Exploring the Complementarity of Pancreatic Ductal Adenocarcinoma Preclinical Models.

Purpose: Compare pancreatic ductal adenocarcinoma (PDAC), preclinical models, by their transcriptome and drug response landscapes to evaluate their complementarity. Experimental Design: Three paired PDAC preclinical models-patient-derived xenografts (PDX), xenograft-derived pancreatic organoids (XDPO) and xenograft-derived primary cell cultures (XDPCC)-were derived from 20 patients and analyzed at the transcriptomic and chemosensitivity level. Transcriptomic characterization was performed using the basal-like/classical subtyping and the PDAC molecular gradient (PAMG). Chemosensitivity for gemcitabine, irinotecan, 5-fluorouracil and oxaliplatin was established and the associated biological pathways were determined using independent component analysis (ICA) on the transcriptome of each model. The selection criteria used to identify the different components was the chemosensitivity score (CSS) found for each drug in each model. Results: PDX was the most dispersed model whereas XDPO and XDPCC were mainly classical and basal-like, respectively. Chemosensitivity scoring determines that PDX and XDPO display a positive correlation for three out of four drugs tested, whereas PDX and XDPCC did not correlate. No match was observed for each tumor chemosensitivity in the different models. Finally, pathway analysis shows a significant association between PDX and XDPO for the chemosensitivity-associated pathways and PDX and XDPCC for the chemoresistance-associated pathways. Conclusions: Each PDAC preclinical model possesses a unique basal-like/classical transcriptomic phenotype that strongly influences their global chemosensitivity. Each preclinical model is imperfect but complementary, suggesting that a more representative approach of the clinical reality could be obtained by combining them. Translational Relevance: The identification of molecular signatures that underpin drug sensitivity to chemotherapy in PDAC remains clinically challenging. Importantly, the vast majority of studies using preclinical in vivo and in vitro models fail when transferred to patients in a clinical setting despite initially promising results. This study presents for the first time a comparison between three preclinical models directly derived from the same patients. We show that their applicability to preclinical studies should be considered with a complementary focus, avoiding tumor-based direct extrapolations, which might generate misleading conclusions and consequently the overlook of clinically relevant features.

PDX-MI: Minimal Information for Patient-Derived Tumor Xenograft Models.

Patient-derived tumor xenograft (PDX) mouse models have emerged as an important oncology research platform to study tumor evolution, mechanisms of drug response and resistance, and tailoring chemotherapeutic approaches for individual patients. The lack of robust standards for reporting on PDX models has hampered the ability of researchers to find relevant PDX models and associated data. Here we present the PDX models minimal information standard (PDX-MI) for reporting on the generation, quality assurance, and use of PDX models. PDX-MI defines the minimal information for describing the clinical attributes of a patient's tumor, the processes of implantation and passaging of tumors in a host mouse strain, quality assurance methods, and the use of PDX models in cancer research. Adherence to PDX-MI standards will facilitate accurate search results for oncology models and their associated data across distributed repository databases and promote reproducibility in research studies using these models. Cancer Res; 77(21); e62-66. ©2017 AACR.

Chemotherapy-Resistant Human Acute Myeloid Leukemia Cells Are Not Enriched for Leukemic Stem Cells but Require Oxidative Metabolism.

