Synthesis and an angiolytic role of novel piperazine–benzothiazole analogues on neovascularization, a chief tumoral parameter in neoplastic development

A novel series of benzoic acid N′-2-(4-benzothiazol-2-yl-piperazin-1-yl)-acetyl-hydrazides 6a–j were synthesized and characterized by IR, 1H, 13C NMR, elemental and mass spectral analyses. The in-vitro cytotoxicity and cell viability assay of the synthesized compounds 6a–j were evaluated against Dalton’s lymphoma ascites (DLA) cells. Our results showed that compound 6c with a bromo group on phenyl ring has showed promising antiproliferative efficacy. Further investigation of compound 6c on in-vivo treatment model depicts the increased tumor suppression through inhibition of angiogenesis

The Novel 4-phenyl-2-phenoxyacetamide thiazoles modulates the tumor hypoxia leading to the crackdown of neoangiogenesis and evoking the cell death

Tumor microenvironment is a complex multistep event which involves several hallmarks that transform the normal cell into cancerous cell. Designing the novel antagonistic molecule to reverse the tumor microenvironment with specific target is essential in modern biological studies. The novel 4-phenyl-2-phenoxyacetamide thiazole analogues 8a-ab were synthesized in multistep process, then screened and assessed for cytotoxic and anti-proliferative effects in vitro against multiple cancer cells of different origin such as MCF-7, A549, EAC and DLA cells which revealed that compound 8f with fluoro and methyl substitute has potential cytotoxic efficacy with an average IC50 value of ˜ 13 μM. The mechanism of cytotoxicity assessed for anti-tumor studies both in ascites and solid tumor models in-vivo inferred the regressed tumor activity. This is due to changes in the cause of tumor microenvironment with crackdown of neovascularization and evoking apoptosis process as assessed by CAM, corneal vascularization and apoptotic hallmarks in 8f treated cells. The molecular gene studies inferred involvement of HIF-1upregulation and stabilization of p53 which are interlinked in signaling as conferred by immunoblot analysis

Quinacrine-Induced Autophagy in Ovarian Cancer Triggers Cathepsin-L Mediated Lysosomal/Mitochondrial Membrane Permeabilization and Cell Death

We previously reported that the antimalarial compound quinacrine (QC) induces autophagy in ovarian cancer cells. In the current study, we uncovered that QC significantly upregulates cathepsin L (CTSL) but not cathepsin B and D levels, implicating the specific role of CTSL in promoting QC-induced autophagic flux and apoptotic cell death in OC cells. Using a Magic Red® cathepsin L activity assay and LysoTracker red, we discerned that QC-induced CTSL activation promotes lysosomal membrane permeability (LMP) resulting in the release of active CTSL into the cytosol to promote apoptotic cell death. We found that QC-induced LMP and CTSL activation promotes Bid cleavage, mitochondrial outer membrane permeabilization (MOMP), and mitochondrial cytochrome-c release. Genetic (shRNA) and pharmacological (Z-FY(tBU)-DMK) inhibition of CTSL markedly reduces QC-induced autophagy, LMP, MOMP, apoptosis, and cell death; whereas induced overexpression of CTSL in ovarian cancer cell lines has an opposite effect. Using recombinant CTSL, we identified p62/SQSTM1 as a novel substrate of CTSL, suggesting that CTSL promotes QC-induced autophagic flux. CTSL activation is specific to QC-induced autophagy since no CTSL activation is seen in ATG5 knockout cells or with the anti-malarial autophagy-inhibiting drug chloroquine. Importantly, we showed that upregulation of CTSL in QC-treated HeyA8MDR xenografts corresponds with attenuation of p62, upregulation of LC3BII, cytochrome-c, tBid, cleaved PARP, and caspase3. Taken together, the data suggest that QC-induced autophagy and CTSL upregulation promote a positive feedback loop leading to excessive autophagic flux, LMP, and MOMP to promote QC-induced cell death in ovarian cancer cells

Synthesis and antiproliferative activity of benzophenone tagged pyridine analogues towards activation of caspase activated DNase mediated nuclear fragmentation in Dalton’s lymphoma

