NKP-1339 is the first-in-class ruthenium-based anticancer drug in clinical development against solid cancer and has recently been studied successfully in a phase I clinical trial. Ruthenium compounds ...such as KP1019 (indazolium
trans
-tetrachloridobis(1
H
-indazole)ruthenate(
iii
)) and NKP-1339 (the sodium salt analogue of KP1019, sodium
trans
-tetrachloridobis(1
H
-indazole)ruthenate(
iii
)) have a high tumour targeting potential based (1) on their strong binding to serum proteins such as albumin and transferrin as well as (2) on their activation in the reductive tumour milieu. The redox activity of ruthenium compounds is believed to represent one major mode of action leading to disturbance of the cellular redox balance and, consequently, induction of G
2
/M cell cycle arrest, blockage of DNA synthesis, and induction of apoptosis
via
the mitochondrial pathway. Moreover, potent synergistic activities of NKP-1339 with the clinically approved tyrosine kinase inhibitor sorafenib were recently reported
in vitro
and
in vivo
. Taken together, KP1019 and NKP-1339 are promising drug candidates, and especially the very limited side effects observed so far in clinical phase I trials seem to be a major advantage of this class of ruthenium drugs as compared to other chemotherapeutics and targeted anticancer compounds.
A résumé with outlooks of the chemical/pharmacological investigations and ongoing clinical development of a prototypic ruthenium-based anticancer compound.
A climate chamber experiment was conducted to assay the effect of low temperatures (chilling) on the diversity of bacteria colonizing the endospheres of two thermophilic sweet pepper (Capsicum anuum ...L.) cultivars, Milder Spiral and Ziegenhorn Bello. Structural diversity was analyzed by 16S rRNA-based terminal restriction fragment length polymorphism (T-RFLP) analysis and by the generation of 16S rRNA gene libraries to determine dominant community members in T-RFLP profiles. Cultivable community members colonizing lines Milder Spiral and Ziegenhorn Bello were identified by 16S rRNA gene analysis. T-RFLP profiles and 16S rRNA gene libraries revealed a high heterogeneity of community composition due to chilling and suggested further the existence of cultivar-specific communities. The majority of isolates obtained from the cultivar Milder Spiral were assigned as high-G+C Gram-positive bacteria (Microbacterium sp., Micrococcus sp., Rhodococcus sp.) and Firmicutes (Staphylococcus sp.). Of the isolated endophytes obtained from cultivar Zeigenhorn Bello, 93% were affiliated with Staphylococcus aureus and Bacillus sp. (Firmicutes). The experimental set-up was suited to demonstrate that chilling and cultivar type can influence the diversity of bacterial endophytes colonizing sweet pepper. We propose additional chilling experiments to investigate the effect of chilling on functional, plant-beneficial abilities of bacterial endophytes associated with low-temperature-sensitive crops, such as sweet pepper.Key words: chilling, thermophilic sweet pepper, bacterial endophyte diversity, 16S rRNA gene analysis.
Sodium
trans
-tetrachloridobis(1
H
-indazole)ruthenate(III) (NKP-1339) is a clinically investigated ruthenium-based metal complex, which shows promising results in solid tumors, such as non-small ...cell lung cancer, colorectal carcinoma, and most distinctively in gastrointestinal neuroendocrine tumors. In previous studies, fast binding to albumin as well as transferrin could be shown. The enhanced permeability and retention (EPR) effect, which is diversely being exploited for tumor targeting, could therefore be applicable for NKP-1339. Here we studied the serum dependence of its biological activity in various methods, influencing its cellular accumulation, cytotoxicity as well as the generation of reactive oxygen species (ROS). ROS lead to Nrf2 activation, which is known to activate antioxidant response gene transcription. GRP78 down-regulation on the protein level suggests ER associated protein degradation (ERAD) as a mode of action, as RNA levels are only mildly affected. Another important part for the mode of action is endoplasmic reticulum (ER) stress, as different factors are highly upregulated on the protein level. For example PERK, a transmembrane receptor which is released by GRP78 when the ER is disturbed, is upregulated and phosphorylated. EIF2α is phosphorylated, which leads to an inhibition of CAP-dependent translation and other stress responses. The transcription factor CHOP (DDIT3), which promotes ER stress dependent apoptosis, is time and concentration dependently upregulated. Finally cytotoxicity tests could prove that inhibition of ER stress and ER stress-mediated apoptosis leads to decreased cytotoxic effects of NKP-1339, which highlights the involvement of this mechanism in the mode of action.
Transient, multi-protein complexes are important facilitators of cellular functions. This includes the chaperome, an abundant protein family comprising chaperones, co-chaperones, adaptors, and ...folding enzymes-dynamic complexes of which regulate cellular homeostasis together with the protein degradation machinery. Numerous studies have addressed the role of chaperome members in isolation, yet little is known about their relationships regarding how they interact and function together in malignancy. As function is probably highly dependent on endogenous conditions found in native tumours, chaperomes have resisted investigation, mainly due to the limitations of methods needed to disrupt or engineer the cellular environment to facilitate analysis. Such limitations have led to a bottleneck in our understanding of chaperome-related disease biology and in the development of chaperome-targeted cancer treatment. Here we examined the chaperome complexes in a large set of tumour specimens. The methods used maintained the endogenous native state of tumours and we exploited this to investigate the molecular characteristics and composition of the chaperome in cancer, the molecular factors that drive chaperome networks to crosstalk in tumours, the distinguishing factors of the chaperome in tumours sensitive to pharmacologic inhibition, and the characteristics of tumours that may benefit from chaperome therapy. We find that under conditions of stress, such as malignant transformation fuelled by MYC, the chaperome becomes biochemically 'rewired' to form a network of stable, survival-facilitating, high-molecular-weight complexes. The chaperones heat shock protein 90 (HSP90) and heat shock cognate protein 70 (HSC70) are nucleating sites for these physically and functionally integrated complexes. The results indicate that these tightly integrated chaperome units, here termed the epichaperome, can function as a network to enhance cellular survival, irrespective of tissue of origin or genetic background. The epichaperome, present in over half of all cancers tested, has implications for diagnostics and also provides potential vulnerability as a target for drug intervention.
