Liguang Lou

YN968D1 is a novel and selective inhibitor of vascular endothelial growth factor receptor-2 tyrosine kinase with potent activity in vitro and in vivo.

Angiogenesis is an important process in cell development, especially in cancer. Vascular endothelial growth factor (VEGF) signaling is an important regulator of angiogenesis. Several therapies that act against VEGF signal transduction have been developed, including YN968D1, which is a potent inhibitor of the VEGF signaling pathway. This study investigated the antitumor activity of YN968D1 (apatinib mesylate) in vitro and in vivo. YN968D1 potently suppressed the kinase activities of VEGFR‐2, c‐kit and c‐src, and inhibited cellular phosphorylation of VEGFR‐2, c‐kit and PDGFRβ. YN968D1 effectively inhibited proliferation, migration and tube formation of human umbilical vein endothelial cells induced by FBS, and blocked the budding of rat aortic ring. In vivo, YN968D1 alone and in combination with chemotherapeutic agents effectively inhibited the growth of several established human tumor xenograft models with little toxicity. A phase I study of YN968D1 has shown encouraging antitumor activity and a manageable toxicity profile. These findings suggest that YN968D1 has promise as an antitumor drug and might have clinical benefits. (Cancer Sci 2011; 102: 1374–1380)

Synthesis and biological evaluation of novel 2,4,5-substituted pyrimidine derivatives for anticancer activity

A series of novel 2,4,5-substituted pyrimidine derivatives were synthesized and evaluated for inhibition against the human hepatocellular carcinoma BEL-7402 cancer cell line. Several compounds showed potent inhibition with an IC(50) value less than 0.10 microM. Structure-activity relationships for this class of compounds at the 2- and 5-position of the pyrimidine scaffold have been elucidated. The most active compound 7gc showed good inhibition of several different human cancer cell lines with IC(50) values from 0.024 to 0.55 microM.

p38 MAPK, but not ERK1/2, is critically involved in the cytotoxicity of the novel vascular disrupting agent combretastatin A4

Combretastatin A4 (CA4) is a novel vascular disrupting agent that has promising clinical efficacy because of its ability to inhibit microtubule assembly and subsequently disrupt tumor blood flow. In this study, we demonstrate that mitogen‐activated protein kinases (MAPKs) are critically involved in the cytotoxicity of CA4. CA4 stimulates both extracellular signal‐regulated kinases (ERK1/2) and p38 MAPK in the BEL‐7402 hepatocellular carcinoma cell line in a time‐ and dose‐dependent manner. This stimulation is a result of CA4‐induced microtubule disassembly, which is a reversible process. Reversibility of microtubule disassembly is evidenced by the ability of disassembled microtubules to reassemble just a few hours after CA4 treatment. p38 MAPK, but not ERK1/2, contributes to this microtubule reassembly following CA4 exposure, and only inhibition of p38 MAPK, but not ERK1/2, synergistically enhances CA4‐induced G2/M cell cycle arrest. Consistent with this, p38 MAPK inhibitors such as SB203580 and SB202190 also synergistically enhance the cytotoxicity of CA4 in cells where p38 MAPK is activated by CA4. This enhancement appears to be specific for CA4 because the cytotoxicity of other microtubule‐targeted agents such as paclitaxel, vinorelbine and colchicine was not affected by p38 MAPK inhibitors. These data indicate that p38 MAPK is a potential anticancer target and that the combination of CA4 with p38 MAPK inhibitors may be a novel and promising strategy for cancer therapy.

Synthesis and anticancer activity of [2-hydroxy-1,3-diaminopropane-κ2N,N'] platinum(II) complexes

A series of novel platinum(II) complexes involving a carrier with HO- peripheral functional group, 2-hydroxy-1,3-propanediamine (HO-pda), cis-[Pt(HO-dpa)X(2)] (X(2)=2Cl(-) (1), C(2)O(4)(2-) (2), malonate (3), 1,1-cyclobutane dicarboxylate (CBDCA) (4), 3-hydroxy-1,1-cyclobutanedicarboxylate (HO-CBDCA) (5)), have been synthesized and characterized by elemental analysis and spectroscopic data along with X-ray diffraction for three representative complexes 1, 4 and 5. The Pt(II) is in a square planar environment and is coordinated in cis position by a chelating HO-pda and 2Cl(-) for 1 and CBDCA for 4 and 5. Pt-N, Pt-Cl and Pt-O distances and coordinate bond angles of N-Pt-N, Cl-Pt-Cl and O-Pt-O are in the normal range. There are two independent molecules in the asymmetric unit of 5, held together by intermolecular hydrogen bonded chain. All the complexes show significant cytotoxicity on the sensitive cell lines SGC-7901, LNcap and A549, and are more active than carboplatin. 4 is also found to be active against the resistant cell A549/ATCC, which suggests that it has less cross-resistance with cisplatin than carboplatin. Moreover 4 shows much greater inhibition of tumor growth than carboplatin in S180-bearing mice, and is therefore worthy of further development as a potential anti-tumor platinum drug.

