Simultaneous assessment of migration and proliferation of murine fibrosarcoma cells, as affected by hydroxyurea, vinblastine, cytochalasin B, Razoxane and interferon

IL-6/STAT3/TFF3 signaling regulates human biliary epithelial cell migration and wound healing in vitro

Interleukin-6 (IL-6), through activation of the signal transducer and activator of transcription 3 (STAT3) and trefoil factor family 3 (TFF3), has been implicated in the promotion of mouse biliary epithelial cell (BEC) proliferation and migration. However, it is still unclear whether the IL-6/STAT3/TFF3 signaling had similar effects on human BECs. Here, we showed that exposure of human BECs to recombinant IL-6 resulted in STAT3 phosphorylation and increased the expression of TFF3 at both mRNA and protein levels. Moreover, inhibition of STAT3 using RNA interference significantly abrogated IL-6-induced TFF3 expression. In an in-vitro wound healing model, IL-6 facilitated human BEC migration. This promotion of cell migration by IL-6 was blocked when STAT3 was knocked down. Interestingly, the addition of exogenous TFF3 could rescue the cell migration defects caused by STAT3 silencing. In conclusion, our data indicate that STAT3 plays a critical role in IL-6-induced TFF3 expression in human BECs and the IL-6/STAT3/TFF3 signaling is involved in human BEC migration and wound healing.

Pseudomonas aeruginosa, under DNA replication inhibition, tends to form biofilms via Arr

Bacteria infecting eukaryotic hosts often encounter therapeutic antimicrobial and DNA damaging agents and respond by forming biofilms. While mechanisms of biofilm response are incompletely understood, they seem to involve bacterial second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) signaling. We hypothesized that DNA replication inhibition induces bacterial biofilm formation via c-di-GMP signaling. Evidently, we found that Pseudomonas aeruginosa mounted a biofilm response to the subinhibitory DNA replication inhibitors hydroxyurea and nalidixic acid, but planktonic proliferation was inhibited. The biofilm response was suppressed either genetically by mutations causing planktonic resistance or biochemically by reversal of replication inhibition. Biofilms were induced by a mechanism of stimulated adhesion of planktonic filaments having impaired DNA replication, as examined under fluorescence microscopy. Induction was suppressed by either inhibition or mutation of Arr-a c-di-GMP phosphodiesterase. These results suggest that P. aeruginosa, under DNA replication stress, tends to form biofilms via Arr. The profound implications of the SOS response, planktonic-sessile and bacteria-cancer relationships are discussed.

Combined vindesine and razoxane shows antimetastatic activity in advanced soft tissue sarcomas

BACKGROUND

Razoxane and vindesine were shown to suppress distant metastasis in animal systems. Both drugs affect main steps of the metastatic cascade. Therefore, a pilot study was performed to study the influence of these drugs on the dynamics of metastasis in advanced soft tissue sarcomas (STS). This study was now updated.

METHODS

Twenty-three patients with unresectable (n = 7) and oligometastatic STS (n = 16) received a basic treatment with razoxane and vindesine supported by radiotherapy and occasionally by surgery. Long-term treatment was intended in patients with metastatic disease. The cumulative number of new metastases after 6 and 9 months were determined. Thirty-six patients with comparable stages of STS treated with contemporary chemotherapy served as non-randomized, retrospective controls. The prognostic parameters of the groups were comparable.

RESULTS

In patients receiving razoxane and vindesine, the median number of new metastases after 6 months was 0 (range, 0-40) and after 9 months likewise 0 (0-70). The corresponding numbers in the control group were 4.5 (range, 0-40) and 9 (0->100) (P < 0.001). The progression-free survival at 6 months was 74% in the study group and 23% in the controls. The median survival time from the occurrence of the first metastasis or the time of unresectability was 20+ months (range, 8-120+) versus 9 months (range, 2-252) (P < 0.001). The combined treatment was associated with a low to moderate toxicity.

CONCLUSIONS

Trimodal treatment with razoxane, vindesine, and radiotherapy is feasible in patients with unresectable primaries and early metastatic STS. The combination inhibits the development of remote metastases in a majority of the patients and prolongs survival.

Prevention of entrance into G2 cell cycle phase by mimosine decreases locomotion of cells from the tumor cell line SW480

Cellular proliferation of tumor cells is thought to impede migratory activity. Using continuous single cell migration analysis of the colon carcinoma cell line SW480 for up to 72 h, we were able to show that cells locomote constantly and stop only for actual cell division. These findings indicate that proliferation (from G1 phase to early mitosis) and migration do occur simultaneously. The presence of the cell cycle marker Ki-67 in individual migrating cells substantiated this observation. Inhibition of cell cycle progression by mimosine (MIM), a reversible cell cycle blocker, reduced the percentage of migrating cells; release from MIM block restored migratory capacity. The corresponding cell cycle phase distributions were confirmed by flow cytometry. In our test system cell cycle events and migration were shown to occur at the same time. Interference with cell cycle progression reduced migratory activity indicating that migration depends on an unhampered cell cycle.