Sulfated and Sulfur-Containing Steroids and Their Pharmacological Profile

The review focuses on sulfated steroids that have been isolated from seaweeds, marine sponges, soft corals, ascidians, starfish, and other marine invertebrates. Sulfur-containing steroids and triterpenoids are sourced from sedentary marine coelenterates, plants, marine sediments, crude oil, and other geological deposits. The review presents the pharmacological profile of sulfated steroids, sulfur-containing steroids, and triterpenoids, which is based on data obtained using the PASS program. In addition, several semi-synthetic and synthetic epithio steroids, which represent a rare group of bioactive lipids that have not yet been found in nature, but possess a high level of antitumor activity, were included in this review for the comparative pharmacological characterization of this class of compounds. About 140 steroids and triterpenoids are presented in this review, which demonstrate a wide range of biological activities. Therefore, out of 71 sulfated steroids, thirteen show strong antitumor activity with a confidence level of more than 90%, out of 50 sulfur-containing steroids, only four show strong antitumor activity with a confidence level of more than 93%, and out of eighteen epithio steroids, thirteen steroids show strong antitumor activity with a confidence level of 91% to 97.4%.

AAPH or Peroxynitrite-Induced Biorelevant Oxidation of Methyl Caffeate Yields a Potent Antitumor Metabolite

Hydroxycinnamic acids represent a versatile group of dietary plant antioxidants. Oxidation of methyl-p-coumarate (pcm) and methyl caffeate (cm) was previously found to yield potent antitumor metabolites. Here, we report the formation of potentially bioactive products of pcm and cm oxidized with peroxynitrite (ONOO¯), a biologically relevant reactive nitrogen species (RNS), or with α,α′-azodiisobutyramidine dihydrochloride (AAPH) as a chemical model for reactive oxygen species (ROS). A continuous flow system was developed to achieve reproducible in situ ONOO¯ formation. Reaction mixtures were tested for their cytotoxic effect on HeLa, SiHa, MCF-7 and MDA-MB-231 cells. The reaction of pcm with ONOO¯ produced two fragments, an o-nitrophenol derivative, and a new chlorinated compound. Bioactivity-guided isolation from the reaction mixture of cm with AAPH produced two dimerization products, including a dihydrobenzofuran lignan that exerted strong antitumor activity in vitro, and has potent in vivo antimetastatic activity which was previously reported. This compound was also detected from the reaction between cm and ONOO¯. Our results demonstrate the ROS/RNS dependent formation of chemically stable metabolites, including a potent antitumor agent (5), from hydroxycinnamic acids. This suggests that diversity-oriented synthesis using ROS/RNS to obtain oxidized antioxidant metabolite mixtures may serve as a valid natural product-based drug discovery strategy.

Identification of trans-AT polyketide clusters in two marine bacteria reveals cryptic similarities between distinct symbiosis factors

Glutaramide-containing polyketides are known as potent antitumoral and antimetastatic agents. However, the associated gene clusters have only been identified and studied in a few Streptomyces producers and sole Burkholderia gladioli symbiont. The new glutaramide-family polyketides, denominated sesbanimides D, E and F along with the previously known sesbanimide A and C, were isolated from two marine alphaproteobacteria Stappia indica PHM037 and Labrenzia aggregata PHM038. Structures of the isolated compounds were elucidated based on 1D and 2D homo and heteronuclear NMR analyses and ESI-MS spectrometry. All compounds exhibited strong antitumor activity in lung, breast and colorectal cancer cell lines. Subsequent whole genome sequencing and genome mining revealed the presence of the trans-AT PKS gene cluster responsible for the sesbanimide biosynthesis, described as sbn cluster, and the sesbanimide modular assembly is proposed. Interestingly, numerous homologous orphan gene clusters were localized in distantly related bacteria and used as comparative genomic assets for a more global characterization of sbn like-clusters. Strikingly, the modular architecture of downstream mixed type PKS/NRPS, SbnQ, revealed high similarity to PedH in pederin and Lab13 in labrenzin gene clusters, although those clusters are responsible for the production of structurally completely different molecules. The unexpected presence of SbnQ homologs in unrelated polyketide gene clusters across phylogenetically distant bacteria, raises intriguing questions about the evolutionary relationship between glutaramide-like and pederin-like pathways, as well as the functionality of their synthetic products.SignificanceGlutaramide-containing polyketides are still a largely understudied group of polyketides, produced mainly by the genera Streptomyces, with a great potential for antitumor drug production. Here, we describe genomes of two cultivable marine bacteria, Stappia indica PHM037 and Labrenzia aggregata PHM038, producers of the cytotoxic glutaramide-family polyketides sesbanimide A and C with chemical elucidation of newly identified analogs D, E and F. Genome mining revealed trans-AT PKS gene cluster responsible for sesbanimide biosynthesis. Although there are numerous homologous gene clusters present in remarkably different bacteria, this is the first time that the biosynthesis product has been reported. The comparative genome analysis reveals stunning, cryptic evolutionary relationship between sesbanimides, glutaramides from Streptomyces spp. and the pederin-family gene clusters.