(5R)-5-hydroxytriptolide (LLDT-8), a novel immunosuppressant in clinical trials, exhibits potent antitumor activity via transcription inhibition

(5R)-5-hydroxytriptolide (LLDT-8), a triptolide derivative, is a low-toxicity immunosuppressant in Phase I clinical trials. Here, we demonstrate that LLDT-8 displays broad-spectrum, potent (nanomolar level IC(50)s) antitumor activity, and induces S-phase cell-cycle arrest and apoptosis in vitro. Notably, LLDT-8 effectively overcomes multidrug resistance mediated by P-glycoprotein. In vivo, LLDT-8 demonstrates potent antitumor activity, particularly against human ovarian cancer 3AO and prostate cancer PC-3 xenografts in nude mice. The antitumor activity of LLDT-8 is achieved by virtue of its general inhibition of gene transcription. Our results indicate that LLDT-8 is a novel transcription inhibitor with potential for cancer therapy, particularly for cancers with drug resistance mediated by P-glycoprotein.

Antitumor activity of lobaplatin alone or in combination with antitubulin agents in non-small-cell lung cancer.

ObjectiveLobaplatin is used to treat patients with breast cancer, small-cell lung cancer, and chronic myelogenous leukemia in China. In this study, we assessed the in-vitro and in-vivo activities of lobaplatin alone or in combination with antitubulin agents against human non-small-cell lung cancer (NSCLC). MethodsThe cytotoxicities of lobaplatin against NSCLC cells were determined by the sulforhodamine B (SRB) assay. Cell cycle analysis and apoptosis were assessed using flow cytometry, and the in-vivo antitumor activities were evaluated in human NSCLC xenografts in nude mice. ResultsThe cytotoxicity of lobaplatin was similar to or higher than that of cisplatin and carboplatin, with a mean IC50 of 2.5 &mgr;mol/l in a variety of NSCLC cells. In addition, lobaplatin arrested cells in the S phase and triggered apoptosis. The combination of lobaplatin with antitubulin agents yielded synergistic cytotoxic activity in vitro. In NSCLC xenografts, lobaplatin alone showed significant antitumor activity. The combination of lobaplatin with antitubulin agents, especially with paclitaxel, led to significantly enhanced activity, which was superior to that of cisplatin combined with antitubulin agents. ConclusionThese data demonstrate that the use of lobaplatin alone or in combination with antitubulin agents might be a rational and novel therapeutic strategy for human NSCLC and warrants further clinical investigation.

A novel water-soluble heptaplatin analogue with improved antitumor activity and reduced toxicity.

A novel water-soluble heptaplatin analogue, cis-[(4R,5R)-4,5-bis-(aminomethyl)-2-isopropyl-1,3-dioxolane](3-hydroxy-1,1-cyclobutanedicarboxylato)platinum(II), has been synthesized and biologically evaluated. The complex shows more activity and less toxicity than its parent drug heptaplatin, exhibiting the great potential for further development.

NL-103, a novel dual-targeted inhibitor of histone deacetylases and hedgehog pathway, effectively overcomes vismodegib resistance conferred by Smo mutations

Misregulation of hedgehog (Hh) signaling has been implicated in the pathogenesis of basal cell carcinoma (BCC) and medulloblastoma. Vismodegib, an orally bioavailable Hh signal pathway inhibitor targeting Smo, has been approved for the treatment of advanced BCC. However, acquired drug resistance to vismodegib induced by point mutation in Smo is emerging as a major problem to vismodegib treatment. In this study, we designed and synthesized a novel chimeric compound NL‐103, which comprises structural elements of Hh pathway inhibitor vismodegib, and histone deacetylase (HDAC) inhibitor vorinostat. NL‐103 simultaneously and significantly inhibited both HDACs and Hh pathway. Importantly, NL‐103, as well as vorinostat, effectively overcame vismodegib resistance induced by Smoothened point mutations. Moreover, NL‐103 and vorinostat, but not vismodegib, significantly downregulated the expression of Gli2 which plays an important role in Hh pathway. These results indicate that HDAC inhibitory activity is essential for NL‐103 to overcome vismodegib resistance and that dual inhibition of HDAC and Hh signaling pathway may be a rational strategy for overcoming vismodegib resistance. Our findings suggest that NL‐103 may be a promising compound for clinical development as a more effective Hh pathway inhibitor.

Synthesis, anticancer activity and toxicity of a water-soluble 4S,5S-derivative of heptaplatin, cis-{Pt(II)[(4S,5S)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]·(3-hydroxyl-cyclobutane-1,1-dicarboxylate)}.

A water-soluble 4S,5S-derivative of heptaplatin, cis-{Pt(II)[(4S,5S)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]·(3-hydroxyl-cyclobutane-1,1-dicarboxylate)} was synthesized. The anticancer activity and toxicity were evaluated by comparing its interaction with DNA, cytotoxicity against four human cancer cell lines, antitumor efficiency in human gastric carcinoma NCI-N87 xenografts in nude mice, and preliminary side-effects in rats to those of its 4R,5R-optical isomer which is under preclinical development. Both isomers induce condensation of DNA to the same extent and have similar cytotoxicity, but show different antitumor activity and toxicity, probably owing to the difference in respective pharmacokinetic profiles. 4S,5S-Isomer seems to exhibit superior antitumor activity and less toxicity than 4R,5R-optical isomer as well as the parent heptaplatin. These results imply that 4S,5S-configuration as a new drug candidate may be better than 4R,5R-counterpart.

Unusual Dimeric Chemical Structure for a Carboplatin Analogue as a Potential Anticancer Complex

An unexpected and unusual dimeric platinum(II) tetracarboxylate complex was obtained by the reaction of cis-[Pt(NH(3))(2)I(2)] with disilver dicarboxylate. The complex exhibits greater in vitro anticancer activity and lower toxicity in mice than its parent compound, carboplatin, and is therefore worthy of further evaluation as a potential antitumor dinuclear platinum agent.