Preliminary application of micro-SPECT/CT imaging by 99m Tc-tricine-EDDA-HYNIC-c-Met for non-small-cell lung cancer.

OBJECTIVE: A novel 99m Tc-tricine-EDDA-Hynic-c-Met molecular probe was synthetized, and nude mice models of human non-small-cell lung cancer (NSCLC) were established in order to preliminarily investigate that whether the molecular probe can be used to screen c-Met inhibitor for targeted drug therapy in NSCLC. METHODS: With Hynic as the chelating agent, 99m TcO4 -labeled c-Met receptor was used to synthetize 99m Tc-tricine-EDDA-HYNIC-c-Met. Two nude mice successfully transplanted with H1993 tumor and two nude mice transplanted with H292 tumor were injected with 99m Tc-tricine-EDDA-HYNIC-c-Met through the tail vein. After 2 and 4 hr, micro-SPECT/CT imaging was performed. RESULTS: micro-SPECT/CT imaging of nude mice transplanted with H1993 and H292 tumors using 99m Tc-tricine-EDDA-HYNIC-c-Met showed that uptake of 99m Tc-tricine-EDDA-HYNIC-c-Met was high in H1993 tumor, while it was mild in H292 tumor both at 2 and 4 hr postinjection. Semiquantitative analysis of the ratio of radioactivity intensity at tumor site to radioactivity intensity of adjacent muscles (T/N value) showed that the average T/N value of H1993 and H292 tumors at 2 hr was 3.90 and 2.85, while it was 4.88 and 2.36 at 4 hr. CONCLUSION: micro-SPECT/CT imaging through 99m Tc-tricine-EDDA-HYNIC-c-Met can be used to screen c-Met indicators of NSCLC in H1993 nude mice models for targeted drug therapy.

Molecular regulation of apoptotic machinery and lipid metabolism by mTORC1/mTORC2 dual inhibitors in preclinical models of HER2+/PIK3CAmut breast cancer.

The mechanistic target of rapamycin (mTOR) is a rational target for cancer treatment. While the mTORC1-selective rapalogs have shown significant benefits in the clinic, antitumor response may be further improved by inhibiting both mTORC1 and mTORC2. Herein, we established target profile of a novel mTOR kinase inhibitor (mTOR-KI) MTI-31 and employed it to study new therapeutic mechanism in breast cancer. MTI-31 demonstrated a potent mTOR binding affinity with >5000 fold selectivity over the related PI3K family isoforms. MTI-31 inhibited mTORC1- and mTORC2 function at ≤120 nM in cellular assays or 5 mg/kg orally in tumor-bearing mice. In a panel of breast cancer lines, the antitumor efficacy of MTI-31 was dependent on HER2+ and/or PIK3CAmut (HER2+/PIK3CAmut) status of the tumors and required mTORC2-specific modulation of Bim, MCL-1 and GSK3. Inactivation of Bim or GSK3 each attenuated apoptotic death resulting in mTOR-KI resistance. The antitumor response also required a suppression of lipid metabolism in therapy-sensitive tumors. Treatment with MTI-31 or AZD8055 substantially reduced lipogenesis and acetyl-CoA homeostasis, which was mechanistically linked to a blockade of mTORC2-dependent glucose-to-lipid conversion rate. We also found that the basal levels of carnitine palmitoyltransferase 1A and lipid catabolism were elevated in HER2+/PIK3CAmut breast cells and were inhibited upon mTOR-KI treatment. A CPT1A inhibitor etomoxir mimicked MTI-31 action in selective downregulation of cellular lipid catabolism. Co-treatments with MTI-31 and etomoxir enhanced the suppression of cyclin D1, c-Myc and cell growth in HER2+/PIK3CAmut tumors. These new mechanistic findings provide a rationale for targeting mTORC1 and mTORC2 in HER2+/PIK3CAmut breast cancer.

Synthesis and antitumor evaluation of novel hybrids of phenylsulfonylfuroxan and epiandrosterone/dehydroepiandrosterone derivatives.

Thirteen novel furoxan-based nitric oxide (NO) releasing hybrids (14a-e, 15a-e, 17b-d) of 16,17-pyrazo-annulated steroidal derivatives were synthesized and evaluated against the MDA-MB-231, HCC1806, SKOV-3, DU145, and HUVEC cell lines for their in vitro anti-proliferative activity. Most of the compounds displayed potent anti-proliferative effects. Among them, 17c exhibited the best activity with IC50 values of 20-1.4nM against four cell lines (MDA-MB-231, SKOV-3, DU145, and HUVEC), and 1.03µM against a tamoxifen resistant breast cancer cell line (HCC1806). Furthermore, five compounds (14a, 15a, 17b-d) were selected to screen for VEGF inhibitory activity. Compounds 15a, 17b,c showed obviously better activity than 2-Methoxyestradiol (2-ME) on reducing levels of VEGF secreted by MDA-MB-231 cell line. In a Capillary-like Tube Formation Assay, compounds 17b,c exhibited a significant suppression of the tubule formation in the concentration of 1.75nM and 58nM, respectively. The preliminary SAR showed that steroidal scaffolds with a linker in 3-position were favorable moieties to evidently increase the bioactivities of these hybrids. Overall, these results implied that 17c merited to be further investigated as a promising anti-cancer candidate.

