Inhibition of the Wnt antagonist sclerostin increases bone mass in patients with osteoporosis and in preclinical animal models. Here we show increased levels of the Wnt antagonist Dickkopf-1 (DKK-1) ...in animals treated with sclerostin antibody, suggesting a negative feedback mechanism that limits Wnt-driven bone formation. To test our hypothesis that co-inhibition of both factors further increases bone mass, we engineer a first-in-class bispecific antibody with single residue pair mutations in the Fab region to promote efficient and stable cognate light-heavy chain pairing. We demonstrate that dual inhibition of sclerostin and DKK-1 leads to synergistic bone formation in rodents and non-human primates. Furthermore, by targeting distinct facets of fracture healing, the bispecific antibody shows superior bone repair activity compared with monotherapies. This work supports the potential of this agent both for treatment and prevention of fractures and offers a promising therapeutic approach to reduce the burden of low bone mass disorders.
The development of bone‐rebuilding anabolic agents for potential use in the treatment of bone loss conditions, such as osteoporosis, has been a long‐standing goal. Genetic studies in humans and mice ...have shown that the secreted protein sclerostin is a key negative regulator of bone formation, although the magnitude and extent of sclerostin's role in the control of bone formation in the aging skeleton is still unclear. To study this unexplored area of sclerostin biology and to assess the pharmacologic effects of sclerostin inhibition, we used a cell culture model of bone formation to identify a sclerostin neutralizing monoclonal antibody (Scl‐AbII) for testing in an aged ovariectomized rat model of postmenopausal osteoporosis. Six‐month‐old female rats were ovariectomized and left untreated for 1 yr to allow for significant estrogen deficiency‐induced bone loss, at which point Scl‐AbII was administered for 5 wk. Scl‐AbII treatment in these animals had robust anabolic effects, with marked increases in bone formation on trabecular, periosteal, endocortical, and intracortical surfaces. This not only resulted in complete reversal, at several skeletal sites, of the 1 yr of estrogen deficiency‐induced bone loss, but also further increased bone mass and bone strength to levels greater than those found in non‐ovariectomized control rats. Taken together, these preclinical results establish sclerostin's role as a pivotal negative regulator of bone formation in the aging skeleton and, furthermore, suggest that antibody‐mediated inhibition of sclerostin represents a promising new therapeutic approach for the anabolic treatment of bone‐related disorders, such as postmenopausal osteoporosis.
A single‐stage clarification was developed using a single‐use chromatographic clarification device (CCD) to recover a recombinant protein from Chinese Hamster Ovary (CHO) harvest cell culture fluid ...(HCCF). Clarification of a CHO HCCF is a complex and costly process, involving multiple stages of centrifugation and/or depth filtration to remove cells and debris and to reduce process‐related impurities such as host cell protein (HCP), nucleic acids, and lipids. When using depth filtration, the filter train consists of multiple filters of varying ratios, layers, pore sizes, and adsorptive properties. The depth filters, in combination with a 0.2‐micron membrane filter, clarify the HCCF based on size‐exclusion, adsorptive, and charge‐based mechanisms, and provide robust bioburden control. Each stage of the clarification process requires time, labor, and utilities, with product loss at each step. Here, use of the 3M™ Harvest RC Chromatographic Clarifier, a single‐stage CCD, is identified as an alternative strategy to a three‐stage filtration train. The CCD results in less overall filter area, less volume for flushing, and higher yield. Using bioprocess cost modeling, the single‐stage clarification process was compared to a three‐stage filtration process. By compressing the CHO HCCF clarification to a single chromatographic stage, the overall cost of the clarification process was reduced by 17%–30%, depending on bioreactor scale. The main drivers for the cost reduction were reduced total filtration area, labor, time, and utilities. The benefits of the single‐stage harvest process extended throughout the downstream process, resulting in a 25% relative increase in cumulative yield with comparable impurity clearance.