A series of benzophenones possessing pyridine nucleus 8a–l were synthesized by multistep reaction sequence and evaluated for antiproliferative activity against DLA cells by in vitro and in vivo studies. The results suggested that, compounds 8b with fluoro group and 8e with chloro substituent at the benzoyl ring of benzophenone scaffold as well as pyridine ring with hydroxy group exhibited significant activity. Further investigation in mouse model suggests that compounds 8b and 8e have the potency to activate caspase activated DNase (endonuclease) which is responsible for DNA fragmentation, a primary hallmark of apoptosis and thereby inhibits the Dalton’s lymphoma ascites tumour growth

A tumoural angiogenic gateway blocker, Benzophenone-1B represses the HIF-1α nuclear translocation and its target gene activation against neoplastic progression

Hypoxia is an important module in all solid tumours to promote angiogenesis, invasion and metastasis. Stabilization and subsequent nuclear localization of HIF-1α subunits result in the activation of tumour promoting target genes such as VEGF, MMPs, Flt-1, Ang-1 etc. which plays a pivotal role in adaptation of tumour cells to hypoxia. Increased HIF-α and its nuclear translocation have been correlated with pronounced angiogenesis, aggressive tumour growth and poor patient prognosis leading to current interest in HIF-1α as an anticancer drug target. Benzophenone-1B (4-(1H-benzimidazol-2-ylmethoxy)-3,5-dimethylphenyl-(4-methoxyphenyl) methanone, or BP-1B) is a new antineoplastic agent with potential angiopreventive effects. Current investigation reports the cellular biochemical modulation underlying BP-1B cytotoxic/antiangiogenic effects. Experimental evidences postulate that BP-1B exhibits the tumour specific cytotoxic actions against various cancer types with prolonged action. Moreover BP-1B efficiently counteracts endothelial cell capillary formation in in-vitro, in-vivo non-tumour and tumour angiogenic systems. Molecular signaling studies reveal that BP-1B arrests nuclear translocation of HIF-1α devoid of p42/44 pathway under CoCl2 induced hypoxic conditions in various cancer cells thereby leading to abrogated HIF-1α dependent activation of VEGF-A, Flt-1, MMP-2, MMP -9 and Ang-1 angiogenic factors resulting in retarded cell migration and invasions. The in-vitro results were reproducible in the reliable in-vivo solid tumour model. Taken together, we conclude that BP-1B impairs angiogenesis by blocking nuclear localization of HIF-1α which can be translated into a potent HIF-1α inhibitor

Modulation of DNA damage response by targeting ATM kinase using newly synthesized di-phenoxy acetamide (DPA) analogs to induce anti-neoplasia

Background: Imbalance and instability in the structure of the DNA have become major characteristics of cancer. In response to DNA damage, DNA damage response (DDR) protein, ataxia telangiectasia mutated (ATM), plays a pivotal role in the modulation of regulatory regions responsible for inhibition of apoptosis, thereby neoplastic progression. Methods: A new series of DPA (7a-t) were synthesized, characterized. Anti-proliferative studies to identify the lead compound were carried out by LDH and MTT assay. Apoptosis/DNA damage was measured through FACS, Annexin-v staining, TUNEL and Comet assay. Elucidation of molecular mechanism through immunoblot and further validation of the drug effect through in vivo approaches. Results: Initial in vitro anti-proliferative screening of Compounds DPA (7a-t) against multiple cancer cell lines identified Compound DPA (7n) as a potent cytotoxic molecule with IC50 value of 4.3 mu M. Down the line, in vitro and in vivo evaluation of Compound DPA (7n) inferred that it has apoptotic inducing potentiality. Further, evaluation of molecular mechanism inferred that Compound DPA (7n) effectively modulates ATM phosphorylation only, eventually altering downstream signalling pathways. Conclusions: Compound DPA (7n) emerged as a potent proapoptotic and anti-neoplastic agent by inhibiting ATM kinase activity both in vitro and in vivo. The conferring results ascertain that the drug could be developed as a new ATM kinase inhibitor with anti-cancer capacity

Synthesis of novel morpholine conjugated benzophenone analogues and evaluation of antagonistic role against neoplastic development

