{2-[1-(3-Methoxycarbonylmethyl-1H-indol-2-yl)-1-methyl-ethyl]-1H-indol-3-yl}-acetic acid methyl ester (MIAM): its anti-cancer efficacy and intercalation mechanism identified via multi-model systems

Indole Alkaloids, Synthetic Dimers and Hybrids with Potential In Vivo Anticancer Activity

Indole, a heterocyclic organic compound, is one of the most promising heterocycles found in natural and synthetic sources since its derivatives possess fascinating structural diversity and various therapeutic properties. Indole alkaloids, synthetic dimers and hybrids could act on diverse targets in cancer cells, and consequently, possess potential antiproliferative effects on various cancers both in vitro and in vivo. Vinblastine, midostaurin, and anlotinib as the representative of indole alkaloids, synthetic dimers and hybrids respectively, have already been clinically applied to treat many types of cancers, demonstrating indole alkaloids, synthetic dimers and hybrids are useful scaffolds for the development of novel anticancer agents. Covering articles published between 2010 and 2020, this review emphasizes the recent development of indole alkaloids, synthetic dimers and hybrids with potential in vivo therapeutic application for cancers.

Current scenario of indole derivatives with potential anti-drug-resistant cancer activity

Cancer chemotherapy is frequently hampered by drug resistance, so the resistance to anticancer agents represents one of the major obstacles for the effective cancer treatment. Indole derivatives have the potential to act on diverse targets in cancer cells and exhibit promising activity against drug-resistant cancers. Moreover, some indole-containing compounds such as Semaxanib, Sunitinib, Vinorelbine, and Vinblastine have already been applied in clinics for various kinds of cancer even drug-resistant cancer therapy. Thus, indole derivatives are one of significant resources for the development of novel anti-drug-resistant cancer agents. This review focuses on the recent development of indole derivatives with potential therapeutic application for drug-resistant cancers, and the mechanisms of action, the critical aspects of design as well as structure-activity relationships, covering articles published from 2010 to 2020.

Nanofibrils of a CuII-Thiophenyltriazine-Based Porous Polymer: A Diverse Heterogeneous Nanocatalyst

Herein, we report knitting of a thiophenyltriazine-based porous organic polymer (TTPOP) with high surface area and high abundance of nitrogen and sulfur sites, synthesized through a simple one-step Friedel-Crafts reaction of 2,4,6-tri(thiophen-2-yl)-1,3,5-triazine and formaldehyde dimethyl acetal in the presence of anhydrous FeCl₃, and thereafter grafting of Cu(OAc)₂·H₂O in the porous polymer framework to achieve the potential catalyst (Cu^II-TTPOP). TTPOP and Cu^II-TTPOP were characterized thoroughly utilizing solid-state ¹³C-CP MAS NMR, Fourier transform infrared, wide-angle powder X-ray diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy and surface imaging by transmission electron microscopy and field emission scanning electron microscopy. The porosity of the nanomaterials was observed in the surface imaging and verified through conducting N₂ gas adsorption techniques. Keeping in mind the tremendous importance of C-C and C-N coupling and cyclization processes, the newly synthesized Cu^II-TTPOP was employed successfully for a wide range of organic catalytic transformations under mild conditions to afford directly valuable diindolylmethanes and spiro-analogues, phthalimidines, propargyl amines, and their sugar-based chiral compounds with high yields using readily available substrates. The highly stable new heterogeneous catalyst showed outstanding sustainability, robustness, simple separation, and recyclability.

Zn(OTf)2-catalyzed access to symmetrical and unsymmetrical bisindoles from α-keto amides

Zn(OTf)2-catalyzed synthesis of 3,3'-bisindolyl acetamides from α-keto amides is developed. Both aromatic α-keto amides substituted with electron-donating as well as -withdrawing groups and aliphatic α-keto amides are well tolerated to provide symmetrical bisindoles in moderate to excellent yields. The chemoselective bisindolylation of the keto group of α-keto amides in the presence of a simple keto functionality is successfully achieved in good yields. The transformation is further extended to the synthesis of challenging unsymmetrical bisindoles by treating indolyl α-hydroxy amides with substituted indoles. The unsymmetrical bisindoles are isolated in good to excellent yields.

Hetero-bimetallic cooperative catalysis for the synthesis of heteroarenes

Review covering the synthesis of 5- and 6-membered as well as condensed heteroarenes, focussing on the combinations in cooperative catalytic systems in strategies used to achieve selectivity and also highlights the mode of action for the cooperative catalysis leading to the synthesis of commercially and biologically relevant heteroarenes.

