Search

Anthracycline dutomycin is a tetracyclic quinone glycoside produced by Streptomyces minoensis NRRL B-5482. SW91 is a C-12 demethylated dutomycin derivative, which was identified in our previous research. In vitro cytotoxicity and apoptosis assays of these two compounds were conducted to demonstrate their antiproliferation activities. The results showed that both dutomycin and SW91 block cells at the S phase, whereas dutomycin shows more significant inhibition of cell growth. Their interactions with calf thymus DNA (CT-DNA) were investigated, with dutomycin exhibiting higher binding affinity. The molecular docking demonstrated that the 12-methyl group makes dutomycin attach to the groove of DNA. These findings suggest that dutomycin has binding higher affinity to DNA and impairs DNA replication resulting in more significant antitumor activity. [ABSTRACT FROM AUTHOR]

Anthracycline dutomycin is a tetracyclic quinone glycoside produced by Streptomyces minoensis NRRL B-5482. SW91 is a C-12 demethylated dutomycin derivative, which was identified in our previous research. In vitro cytotoxicity and apoptosis assays of these two compounds were conducted to demonstrate their antiproliferation activities. The results showed that both dutomycin and SW91 block cells at the S phase, whereas dutomycin shows more significant inhibition of cell growth. Their interactions with calf thymus DNA (CT-DNA) were investigated, with dutomycin exhibiting higher binding affinity. The molecular docking demonstrated that the 12-methyl group makes dutomycin attach to the groove of DNA. These findings suggest that dutomycin has binding higher affinity to DNA and impairs DNA replication resulting in more significant antitumor activity.

The TBX2 transcription factor plays critical roles during embryonic development and it is overexpressed in several cancers, where it contributes to key oncogenic processes including the promotion of proliferation and bypass of senescence. Importantly, based on compelling biological evidences, TBX2 has been considered as a potential target for new anticancer therapies. There has therefore been a substantial interest to identify molecules with TBX2-modulatory activity, but no such substance has been found to date. Here, we adopt a targeted approach based on a reverse-affinity procedure to identify the ability of chromomycins A5 (CA5) and A6 (CA6) to interact with TBX2. Briefly, a TBX2-DNA-binding domain recombinant protein was N-terminally linked to a resin, which in turn, was incubated with either CA5 or CA6. After elution, bound material was analyzed by UPLC-MS and CA5 was recovered from TBX2-loaded resins. To confirm and quantify the affinity (KD) between the compounds and TBX2, microscale thermophoresis analysis was performed. CA5 and CA6 modified the thermophoretic behavior of TBX2, with a KD in micromolar range. To begin to understand whether these compounds exerted their anti-cancer activity through binding TBX2, we next analyzed their cytotoxicity in TBX2 expressing breast carcinoma, melanoma and rhabdomyosarcoma cells. The results show that CA5 was consistently more potent than CA6 in all tested cell lines with IC50 values in the nM range. Of the cancer cell types tested, the melanoma cells were most sensitive. The knockdown of TBX2 in 501mel melanoma cells increased their sensitivity to CA5 by up to 5 times. Furthermore, inducible expression of TBX2 in 501mel cells genetically engineered to express TBX2 in the presence of doxycycline, were less sensitive to CA5 than the control cells. Together, the data presented in this study suggest that, in addition to its already recognized DNA-binding properties, CA5 may be binding the transcription factor TBX2, and it can contribute to its cytotoxic activity.

A new series of trimethoprim (TMP) analogs containing amide bonds (1−6) have been synthesized. Molecular docking, as well as dihydrofolate reductase (DHFR) inhibition assay were used to confirm their affinity to bind dihydrofolate reductase enzyme. Data from the ethidium displacement test showed their DNA-binding capacity. Tests confirming the possibility of DNA binding in a minor groove as well as determination of the association constants were performed using calf thymus DNA, T4 coliphage DNA, poly (dA-dT)2 and poly (dG-dC)2. Additionally, the mechanism of action of the new compounds was studied. In conclusion, some of our new analogs inhibited DHFR activity more strongly than TMP did, which confirms, that the addition of amide bonds into the analogs of TMP increases their affinity towards DHFR.