Chemotherapy-resistant human acute myeloid leukemia (AML) cells are thought to be enriched in quiescent immature leukemic stem cells (LSC). To validate this hypothesis in vivo, we developed a clinically relevant chemotherapeutic approach treating patient-derived xenografts (PDX) with cytarabine (AraC). AraC residual AML cells are enriched in neither immature, quiescent cells nor LSCs. Strikingly, AraC-resistant preexisting and persisting cells displayed high levels of reactive oxygen species, showed increased mitochondrial mass, and retained active polarized mitochondria, consistent with a high oxidative phosphorylation (OXPHOS) status. AraC residual cells exhibited increased fatty-acid oxidation, upregulated CD36 expression, and a high OXPHOS gene signature predictive for treatment response in PDX and patients with AML. High OXPHOS but not low OXPHOS human AML cell lines were chemoresistant in vivo. Targeting mitochondrial protein synthesis, electron transfer, or fatty-acid oxidation induced an energetic shift toward low OXPHOS and markedly enhanced antileukemic effects of AraC. Together, this study demonstrates that essential mitochondrial functions contribute to AraC resistance in AML and are a robust hallmark of AraC sensitivity and a promising therapeutic avenue to treat AML residual disease.Significance: AraC-resistant AML cells exhibit metabolic features and gene signatures consistent with a high OXPHOS status. In these cells, targeting mitochondrial metabolism through the CD36-FAO-OXPHOS axis induces an energetic shift toward low OXPHOS and strongly enhanced antileukemic effects of AraC, offering a promising avenue to design new therapeutic strategies and fight AraC resistance in AML. Cancer Discov; 7(7); 716-35. ©2017 AACR.See related commentary by Schimmer, p. 670This article is highlighted in the In This Issue feature, p. 653.

Steroidal saponins from Dioscorea preussii.

Three new steroidal saponins, named diospreussinosides A-C (1-3), along with two known ones (4, 5) were isolated from rhizomes of Dioscorea preussii. Their structures were elucidated mainly by 1D and 2D NMR spectroscopic analysis and mass spectrometry as (25S)-17α,25-dihydroxyspirost-5-en-3ß-yl-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-ß-D-glucopyranoside (1), (25S)-17α,25-dihydroxyspirost-5-en-3ß-yl-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside (2), and (24S,25R)-17α,24,25-trihydroxyspirost-5-en-3ß-yl-O-α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→4)-[α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside (3). The spirostane-type skeleton of compound 3 possessing an unusual dihydroxylation pattern on the F-ring is reported for the first time. Cytotoxicity of compounds 2-5 was evaluated against two human colon carcinoma cell lines (HT-29 and HCT 116).

Structure and cytotoxicity of steroidal glycosides from Allium schoenoprasum.

A phytochemical analysis of the whole plant of Allium schoenoprasum, has led to the isolation of four spirostane-type glycosides (1-4), and four known steroidal saponins. Their structures were elucidated mainly by 2D NMR spectroscopic analysis and mass spectrometry as (20S,25S)-spirost-5-en-3ß,12ß,21-triol 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranoside (1), (20S,25S)-spirost-5-en-3ß,11α,21-triol 3-O-α-L-rhamnopyranosyl-(1→2)-ß-D-glucopyranoside (2), laxogenin 3-O-α-L-rhamnopyranosyl-(1→2)-[ß-D-glucopyranosyl-(1→4)]-ß-D-glucopyranoside (3), and (25R)-5α-spirostan-3ß,11α-diol 3-O-ß-D-glucopyranosyl-(1→3)-[ß-D-glucopyranosyl-(1→4)]-ß-D-galactopyranoside (4). Four of the isolated compounds were tested for cytotoxic activity against the HCT 116 and HT-29 human colon cancer cell lines.

In-vivo metabolic characterization of healthy prostate and orthotopic prostate cancer in rats using proton magnetic resonance spectroscopy at 4.7 T.

