An Anilinoquinazoline Derivative Inhibits Tumor Growth through Interaction with hCAP-G2, a Subunit of Condensin II

We screened 46 novel anilinoquinazoline derivatives for activity to inhibit proliferation of a panel of human cancer cell lines. Among them, Q15 showed potent in vitro growth-inhibitory activity towards cancer cell lines derived from colorectal cancer, lung cancer and multiple myeloma. It also showed antitumor activity towards multiple myeloma KMS34 tumor xenografts in lcr/scid mice in vivo. Unlike the known anilinoquinazoline derivative gefitinib, Q15 did not inhibit cytokine-mediated intracellular tyrosine phosphorylation. Using our mRNA display technology, we identified hCAP-G2, a subunit of condensin II complex, which is regarded as a key player in mitotic chromosome condensation, as a Q15 binding partner. Immunofluorescence study indicated that Q15 compromises normal segregation of chromosomes, and therefore might induce apoptosis. Thus, our results indicate that hCAP-G2 is a novel therapeutic target for development of drugs active against currently intractable neoplasms.     

A Novel Phthalimide Derivative,TC11, Has Preclinical Effects on High-Risk Myeloma Cells and Osteoclasts

Despite the recent advances in the treatment of multiple myeloma (MM), MM patients with high-risk cytogenetic changes such as t(4;14) translocation or deletion of chromosome 17 still have extremely poor prognoses. With the goal of helping these high-risk MM patients, we previously developed a novel phthalimide derivative, TC11. Here we report the further characterization of TC11 including anti-myeloma effects in vitro and in vivo, a pharmacokinetic study in mice, and anti-osteoclastogenic activity. Intraperitoneal injections of TC11 significantly delayed the growth of subcutaneous tumors in human myeloma-bearing SCID mice. Immunohistochemical analyses showed that TC11 induced apoptosis of MM cells in vivo. In the pharmacokinetic analyses, the C_max was 2.1 μM at 1 h after the injection of TC11, with 1.2 h as the half-life. TC11 significantly inhibited the differentiation and function of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts in mouse osteoclast cultures using M-CSF and RANKL. We also revealed that TC11 induced the apoptosis of myeloma cells accompanied by α-tubulin fragmentation. In addition, TC11 and lenalidomide, another phthalimide derivative, directly bound to nucleophosmin 1 (NPM1), whose role in MM is unknown. Thus, through multiple molecular interactions, TC11 is a potentially effective drug for high-risk MM patients with bone lesions. The present results suggest the possibility of the further development of novel thalidomide derivatives by drug designing.     

New lithocholic and chenodeoxycholic piperazinylcarboxamides with antiproliferative and pro-apoptotic effects on human cancer cell lines

Six new synthetic bile acid derivatives were synthesized and tested in vitro against various human cancer cells (glioblastoma multiforme (GBM), multiple myeloma (KMS-11), and colonic carcinoma (HCT-116) cell lines. The best activity was obtained with compound IIIb on multiple myeloma cells (LD(50): 8.5+/-0.5 microM). This activity was associated with Mcl-1 and PARP-1 cleavage, inhibition of NFkappaB signaling, and DNA fragmentation, demonstrating an apoptotic cell death signaling pathway.     

Directly targeting c-Myc contributes to the anti-multiple myeloma effect of anlotinib

Despite the significant advances in the treatment of multiple myeloma (MM), this disease is still considered incurable because of relapse and chemotherapy resistance, underscoring the need to seek novel therapies with different mechanisms. Anlotinib, a novel multi-targeted tyrosine kinase inhibitor (TKI), has exhibited encouraging antitumor activity in several preclinical and clinical trials, but its effect on MM has not been studied yet. In this study, we found that anlotinib exhibits encouraging cytotoxicity in MM cells, overcomes the protective effect of the bone marrow microenvironment and suppresses tumor growth in the MM mouse xenograft model. We further examined the underlying molecular mechanism and found that anlotinib provokes cell cycle arrest, induces apoptosis and inhibits multiple signaling pathways. Importantly, we identify c-Myc as a novel direct target of anlotinib. The enhanced ubiquitin proteasomal degradation of c-Myc contributes to the cell apoptosis induced by anlotinib. In addition, anlotinib also displays strong cytotoxicity against bortezomib-resistant MM cells. Our study demonstrates the extraordinary anti-MM effect of anlotinib both in vitro and in vivo, which provides solid evidence and a promising rationale for future clinical application of anlotinib in the treatment of human MM.Subject terms: Myeloma, Target identification     

