A novel glycosylated indolocarbazole derivative LCS1269 effectively inhibits growth of human cancer cells in vitro and in vivo through driving of both apoptosis and senescence by inducing of DNA damage and modulating of AKT/mTOR/S6K and ERK pathways

In recent decades, indolocarbazole glycosides containing sugar moieties have attracted attention due to their diverse anti-tumor activities. In the present study, a series of new indolo [2,3-a]pyrrolo [3,4-c]carbazole derivatives were synthesized for the first time. First of all, we have shown that compound 6e (LCS1269) had the most pronounced effect on inhibiting tumor growth in the transferable solid and non-solid murine tumors as compared with other synthesized indolocarbazole derivatives. The results of the in vivo nude mice xenoraft study also confirmed that LCS1269 treatment strongly suppressed the growth of human colon cancer SW620 xenografts. It is important to note that the antiproliferative activity of LCS1269 against three human cancer cell lines (MCF-7, HCT-116 and A549) was considerably higher than that against the non-tumor cell lines (immortalized breast cells and normal embryonic fibroblasts). Furthermore, the treatment of MCF-7, HCT-116 and A549 cells with LCS1269 caused the statistically significant inhibition of anchorage-dependent and anchorage-independent colony formation. We further revealed that LCS1269 treatment of investigated human cancer cells resulted in the DNA damage and G2/M cell cycle arrest followed by the decrease of mitochondrial membrane potential with subsequent initiation of intrinsic apoptosis and the triggering of senescence via p53-dependent mechanisms. In addition, our western blotting findings and molecular docking data suppose that LCS1269 could at least partially attenuate cancer cells growth by modulation of AKT/mTOR/S6K and ERK signaling pathways. Therefore, we concluded that LCS1269 might be the promising compound for implementation and probable use in the clinical practice.

Antiproliferative activity of a new derivative from the class of N-glycoside of indolo[2,3-a]pyrrolo[3,4-c]carbazoles

Introduction: The creation of highly effective original anticancer drugs remains an urgent direction of scientific research in tumor therapy. One of the promising groups in this regard is indolocarbazoles and their derivatives, which are capable of initiating various pathways of tumor cell death. The aim of the study was to evaluate an antiproliferative activity of a new, Russian derivative of N-glycoside substituted indolocarbazole 6-amino-12-(α-L-arabinopyranosyl)indolo[2,3-a]pyrrolo[3,4-c]carbazole-5,7-dione (LCS-1208) on models of transplantable tumors of mice and on human tumors in Balb/c nude mice.

Materials and methods: Indolocarbazole sensitivity to LCS-1208 was assessed on transplantable tumors of mice – lymphatic leukemia L-1210, cervical carcinoma (CC-5), and colon adenocarcinoma (CAC) by five-fold intraperitoneal administration (ip) of the LCS-1208 substance in single doses of 50, 75, 100 mg/kg. Investigation into the effectiveness of the LCS-1208 lyo dosage form was performed on subcutaneous xenografts of human colon cancer SW620 by an intravenous administration (iv). The antitumor effect was evaluated by the tumor growth inhibition (TGI) and an increase in life span (ILS) of the treated animals as compared with the control ones. Evaluation of specific antitumor activity on xenografts was performed according to the tumor/control (T/C%) criterion (maximum criterion T/C≤42%).

Results and discussion: According to the results of the study, the most sensitive to the action of the LCS-1208 substance in the case of an ip administration of a total dose of 375 mg/kg were CAC with TGI=97–62%, p≤0.001 up to 16 days after the treatment, and ILS=36% (criteria for TGI≥70% and ILS≥25%). On xenografts of a human colon cancer SW620, the effectiveness of the LCS-1208 lyo drug dosage form within the range of total doses from 50 to 150 mg/kg in case of iv to Balb/c nude mice was set at T/C = 35–2% (criterion T/C<42%).

Conclusion: The presented results suggest possible effectiveness of LCS-1208 in treatment of colon malignant tumors of humans.