BACKGROUND: To assist the development of new anti-cancer drugs, it is important to identify biomarkers of treatment efficacy in the preclinical phases of drug development. In order to improve the predictivity of preclinical experiments, more realistic animal models are needed, for example, tumors xenografted directly on the prostate gland of rodents. PURPOSE: To characterize the in-vivo metabolism of healthy rat prostate and of an orthotopic human prostate cancer model using proton magnetic resonance spectroscopy (MRS). MATERIAL AND METHODS: The highly metastatic and hormone-independent PC3-MM2 human prostate cancer model was implanted into the ventral prostate lobe of three Nude rats. Healthy Nude (n = 6) and Sprague-Dawley (n = 6) rats were also studied for interspecies comparison of normal prostate metabolism. Magnetic resonance imaging and short echo-time (TE 11.2 ms) single voxel PRESS spectroscopy were performed on dorsal (DP) and ventral (VP) prostate as well as tumor at 4.7 T. The metabolic content and volume of dorsal and ventral lobes were characterized as a function of species and age. RESULTS: Slightly lower total creatine (tCr)/water (11.3 ± 2.6 vs. 15.3 ± 3.0, NS), but significantly higher Inositol (Ins)/water (18.9 ± 1.9 vs. 6.6 ± 3.3, P < 0.003) and total choline (tCho)/water (15.0 ± 2.1 vs. 5.6 ± 1.1, P < 0.00007) were observed within healthy DP lobes with respect to VP lobes. No significant variation in metabolic content was seen in healthy DP and VP lobes of Nude rats as a function of age, and no species dependence was observed in their metabolic content. For the orthotopic PC3-MM2 tumor, implanted in VP, the tCr/water ratio was significantly lower (3.1 ± 0.9) than neighboring DP (12.8 ± 1.8, P < 0.00003) and healthy VP (15.3 ± 3.0, P < 0.00006). For Ins, the metabolite ratio in PC3-MM2 was close to that of healthy VP (4.3 ± 2.8 vs. 6.6 ± 3.3, p = NS), but much lower than in neighboring DP (19.1 ± 1.3, P < 0.00005). A similar trend was also observed for tCho, where metabolite ratios in PC3-MM2, healthy VP and neighboring DP were 3.5 ± 0.9, 5.6 ± 1.1, and 15.9 ± 0.8, respectively. CONCLUSION: The in-vivo MRS study of healthy prostate and orthotopic prostate cancer is feasible in rats. Such baseline data could be important when following the modifications in metabolism, including during anti-cancer drug development protocols or following radiotherapy.

Characterization of a large panel of patient-derived tumor xenografts representing the clinical heterogeneity of human colorectal cancer.

PURPOSE: Patient-derived xenograft models are considered to represent the heterogeneity of human cancers and advanced preclinical models. Our consortium joins efforts to extensively develop and characterize a new collection of patient-derived colorectal cancer (CRC) models. EXPERIMENTAL DESIGN: From the 85 unsupervised surgical colorectal samples collection, 54 tumors were successfully xenografted in immunodeficient mice and rats, representing 35 primary tumors, 5 peritoneal carcinoses and 14 metastases. Histologic and molecular characterization of patient tumors, first and late passages on mice includes the sequence of key genes involved in CRC (i.e., APC, KRAS, TP53), aCGH, and transcriptomic analysis. RESULTS: This comprehensive characterization shows that our collection recapitulates the clinical situation about the histopathology and molecular diversity of CRC. Moreover, patient tumors and corresponding models are clustering together allowing comparison studies between clinical and preclinical data. Hence, we conducted pharmacologic monotherapy studies with standard of care for CRC (5-fluorouracil, oxaliplatin, irinotecan, and cetuximab). Through this extensive in vivo analysis, we have shown the loss of human stroma cells after engraftment, observed a metastatic phenotype in some models, and finally compared the molecular profile with the drug sensitivity of each tumor model. Through an experimental cetuximab phase II trial, we confirmed the key role of KRAS mutation in cetuximab resistance. CONCLUSIONS: This new collection could bring benefit to evaluate novel targeted therapeutic strategies and to better understand the basis for sensitivity or resistance of tumors from individual patients.

Solanum incanum and S. heteracanthum as sources of biologically active steroid glycosides: confirmation of their synonymy.

A new spirostanol saponin (1), along with four known saponins, dioscin (2), protodioscin (3), methyl-protodioscin (4), and indioside D (5), and one known steroid glycoalkaloid solamargine (6) were isolated from the two synonymous species, Solanum incanum and S. heteracanthum. The structure of the new saponin was established as (23S,25R)-spirost-5-en-3ß,23-diol 3-O-{ß-D-xylopyranosyl-(1→2)-O-α-L-rhamnopyranosyl-(1→4)-[O-α-L-rhamnopyranosyl-(1→2)]-ß-D-glucopyranoside}, by using a combination of 1D and 2D NMR techniques including (1)H, (13)C, COSY, TOCSY, NOESY, HSQC and HMBC experiments and by mass spectrometry. The compounds 1, 3, 4 and 5 were evaluated for cytotoxicity against five cancer cell lines and for antioxidant and cytoprotective activity.

