tetrodotoxin and Adenocarcinoma

Tumor fluid accumulation occurs in both human cancer and experimental tumor models. Solid tumors show a tendency to tumor fluid accumulation because of their anatomical and physiological features and this may be influenced by molecular factors. Fluid accumulation in the peri-tumor area also occurs in the Dunning model of rat prostate cancer as the tumor grows. In this study, the effects of tumor fluids that were obtained from Dunning prostate tumor-bearing Copenhagen rats on the strongly metastatic MAT-LyLu cell line were investigatedby examining the cell's migration and tumor fluid's toxicity and the kinetic parameters such as cell proliferation, mitotic index, and labelling index. In this research, tumor fluids were obtained from rats injected with 25105 MAT- LyLu cells and treated with saline solution, and 200 nM tetrodotoxin (TTX), highly specific sodium channel blocker was used. Sterilized tumor fluids were added to medium of MAT-LyLu cells with the proportion of 20% in vitro. Consequently, it was demonstrated that Dunning rat prostate tumor fluid significantly inhibited proliferation (up to 50%), mitotic index, and labeling index of MAT-LyLu cells (up to 75%) (p<0.05) but stimulated the motility of the cells in vitro.

Topics: Adenocarcinoma; Animals; Cell Proliferation; Extracellular Fluid; Humans; Lung Neoplasms; Male; Mitotic Index; Neoplasms, Experimental; Prostate; Prostatic Neoplasms; Rats; Sodium Channel Blockers; Tetrodotoxin; Tumor Cells, Cultured

Retrospective analysis of patients undergoing cancer surgery suggests the use of regional anesthesia may reduce cancer recurrence and improve survival. Amide-linked local anesthetics have antiinflammatory properties, although the mechanism of action in this regard is unclear. As inflammatory processes involving Src tyrosine protein kinase and intercellular adhesion molecule-1 are important in tumor growth and metastasis, we hypothesized that amide-linked local anesthetics may inhibit inflammatory Src-signaling involved in migration of adenocarcinoma cells.. NCI-H838 lung cancer cells were incubated with tumor necrosis factor-α in absence/presence of ropivacaine, lidocaine, or chloroprocaine (1 nM-100 μM). Cell migration and total cell lysate Src-activation and intercellular adhesion molecule-1 phosphorylation were assessed. The role of voltage-gated sodium-channels in the mechanism of local anesthetic effects was also evaluated.. Ropivacaine treatment (100 μM) of H838 cells for 20 min decreased basal Src activity by 62% (P=0.003), and both ropivacaine and lidocaine coadministered with tumor necrosis factor-α statistically significantly decreased Src-activation and intercellular adhesion molecule-1 phosphorylation, whereas chloroprocaine had no such effect. Migration of these cells at 4 h was inhibited by 26% (P=0.005) in presence of 1 μM ropivacaine and 21% by 1 μM lidocaine (P=0.004). These effects of ropivacaine and lidocaine were independent of voltage-gated sodium-channel inhibition.. This study indicates that amide-, but not ester-linked, local anesthetics may provide beneficial antimetastatic effects. The observed inhibition of NCI-H838 cell migration by lidocaine and ropivacaine was associated with the inhibition of tumor necrosis factor-α-induced Src-activation and intercellular adhesion molecule-1 phosphorylation, providing the first evidence of a molecular mechanism that appears to be independent of their known role as sodium-channel blockers.

Topics: Adenocarcinoma; Amides; Anesthetics, Local; Cell Line, Tumor; Cell Movement; Humans; Intercellular Adhesion Molecule-1; Lidocaine; Lung Neoplasms; Neoplasm Metastasis; Phosphorylation; Procaine; Retrospective Studies; Ropivacaine; Signal Transduction; Sodium Channel Blockers; src-Family Kinases; Tetrodotoxin; Veratridine

Pulsatile secretion of gonadotropin-releasing hormone-1 (GnRH-1) is essential for reproduction. GnRH-1 induces gonadotropin release and is regulated by 17beta-estradiol (E2). Although a subpopulation of GnRH-1 neurons expresses estrogen receptor (ER) beta, it is unclear whether E2 acts directly on GnRH-1 neurons or indirectly through interneuronal connections. To test the hypothesis that E2 acts directly on GnRH-1 neurons to regulate neuronal activity, we used calcium imaging to monitor intracellular calcium oscillations in GnRH-1 neurons maintained in nasal explants. TTX was used to minimize synaptic input from other cells. Consistent with previous studies, TTX reduced the activity of individual GnRH-1 neurons to a basal level, while the population of cells maintained synchronized calcium oscillations. Exposure of GnRH-1 cells to TTX plus E2 increased the number of calcium peaks/cell, percentage of cells with > or =10 peaks, mean peak amplitude, and percentage of cells that contributed to each calcium pulse in explants maintained in vitro for 7 d (7 div) compared with TTX alone. These effects were induced within 30 min and were not mimicked by 17alpha-estradiol, E2 conjugated to BSA (which does not cross the plasma membrane), or seen at 21 div, when the percentage of GnRH-1 cells expressing ERbeta transcripts declines. In addition, these effects were inhibited by the ER antagonist ICI 182,780 and prevented by inhibition of gene transcription. These data suggest that, via ERbeta, E2 can rapidly act as a hormone-activated transcription complex and are the first to show that E2 directly increases GnRH-1 neuronal activity and synchronization.

Topics: Adenocarcinoma; Animals; Breast Neoplasms; Calcium; Calcium Signaling; Estradiol; Estrogen Receptor beta; Estrogen Receptor Modulators; Female; Fluorescent Dyes; Fulvestrant; Gonadotropin-Releasing Hormone; Humans; Mice; Nasal Mucosa; Neurons; Organ Culture Techniques; Organic Chemicals; Secretory Rate; Sodium Channel Blockers; Tetrodotoxin; Transcription, Genetic