Molecular Programming of Tumor-Infiltrating CD8+ T Cells and IL15 Resistance.

Despite clinical potential and recent advances, durable immunotherapeutic ablation of solid tumors is not routinely achieved. IL15 expands natural killer cell (NK), natural killer T cell (NKT) and CD8(+) T-cell numbers and engages the cytotoxic program, and thus is under evaluation for potentiation of cancer immunotherapy. We found that short-term therapy with IL15 bound to soluble IL15 receptor α-Fc (IL15cx; a form of IL15 with increased half-life and activity) was ineffective in the treatment of autochthonous PyMT murine mammary tumors, despite abundant CD8(+) T-cell infiltration.

The Diagnostic Significance of a Mucocele of the Appendix.

Appendiceal mucoceles are rare lesions with a variable clinical presentation often identified incidentally on imaging or at laparotomy/laparoscopy for an unrelated diagnosis. Mucocele of the appendix may be a benign or malignant process, making early recognition based on symptoms and key radiographic characteristics of the utmost importance for optimal patient management. Here we present the case of a patient presenting with non-specific abdominal complaints suffering from appendiceal mucocele perforation due to low-grade mucinous adenocarcinoma.

Ex vivo interleukin-12-priming during CD8(+) T cell activation dramatically improves adoptive T cell transfer antitumor efficacy in a lymphodepleted host.

Background: Clinical application of adoptive T cell therapy has been hindered by an inability to generate adequate numbers of nontolerized, functionally active, tumor-specific T cells, which can persist in vivo. In order to address this, we evaluated the impact of interleukin (IL)-12 signaling during tumor-specific CD8(+) T cell priming in terms of persistence and antitumor efficacy using an established B16 melanoma tumor adoptive therapy model.

Study Design: B6 mice were injected subcutaneously with B16 melanoma tumor cells.

Isoform-specific modulation of pressure-stimulated cancer cell proliferation and adhesion by α-actinin.

Background: Intratumoral pressure may stimulate cancer proliferation whereas intravascular pressure promotes metastatic adhesion. α-Actinin proteins facilitate focal adhesion formation and link focal adhesion complexes to the cytoskeleton. We hypothesized that α-actinin is the mechanotransducer that mediates the effects of pressure on cancer cell proliferation and adhesion.

ERK regulates strain-induced migration and proliferation from different subcellular locations.

Repetitive deformation like that engendered by peristalsis or villous motility stimulates intestinal epithelial proliferation on collagenous substrates and motility across fibronectin, each requiring ERK. We hypothesized that ERK acts differently at different intracellular sites. We stably transfected Caco-2 cells with ERK decoy expression vectors that permit ERK activation but interfere with its downstream signaling.

beta(1)-integrin mediates pressure-stimulated phagocytosis.

Background: Extracellular pressure alterations in infection, inflammation, or positive pressure ventilation may influence macrophage phagocytosis. We hypothesized that pressure modulates beta1-integrins to stimulate phagocytosis.

Methods: We assayed fibroblast phagocytosis of fluorescent latex beads at ambient or 20 mm Hg increased pressure, and macrophage integrin phosphorylation by Western blot.

Increased extracellular pressure provides a novel adjuvant stimulus for enhancement of conventional dendritic cell maturation strategies.

Dendritic cell (DC)-based vaccine strategies have gained increasing popularity in recent years. Methods for ex vivo generation of immunocompetent mature DCs still require optimization. DCs have been shown to phenotypically mature under elevated pressure.

Irrigant divalent cation concentrations influence bacterial adhesion.

Background: Surgical wounds are frequently contaminated by microbes, but rarely become infected if the bacterial burden is low, and irrigation is used to reduce contamination. Wound fluids are low in calcium and high in magnesium. We hypothesized that manipulating irrigant divalent cation concentrations might influence bacterial adhesion.

The effects of increased extracellular deformation, pressure, and integrin phosphorylation on fibroblast migration.

Wound healing requires fibroblast migration. Increased pressure slows migration and ulcer healing. Pressure also induces beta1 integrin phosphorylation.

Biological impact of mechanical stimuli on tumor metastasis.