DOTAGA-trastuzumab. A new antibody conjugate targeting HER2/Neu antigen for diagnostic purposes.

Improved bifunctional chelating agents (BFC) are required for indium-111 radiolabeling of monoclonal antibodies (mAbs) under mild conditions to yield stable, target-specific agents. 2,2',2"-(10-(2,6-Dioxotetrahydro-2H-pyran-3-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid (DOTAGA-anhydride) was evaluated for mAb conjugation and labeling with indium-111. The DOTA analogue was synthesized and conjugated to trastuzumab-which targets the HER2/neu receptor-in mild conditions (PBS pH 7.4, 25 °C, 30 min) and gave a mean degree of conjugation of 2.6 macrocycle per antibody. Labeling of this immunoconjugate with indium-111 was performed in 75% yield after 1 h at 37 °C, and the proportion of (111)In-DOTAGA-trastuzumab reached 97% after purification. The affinity of DOTAGA-trastuzumab was 5.5 ± 0.6 nM as evaluated by in vitro saturation assays using HCC1954 breast cancer cell line. SPECT/CT imaging and biodistribution studies were performed in mice bearing breast cancer BT-474 xenografts. BT-474 tumors were clearly visualized on SPECT images at 24, 48, and 72 h postinjection. The tumor uptake of [(111)In-DOTAGA]-trastuzumab reached 65%ID/g 72 h postinjection. These results show that the DOTAGA BFC appears to be a valuable tool for biologics conjugation.

An evaluation of 2-deoxy-2-[18F]fluoro-D-glucose and 3'-deoxy-3'-[18F]-fluorothymidine uptake in human tumor xenograft models.

PURPOSE: The aim of this study is to assess the variability of 2-deoxy-2-[(18)F]fluoro-D: -glucose ([(18)F]-FDG) and 3'-deoxy-3'-[(18)F]-fluorothymidine ([(18)F]-FLT) uptake in pre-clinical tumor models and examine the relationship between imaging data and related histological biomarkers. PROCEDURES: [(18)F]-FDG and [(18)F]-FLT studies were carried out in nine human tumor xenograft models in mice. A selection of the models underwent histological analysis for endpoints relevant to radiotracer uptake. Comparisons were made between in vitro uptake, in vivo imaging, and ex vivo histopathology data using quantitative and semi-quantitative analysis. RESULTS: In vitro data revealed that [1-(14)C]-2-deoxy-D: -glucose ([(14)C]-2DG) uptake in the tumor cell lines was variable. In vivo, [(18)F]-FDG and [(18)F]-FLT uptake was highly variable across tumor types and uptake of one tracer was not predictive for the other. [(14)C]-2DG uptake in vitro did not predict for [(18)F]-FDG uptake in vivo. [(18)F]-FDG SUV was inversely proportional to Ki67 and necrosis levels and positively correlated with HKI. [(18)F]-FLT uptake positively correlated with Ki67 and TK1. CONCLUSION: When evaluating imaging biomarkers in response to therapy, the choice of tumor model should take into account in vivo baseline radiotracer uptake, which can vary significantly between models.

Triterpenoid saponins from Hydrocotyle bonariensis Lam.

Phytochemical investigation of the under-ground parts of Hydrocotyle bonariensis led to the isolation of five oleanane-type triterpenoid saponins, 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-21-O-(2-methylbutyroyl)-22-O-acetyl-R(1)-barrigenol, 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-21-O-(2-methylbutyroyl)-28-O-acetyl-R(1)-barrigenol, 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-21-O-acetyl-R(1)-barrigenol, 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-R(1)-barrigenol, and 3-O-{ß-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-ß-D-glucuronopyranosyl}-22-O-(2-methylbutyroyl)-A(1)-barrigenol, together with the known saniculoside-R1. Their structures were established by 2D NMR techniques and mass spectrometry. Six compounds were evaluated against two human colon cancer cell lines, HCT 116 and HT-29. Two compounds showed weak cytotoxicity with IC(50) 24.1 and 24.0, 83.0 and 83.6 µM against HT-29 and HCT 116, respectively.