Discovery of DEBIC to correlate P-selectin inhibition and DNA intercalation in cancer therapy and complicated thrombosis

Arterial thrombosis is one of the major complications of cancer and can seriously worsen the prognosis of the patients. These clinical findings encouraged this paper to correlate P-selectin inhibition and DNA intercalation in cancer therapy and complicated thrombosis. By designing and docking 12 derivatives of bisindole- 2-carboxylic acids into the active sites of P-selectin and d(CGATCG)2 9 derivatives were assigned to receive in vivo anti-tumor assay, and finally provided dimethyl 2,2'-[(2,2'-(ethane-1,1-diyl)bis(1H-indole-3,2-diyl)]diacetate (DEBIC) to receive assays. DEBIC intercalated DNA and inhibited proliferation of tumor cells but not non-tumor cells. It slowed tumor growth of S180 mice at a dose of 0.36 μmol/kg, and slowed tumor growth of A549 bearing BABL/C mice at a dose of 8.9 μmol/kg. DEBIC was also found to inhibit arterial thrombosis by down regulating P-selectin effectively at a dose of 0.36 μmol/kg.

A one-pot synthesis of 2,2'-disubstituted diindolylmethanes (DIMs) via a sequential Sonogashira coupling and cycloisomerization/C3-functionalization of 2-iodoanilines

A Pd(ii)-Ag(i) catalyzed highly efficient synthesis of diindolylmethane has been developed. This transformation consists of a one-pot sequential Sonogashira coupling (and desilylation) followed by cycloisomerization/C3-functionalization of 2-iodoanilines. Six new bonds (four C-C and two C-N) are formed in a one-pot fashion. A variety of diindolylmethanes were obtained in excellent yields (up to 94%) under mild reaction conditions and this strategy is amenable to gram scale synthesis also. The products were transformed into various synthetically useful compounds.

5-(Bis(3-(2-hydroxyethyl)-1H-indol-2-yl)methyl)-2-hydroxybenzoic acid (BHIMHA): showing a strategy of designing drug to block lung metastasis of tumors

Early metastasis is still the most recalcitrant factor in the treatment of lung cancer patients. By analyzing the structures and comparing the docking scores of the known pharmacophores, the authors of this paper designed 5-(bis(3-(2-hydroxyethyl)-1H-indol-2-yl)methyl)-2-hydroxybenzoic acid (BHIMHA) as a promising lead compound to develop metastasis inhibitors. In vitro 5, 10, and 20 µM of BHIMHA concentration dependently inhibited the migration and invasion of A549 cells. In vivo 0.4, 2.0, and 8.9 µmol/kg of BHIMHA dose dependently inhibited the metastasis of LLC (Lewis Lung Carcinoma) toward lung. In vivo, 2 µmol/kg of BHIMHA showed additional actions of slowing the growth of the primary tumor of C57BL/6 mice and S180 mice as well as inhibiting xylene-induced ear edema of the mice. Therefore, BHIMHA simultaneously blocked tumor metastasis toward lung, slowed the primary tumor growth, and limited the inflammation. These pharmacological actions were correlated with the inhibition of PKCα and NF-κB expression.

{2-[1-(3-Methoxycarbonylmethyl-1H-indol-2-yl)-1-methyl-ethyl]-1H-indol-3-yl}-acetic Acid Methyl Ester Inhibited Hepatocellular Carcinoma Growth in Bel-7402 Cells and Its Resistant Variants by Activation of NOX4 and SIRT3

{2-[1-(3-Methoxycarbonylmethyl-1H-indol-2-yl)-1-methyl-ethyl]-1H-indol-3-yl}-acetic acid methyl ester (MIAM) is a novel indole compound, which possessed high efficacy against many cancers xenografted in mice without obvious toxicity. In this study, we aimed to investigate the effects of MIAM on human hepatocellular carcinoma (HCC) Bel-7402 cells and its resistant variants Bel-7402/5FU. MIAM inhibited the growth of HCC more potent in Bel-7402/5FU cells than its parent cells. MIAM increased cellular reactive oxygen species (ROS) levels, induced cell apoptosis, and arrested cell cycle in G₀/G₁ phase. MIAM might exert its action on Bel-7402/5FU cells through activation of NADPH oxidase 4 (NOX4)/p22^phox, Sirtuin3 (SIRT3)/SOD2, and SIRT3/p53/p21^Waf1/Cip pathways. MIAM might inhibit HCC growth through the modulation of SIRT3. When SIRT3 was silenced, the inhibitory effect of MIAM on Bel-7402/5FU was lowered, showing the characteristic of resistance against MIAM, whereas Bel-7402/5FU cells with high expression of SIRT3 by SIRT3 adenovirus infection demonstrated the high sensitivity to MIAM. These results suggested that MIAM might exert its action against Bel-7402/5FU growth through upregulation of SIRT3. We suggested that MIAM might be a promising candidate compound which could develop as a potent anticancer agent targeting NOX4 and SIRT3 activation.