A series of novel 4-benzyl-morpholine-2-carboxylic acid N′-2-(4-benzoyl-phenoxy)-acetyl-hydrazide derivatives 8a-j has been synthesized from (4-hydroxy-aryl)-aryl methanones through a multi-step reaction sequence and then evaluated for anti-proliferative activity in vitro against various types of neoplastic cells of mouse and human such as DLA, EAC, MCF-7 and A549 cells. From the cytotoxic studies and structural activity relationship of compounds 8a-j, it is clear that methyl group on the B ring of benzophenone is essential for antiproliferative activity and bromo at ortho position (compound 8b) and methyl at para position (compound 8f) on A ring of benzophenone are significant for extensive anti-mitogenic activity. Investigation on clonogenesis and Fluorescence-activated cell sorting suggests that compounds 8b and 8f have the potency to exhibit the prolonged activity with cell cycle arrest on G2/M phase against cancer progression. Further, the compounds 8b and 8f inhibit murine ascites lymphoma through caspase activated DNase mediated apoptosis

The anti-invasive role of novel synthesized pyridazine hydrazide appended phenoxy acetic acid against neoplastic development targeting matrix metallo proteases

Neoplastic metastasis is a major process where tumor cells migrate from the primary tumor and colonize at other parts of our body to form secondary tumor. Cancer incidences are rising and novel anti-neoplastic compounds with new mechanism of actions are essential for preventing cancer related deaths. In the current examination, a novel series of pyridazine analogues 6a-l was synthesized and evaluated against metastatic neoplastic cells. Experimental data postulated compound 6j has potential cytotoxic efficacy with prolonged activity against various cancer cells, including A549, HepG2, A498, CaSki and SiHa cells. Moreover, compound 6j arrests the A549 migration and invasions markedly by counteracting matrix metalloproteinase (MMP)-2 and MMP-9 expressions. Also, compound 6j proved its potentiality against Dalton’s solid lymphoma progression in-vivo by abridging MVD and MMP expressions. Compound 6j interacts with MMP-2 and MMP-9 by H- bond in-silico, thereby down regulates the MMPs action in tumourigenesis. Altogether, we concluded that compound 6j down regulates MMP-2 and MMP-9 and thereby impairs metastatic cancer cell migration and invasions which can be translated into a potent anti-neoplastic agent

Quinacrine Induces Nucleolar Stress in Treatment-Refractory Ovarian Cancer Cell Lines

A considerable subset of gynecologic cancer patients experience disease recurrence or acquired resistance, which contributes to high mortality rates in ovarian cancer (OC). Our prior studies showed that quinacrine (QC), an antimalarial drug, enhanced chemotherapy sensitivity in treatment-refractory OC cells, including artificially generated chemoresistant and high-grade serous OC cells. In this study, we investigated QC-induced transcriptomic changes to uncover its cytotoxic mechanisms of action. Isogenic pairs of OC cells generated to be chemoresistant and their chemosensitive counterparts were treated with QC followed by RNA-seq analysis. Validation of selected expression results and database comparison analyses indicated the ribosomal biogenesis (RBG) pathway is inhibited by QC. RBG is commonly upregulated in cancer cells and is emerging as a drug target. We found that QC attenuates the in vitro and in vivo expression of nucleostemin (NS/GNL3), a nucleolar RBG and DNA repair protein, and the RPA194 catalytic subunit of Pol I that results in RBG inhibition and nucleolar stress. QC promotes the redistribution of fibrillarin in the form of extranuclear foci and nucleolar caps, an indicator of nucleolar stress conditions. In addition, we found that QC-induced downregulation of NS disrupted homologous recombination repair both by reducing NS protein levels and PARylation resulting in reduced RAD51 recruitment to DNA damage. Our data suggest that QC inhibits RBG and this inhibition promotes DNA damage by directly downregulating the NS–RAD51 interaction. Additionally, QC showed strong synergy with PARP inhibitors in OC cells. Overall, we found that QC downregulates the RBG pathway, induces nucleolar stress, supports the increase of DNA damage, and sensitizes cells to PARP inhibition, which supports new therapeutic stratagems for treatment-refractory OC. Our work offers support for targeting RBG in OC and determines NS to be a novel target for QC