Targeting Trop-2 in cancer: Recent research progress and clinical application

The development of new antitumor drugs depends mainly upon targeting tumor cells precisely. Trophoblast surface antigen 2 (Trop-2) is a type I transmembrane glycoprotein involved in Ca²⁺ signaling in tumor cells. It is highly expressed in various tumor tissues than in normal tissues and represents a novel and promising molecular target for caner targeted therapy. Up to now, the mechanisms and functions associated with Trop-2 have been extensively studied in a variety of solid tumors. According to these findings, Trop-2 plays an important role in cell proliferation, apoptosis, cell adhesion, epithelial-mesenchymal transition, as well as tumorigenesis and tumor progression. In addition, Trop-2 related drugs are also being developed widely. There are a number of Trop-2 related ADC drugs that have demonstrated potent antitumor activity and are currently been studied, such as Sacituzumab Govitecan (SG) and Datopotamab Deruxtecan (Dato-Dxd). In this study, we reviewed the progress of Trop-2 research in solid tumors. We also sorted out the composition and rationale of Trop-2 related drugs and summarized the related clinical trials. Finally, we discussed the current status of Trop-2 research and expanded our perspectives on its future research directions. Importantly, we found that Trop-2 targeted ADCs have great potential for combination with other antitumor therapies. Trop-2 targeted ADCs can reprogramme tumor microenvironment through multiple signaling pathways, ultimately activating antitumor immunity.     

Targeting Proliferating Cell Nuclear Antigen and Its Protein Interactions Induces Apoptosis in Multiple Myeloma Cells

Multiple myeloma is a hematological cancer that is considered incurable despite advances in treatment strategy during the last decade. Therapies targeting single pathways are unlikely to succeed due to the heterogeneous nature of the malignancy. Proliferating cell nuclear antigen (PCNA) is a multifunctional protein essential for DNA replication and repair that is often overexpressed in cancer cells. Many proteins involved in the cellular stress response interact with PCNA through the five amino acid sequence AlkB homologue 2 PCNA-interacting motif (APIM). Thus inhibiting PCNA’s protein interactions may be a good strategy to target multiple pathways simultaneously. We initially found that overexpression of peptides containing the APIM sequence increases the sensitivity of cancer cells to contemporary therapeutics. Here we have designed a cell-penetrating APIM-containing peptide, ATX-101, that targets PCNA and show that it has anti-myeloma activity. We found that ATX-101 induced apoptosis in multiple myeloma cell lines and primary cancer cells, while bone marrow stromal cells and primary healthy lymphocytes were much less sensitive. ATX-101-induced apoptosis was caspase-dependent and cell cycle phase-independent. ATX-101 also increased multiple myeloma cells’ sensitivity against melphalan, a DNA damaging agent commonly used for treatment of multiple myeloma. In a xenograft mouse model, ATX-101 was well tolerated and increased the anti-tumor activity of melphalan. Therefore, targeting PCNA by ATX-101 may be a novel strategy in multiple myeloma treatment.     

