Production of levan from Bacillus subtilis var. natto and apoptotic effect on SH-SY5Y neuroblastoma cells.

Levan is a high-valued polysaccharide of fructose produced by several microbial species. These polysaccharides have been described as effective therapeutic agents in some human disease conditions, such as cancer, heart diseases and diabetes. The objective of this study was to examine the effect of levan (ß-(2 â†’ 6)-fructan) produced through sucrose fermentation by B. subtilis var. natto on the proliferation rate, cytotoxicity, and apoptosis of human neuroblastoma SH-SY5Y cells. It was obtained 41.44 g/L of levan in 18 h by biotechnological fermentation and SH-SY5Y cells were exposed to 1000 µg/mL of levan. The treatment with 1000 µg/mL of levan induced apoptosis in SH-SY5Y cancer cells by the significant increase in Annexin V/7-AAD and caspase 3/7 activation, but did not decrease proliferation or triggered a cytotoxic effect. 1000 µg/mL levan treatment is a promising therapeutic strategy for SH-SY5Y neuroblastoma cells.

Synthesis of novel purpurealidin analogs and evaluation of their effect on the cancer-relevant potassium channel KV10.1.

In the search for novel anticancer drugs, the potassium channel KV10.1 has emerged as an interesting cancer target. Here, we report a new group of KV10.1 inhibitors, namely the purpurealidin analogs. These alkaloids are produced by the Verongida sponges and are known for their wide variety of bioactivities. In this study, we describe the synthesis and characterization of 27 purpurealidin analogs. Structurally, bromine substituents at the central phenyl ring and a methoxy group at the distal phenyl ring seem to enhance the activity on KV10.1. The mechanism of action of the most potent analog 5 was investigated. A shift of the activation curve to more negative potentials and an apparent inactivation was observed. Since KV10.1 inhibitors can be interesting anticancer drug lead compounds, the effect of 5 was evaluated on cancerous and non-cancerous cell lines. Compound 5 showed to be cytotoxic and appeared to induce apoptosis in all the evaluated cell lines.

Rationally co-targeting divergent pathways in KRAS wild-type colorectal cancers by CANscript technology reveals tumor dependence on Notch and Erbb2.

KRAS mutation status can distinguish between metastatic colorectal carcinoma (mCRC) patients who may benefit from therapies that target the epidermal growth factor receptor (EGFR), such as cetuximab. However, patients whose tumors harbor mutant KRAS (codons 12/13, 61 and 146) are often excluded from EGFR-targeted regimens, while other patients with wild type KRAS will sometimes respond favorably to these same drugs. These conflicting observations suggest that a more robust approach to individualize therapy may enable greater frequency of positive clinical outcome for mCRC patients. Here, we utilized alive tumor tissues in ex-vivo platform termed CANscript, which preserves the native tumor heterogeneity, in order to interrogate the antitumor effects of EGFR-targeted drugs in mCRC (n = 40). We demonstrated that, irrespective of KRAS status, cetuximab did not induce an antitumor response in a majority of patient tumors. In the subset of non-responsive tumors, data showed that expression levels of EGFR ligands contributed to a mechanism of resistance. Transcriptomic and phosphoproteomic profiling revealed deregulation of multiple pathways, significantly the Notch and Erbb2. Targeting these nodes concurrently resulted in antitumor efficacy in a majority of cetuximab-resistant tumors. These findings highlight the importance of integrating molecular profile and functional testing tools for optimization of alternate strategies in resistant population.

Potassium channels in cell cycle and cell proliferation.

Normal cell-cycle progression is a crucial task for every multicellular organism, as it determines body size and shape, tissue renewal and senescence, and is also crucial for reproduction. On the other hand, dysregulation of the cell-cycle progression leading to uncontrolled cell proliferation is the hallmark of cancer. Therefore, it is not surprising that it is a tightly regulated process, with multifaceted and very complex control mechanisms. It is now well established that one of those mechanisms relies on ion channels, and in many cases specifically on potassium channels. Here, we summarize the possible mechanisms underlying the importance of potassium channels in cell-cycle control and briefly review some of the identified channels that illustrate the multiple ways in which this group of proteins can influence cell proliferation and modulate cell-cycle progression.