Abstract 1550: FT576 path to first-of-kind clinical trial: translation of a versatile multi-antigen specific off-the-shelf NK cell for treatment of multiple myeloma

Chimeric antigen receptor (CAR) directed therapies have been used successfully to treat a variety of hematological malignancies. With the advent of multi-modal engineering, adoptive cell therapy offers the opportunity to tackle increasingly complex disease settings such as multiple myeloma (MM), where targeting of single tumor associated antigen by CAR or monoclonal antibodies (mAb) is confounded by antigen loss and clonal heterogeneity. Further, expanding treatment options beyond primary T and NK cell based therapies has multiple advantages, including the use of induced pluripotent stem cells (iPSC) to derive effector cells using precision genetic engineering that can be uniformly manufactured at scale from a clonally-derived master cell bank (MCB).FT576 is a multiplex-edited, iPSC-derived CAR-NK (CAR-iNK) cell therapy designed for treatment of Multiple Myeloma. FT576 is engineered 1) to express a recombinant IL-15/IL-15 receptor signaling complex (IL-15RF) for enhanced persistence; 2) to express an enhanced high-affinity, non-cleavable CD16 (hnCD16) ; 3) to disrupt expression of CD38, allowing for enhanced ADCC without NK cell fratricide; and 4) to express a BCMA-targeted CAR with NK-cell optimized signaling.CAR-directed specificity of the FT576 cells for BCMA was demonstrated using a short-term cytotoxicity assay (90.8% cytotoxicity against BCMA+ vs 22.1% BCMA- cells, p<0.0001). Utilizing a long-range tumor clearance assay without exogenous cytokine support, serial restimulation by repeated rounds of exposure to fresh MM target cells showed remarkable persistence and antigen-mediated expansion of FT576 by CAR alone or combined with anti-CD38 mAb. Continuous long-range clearance assays demonstrated levels of BCMA targeting activity of FT576 alone was equivalent to primary BCMA-targeted CAR-T cells against a panel of BCMA+ target cells. BCMA-CAR targeting was tested in combination with multiple therapeutic mAbs to explore breadth of tumor clearance in primary bone marrow samples.In xenograft models, dosing of FT576 as a monotherapy was highly protective against MM progression, resulting in deeper tumor regression and delayed outgrowth. The treatment of MM-bearing mice with both FT576 and daratumumab produced greater myeloma control than either agent alone, demonstrating combined CAR and antibody-directed cytotoxicity. Additionally, FT576 demonstrated enhanced persistence compared to peripheral blood NK cells, suggestive of antigen mediated expansion. Together, these studies demonstrate the versatility of FT576 as a highly effective multi-antigen targeting and cost-effective, off-the-shelf BCMA-CAR iNK cell product and support the rational for a first-of-kind Phase I Study of FT576 as a monotherapy or in combination with therapeutic mAbs targeted to MM-associated surface antigens.

Citation Format: Jode P. Goodridge, Ryan Bjordahl, Sajid Mahmood, John Reiser, Svetlana Gaidarova, Robert Blum, Frank Cichocki, Hui-yi Chu, Greg Bonello, Tom Lee, Brian Groff, Miguel Meza, Thomas Daley, Yu-waye Chu, Bruce Walcheck, Karl-Johan Malmberg, Jeffrey S. Miller, Armin Rehm, Bahram Valamehr. FT576 path to first-of-kind clinical trial: translation of a versatile multi-antigen specific off-the-shelf NK cell for treatment of multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1550.

Monitoring the process of formation of ZnO from ZnO2usingin situcombined XRD/XAS technique

Use ofin situcombined x-ray diffraction and x-ray absorption spectroscopy for the study of the thermal decomposition of zinc peroxide to zinc oxide is reported here. Comparison of data extracted from both x-ray diffraction (XRD) and x-ray absorption spectroscopy (XAS) with thermo gravimetric analysis (TGA) enabled us to follow the nature of the conversion of ZnO₂to ZnO. A temperature range between 230 °C and 350 °C appears to show that a very poorly crystalline ZnO is formed prior to the formation of an ordered ZnO material. Both the decrease in white line intensity in the Zn K-edge XANES and resulting lower coordination numbers estimated from analysis of the Zn K-edge data of ZnO heated at 500 °C, in comparison to bulk ZnO, suggest that the ZnO produced by this method has significant defects in the system.

"I Couldn't See a Downside": Decision-Making About Gender-Affirming Hormone Therapy

PURPOSE

The aim of the article was to understand adolescents' and parents' decision-making process related to gender-affirming hormone therapy (GAHT).