Synthesis and biological evaluation of novel 4β-(1,3,4-oxadiazole-2-amino)-podophyllotoxin derivatives

A series of new 4β-(1,3,4-oxadiazole-2-amino)-podophyllotoxin derivatives were designed and synthesized. Their cytotoxicity in vitro against six tumor cell lines (DU-145, SGC-7901, A549, SH-SY5Y, HepG2 and HeLa) were evaluated by standard MTT assay. The pharmacological results showed that most of the newly synthesized podophyllotoxin derivatives displayed potent cytotoxicity against at least one of the tested tumor cells; and among the new derivatives, 11b was more potent than podophyllotoxin against HepG2 and Hela cell lines. Furthermore, 11b exhibited much better selectivity toward the normal cell lines L929 and Vero than etoposide, 5-Fu and podophyllotoxin. The possible antitumor mechanism of 11b is to inhibit the activity of DNA topoisomerase II, result in the S-phase arrest, and then cause apoptotic cell death.     

Synthesis and biological evaluation of the natural product komaroviquinone and related compounds aiming at a potential therapeutic lead compound for high-risk multiple myeloma

Alternatives of treatments for multiple myeloma (MM) have become increasingly available with the advent of new drugs such as proteasome inhibitors, thalidomide derivatives, histone deacetylase inhibitors, and antibody drugs. However, high-risk MM cases that are refractory to novel drugs remain, and further optimization of chemotherapeutics is urgently needed.We had achieved asymmetric total synthesis of komaroviquinone, which is a natural product from the plant Dracocephalum komarovi. Similar to several leading antitumor agents that have been developed from natural compounds, we describe the antitumor activity and cytotoxicity of komaroviquinone and related compounds in bone marrow cells. Our data suggested that komaroviquinone-related agents have potential as starting compounds for anticancer drug development.     

Interferon alpha induces cell death through interference with interleukin 6 signaling and inhibition of STAT3 activity

In multiple myeloma, which commonly depends on interleukin 6, IL-6, survival signaling induced by this cytokine is largely mediated by activation of STAT3. Interferon alpha (IFNalpha) treatment of cell lines derived from multiple myeloma or of myeloma tumor cells ex vivo leads to apoptosis. In this study we demonstrate that IFNalpha treatment of the two myeloma cell lines, U266-1984 and U-1958, results in the decrease of STAT3 activity as demonstrated by a diminished STAT3/3 DNA-binding activity and the shift from STAT3/3 towards STAT1/1 and STAT3/1 complexes in EMSA, leading to the down-regulation of known STAT3 target genes such as Bcl-X(L), Mcl-1 and survivin. Ectopic expression of a form of STAT3, STAT3C, rescued U266-1984 cells from IFNalpha-induced apoptosis. IFNalpha promoted sustained accumulation of tyrosine phosphorylated STAT3C in the nucleus and a prolonged DNA binding of the STAT3/3 homodimers in EMSA. The shift towards a sustained STAT3 response in IFNalpha-treated STAT3C-transfected cells led to a hyper-induction of Bcl-2 and Mcl-1 proteins. Thus our data demonstrated that IFNalpha is able to interfere with IL-6 signaling by inhibiting STAT3 activity and that the abrogation of STAT3 activity accounts for the ability of IFNalpha to induce apoptosis in myeloma cells.     

Elevation of Proteasomal Substrate Levels Sensitizes Cells to Apoptosis Induced by Inhibition of Proteasomal Deubiquitinases

Inhibitors of the catalytic activity of the 20S proteasome are cytotoxic to tumor cells and are currently in clinical use for treatment of multiple myeloma, whilst the deubiquitinase activity associated with the 19S regulatory subunit of the proteasome is also a valid target for anti-cancer drugs. The mechanisms underlying the therapeutic efficacy of these drugs and their selective toxicity towards cancer cells are not known. Here, we show that increasing the cellular levels of proteasome substrates using an inhibitor of Sec61-mediated protein translocation significantly increases the extent of apoptosis that is induced by inhibition of proteasomal deubiquitinase activity in both cancer derived and non-transformed cell lines. Our results suggest that increased generation of misfolded proteasome substrates may contribute to the mechanism(s) underlying the increased sensitivity of tumor cells to inhibitors of the ubiquitin-proteasome system.     

