Cellular microparticles are vesicular plasma membrane fragments with a diameter of 100-1,000 nanometres that are shed by cells in response to various physiological and artificial stimuli. Here we demonstrate that tumour cell-derived microparticles can be used as vectors to deliver chemotherapeutic drugs. We show that tumour cells incubated with chemotherapeutic drugs package these drugs into microparticles, which can be collected and used to effectively kill tumour cells in murine tumour models without typical side effects. We describe several mechanisms involved in this process, including uptake of drug-containing microparticles by tumour cells, synthesis of additional drug-packaging microparticles by these cells that contribute to the cytotoxic effect and the inhibition of drug efflux from tumour cells. This study highlights a novel drug delivery strategy with potential clinical application.

Lipid rafts, the sphingolipid and cholesterol-enriched membrane microdomains, are able to form different membrane macrodomains or platforms upon stimulations, including redox signaling platforms, which serve as a critical signaling mechanism to mediate or regulate cellular activities or functions. In particular, this raft platform formation provides an important driving force for the assembling of NADPH oxidase subunits and the recruitment of other related receptors, effectors, and regulatory components, resulting, in turn, in the activation of NADPH oxidase and downstream redox regulation of cell functions. This comprehensive review attempts to summarize all basic and advanced information about the formation, regulation, and functions of lipid raft redox signaling platforms as well as their physiological and pathophysiological relevance. Several molecular mechanisms involving the formation of lipid raft redox signaling platforms and the related therapeutic strategies targeting them are discussed. It is hoped that all information and thoughts included in this review could provide more comprehensive insights into the understanding of lipid raft redox signaling, in particular, of their molecular mechanisms, spatial-temporal regulations, and physiological, pathophysiological relevances to human health and diseases. Antioxid. Redox Signal. 15, 1043-1083.

Gluconeogenesis is a fundamental feature of hepatocytes. Whether this gluconeogenic activity is also present in malignant hepatocytes remains unexplored. A better understanding of this biological process may lead to novel therapeutic strategies. Here we show that gluconeogenesis is not present in mouse or human malignant hepatocytes. We find that two critical enzymes 11b-HSD1 and 11b-HSD2 that regulate glucocorticoid activities are expressed inversely in malignant hepatocytes, resulting in the inactivation of endogenous glucocorticoids and the loss of gluconeogenesis. In patients' hepatocarcinoma, the expression of 11b-HSD1 and 11b-HSD2 is closely linked to prognosis and survival. Dexamethasone, an active form of synthesized glucocorticoids, is capable of restoring gluconeogenesis in malignant cells by bypassing the abnormal regulation of 11b-HSD enzymes, leading to therapeutic efficacy against hepatocarcinoma. These findings clarify the molecular basis of malignant hepatocyte loss of gluconeogenesis and suggest new therapeutic strategies.

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Mast cells are of paramount importance to allergies, pathogen immune responses during infections, and angiogenesis, as well as innate and adaptive immune regulations. Beyond all these roles, mast cells are now more and more being recognized as modulators of tumor microenvironment. Notwithstanding mounting evidences of mast cell accumulation in tumors, their exact role in tumor microenvironment is still incompletely understood. In this review, we discuss the significant role of mast cells in the remodeling of tumor microenvironment by either releasing various factors after activation or interacting with other cells within tumor and, as a result, the possible role of mast cell in cancer invasion and metastasis. We also discuss recent findings that mast cells actively release microparticles, which account for the transfer of membrane-type receptor signal and regulatory molecules such as microRNAs to tumor cells and immune cells. These findings on mast cells provide further insights into the complexity of tumor microenvironment remodeling.

Mechanisms by which tumor cells metastasize to distant organs still remain enigmatic. Immune cells have been assumed to be the root of metastasis by their fusing with tumor cells. This fusion theory, although interpreting tumor metastasis analogically and intriguingly, is arguable to date. We show in this study an alternative explanation by immune cell–derived microparticles (MPs). Upon stimulation by PMA or tumor cell–derived supernatants, immune cells released membrane-based MPs, which were taken up by H22 tumor cells, leading to tumor cell migration in vitro and metastasis in vivo. The underlying molecular basis was involved in integrin αMβ2 (CD11b/CD18), which could be effectively relayed from stimulated innate immune cells to MPs, then to tumor cells. Blocking either CD11b or CD18 led to significant decreases in MP-mediated tumor cell metastasis. This MP-mediated transfer of immune phenotype to tumor cells might also occur in vivo. These findings suggest that tumor cells may usurp innate immune cell phenotypes via MP pathway for their metastasis, providing new insight into tumor metastatic mechanism.

Despite various suspected causes, ranging from endocrine and genetic to infectious and immunological aspects, the molecular mechanisms of miscarriage still remain enigmatic. This work provides evidence that downregulation of 11β-hydroxysteroid dehydrogenase (HSD) type 2, the key enzyme inactivating glucocorticoid activities, insults the pregnant inflammatory milieu by inhibiting the biosynthesis of lipoxin A4 (LXA4), a metabolite of arachidonic acid, leading to an early loss of the pregnancy. Both LXA4 and its biosynthetic enzymes were found to be decreased in women with spontaneous miscarriages and in the murine miscarriage model. Replenishing LXA4 reversed LPS-induced miscarriages in mouse models, whereas blocking LXA4 signaling resulted in miscarriages in the pregnant mice. The protective effect of LXA4 might be explained by LXA4’s role in regulating uterine and placental inflammatory factors and mast cells. The underlying molecular mechanism involved miscarriage-inducing infections or stresses that downregulate the expression of 11β-HSD2, but not 11β-HSD1, resulting in increases in glucocorticoid activity and decreases in LXA4. Together, these findings suggest that the stress/glucocorticoid/LXA4 axis might be a common pathway through which miscarriages occur.

PurposeThis study is to develop a new suturing technique for flexor tendon repair by modifying the extant Tsuge repair techniques and to use biomechanical analysis to compare the new method with four established repair techniques and evaluate its clinical efficacy in the repair of 47 flexor tendons in 22 patients.MethodsThe biomechanical analysis relied on 50 flexor digitorum profundus tendons harvested from fresh cadavers. The tendons were randomly divided into five groups, transected, and repaired by use of a 1. double-loop suture, 2. double modified locking Kessler, 3. four-strand Savage, 4. modified six-strand Savage, and 5. the new technique. The tensile force and breaking force of all repaired tendons were measured by static loading trials. For clinical application, 22 patients with acute flexor tendon injuries were treated with the new modified Tsuge suture and follow-up for more than 12 months.ResultsWhile differences in the tensile force and breaking force in the modified Tsuge sutures and modified six-strand Savage sutures were not statistically significant, static loading trials showed the tensile force, in the form of a 2-mm gap formation, and the breaking force of the new modified Tsuge sutures were, statistically, both higher than the ones characteristic of double-loop sutures, double modified locking Kessler, and four-strand Savage sutures. After 12 months, restored functions were observed in all the patients during the postoperative 12 months. Total active motion (TAM) score demonstrated that more than 90% fingers were estimated as excellent or good.ConclusionThe new modified Tsuge sutures described here have evident higher tensile and breaking forces compared to other four-strand core suture techniques, suggesting, in turn, that this new technique is a good alternative for flexor tendon repairs in clinical applications.