Synthesis, Characterization, and Preclinical Evaluation of a Small-Molecule Prostate-Specific Membrane Antigen-Targeted Monomethyl Auristatin E Conjugate

Prostate cancer is the second most common type of cancer among men. Its main method of treatment is chemotherapy, which has a wide range of side effects. One of the solutions to this challenge is targeted delivery to prostate cancer cells. Here we synthesized a novel small-molecule PSMA-targeted conjugate based on the monomethyl auristatin E. Its structure and conformational properties were investigated by NMR spectroscopy. Cytotoxicity, intracellular reactive oxygen species induction, and stability under liver microsomes and P450-cytochrome species were investigated for this conjugate. The conjugate demonstrated 77-85% tumor growth inhibition levels on 22Rv1 (PSMA (+)) xenografts, compared with a 37% inhibition level on PC-3 (PSMA (-)) xenografts, in a single dose of 0.3 mg/kg and a sufficiently high therapeutic index of 21. Acute, chronic, and subchronic toxicities and pharmacokinetics have shown that the synthesized conjugate is a promising potential agent for the chemotherapy of prostate cancer.

PSMA-targeted small-molecule docetaxel conjugate: Synthesis and preclinical evaluation

Prostate cancer is one of the most commonly diagnosed men's cancers and remains one of the leading causes of cancer death. The development of approaches to the treatment of this oncological disease is an ongoing process. In this work, we have carried out the selection of ligands for the creation of conjugates based on the drug docetaxel and synthesized a series of three docetaxel conjugates. In vitro cytotoxicity of these molecules was evaluated using the MTT assay. Based on the assay results, we selected the conjugate which showed cytotoxic potential close to unmodified docetaxel. At the same time, the molar solubility of the resulting compound increased up to 20 times in comparison with the drug itself. In vivo evaluation on 22Rv1 (PSMA+) xenograft model demonstrated a good potency of the synthesized conjugate to inhibit tumor growth: the inhibition turned out to be more than 80% at a dose of 30 mg/kg. Pharmacokinetic parameters of conjugate distribution were analyzed. Also, it was found that PSMA-targeted docetaxel conjugate is less toxic than docetaxel itself, the decrease of molar acute toxicity in comparison with free docetaxel was up to 20%. Obtained conjugate PSMA-DOC is a good candidate for further expanded preclinical trials because of high antitumor activity, fewer side toxic effects and better solubility.

Synthesis and Biological Evaluation of PSMA Ligands with Aromatic Residues and Fluorescent Conjugates Based on Them

Prostate-specific membrane antigen (PSMA), also known as glutamate carboxypeptidase II (GCPII), is a suitable target for specific delivery of antitumor drugs and diagnostic agents due to its overexpression in prostate cancer cells. In the current work, we describe the design, synthesis, and biological evaluation of novel low-molecular PSMA ligands and conjugates with fluorescent dyes FAM-5, SulfoCy5, and SulfoCy7. In vitro evaluation of synthesized PSMA ligands on the activity of PSMA shows that the addition of aromatic amino acids into a linker structure leads to a significant increase in inhibition. The conjugates of the most potent ligand with FAM-5 as well as SulfoCy5 demonstrated high affinities to PSMA-expressing tumor cells in vitro. In vivo biodistribution in 22Rv1 xenografts in Balb/c nude mice of PSMA-SulfoCy5 and PSMA-SulfoCy7 conjugates with a novel PSMA ligand demonstrated good visualization of PSMA-expressing tumors. Also, the conjugate PSMA-SulfoCy7 demonstrated the absence of any explicit toxicity up to 87.9 mg/kg.