Sensitivity of tumor cells towards CIGB‐300 anticancer peptide relies on its nucleolar localization

CIGB‐300 is a novel anticancer peptide that impairs the casein kinase 2‐mediated phosphorylation by direct binding to the conserved phosphoacceptor site on their substrates. Previous findings indicated that CIGB‐300 inhibits tumor cell proliferation in vitro and induces tumor growth delay in vivo in cancer animal models. Interestingly, we had previously demonstrated that the putative oncogene B23/nucleophosmin (NPM) is the major intracellular target for CIGB‐300 in a sensitive human lung cancer cell line. However, the ability of this peptide to target B23/NPM in cancer cells with differential CIGB‐300 response phenotype remained to be determined. Interestingly, in this work, we evidenced that CIGB‐300's antiproliferative activity on tumor cells strongly correlates with its nucleolar localization, the main subcellular localization of the previously identified B23/NPM target. Likewise, using CIGB‐300 equipotent doses (concentration that inhibits 50% of proliferation), we demonstrated that this peptide interacts and inhibits B23/NPM phosphorylation in different cancer cell lines as evidenced by in vivo pull‐down and metabolic labeling experiments. Moreover, such inhibition was followed by a fast apoptosis on CIGB‐300‐treated cells and also an impairment of cell cycle progression mainly after 5 h of treatment. Altogether, our data not only validates B23/NPM as a main target for CIGB‐300 in cancer cells but also provides the first experimental clues to explain their differential antiproliferative response. Importantly, our findings suggest that further improvements to this cell penetrating peptide‐based drug should entail its more efficient intracellular delivery at such subcellular localization. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Inhibition of the MDM2 E3 Ligase Induces Apoptosis and Autophagy in Wild-Type and Mutant p53 Models of Multiple Myeloma,and Acts Synergistically with ABT-737

Intracellular proteolytic pathways have been validated as rational targets in multiple myeloma with the approval of two proteasome inhibitors in this disease, and with the finding that immunomodulatory agents work through an E3 ubiquitin ligase containing Cereblon. Another E3 ligase that could be a rational target is the murine double minute (MDM) 2 protein, which plays a role in p53 turnover. A novel inhibitor of this complex, MI-63, was found to induce apoptosis in p53 wild-type myeloma models in association with activation of a p53-mediated cell death program. MI-63 overcame adhesion-mediated drug resistance, showed anti-tumor activity in vivo, enhanced the activity of bortezomib and lenalidomide, and also overcame lenalidomide resistance. In mutant p53 models, inhibition of MDM2 with MI-63 also activated apoptosis, albeit at higher concentrations, and this was associated with activation of autophagy. When MI-63 was combined with the BH3 mimetic ABT-737, enhanced activity was seen in both wild-type and mutant p53 models. Finally, this regimen showed efficacy against primary plasma cells from patients with newly diagnosed and relapsed/refractory myeloma. These findings support the translation of novel MDM2 inhibitors both alone, and in combination with other novel agents, to the clinic for patients with multiple myeloma.     

Design and synthesis of chromone-nitrogen mustard derivatives and evaluation of anti-breast cancer activity

Chromone has emerged as one of the most important synthetic scaffolds for antitumor activity, which promotes the development of candidate drugs with better activity. In this study, a series of nitrogen mustard derivatives of chromone were designed and synthesised, in order to discover promising anti-breast tumour candidates. Almost all target derivatives showed antiproliferative activity against MCF-7 and MDA-MB-231 cell lines. In particular, methyl (S)-3-(4-(bis(2-chloroethyl)amino)phenyl)-2-(5-(((6-methoxy-4-oxo-4H-chromen-3-yl)methyl)amino)-5-oxopentanamido)propanoate showed the most potent antiproliferative activity with IC₅₀ values of 1.83 and 1.90 μM, respectively, and it also exhibited certain selectivity between tumour cells and normal cells. Further mechanism exploration against MDA-MB-231 cells showed that it possibly induced G2/M phase arrest and apoptosis by generating intracellular ROS and activating DNA damage. In addition, it also inhibited MDA-MB-231 cells metastasis, invasion and adhesion. Overall, methyl (S)-3-(4-(bis(2-chloroethyl)amino)phenyl)-2-(5-(((6-methoxy-4-oxo-4H-chromen-3-yl)methyl)amino)-5-oxopentanamido)propanoate showed potent antitumor activities and relatively low side effects, and deserved further investigation.     