Novel Multitarget Therapies for Lung Cancer and Respiratory Disease

In recent years, multitarget drugs for neurological diseases such as Alzheimer’s disease have been developed and well researched. Many studies have revealed that multitarget drugs are also useful for lung cancer and respiratory diseases. Pemetrexed is a multitargeted antifolate with strong antitumor activity against mesothelioma and lung adenocarcinoma. Crizotinib is an ATP-competitive tyrosine kinase inhibitor that targets c-MET, ROS1, and ALK. Alectinib is known as an ALK inhibitor but also targets LTK, CHEK2, FLT3, PHKG2, and RET. Sorafenib is a tyrosine kinase inhibitor that targets RAF kinase, KIT, VEGFR, PDGFR1β, FLT3, and RET. Nintedanib is a multiple tyrosine kinase inhibitor that targets FGFR, PDGFR, and VEGFR. In this review, we summarize the mechanisms of action of multitarget therapies and report the results of the latest clinical trials.

Dihydroartemisinin Modulates Apoptosis and Autophagy in Multiple Myeloma through the P38/MAPK and Wnt/β-Catenin Signaling Pathways

Dihydroartemisinin (DHA), an active metabolite and derivative of artemisinin, is the most effective antimalarial drug and has strong antitumor activity in various tumor types. It has recently been reported that DHA can induce autophagy and has significant effects on multiple myeloma (MM), but the mechanisms and the relationship between the autophagy and apoptosis induced by DHA remain to be elucidated. Herein, we demonstrated that DHA significantly induces cell death in a dose- and time-dependent manner via the extrinsic and intrinsic apoptosis pathways. Moreover, DHA-induced autophagy, which plays a prodeath role in MM, can regulate canonical apoptosis and vice versa. Furthermore, the P38/MAPK signaling pathway is responsible for decreased autophagy and increased apoptosis. DHA induces autophagy and apoptosis also through the inhibition of the Wnt/β-catenin signaling pathway. In addition, DHA shows a strong effect in a xenograft mouse model. Collectively, these findings reveal that DHA, as an artemisinin-based drug, could be an effective and safe therapeutic agent for MM.

Potential Cytotoxicity, Pharmacokinetics, and Excretion Properties of Sapindoside B from the Seeds of Nigella sativa var. hispidula

The seeds of Nigella sativa var. hispidula are widely used in food preparation by the Uighur people in western China. Recently, series of oleanane triterpenoid saponins were extracted from the seeds of Nigella sativa var. hispidula, especially α-hederin as representative that exhibited strong antitumor activity. Compared to α-hederin, sapindoside B has just 1 more terminal xylopyranose in the 3-O position and displays similar effects against various human cancer cell lines with cisplatin. Considering this potential cytotoxic activity, a reliable LC-MS/MS method was developed to quantify sapindoside B in rat plasma, urine, and feces. Chromatographic separation was conducted on an Agilent Zorbax SB-Aq (3.0 × 150 mm, 3.5 µm) column via an isocratic elution procedure with acetonitrile and water containing 0.1% formic acid. Mass spectrometric detection was coupled with an electrospray ionization source in the MRM mode. The linear range of calibration curves was 15 ~ 3000 ng/mL in plasma/urine and 30 ~ 3000 ng/g in feces. The intra-day and inter-day precision was less than 11.1%, and accuracy ranged from 92.2% to 108.7%. The proposed method was validated and shown to be reliable, precise, and accurate and was successfully applied to its pharmacokinetics and excretion studies. Sapindoside B exhibited dosage-dependent pharmacokinetics in the range of 2.5 mg/kg to 12.5 mg/kg, and only about 2% of intravenous dose of sapindoside B was excreted by the feces and urine in its unchanged form over 48 h. These results provide further data support for evaluating the druggability of sapindoside B.

Mitochondrial DNA targeting and impairment by a dinuclear Ir–Pt complex that overcomes cisplatin resistance

A dinuclear complex [(ppy)Ir(tpy)PtCl]2+ (Ir–Pt) can exhibit strong antitumor activity towards cisplatin-resistant cancer cells and induce cell necrosis via mtDNA damage and mitochondrial dysfunction.

Highly efficient site-directed gene insertion in primary human natural killer cells using homologous recombination and CRISPaint delivered by AAV

Human peripheral blood natural killer (NK) cells have strong antitumor activity and have been used successfully in several clinical trials. Modifying NK cells with a chimeric antigen receptor (CAR) can improve their targeting and increase specificity. However, genetic modification of NK cells has been challenging due to the high expression of innate sensing mechanisms for viral nucleic acids. Recently, we described an efficient vector-free method using Cas9/ribonucleoprotein complexes for gene deletion in NK cells. Here, we combined this approach with single-stranded (ss) or self-complementary (sc) Adeno-associated virus (AAV)-mediated gene delivery for gene insertion into a user-defined locus using homology repair (HR) and non-homologous directed CRISPR-assisted insertion tagging (CRISPaint) approaches. Using these approaches, we identified scAAV6 as the superior serotype for successful generation of stable mCherry-expressing primary NK cells (up to 89%). To maximize transgene packaging in HR-directed gene insertion, we identified minimum optimal homology arm lengths of 300bp for the flanking region of the Cas9-targeting site. Lastly, we demonstrate that mCherry positive NK cells can be expanded to large numbers using feeder cells expressing membrane-bound IL-21. This efficient method for site-directed insertion of genetic material into NK cells has broad potential for basic discovery and therapeutic applications for primary NK cells.