The TBX2 transcription factor plays critical roles during embryonic development and it is overexpressed in several cancers, where it contributes to key oncogenic processes including the promotion of proliferation and bypass of senescence. Importantly, based on compelling biological evidences, TBX2 has been considered as a potential target for new anticancer therapies. There has therefore been a substantial interest to identify molecules with TBX2-modulatory activity, but no such substance has been found to date. Here, we adopt a targeted approach based on a reverse-affinity procedure to identify the ability of chromomycins A 5 (CA 5 ) and A 6 (CA 6 ) to interact with TBX2. Briefly, a TBX2-DNA-binding domain recombinant protein was N-terminally linked to a resin, which in turn, was incubated with either CA 5 or CA 6 . After elution, bound material was analyzed by UPLC-MS and CA 5 was recovered from TBX2-loaded resins. To confirm and quantify the affinity (K D ) between the compounds and TBX2, microscale thermophoresis analysis was performed. CA 5 and CA 6 modified the thermophoretic behavior of TBX2, with a K D in micromolar range. To begin to understand whether these compounds exerted their anti-cancer activity through binding TBX2, we next analyzed their cytotoxicity in TBX2 expressing breast carcinoma, melanoma and rhabdomyosarcoma cells. The results show that CA 5 was consistently more potent than CA 6 in all tested cell lines with IC 50 values in the nM range. Of the cancer cell types tested, the melanoma cells were most sensitive. The knockdown of TBX2 in 501mel melanoma cells increased their sensitivity to CA 5 by up to 5 times. Furthermore, inducible expression of TBX2 in 501mel cells genetically engineered to express TBX2 in the presence of doxycycline, were less sensitive to CA 5 than the control cells. Together, the data presented in this study suggest that, in addition to its already recognized DNA-binding properties, CA 5 may be binding the transcription factor TBX2, and it can contribute to its cytotoxic activity., (Copyright © 2020 Sahm, Peres, Rezende-Teixeira, Santos, Branco, Bauermeister, Kimani, Moreira, Bisi-Alves, Bellis, Mlaza, Jimenez, Lopes, Machado-Santelli, Prince and Costa-Lotufo.)

A new series of trimethoprim (TMP) analogs containing amide bonds (1–6) have been synthesized. Molecular docking, as well as dihydrofolate reductase (DHFR) inhibition assay were used to confirm their affinity to bind dihydrofolate reductase enzyme. Data from the ethidium displacement test showed their DNA-binding capacity. Tests confirming the possibility of DNA binding in a minor groove as well as determination of the association constants were performed using calf thymus DNA, T4 coliphage DNA, poly (dA-dT)2 and poly (dG-dC)2. Additionally, the mechanism of action of the new compounds was studied. In conclusion, some of our new analogs inhibited DHFR activity more strongly than TMP did, which confirms, that the addition of amide bonds into the analogs of TMP increases their affinity towards DHFR. [ABSTRACT FROM AUTHOR]

A new series of trimethoprim (TMP) analogs containing amide bonds ( 1 - 6 ) have been synthesized. Molecular docking, as well as dihydrofolate reductase (DHFR) inhibition assay were used to confirm their affinity to bind dihydrofolate reductase enzyme. Data from the ethidium displacement test showed their DNA-binding capacity. Tests confirming the possibility of DNA binding in a minor groove as well as determination of the association constants were performed using calf thymus DNA, T4 coliphage DNA, poly (dA-dT) 2 and poly (dG-dC) 2 . Additionally, the mechanism of action of the new compounds was studied. In conclusion, some of our new analogs inhibited DHFR activity more strongly than TMP did, which confirms, that the addition of amide bonds into the analogs of TMP increases their affinity towards DHFR.

We have recently reported the isolation and characterization of Plasmodium falciparum Dbp5/DDX19 homolog PfD66 and the results indicate that it contains ATP-dependent bipolar DNA and RNA unwinding activity, intrinsic nucleic acid-dependent ATPase and RNA-binding activities. In the present study we report the effect of a number of compounds such as actinomycin D, aphidicolin, camptothecin, cyclophosphamide, 4',6'-di-amidino-2-phenylindole (DAPI), daunorubicin, distamycin, ethidium bromide, ellipticine, genistein, mitoxantrone, nalidixic acid, netropsin, nogalamycin, novobiocin and VP-16 on the DNA unwinding and ATPase activities of PfD66. The results indicate that DAPI, ethidium bromide, netropsin and nogalamycin efficiently inhibited the helicase and ATPase activities of PfD66. These studies will make an important contribution in understanding the mechanism of DNA unwinding by Plasmodium falciparum helicase PfD66.