Site-specific antibody-drug conjugation through glycoengineering

Antibody-drug conjugates (ADCs) have been proven clinically to be more effective anti-cancer agents than native antibodies. However, the classical conjugation chemistries to prepare ADCs by targeting primary amines or hinge disulfides have a number of shortcomings including heterogeneous product profiles and linkage instability. We have developed a novel site-specific conjugation method by targeting the native glycosylation site on antibodies as an approach to address these limitations. The native glycans on Asn-297 of antibodies were enzymatically remodeled in vitro using galactosyl and sialyltransferases to introduce terminal sialic acids. Periodate oxidation of these sialic acids yielded aldehyde groups which were subsequently used to conjugate aminooxy functionalized cytotoxic agents via oxime ligation. The process has been successfully demonstrated with three antibodies including trastuzumab and two cytotoxic agents. Hydrophobic interaction chromatography and LC-MS analyses revealed the incorporation of ~1.6 cytotoxic agents per antibody molecule, approximating the number of sialic acid residues. These glyco-conjugated ADCs exhibited target-dependent antiproliferative activity toward antigen-positive tumor cells and significantly greater antitumor efficacy than naked antibody in a Her2-positive tumor xenograft model. These findings suggest that enzymatic remodeling combined with oxime ligation of the native glycans of antibodies offers an attractive approach to generate ADCs with well-defined product profiles. The site-specific conjugation approach presented here provides a viable alternative to other methods, which involve a need to either re-engineer the antibody sequence or develop a highly controlled chemical process to ensure reproducible drug loading.

QTL verification of grain protein content and its correlation with oil content by using connected RIL populations of high-oil maize

Maize with high grain protein and oil contents offers great advantages for human food and animal feed. In this study, grain protein contents of 282 and 263 F7:8 recombinant inbred lines (RILs) of 2 crosses were evaluated in 4 environments within and between populations. The RILs were developed from crosses between an inbred high-oil maize line and 2 normal dent inbred maize lines. A total of 16 single-population QTLs and 19 joint-population QTLs were identified for protein content, and 21 QTLs were detected for protein-oil in each of the 4 environments tested and in combination. Most of the QTLs for protein content were greatly influenced by variation among populations and environments. Seven QTLs showed generational consistency compared with QTLs detected in the 2 F2:3 populations. However, 7 and 6 QTLs were detected in only the RIL and F2:3 populations, respectively. Protein and protein-oil QTLs with the same parental effects were detected at bins 3.03-3.05, 5.04-5.06, 6.03-6.05, 8.03-8.04, and 8.04-8.06, demonstrating that tightly linked and/or pleiotropic QTLs are controlling both traits at these bins. Four single-population QTLs and 11 joint-population QTLs identified at bins 3.02-3.03, 3.05, 7.01, 8.02, 8.03, 8.04-8.05, 8.05, 9.03, and 9.05 with intervals <5 cM could be used in marker-assisted selection. Along with the previously detected QTLs qPRO1-8-1 and qPRO1-5-1 at bins 8.03-8.04 and 5.02-5.04, the QTLs detected herein could be used to develop near isogenic lines and chromosome segment substitution lines in future studies.

[Analysis and identification of Poria cocos peels harvested from different producing areas by FTIR and 2D-IR correlation spectroscopy]

Different geographical regions of traditional Chinese medicine (TCM), its chemical composition is different, the accumulation of drug and medicinal properties is different. The accurate identification and analysis of different production area of medicinal herbs is critical for the quality control and pharmacological research of TCM. In this paper, a tri-step infrared spectroscopy (Fourier transform infrared spectroscopy (FTIR) combined with second derivative spectra and two-dimensional correlation infrared spectroscopy (2D-COS) were employed to identify and analyze the main components of Hubei (HB), Anhui (AH), Yun-nan (YN) genuine Poria Cocos peels. The emergence of several characteristic absorption peaks of carbohydrates including 1149, 1079 1036 cm(-1), peaks around 1619, 1315, 780 cm(-1) belonged to calcium oxalate suggested that HB and AH Poria Cocos peels contained calcium oxalate, but peaks around 797, 779, 537, 470 cm(-1) belonged to kaoline suggested that YN Poria Cocos peels contained kaoline. Their carbohydrates were different by comparing the second derivative infrared spectra in the range of 1640-450 cm(-1) and Yongping come from YN contains both calcium oxalate and kaoline. Furthermore, the above differences were visually validated by two-dimensional correlation spectroscopy (2D-COS). It was demonstrated that the Tri-step infrared spectroscopy were successfully applied to fast analyze and identify Poria Cocos peels from different geographical regions and subsequently would be applicable to explain the relevance of geographical regions and medicinal properties for the TCM.

Porous TiO2 nanoribbons and TiO2 nanoribbon/carbon dot composites for enhanced Li-ion storage

Porous TiO₂ nanoribbons and nano-composites of TiO₂ nanoribbons/carbon dots with excellent performances in lithium-ion batteries were prepared via a simple and efficient method.

Examining estrogen regulation of cancer stem cells through multicolor lineage tracing

We have designed a dual-color fluorescent reporter that can track microRNA expression in vitro, which can be used for lineage tracing experiments. We have used this system to track miR-140 promoter activity in breast cancer cells and to follow the impact of estrogen signaling in cancer stem cell subpopulations.

Interfacial mechanical testing of atomic layer deposited TiO2 and Al2O3 on a silicon substrate by the use of embedded SiO2 microspheres

A novel measurement technique is presented for interfacial mechanical evaluation of especially atomic layer deposited (ALD) thin films.