Intracellular generation of reactive oxygen species (ROS) via thiol-mediated reduction of copper(II) to copper(I) has been assumed as the major mechanism underlying the anticancer activity of ...copper(II) complexes. The aim of this study was to compare the anticancer potential of copper(II) complexes of Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone; currently in phase II clinical trials) and its terminally dimethylated derivative with that of 2-formylpyridine thiosemicarbazone and that of 2,2′-bipyridyl-6-carbothioamide. Experiments on generation of oxidative stress and the influence of biologically relevant reductants (glutathione, ascorbic acid) on the anticancer activity of the copper complexes revealed that reductant-dependent redox cycling occurred mainly outside the cells, leading to generation and dismutation of superoxide radicals resulting in cytotoxic amounts of H
2
O
2
. However, without extracellular reductants only weak intracellular ROS generation was observed at IC
50
levels, suggesting that cellular thiols are not involved in copper-complex-induced oxidative stress. Taken together, thiol-induced intracellular ROS generation might contribute to the anticancer activity of copper thiosemicarbazone complexes but is not the determining factor.
Pancreatic cancer (PC) ranks among the deadliest malignancies worldwide. In the MPACT study, first-line nab-paclitaxel plus gemcitabine (nab-P/G) demonstrated activity (median overall survival OS, ...8.7 months) and tolerability in patients with metastatic PC (mPC). However, the clinical evidence of nab-P/G in the elderly (>70 years), who account for the majority of patients with mPC, is limited. This is the first prospective, multicentre, non-interventional study evaluating the tolerability and effectiveness of nab-P/G in younger (≤70 years) versus elderly (>70 years) patients with mPC in the daily clinical routine.
Eligible patients with mPC were treated with nab-P/G and observed until disease progression or unacceptable toxicity. The primary objectives were safety and tolerability of nab-P/G, and the secondary objectives were efficacy and real-life dosing.
A total of 317 patients with mPC (median age, 70 years) were recruited, of which 299, aged ≤70 (n = 162) and >70 (n = 137) years, were eligible for analysis. Baseline characteristics and the safety profile were comparable between the groups. However, fatigue (22.8% versus 13.0%) and decreased appetite (8.8% versus 1.2%) were more frequent in elderly patients. Younger versus elderly patients equally benefited in terms of objective response rate (36% versus 48%), median progression-free survival (5.6 versus 5.5 months; hazard ratio HR = 1.03; p = 0.81) and OS (10.6 versus 10.2 months; HR = 0.89; p = 0.4). In addition, the median treatment duration (5 versus 4 cycles), relative dose intensity (70% versus 74%) or reasons for treatment discontinuation were similar. Most patients (56.2% versus 47.4%) benefited from a second-line therapy.
This prospective real-world analysis confirms the feasibility and tolerability of nab-P/G treatment and reveals OS data similar for younger patients and elderly patients aged >70 years.
NCT02555813.
NIS005071.
•This is a prospective non-interventional study evaluating nab-paclitaxel and gemcitabine in metastatic pancreatic cancer (mPC).•The study includes a large cohort of elderly (>70 years) patients with mPC.•Elderly patients show a manageable safety profile.•Efficacy and overall survival of elderly patients is comparable with those of younger patients.
Ru(II)(arene)-flavonoids with high in vitro antitumour activity were synthesised. These compounds are capable of inhibiting human topoisomerase IIα and binding covalently to DNA.
The first metal complexes of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (Triapine) were synthesized. Triapine was prepared by a novel three-step procedure in 64% overall yield. In addition, a ...series of related ligands, namely, 2-formylpyridine thiosemicarbazone, 2-acetylpyridine thiosemicarbazone, 2-pyridineformamide thiosemicarbazone, and their N4-dimethylated derivatives (including the N4-dimethylated analogue of Triapine) were prepared, along with their corresponding gallium(III) and iron(III) complexes with the general formula M(L)2+, where HL is the respective thiosemicarbazone. The compounds were characterized by elemental analysis, 1H and 13C NMR, IR and UV−vis spectroscopies, mass spectrometry, and cyclic voltammetry. In addition, Triapine and its iron(III) and gallium(III) complexes were studied by X-ray crystallography. All ligands and complexes were tested for their in vitro antiproliferative activity in two human cancer cell lines (41M and SK-BR-3), and structure−activity relationships were established. In general, the coordination to gallium(III) increased the cytotoxicity while the iron(III) complexes show reduced cytotoxic activity compared to the metal-free thiosemicarbazones. Selected compounds were investigated for the capacity of inhibiting ribonucleotide reductase by incorporation of 3H-cytidine into DNA.
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