Enantioselective construction of a 2,2′-bisindolylmethane scaffold via catalytic asymmetric reactions of 2-indolylmethanols with 3-alkylindoles

A chiral phosphoric acid-catalyzed asymmetric reaction of 2-indolylmethanols with 3-alkylindoles has been established to construct 2,2′-bisindolylmethane scaffold in good enantioselectivities.

{2-[1-(3-Methoxycarbonylmethyl-1H-indol-2-yl)-1-methyl-ethyl]-1H-indol-3-yl}-acetic acid methyl ester (MIAM) inhibited human hepatocellular carcinoma growth through upregulation of Sirtuin-3 (SIRT3)

{2-[1-(3-Methoxycarbonylmethyl-1H-indol-2-yl)-1-methyl-ethyl]-1H-indol-3-yl}-acetic acid methyl ester (MIAM) is a novel indole compound. Our previous studies showed that MIAM possessed activity against many cancers xenografted in mice without significant toxicity. In this study, we determined the effect of MIAM on human hepatocellular carcinoma (HCC) by both in vitro and in vivo assays. In in vitro assay, the experiments were performed in the hypoxic incubator. MIAM inhibited HCC growth with dose-dependent manner. The effects of MIAM on HCC might be due to its activities in induction of apoptosis, arrest of cell cycle in G0/G1 phase. Further studies showed that MIAM might exert its actions through multiple mechanisms. MIAM could reduce intracellular ATP, increase levels of p53/p21 and SIRT3/SOD2/Bax. MIAM also had the activity of reducing HIF1α and hexokinase II (HK II) in HCC. MIAM had the activity of increasing cellular reactive oxygen species (ROS) in HCC. However, the increase of ROS might not be its main mechanism in inhibition of HCC. MIAM might inhibit HepG2 growth through induction of apoptosis. We determined the relationship between level of SIRT3 and cell viability in the MIAM-treated cells. MIAM treatment resulted in increase of SIRT3 in HCC. Further, HepG2 cells infected with human SIRT3 were more sensitive to MIAM than the cells without infection of SIRT3. These results suggested that MIAM might inhibit HCC growth through upregulation of SIRT3. Importantly, the effect of MIAM was confirmed in the HepG2 xenografts bearing in mice. MIAM treatment did not induce significant toxicology to mice. Together, MIAM could be developed as potential agent for treatment of HCC.

Anticancer peptidylarginine deiminase (PAD) inhibitors regulate the autophagy flux and the mammalian target of rapamycin complex 1 activity

Tumor suppressor genes are frequently silenced in cancer cells by enzymes catalyzing epigenetic histone modifications. The peptidylarginine deiminase family member PAD4 (also called PADI4) is markedly overexpressed in a majority of human cancers, suggesting that PAD4 is a putative target for cancer treatment. Here, we have generated novel PAD inhibitors with low micromolar IC(50) in PAD activity and cancer cell growth inhibition. The lead compound YW3-56 alters the expression of genes controlling the cell cycle and cell death, including SESN2 that encodes an upstream inhibitor of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway. Guided by the gene expression profile analyses with YW3-56, we found that PAD4 functions as a corepressor of p53 to regulate SESN2 expression by histone citrullination in cancer cells. Consistent with the mTORC1 inhibition by SESN2, the phosphorylation of its substrates including p70S6 kinase (p70S6K) and 4E-BP1 was decreased. Furthermore, macroautophagy is perturbed after YW3-56 treatment in cancer cells. In a mouse xenograft model, YW3-56 demonstrates cancer growth inhibition activity with little if any detectable adverse effect to vital organs, whereas a combination of PAD4 and histone deacetylase inhibitors further decreases tumor growth. Taken together, our work found that PAD4 regulates the mTORC1 signaling pathway and that PAD inhibitors are potential anticancer reagents that activate tumor suppressor gene expression alone or in combination with histone deacetylase inhibitors.