Assessment of PET tracer uptake in hormone-independent and hormone-dependent xenograft prostate cancer mouse models.

UNLABELLED: The pharmacokinetics of (18)F-fluorodeoxythymidine (FLT), (18)F-FDG, (11)C-choline, and (18)F-fluoroethylcholine (FEC) in 2 hormone-independent (PC-3, DU145) and 2 hormone-dependent (CWR22, PAC120) prostate cancer xenograft mouse models were evaluated by PET and compared by immunohistochemistry. Further investigation was performed to determine whether PET can detect early changes in tumor metabolism after androgen ablation therapy through surgical castration. METHODS: PET was performed on 4 consecutive days. In addition, the CWR22 and PAC120 tumor models were surgically castrated after the baseline measurement and imaged again after castration. The tracer uptake was analyzed using time-activity curves, percentage injected dose per volume (%ID/cm(3)), and tumor-to-muscle ratio (T/M). RESULTS: Regarding the hormone-independent prostate tumor models, (18)F-FLT showed the best T/M and highest %ID/cm(3) in PC-3 (2.97 ± 0.63 %ID/cm(3)) and DU145 (2.06 ± 0.75 %ID/cm(3)) tumors. (18)F-FDG seemed to be the tracer of choice for delineation of the PC-3 tumors but not for the DU145 tumors. Using (11)C-choline (PC-3: 1.33 ± 0.29 %ID/cm(3), DU145: 1.60 ± 0.27 %ID/cm(3)) and (18)F-FEC, we did not find any significant uptake in the tumors, compared with muscle tissue. Regarding the hormone-dependent prostate tumor models, the CWR22 model showed a highly significant (P < 0.01) decrease in tumor (18)F-FDG uptake from 4.11 ± 1.29 %ID/cm(3) to 2.19 ± 1.45 %ID/cm(3) after androgen ablation therapy. However, the (18)F-FLT, (11)C-choline, or (18)F-FEC tracers did not provide sufficient uptake or reliable information about therapy response in CWR22 tumors. The PAC120 model showed a significant increase in (18)F-FLT tumor uptake (P = 0.015) after androgen ablation therapy. The accumulation of (18)F-FEC (before: 2.32 ± 1.01 %ID/cm(3), after: 1.36 ± 0.39 %ID/cm(3)) was found to be the next highest after (18)F-FDG (before: 2.45 ± 0.93 %ID/cm(3), after: 2.18 ± 0.65 %ID/cm(3)) in PAC120 tumors before castration and is better suited for monitoring therapy response. CONCLUSION: This comprehensive study in 2 hormone-dependent and 2 hormone-independent prostate tumor mouse models shows that (18)F-FLT and (18)F-FDG are the most appropriate tracers for delineation of PC-3, DU145 (except (18)F-FDG), and CWR22 tumors, but not for PAC120 tumors. (18)F-FEC and (11)C-choline, in particular, revealed insufficient T/M ratio in the prostate tumor models. The results may indicate that radiolabeled choline and choline derivatives compete with a high concentration of the precursor dimethylaminoethanol, resulting in reduced uptake in small-rodent tumor models, a hypothesis that is currently under investigation in our laboratory.

Assessment of multiparametric MRI in a human glioma model to monitor cytotoxic and anti-angiogenic drug effects.