Investigations of (99m)Tc-labeled glucarate as a SPECT radiotracer for non-small cell lung cancer (NSCLC) and potential tumor uptake mechanism.

This study attempted to evaluate the feasibility of (99m)Tc-labeled glucarate ((99m)Tc-GLA) imaging in non-small cell lung cancer (NSCLC) and the potential tumor uptake mechanism. Cell lysates from two NSCLC cell lines, H292 and H1975, were immunoblotted with anti-glucose transporter 5 (GLUT5) antibody for Western blotting. Thereafter, the two cell lines were used to examine cellular uptake of (99m)Tc-GLA with or without fructose. SPECT/CT imaging studies were performed on small animals bearing H292 and H1975 tumors. Biodistribution studies were also conducted to achieve accurate tissue uptake of this tracer in two tumor models. Hematoxylin & eosin (H&E) staining and GLUT5, Ki67 and cytokeratin-7 (CK-7) immunohistochemistry (IHC) analysis were further investigated on tumor tissues. In Western blotting, H292 cells showed higher levels of GLUT5 compared to the H1975 cells. Meanwhile, the in vitro cell assays indicated GLUT5-dependent uptake of (99m)Tc-GLA in H292 and H1975 cells. The fructose competition assays showed a significant decrease in (99m)Tc-GLA uptake by H292 and H1975 cells when fructose was added. The (99m)Tc-GLA accumulation was as much as two-fold higher in H292 implanted tumors than in H1975 implanted tumors. (99m)Tc-GLA exhibited rapid clearance pharmacokinetics and reasonable uptake in human NSCLC H292 (1.69±0.37 ID%/g) and H1975 (0.89±0.06 ID%/g) implanted tumors at 30min post injection. Finally, the expression of GLUT5, Ki67 and CK-7 on tumor tissues also exhibited positive correlation with the in vitro cell test results and in vivo SPECT/CT imaging results in xenograft tumors. Both in vitro and ex vivo studies demonstrated that the uptake of (99m)Tc-GLA in NSCLC is highly related to GLUT5 expression. Imaging and further IHC results support that (99m)Tc-GLA could be a promising SPECT imaging agent for NSCLC diagnosis and prognosis evaluation.

A novel lead compound CM-118: antitumor activity and new insight into the molecular mechanism and combination therapy strategy in c-Met- and ALK-dependent cancers.

The anaplastic lymphoma kinase (ALK) and the c-Met receptor tyrosine kinase play essential roles in the pathogenesis in multiple human cancers and present emerging targets for cancer treatment. Here, we describe CM-118, a novel lead compound displaying low nanomolar biochemical potency against both ALK and c-Met with selectivity over>90 human kinases. CM-118 potently abrogated hepatocyte growth factor (HGF)-induced c-Met phosphorylation and cell migration, phosphorylation of ALK, EML4-ALK, and ALK resistance mutants in transfected cells. CM-118 inhibited proliferation and/or induced apoptosis in multiple c-Met- and ALK-addicted cancer lines with dose response profile correlating target blockade. We show that the CM-118-induced apoptosis in c-Met-amplified H1993 NSCLC cells involved a rapid suppression of c-Met activity and c-Met-to-EGFR cross-talk, and was profoundly potentiated by EGFR inhibitors as shown by the increased levels of apoptotic proteins cleaved-PARP and Bim as well as reduction of the survival protein Mcl-1. Bim-knockdown or Mcl-1 overexpression each significantly attenuated apoptosis. We also revealed a key role by mTOR in mediating CM-118 action against the EML4-ALK-dependent NSCLC cells. Abrogation of EML4-ALK in H2228 cells profoundly reduced signaling capacity of the rapamycin-sensitive mTOR pathway leading to G 1 cell cycle arrest and mitochondrial hyperpolarization, a metabolic perturbation linked to mTOR inhibition. Depletion of mTOR or mTORC1 inhibited H2228 cell growth, and mTOR inhibitors potentiated CM-118's antitumor activity in vitro and in vivo. Oral administration of CM-118 at a wide range of well tolerated dosages diminished c-Met- and ALK phosphorylation in vivo, and caused tumor regression or growth inhibition in multiple c-Met- and ALK-dependent tumor xenografts in mice. CM-118 exhibits favorable pharmacokinetic and drug metabolism properties hence presents a candidate for clinical evaluation.