Characterization of a stem-like subpopulation in basal-like ductal carcinoma in situ (DCIS) lesions

Previously, we found that basal-like ductal carcinoma in situ (DCIS) contains cancer stem-like cells. Here, we characterize stem-like subpopulations in a model of basal-like DCIS and identify subpopulations of CD49f+/CD24- stem-like cells that possess aldehyde dehydrogenase 1 activity. We found that these cells show enhanced migration potential compared with non-stem DCIS cells. We also found that the chemopreventive agent sulforaphane can target these DCIS stem-like cells, reduce aldehyde dehydrogenase 1 (ALDH1) expression, and decrease mammosphere and progenitor colony formation. Furthermore, we characterized exosomal trafficking of microRNAs in DCIS and found that several microRNAs (miRs) including miR-140, miR-29a, and miR-21 are differentially expressed in exosomes from DCIS stem-like cells. We found that SFN treatment could reprogram DCIS stem-like cells as evidenced by significant changes in exosomal secretion more closely resembling that of non-stem cancer cells. Finally, we demonstrated that exosomal secretion of miR-140 might impact signaling in nearby breast cancer cells.

Adalimumab maintains remission of Crohn's disease after up to 4 years of treatment: data from CHARM and ADHERE

BACKGROUND

Therapies that maintain remission for patients with Crohn's disease are essential. Stable remission rates have been demonstrated for up to 2 years in adalimumab-treated patients with moderately to severely active Crohn's disease enrolled in the CHARM and ADHERE clinical trials.

AIM

To present the long-term efficacy and safety of adalimumab therapy through 4 years of treatment.

METHODS

Remission (CDAI <150), response (CR-100) and corticosteroid-free remission over 4 years, and maintenance of these endpoints beyond 1 year were assessed in CHARM early responders randomised to adalimumab. Corticosteroid-free remission was also assessed in all adalimumab-randomised patients using corticosteroids at baseline. Fistula healing was assessed in adalimumab-randomised patients with fistula at baseline. As observed, last observation carried forward and a hybrid nonresponder imputation analysis for year 4 (hNRI) were used to report efficacy. Adverse events were reported for any patient receiving at least one dose of adalimumab.

RESULTS

Of 329 early responders randomised to adalimumab induction therapy, at least 30% achieved remission (99/329) or CR-100 (116/329) at year 4 of treatment (hNRI). The majority of patients (54%) with remission at year 1 maintained this endpoint at year 4 (hNRI). At year 4, 16% of patients taking corticosteroids at baseline were in corticosteroid-free remission and 24% of patients with fistulae at baseline had healed fistulae. The incidence rates of adverse events remained stable over time.

CONCLUSIONS

Prolonged adalimumab therapy maintained clinical remission and response in patients with moderately to severely active Crohn's disease for up to 4 years. No increased risk of adverse events or new safety signals were identified with long-term maintenance therapy. (clinicaltrials.gov number: NCT00077779).

Expression of nestin in ovarian serous cancer and its clinicopathologic significance

OBJECTIVE

Nestin has been found to be overexpressed in several human malignancies. The primary goal of this research was to investigate whether nestin expression correlates with the occurrence and development of ovarian cancer.

PATIENTS AND METHODS

Expression of nestin was evaluated by immunohistochemistry in 315 cases of various epithelial ovarian lesions as well as 52 cases of normal ovarian epithelia. The association between nestin expression and various clinical pathological parameters was analysed.

RESULTS

Immunohistochemical results showed that the positive correlation of nestin expression gradually increased from benign and borderline to malignant ovarian tumours. Nestin overexpression was associated with more advanced International Federation of Gynaecology and Obstetrics stage and higher histological grade in serous adenocarcinoma. Nestin expression was significantly associated with chemoresistance. However, there was no significant correlation between nestin expression and the age and level of CA125 in patients.

CONCLUSIONS

We propose that nestin expression might contribute to the initiation, promotion, and progression of serous ovarian carcinoma; nestin expression is associated with poor chemoresponse. It could be a potential therapeutic target in patients with epithelial ovarian carcinoma.

Direct observation of bulk and surface chemical morphologies of Ginkgo biloba leaves by Fourier transform mid- and near-infrared microspectroscopic imaging

Fourier transform infrared microspectroscopy is a powerful tool to obtain knowledge about the spatial and/or temporal distributions of the chemical compositions of plants for better understanding of their biological properties. However, the chemical morphologies of plant leaves in the plane of the blade are barely studied, because sections in this plane for mid-infrared transmission measurements are difficult to obtain. Besides, native compositions may be changed by chemical reagents used when plant samples are microtomed. To improve methods for direct infrared microspectroscopic imaging of plant leaves in the plane of the blade, the bulk and surface chemical morphologies of nonmicrotomed Ginkgo biloba leaves were characterized by near-infrared transmission and mid-infrared attenuated total reflection microspectroscopic imaging. A new self-modeling curve resolution procedure was proposed to extract the spectral and concentration information of pure compounds. Primary and secondary metabolites of secretory cavities, veins, and mesophylls of Ginkgo biloba leaf blades were analyzed, and the distributions of cuticle, protein, calcium oxalate, cellulose, and ginkgolic acids on the adaxial surface were determined. By the integration of multiple infrared microspectroscopic imaging and chemometrics methods, it is possible to analyze nonmicrotomed leaves and other plant samples directly to understand their native chemical morphologies in detail.