Early imaging or blood biomarkers of tumor response is needed to customize anti-tumor therapy on an individual basis. This study evaluates the sensitivity and relevance of five potential MRI biomarkers. Sixty nude rats were implanted with human glioma cells (U-87 MG) and randomized into three groups: one group received an anti-angiogenic treatment (Sorafenib), a second a cytotoxic drug [1,3-bis(2-chloroethyl)-1-nitrosourea, BCNU (Carmustine)] and a third no treatment. The tumor volume, apparent diffusion coefficient (ADC) of water, blood volume fraction (BVf), microvessel diameter (vessel size index, VSI) and vessel wall integrity (contrast enhancement, CE) were monitored before and during treatment. Sorafenib reduced tumor CE as early as 1 day after treatment onset. By 4 days after treatment onset, tumor BVf was reduced and tumor VSI was increased. By 14 days after treatment onset, ADC was increased and the tumor growth rate was reduced. With BCNU, ADC was increased and the tumor growth rate was reduced 14 days after treatment onset. Thus, the estimated MRI parameters were sensitive to treatment at different times after treatment onset and in a treatment-dependent manner. This study suggests that multiparametric MR monitoring could allow the assessment of new anti-tumor drugs and the optimization of combined therapies.

Unusual oleanane-type saponins from Arenaria montana.

Three oleanane-type saponins, 3-O-ß-d-glucopyranosylechinocystic acid 28-O-ß-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-α-l-rhamnopyranosyl ester (1), 3-O-ß-d-glucopyranosylechinocystic acid 28-O-α-l-arabinopyranosyl-(1→3)-ß-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-α-l-rhamnopyranosyl ester (2), 3-O-ß-d-glucopyranosylcaulophyllogenin 28-O-ß-d-apiofuranosyl-(1→3)-ß-d-xylopyranosyl-(1→4)-[ß-d-apiofuranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-α-l-rhamnopyranosyl ester (3) were isolated from the whole plant of Arenaria montana. Their unusual structures for the Caryophyllaceae family were established mainly by 2D NMR techniques and mass spectrometry.

Glaucasides A-C, three saikosaponins from Atriplex glauca L. var. ifiniensis (Caball) Maire.

From the roots of Atriplex glauca L. var. ifiniensis (Caball) Maire (syn. of Atriplex parvifolia Lowe var. genuina Maire), three new saikosaponins designated as glaucasides A-C (1-3) were isolated together with the known 3-O-ß-D-glucopyranosyl-(1 → 2)-ß-D-galactopyranosyl-saikogenin F (4). The structures of the new compounds were elucidated by extensive analysis of one-dimensional and two-dimensional NMR spectroscopy, FABMS, HR-ESIMS and chemical evidence as 13ß,28-epoxy-16ß,21ß-dihydroxyolean-11-en-3ß-yl O-ß-D-[2-O-sulfate]-glucopyranosyl-(1 → 2)-α-L-arabinopyranoside (1), 13ß,28-epoxy-16ß,21ß-dihydroxyolean-11-en-3ß-yl O-ß-D-[2-O-sulfate]-glucopyranosyl-(1 → 2)-α-L-arabinopyranosyl 21-O-{4-(secbutylamido)-butanoyl ester} (2) and 3-O-ß-D-glucopyranosyl-(1 → 2)-ß-D-galactopyranosyl saikogenin G (3). The cytotoxic activities of these compounds were evaluated against the HT-29 and HCT 116 human colon cancer cell lines.

Triterpene saponins from Cyclamen persicum.

A new triterpene saponin 3-O-beta-D-glucopyranosyl-(1 --> 4)-alpha-L-arabinopyranosyl-16alpha-hydroxy-13beta,28-epoxy-oleanan-30-al (1), along with four known triterpene glycosides (2-5) were isolated from Cyclamen persicum. Their structures were characterized by a combination of 1D- and 2D-NMR (1H-1H COSY, TOCSY, NOESY, HSQC, and HMBC) and MS spectrocopic data. The cytotoxicity of compounds 2 and 4 was evaluated using two human colon cancer cell lines HT-29 and HCT 116.

Steroidal saponins from two species of Dracaena.