Synthesis and biological evaluation of some 17-picolyl and 17-picolinylidene androst-5-ene derivatives

Starting from dehydroepiandrosterone (1) 17-picolyl (2), 17-picolinylidene (7), 17-picolinylidene-16-one (10 and 11), and 17-picolyl-16-one (15) derivatives of androst-5-ene were synthesized in one, two, four and five steps respectively. By the Oppenauer oxidation or dehydration of 2, 7, 10, and 11 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), the corresponding A and B ring modified derivatives 3, 5, 6, 8, 9, and 12-14 were obtained. The structure of 2 was unambiguously proved by the appropriate X-ray structural analysis. Compounds 3, 5, 9, 12-14 showed inhibitory activity against the enzyme aromatase. Antibacterial activity, toxicity to brine shrimp Artemia salina, antitumor activity against three tumor cell lines (human cervix carcinoma HeLa cells, human melanoma FemX cells, and human myelogenous leukemia K562 cells) and toxicity against peripheral blood mononuclear cells were evaluated. Three tested compounds, namely 11, 13, and 15, showed strong activity against all three cell lines, the IC(50) values being in the range of 4-10 microM.     

Synthesis,biological evaluation,and in silico studies of new CDK2 inhibitors based on pyrazolo[3,4-d]pyrimidine and pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine scaffold with apoptotic activity

Cyclin-dependent kinase inhibition is considered a promising target for cancer treatment for its crucial role in cell cycle regulation. Pyrazolo pyrimidine derivatives were well established for their antitumor activity via CDK2 inhibition. In this research, new series of pyrazolopyrimidine derivatives (4–15) was designed and synthesised as novel CDK2 inhibitors. The anti-proliferative activities against MCF-7, HCT-116, and HepG-2 were used to evaluate their anticancer activity as novel CDK2 inhibitors. Most of the compounds showed superior cytotoxic activity against MCF-7 and HCT-116 compared to Sorafenib. Only compounds 8, 14, and 15 showed potent activity against HepG-2. The CDK2/cyclin A2 enzyme inhibitory activity was tested for all synthesised compounds. Compound 15 showed the most significant inhibitory activity with IC₅₀ 0.061 ± 0.003 µM. It exerted remarkable alteration in Pre G1 and S phase cell cycle progression and caused apoptosis in HCT cells. In addition, the normal cell line cytotoxicity for compound 15 was assigned revealing low cytotoxic results in normal cells rather than cancer cells. Molecular docking was achieved on the designed compounds and confirmed the two essential hydrogen binding with Leu83 in CDK2 active site. In silico ADMET studies and drug-likeness showed proper pharmacokinetic properties which helped in structure requirements prediction for the observed antitumor activity.     

NMR studies on novel antitumor drug candidates, deoxoartemisinin and carboxypropyldeoxoartemisinin

Artemisinin and its derivatives, which have been known as antimalarial drugs, have also demonstrated their cytotoxicity against tumor cells. It has been proposed that antitumor activity depends on the lipophilicity of functional group on artemisinin derivatives. Solution structures of two artemisinin derivatives as antitumor drug candidates, deoxoartemisinin and carboxypropyldeoxoartemisinin, were determined by NMR spectroscopy to elucidate structure-activity relationship. According to biological assay, antitumor efficiencies are not dependent upon lipophilicity. Instead, these compounds demonstrated their distinctive structural features of boat/chair conformation and capability to interact with receptors, as they have different efficiencies on antitumor activity. Especially, carboxypropyl moiety or carbonyl moiety in artemisinin derivatives influences the conformation and stability of ring structure. Although the detailed mechanism of antitumor activity by artemisinin derivatives has not been addressed, we suggest that antitumor activity is not determined only with lipophilicity and that artemisinin derivatives have specific target proteins in each type of cancer.     