Abstract
Ovarian cancer is the seventh most commonly diagnosed cancer in women. Standard treatments typically include surgery followed by radiation and/or chemotherapy. However, currently 5-year ...survival rates are 44%, underlining the need for new effective therapies. The Folate receptor 1 (FOLR1, FRα) is expressed in 80% of ovarian tumors, making it an attractive target for CD3-based bispecific antibody therapies. Bispecific engagement of activated host T-cells in the tumor microenvironment is highly effective at eliminating tumor cells. We have developed an anti-CD3 Fab-folate bispecific antibody by engineering non-native amino acids (NNAAs) at a specific region within the Fab domain and conjugated a PEGylated folate molecule to these sites. Our data demonstrate that Ambrx’s proprietary site-specific conjugation technology provides significant advantages over non-PEGylated proteins.
Citation Format: Michael J. Gray, Wisam Barkho, Barbara Tipton, Prathap Shastri, Hyun-Bae Jie, Jeff Steen, Rik Frank, Feng Tian, Dowdy Jackson, Shawn Zhang. Site specific conjugation of engineered non-native amino acids in an anti-CD3 Fab-folate bispecific antibody significantly enhances its antitumor properties in gynecologic cancers abstract. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B013.
Wnt-modulator in surface ectoderm (WISE) is a secreted modulator of Wnt signaling expressed in the adult kidney. Activation of Wnt signaling has been observed in renal transplants developing ...interstitial fibrosis and tubular atrophy; however, whether WISE contributes to chronic changes is not well understood. Here, we found moderate to high expression of WISE mRNA in a rat model of renal transplantation and in kidneys from normal rats. Treatment with a neutralizing antibody against WISE improved proteinuria and graft function, which correlated with higher levels of β-catenin protein in kidney allografts. In addition, treatment with the anti-WISE antibody reduced infiltration of CD68(+) macrophages and CD8(+) T cells, attenuated glomerular and interstitial injury, and decreased biomarkers of renal injury. This treatment reduced expression of genes involved in immune responses and in fibrogenic pathways. In summary, WISE contributes to renal dysfunction by promoting tubular atrophy and interstitial fibrosis.
The researcher examined non-returning first-year teachers and second year teachers who taught during the 1994-95 school year. The research design included five research questions with six null ...hypotheses testing for differences among second year teachers' perceptions and non-returning teachers' perceptions of their mentor teachers. After calculating ratings on desired and demonstrated scales by 464 subjects, criteria were ranked on mentor characteristics on 12 tasks. The extent to which each task was demonstrated during their first year's teaching experience was also calculated. Participants indicated that the ideal mentor would advocate for the novice and would demonstrate a sensitive approach in assisting. However, study participants responded that the more essential characteristics were not present in their experience with mentors. When examining differences between returning and non-returning teachers' perceptions of mentor characteristics, non-returning teachers expressed a stronger desire to have their mentor be understanding, empathetic, and communicative and to teach in a similar curricular area. Further, they would have liked to have had more discussion regarding their teaching practice and a convenient time to meet and share information. When exploring the differences on desired and demonstrated scales in the perception of their actual experiences, significant differences were found in all 12 tasks. Additional analyses revealed significant differences in male and female perceptions but no differences were found when considering grade level teaching assignment.
In the course of developing a cost-effective, scaleable process for the purification of a recombinant protein from Chinese hamster ovary (CHO) suspension cell culture, we investigated direct capture ...of this molecule using expanded bed adsorption (EBA). EBA combines clarification, purification, and concentration of the product into a single step. The unclarified bioreactor material was directly applied to a STREAMLINE 25 column containing an affinity STREAMLINE adsorbent. This work focused on simplifying the EBA operations and minimizing the overall processing time by running the EBA column unidirectionally, eluting in the expanded bed mode, and coupling the EBA column directly with ion exchange or hydrophobic interaction chromatography. Unidirectional EBA was clearly a simpler unit operation and did not require the use of specialized equipment. The increase in the elution pool volume was insignificant, especially when the EBA column was eluted directly onto the downstream column. Scale-down was simple and could be automated. Coupling of unidirectional EBA with a downstream purification step reduced processing time, equipment requirements and cost.
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