Increasing evidence suggests tumor cell exposure to mechanical stimuli during the perioperative period as well as throughout the normal disease process may have a discernable impact on tumor metastasis and patient outcome. In vitro studies have demonstrated that transient exposure to increased extracellular pressure and shear forces modulates integrin binding affinity and stimulates cancer cell adhesion through a cytoskeleton- and focal adhesion complex-dependent signaling mechanism. More prolonged exposure to elevated pressures stimulates tumor cell proliferation by a distinct signaling pathway.

Strain-induced proliferation requires the phosphatidylinositol 3-kinase/AKT/glycogen synthase kinase pathway.

The intestinal epithelium is repetitively deformed by shear, peristalsis, and villous motility. Such repetitive deformation stimulates the proliferation of intestinal epithelial cells on collagen or laminin substrates via ERK, but the upstream mediators of this effect are poorly understood. We hypothesized that the phosphatidylinositol 3-kinase (PI3K)/AKT cascade mediates this mitogenic effect.

Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of beta1-integrin at threonine 788/789.

Increased extracellular pressure stimulates beta1-integrin-dependent cancer cell adhesion. We asked whether pressure-induced adhesion is mediated by changes in beta1-integrin binding affinity or avidity and whether these changes are phosphorylation dependent. We evaluated integrin affinity and clustering in human SW620 colon cancer cells by measuring differences in binding between soluble Arg-Gly-Asp (RGD)-Fc ligands and RGD-Fc-F(ab')2 multimeric complexes under ambient and 15-mmHg increased pressures.

Colchicine inhibits pressure-induced tumor cell implantation within surgical wounds and enhances tumor-free survival in mice.

Iatrogenic tumor cell implantation within surgical wounds can compromise curative cancer surgery. Adhesion of cancer cells, in particular colon cancer cells, is stimulated by exposure to increased extracellular pressure through a cytoskeleton-dependent signaling mechanism requiring FAK, Src, Akt, and paxillin. Mechanical stimuli during tumor resection may therefore negatively impact patient outcome.

SiRNA-mediated reduction of alpha-actinin-1 inhibits pressure-induced murine tumor cell wound implantation and enhances tumor-free survival.

Viable cancer cells can commonly be recovered from surgical sites and venous blood during tumor resection. The adhesion of these cells to surrounding tissues may impact patient outcomes. Iatrogenic exposure to increased extracellular pressure modulates integrin binding affinity and stimulates colon cancer cell adhesion in vitro through an alpha-actinin-1-dependent signaling pathway.

Increased pressure stimulates aberrant dendritic cell maturation.

Patients with malignancy typically exhibit abnormal dendritic cell profiles. Interstitial tumor pressure is increased 20-50 mmHg over that in normal tissue. We hypothesized that elevated pressure in the tumor microenvironment may influence dendritic cell (DC) phenotype and function.

Cytoskeletal signaling by way of alpha-actinin-1 mediates ERK1/2 activation by repetitive deformation in human Caco2 intestinal epithelial cells.

Background: Repetitive deformation stimulates proliferation in human Caco2 intestinal epithelial cells by way of an ERK1/2-dependent pathway. We examined the effects of cytoskeletal perturbation on deformation-induced signaling in Caco2 cells.

Methods: The Caco2 cell cytoskeleton was disrupted with either cytochalasin D, phalloidin, colchicine, or paclitaxel.

Alpha-actinin-1 phosphorylation modulates pressure-induced colon cancer cell adhesion through regulation of focal adhesion kinase-Src interaction.

Physical forces including pressure, strain, and shear can be converted into intracellular signals that regulate diverse aspects of cell biology. Exposure to increased extracellular pressure stimulates colon cancer cell adhesion by a beta(1)-integrin-dependent mechanism that requires an intact cytoskeleton and activation of focal adhesion kinase (FAK) and Src. alpha-Actinin facilitates focal adhesion formation and physically links integrin-associated focal adhesion complexes with the cytoskeleton.

FAK association with multiple signal proteins mediates pressure-induced colon cancer cell adhesion via a Src-dependent PI3K/Akt pathway.

Cancer cell adhesion is traditionally viewed as random, occurring if the cell's receptors match the substrate. Cancer cells are subjected to pressure and shear during growth against a constraining stroma, surgical manipulation, and passage through the venous and lymphatic system. Cells shed into a cavity such as the abdomen postoperatively also experience increased pressure from postoperative edema.