammatory conditions are associated with tumor development. IL-1β is a multifunctional and proinflammatory cytokine that affects nearly all types of cells. To investigate the role of IL-1β in tumor growth in vivo, we transduced the retroviral vector coding human IL-1β gene into mouse Lewis lung carcinoma (LLC) cells and subsequently inoculated the transformant (LLC/IL-1β) to syngeneic C57BL/6 mice. Tumors derived from LLC/IL-1β grew faster (240%, day 18, vs null-vector control LLC/neo; p < 0.01) and showed more abundant vasculature (250%, vs LLC/neo; p < 0.05), whereas LLC/IL-1β cells, LLC/neo cells, and wild-type LLC cells did not show any significant difference in the growth rate in vitro. As compared with LLC/neo cells, LLC/IL-1β cells secreted 2-fold the amount of vascular endothelial growth factor and >10-fold the amount of macrophage-inflammatory protein-2 (CXCL2), one of whose main functions is angiogenesis. Although LLC/IL-1β itself did not secrete hepatocyte growth factor (HGF), the tumor derived from LLC/IL-1β cells also contained a >4-fold higher concentration of HGF, another angiogenic factor. In situ hybridization of HGF mRNA in LLC/IL-1β tumor sections demonstrated that stromal fibroblasts and infiltrating cells overexpressed HGF mRNA. Moreover, when cultured in the presence of HGF in vitro, LLC/IL-1β cells secreted even larger amounts of vascular endothelial growth factor and macrophage-inflammatory protein-2. The antiangiogenic agent TNP-470 and anti-CXCR2 Ab inhibited the tumor growth of LLC/IL-1β cells in vivo. These results indicated that secreting IL-1β into the tumor milieu induces several angiogenic factors from tumor and stromal cells and thus promotes tumor growth through hyperneovascularization.

Background: Adherence has recently been suggested to be divided into these two components: persistence (i.e., whether patients continue treatment or not) and compliance (i.e., whether patients take doses as instructed). However, no study has yet assessed these two clinically relevant components at the same time in adherence to antidepressant treatment in the clinical outpatient setting.

Nephrotoxicity induced by antimicrobial or anticancer drugs is a serious clinical problem. Megalin, an endocytic receptor expressed at the apical membranes of proximal tubules, mediates the nephrotoxicity of aminoglycosides and colistin, key antimicrobials for multidrug-resistant organisms. The mechanisms underlying the nephrotoxicity induced by vancomycin, an antimicrobial for methicillin-resistant , and cisplatin, an important anticancer drug, are unknown, although the nephrotoxicity of these drugs and gentamicin, an aminoglycoside, is suppressed experimentally with cilastatin. In the clinical setting, cilastatin has been used safely to suppress dehydropeptidase-I-mediated renal metabolism of imipenem, a carbapenem antimicrobial, and thereby limit tubular injury. Here, we tested the hypothesis that cilastatin also blocks megalin-mediated uptake of vancomycin, cisplatin, colistin, and aminoglycosides, thereby limiting the nephrotoxicity of these drugs. Quartz crystal microbalance analysis showed that megalin also binds vancomycin and cisplatin and that cilastatin competes with megalin for binding to gentamicin, colistin, vancomycin, and cisplatin. In kidney-specific mosaic megalin knockout mice treated with colistin, vancomycin, or cisplatin, the megalin-replete proximal tubule epithelial cells exhibited signs of injury, whereas the megalin-deficient cells did not. Furthermore, concomitant cilastatin administration suppressed colistin-induced nephrotoxicity in C57BL/6J mice. Notably, cilastatin did not inhibit the antibacterial activity of gentamicin, colistin, or vancomycin, just as cilastatin did not affect the anticancer activity of cisplatin in previous studies. In conclusion, megalin blockade with cilastatin efficiently suppresses the nephrotoxicity induced by gentamicin, colistin, vancomycin, or cisplatin. Cilastatin may be a promising agent for inhibiting various forms of drug-induced nephrotoxicity mediated megalin in the clinical setting.

ABSTRACT

Secretory leukoprotease inhibitor (SLPI) protects tissue against the destructive action of neutrophil elastase at the site of inflammation. Recent studies on new functions of SLPI have demonstrated that SLPI may play a larger role in innate immunity than merely as a protease inhibitor. To clarify the functions of SLPI in bacterial infections, we generated SLPI-deficient mice (SLPI−/− mice) and analyzed their response to experimental endotoxin shock induced by lipopolysaccharide (LPS). SLPI−/− mice showed a higher mortality from endotoxin shock than did wild type mice. This may be explained in part by our observation that SLPI−/− macro-phages show higher interleukin 6 and high-mobility group (HMG)-1 production and nuclear factor κB activities after LPS treatment than do SLPI+/+ macrophages. SLPI also affects B cell function. SLPI−/− B cells show more proliferation and IgM production after LPS treatment than SLPI+/+ B cells. Our results suggest that SLPI attenuates excessive inflammatory responses and thus assures balanced functioning of innate immunity.

Previous studies have demonstrated that mesenchymal stromal cells (MSCs) enhance cell survival through upregulation and secretion of stanniocalcin-1 (STC1). This study shows that MSC-derived STC1 promotes survival of lung cancer cells by uncoupling oxidative phosphorylation, reducing intracellular reactive oxygen species (ROS), and shifting metabolism towards a more glycolytic metabolic profile. MSC-derived STC1 upregulated uncoupling protein 2 (UCP2) in injured A549 cells in an STC1-dependent manner. Knockdown of UCP2 reduced the ability of MSCs and recombinant STC1 (rSTC1) to reduce cell death in the A549 population. rSTC1-treated A549 cells displayed decreased levels of ROS, mitochondrial membrane potential (MMP), and increased lactate production, all of which were dependent on the upregulation of UCP2. Our data suggest that MSCs can promote cell survival by regulating mitochondrial respiration via STC1.