Pharmacophore hybridization approach to discover novel pyrazoline-based hydantoin analogs with anti-tumor efficacy

In search for new and safer anti-cancer agents, a structurally guided pharmacophore hybridization strategy of two privileged scaffolds, namely diaryl pyrazolines and imidazolidine-2,4-dione (hydantoin), was adopted resulting in a newfangled series of compounds (H1-H22). Herein, a bio-isosteric replacement of "pyrrolidine-2,5-dione" moiety of our recently reported antitumor hybrid incorporating diaryl pyrazoline and pyrrolidine-2,5-dione scaffolds with "imidazoline-2,4-dione" moiety has been incorporated. Complete biological studies revealed the most potent analog among all i.e. compound H13, which was at-least 10-fold more potent compared to the corresponding pyrrolidine-2,5-dione, in colon and breast cancer cells. In-vitro studies showed activation of caspases, arrest of G0/G1 phase of cell cycle, decrease in the expression of anti-apoptotic protein (Bcl-2) and increased DNA damage. In-vivo assay on HT-29 (human colorectal adenocarcinoma) animal xenograft model unveiled the significant anti-tumor efficacy along with oral bioavailability with maximum TGI 36% (i.p.) and 44% (per os) at 50 mg/kg dose. These findings confirm the suitability of hybridized pyrazoline and imidazolidine-2,4-dione analog H13 for its anti-cancer potential and starting-point for the development of more efficacious analogs.

Synthesis and Biological Evaluation of Pyrazoline and Pyrrolidine-2,5-dione Hybrids as Potential Antitumor Agents

In search of novel and effective antitumor agents, pyrazoline-substituted pyrrolidine-2,5-dione hybrids were designed, synthesized and evaluated in silico, in vitro and in vivo for anticancer efficacy. All the compounds exhibited remarkable cytotoxic effects in MCF7 and HT29 cells. The excellent antiproliferative activity toward MCF7 (IC₅₀ =0.78±0.01 μM), HT29 (IC₅₀ =0.92±0.15 μM) and K562 (IC₅₀ =47.25±1.24 μM) cell lines, prompted us to further investigate the antitumor effects of the best compound S2 (1-(2-(3-(4-fluorophenyl)-5-(p-tolyl)-4,5-dihydro-1H-pyrazol-1-yl)-2-oxoethyl)pyrrolidine-2,5-dione). In cell-cycle analysis, S2 was found to disrupt the growth phases with increased cell population in G₁ /G₀ phase and decreased cell population in G₂ /M phase. The excellent in vitro effects were also supported by inhibition of anti-apoptotic protein Bcl-2. In vivo tumor regression studies of S2 in HT29 xenograft nude mice, exhibited equivalent and promising tumor regression with maximum TGI, 66 % (i. p. route) and 60 % (oral route) at 50 mg kg^-1 dose by both the routes, indicating oral bioavailability and antitumor efficacy. These findings advocate that hybridization of pyrazoline and pyrrolidine-2,5-dioes holds promise for the development of more potent and less toxic anticancer agents.

New Poly(3-hydroxybutyrate) Microparticles with Paclitaxel Sustained Release for Intraperitoneal Administration

BACKGROUND

Poly(hydroxyalkanoates) (PHA) have recently attracted increasing attention due to their biodegradability and high biocompatibility, which makes them suitable for the development of new prolong drug formulations.

OBJECTIVE

This study was conducted to develop new prolong paclitaxel (PTX) formulation based on poly(3- hydroxybutyrate) (PHB) microparticles.

METHOD

PHB microparticles loaded with antitumor cytostatic drug PTX were obtained by spray-drying method using Nano Spray Dryer B-90. The PTX release kinetics in vitro from PHB microparticles and their cytotoxity on murine hepatoma cell line MH-22a were studied. Microparticles antitumor activity in vivo was studied using intraperitoneally (i.p.) transplanted tumor models: murine Lewis lung carcinoma and xenografts of human breast cancer RMG1.

RESULTS

Uniform PTX release from PHB-microparticles during 2 months was observed. PTX-loaded PHB microparticles have demonstrated a significant antitumor activity versus pure drug both in vitro in murine hepatoma cells and in vivo when administered i.p. to mice with murine Lewis lung carcinoma and xenografts of human breast cancer RMG1.