Four new steroidal saponins (1-4) were isolated from the stem and bark of two species of Dracaena: deistelianosides A and B (1 and 2) from D. deisteliana and arboreasaponins A and B (3 and 4) from D. arborea. Six known saponins and one known sapogenin were also isolated. The structures of 1-4 were established as diosgenin 3-O-[3-O-sulfate-alpha-l-rhamnopyranosyl-(1-->4)]-beta-d-glucopyranoside (1), 1-O-beta-d-xylopyranosyl-(1-->2)-[alpha-l-rhamnopyranosyl-(1-->3)]-beta-d-fucopyranosyl(23S,24S)-spirosta-5,25(27)-diene-1beta,3beta,23alpha,24alpha-tetrol 24-O-alpha-l-arabinopyranoside (2), pennogenin-3-O-alpha-l-rhamnopyranosyl-(1-->2)-[alpha-l-rhamnopyranosyl-(1-->3)]-[6-O-acetyl]-beta-d-glucopyranoside (3), and 24alpha-hydroxypennogenin 3-O-alpha-l-rhamnopyranosyl-(1-->2)-[alpha-l-rhamnopyranosyl-(1-->3)]-beta-d-glucopyranoside (4) using extensive 1D and 2D NMR spectroscopic analyses and mass spectrometry. Cytotoxic activity of several of these compounds was evaluated against the HT-29 and HCT 116 human colon cancer cell lines.

Structure elucidation of new oleanane-type glycosides from three species of Acanthophyllum.

From the roots of three species of Acanthophyllum (Caryophyllaceae), two new gypsogenic acid glycosides, 1 and 2, were isolated, 1 from A. sordidum and A. lilacinum, 2 from A. elatius and A. lilacinum, together with three known saponins, glandulosides B and C, and SAPO50. The structures of 1 and 2 were established mainly by 2D NMR techniques as 23-O-beta-D-galactopyranosylgypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->6)]-beta-D-galactopyranoside (1) and gypsogenic acid-28-O-beta-D-glucopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->6)]-beta-D-galactopyranoside (2). The cytotoxicity of several of these saponins was evaluated against two human colon cancer cell lines (HT-29 and HCT 116).

Two new sesquiterpene derivatives from the Tunisian endemic Ferula tunetana Pom.

A new sesquiterpene ester, tunetanin A (1), a new sesquiterpene coumarin, tunetacoumarin A (2), together with eight known compounds, i.e., coladin (3), coladonin (4), isosmarcandin (5), 13-hydroxyfeselol (6), umbelliprenin (7) propiophenone (8), beta-sitosterol (9), and stigmasterol (10), were isolated from the roots of Ferula tunetana. Their structures were elucidated on the basis of extensive spectroscopic methods, including 1D- and 2D-NMR experiments and MS analysis, as well as by comparison with published data. The cytotoxicity of compounds 1-7 towards two human colon cancer cell lines, HT-29 and HCT 116, was evaluated. Compounds 3, 4, and 6 showed weak cytotoxic activities.

Triterpene saponins from Cyclamen trocopteranthum.

Two new triterpene saponins ( 1- 2) together with three known saponins, deglucocyclamin I ( 3), cyclamin ( 4), and mirabilin ( 5), were isolated from the tubers of Cyclamen trocopteranthum. They were elucidated as 3 beta- O-{4- O-[3-hydroxyl-3-methylglutaryl]- beta-D-xylopyranosyl-(1 --> 2)- beta-D-glucopyranosyl-(1 --> 4)-[ beta-D-glucopyranosyl-(1 --> 2)]- alpha-L-arabinopyranosyl}-16 alpha-hydroxy-13 beta,28-epoxy-oleanan-30-al ( 1) and 3 beta- O-{4- O-[3-hydroxyl-3-methylglutaryl]- beta-D-xylopyranosyl-(1 --> 2)-[ beta-D-glucopyranosyl-(1 --> 6)]- beta-D-glucopyranosyl-(1 --> 4)-[ beta-D-glucopyranosyl-(1 --> 2)]- alpha-L-arabinopyranosyl}-16 alpha-hydroxy-20,30-lactone-olean-12-ene ( 2). Their structures were characterized mainly by a combination of 1D- and 2D-NMR techniques ( (1)H- (1)H COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectroscopy. Saponins 1, 3, and 4 showed a weak cytotoxic activity when tested against HT-29 and HCT 116 tumor colon cancer cells.