PHA-767491抑制多种肿瘤细胞生长

Cdc7激酶抑制剂PHA-767491是最新发现的一类抗肿瘤新药.本实验利用不同浓度的PHA-767491对肿瘤细胞进行抑制研究.实验结果显示,PHA-767491对肿瘤细胞有很强的生长抑制作用,且抑制效果随着药物浓度或时间的增加而增强;通过和化疗药物5-氟尿嘧啶对比发现,PHA-767491只需较低剂量就能发挥出抑制肿瘤的作用,且疗效远高于5-氟尿嘧啶.研究进一步还发现,PHA-767491可通过促使PARP和casepase3蛋白的剪切诱导肿瘤细胞凋亡,同时PHA-767491还可以引起肿瘤细胞自噬.综上研究表明,PHA-767491可以通过诱导细胞凋亡和引起细胞自噬作用对多种肿瘤细胞有较好的治疗效果,而对正常细胞毒性很低.因此该实验研究为今后抗肿瘤新药PHA-767491的进一步应用于癌症的临床治疗提供了重要的实验依据.     

Manipulation of cellular redox parameters for improving therapeutic responses in B-cell lymphoma and multiple myeloma

Developing novel combined-modality therapeutic approaches based on understanding of the involvement of redox biology in apoptosis of malignant cells is a promising approach for improving clinical responses in B-cell lymphoma and multiple myeloma. Therapeutic modalities that generate reactive oxygen species (i.e., radiation, photodynamic therapy, and specific chemotherapeutic drugs) have been shown to be selectively cytotoxic to malignant B-cells. In this review, we will discuss agents that induce apoptosis in B-cell tumors by oxidative stress. Subsequently, a novel biochemical rationale (based on fundamental differences in cancer vs. normal cell oxidative metabolism) for combining oxidative stressors with radiotherapy and chemotherapy, that may lead to designing of more effective treatment strategies for B-cell malignancies, will be discussed. Besides providing potential curative benefit, such novel therapies could also selectively target and inhibit the emergence of drug-resistance in tumor cells, which is a major determinant of treatment failure in many B-cell malignancies.     

Targeting Poly (ADP-Ribose) Polymerase Partially Contributes to Bufalin-Induced Cell Death in Multiple Myeloma Cells

Despite recent pharmaceutical advancements in therapeutic drugs, multiple myeloma (MM) remains an incurable disease. Recently, ploy(ADP-ribose) polymerase 1 (PARP1) has been shown as a potentially promising target for MM therapy. A previous report suggested bufalin, a component of traditional Chinese medicine (“Chan Su”), might target PARP1. However, this hypothesis has not been verified. We here showed that bufalin could inhibit PARP1 activity in vitro and reduce DNA–damage-induced poly(ADP-ribosyl)ation in MM cells. Molecular docking analysis revealed that the active site of bufalin interaction is within the catalytic domain of PAPR1. Thus, PARP1 is a putative target of bufalin. Furthermore, we showed, for the first time that the proliferation of MM cell lines (NCI-H929, U266, RPMI8226 and MM.1S) and primary CD138⁺ MM cells could be inhibited by bufalin, mainly via apoptosis and G₂-M phase cell cycle arrest. MM cell apoptosis was confirmed by apoptotic cell morphology, Annexin-V positive cells, and the caspase3 activation. We further evaluated the role of PARP1 in bufalin-induced apoptosis, discovering that PARP1 overexpression partially suppressed bufalin-induced cell death. Moreover, bufalin can act as chemosensitizer to enhance the cell growth-inhibitory effects of topotecan, camptothecin, etoposide and vorinostat in MM cells. Collectively, our data suggest that bufalin is a novel PARP1 inhibitor and a potentially promising therapeutic agent against MM alone or in combination with other drugs.