CONCLUSION

The developed technique of PTX sustained delivery from PHB-microparticles has therapeutic potential as prolong anticancer drug formulation.

Effect of mesna on lethal effect and hematological toxicity of taxol and vepeside in mice

Mesna, an SH-containing uroprotector, attenuates the lethal effect and hematological toxicity of vepeside and taxol, but did not reduce specific activities of the studied cytostatics in mice with transplanted tumors. This selective antitoxic effect of mesna towards vepeside and taxol allows to intensify the anticancer chemotherapy with these highly effective but extremely toxic cytostatics and to improve the efficiency of anticancer therapy.

[A new method for the intravital assessment of the functional activity of the membrane transporters performing the efflux of antitumor preparations from the cells of solid tumor specimens]

A new method for intravital assessment of the functional activity of anticancer drug efflux transporters in intact solid tumor specimens was developed. The method is based on the well-known approach to the transporter functional evaluation by intracellular accumulation of antitumor drugs and particularly the anthracycline antibiotic doxorubicin (Dox). The main new point of the method providing investigation of intact solid tumor specimens which markedly simplified the procedure is the fact that the intratissue and intracellular accumulation of Dox is determined not by the level of the drug in the tissue but by its fluorescence decrease in the incubation medium. To assess just the intracellular content of Dox and to estimate the transporter functional activity, investigation of the influence of membrane transporter inhibitors such as verapamil (P-gp inhibitor) and sodium azide (inhibitor of all the energy-dependent ABC transporters) on the drug fluorescence decrease in the incubation medium is stipulated. The validity of such an approach was experimentally proved with the specimens of the Ehrlich solid tumor transplants in mice (a sensitive variant of the tumor and the tumor with induced drug resistance). Biopsy specimens of human breast tumors were investigated with the new method and functional activity of various efflux transporters was revealed: (1) only P-gp, (2) both P-gp and other ABC transporters, (3) only transporters different from P-gp, (4) no functional activity of efflux transporters. The main trends of the further investigation of efflux transporter functional activity in human solid tumors possible for the first time with the use of the new method are defined.

[Effect of calcium gluconate on the toxicity and antitumor of doxorubicin in mice]

The effect of calcium gluconate on the toxicity and specific activity of the anthracycline antibiotic doxorubicin was studied on mice with transplanted hemoblastosis La or plasmocytoma MOPS-406. In both cases after the animal exposure to nontoxic therapeutic doses of doxorubicin no influence of calcium gluconate on the antibiotic antitumor activity was observed. When doxorubicin was used in toxic (and even lethal) doses the antitoxic effect of calcium gluconate and an increase of the antibiotic therapeutic activity were stated. The combination of calcium gluconate and doxorubicin made it possible to significantly increase the maximum therapeutic effect of doxorubicin (higher levels of the animal survival and some cures) and to widen the ranges of the drug therapeutic doses at the account of decreasing the toxicity of the antibiotic and increasing its dose. The results suggested that the antitoxic modifier calcium gluconate could be used for increasing anticancer efficacy of doxorubicin which is given now at the total dose limit of 550 mg/m2 even in cases with preserved tumor sensitivity to the drug.

[Effect of MESNA on intracellular accumulation of doxorubicin and its interaction with DNA]

The effect of MESNA, an uroprotector (sodium 2-mercaptoethane sulfonate) on intracellular accumulation of doxorubicin and its interaction with DNA was studied in the cultures of the cells of human ovary carcinoma (CaOV) and normal epithelial kidney cells of green monkeys (VERO). The study was performed with methods developed by the authors. The results showed that MESNA had no effect on the qualitative and quantitative characteristics of the indicated processes in both the types of the doxorubicin sensitive cells. It was concluded that with the combined use of doxorubicin and phosphamide or cyclophosphane the use of MESNA for lowering the urotoxic action of oxazophosphorines had no effect on the biological efficacy of doxorubicin. The necessity of studying the possible modifying effect of MESNA in the cultures of doxorubicin resistant cells and in vivo is indicated.