METHODS

We conducted qualitative semistructured interviews with transgender adolescents who began testosterone for GAHT in the prior year and the parents of such adolescents. Questions focused on decision-making roles, steps in the decision process, and factors considered in the decision. Participants used pie charts to describe the division of responsibility for the decision. All interviews were coded by at least two members of the research team with disagreements resolved through discussion. Thematic analysis was used to analyze the data.

RESULTS

Seventeen adolescents and 13 parents were interviewed (12 dyads). The process of deciding about GAHT involves a series of small conversations, typically with the adolescent advocating to start treatment and the parent feeling hesitant. In most cases, after seeking information from the Internet, healthcare providers and personal contacts move toward acceptance and agree to start treatment. Although adolescents have some short-term concerns, such as about needles, parents' concerns relate more to long-term risks. Ultimately, for both parents and adolescents, the benefits of treatment outweigh any concerns, and they are in agreement about the goals of personal confidence, comfort in one's body and happiness.

CONCLUSIONS

To the extent that the decision about GAHT is a medical decision, the decision process is similar to others. However, decisions about GAHT are much more about gender identity than medical risks, suggesting that interventions based in a medical framework may not aid in supporting decision-making.

Distributed Acoustic Sensing Using Dark Fiber for Near-Surface Characterization and Broadband Seismic Event Detection

We present one of the first case studies demonstrating the use of distributed acoustic sensing deployed on regional unlit fiber-optic telecommunication infrastructure (dark fiber) for broadband seismic monitoring of both near-surface soil properties and earthquake seismology. We recorded 7 months of passive seismic data on a 27 km section of dark fiber stretching from West Sacramento, CA to Woodland, CA, densely sampled at 2 m spacing. This dataset was processed to extract surface wave velocity information using ambient noise interferometry techniques; the resulting V_S profiles were used to map both shallow structural profiles and groundwater depth, thus demonstrating that basin-scale variations in hydrological state could be resolved using this technique. The same array was utilized for detection of regional and teleseismic earthquakes and evaluated for long period response using records from the M8.1 Chiapas, Mexico 2017, Sep 8th event. The combination of these two sets of observations conclusively demonstrates that regionally extensive fiber-optic networks can effectively be utilized for a host of geoscience observation tasks at a combination of scale and resolution previously inaccessible.

The expression and immunohistochemical localization of periostin in odontogenic tumors of mixed epithelial/mesenchymal origin

OBJECTIVE

The object of this study was to determine the expression and localization of periostin in the major mixed odontogenic tumors and to correlate any differential staining of the mesenchymal components to the interrelationship of these tumors.

STUDY DESIGN

Five ameloblastic fibromas, 8 ameloblastic fibro-odontomas and 10 odontomas were assessed immunohistochemically for periostin staining. Because mesenchymal tissues were consistently present in all studied cases, these tissues were selected for statistical analysis of differential periostin staining.

RESULTS

Periostin was variably localized to the mesenchymal component of the tumors as well as to preameloblasts and ameloblasts. Analysis of the mesenchymal staining intensity was statistically significantly different between ameloblastic fibro-odontomas and odontomas (P < .001; Dunn multiple comparisons test).

CONCLUSIONS

Our results document periostin staining in human mixed odontogenic tumors. Statistical analysis of differential stromal staining supports the concept that the ameloblastic fibroma is a histogenetically distinct neoplasm as compared to ameloblastic fibro-odontoma and odontoma.

Automated classification of four types of developmental odontogenic cysts

Odontogenic cysts originate from remnants of the tooth forming epithelium in the jaws and gingiva. There are various kinds of such cysts with different biological behaviours that carry different patient risks and require different treatment plans. Types of odontogenic cysts can be distinguished by the properties of their epithelial layers in H&E stained samples. Herein we detail a set of image features for automatically distinguishing between four types of odontogenic cyst in digital micrographs and evaluate their effectiveness using two statistical classifiers - a support vector machine (SVM) and bagging with logistic regression as the base learner (BLR). Cyst type was correctly predicted from among four classes of odontogenic cysts between 83.8% and 92.3% of the time with an SVM and between 90 ± 0.92% and 95.4 ± 1.94% with a BLR. One particular cyst type was associated with the majority of misclassifications. Omission of this cyst type from the data set improved the classification rate for the remaining three cyst types to 96.2% for both SVM and BLR.

Segmentation of epithelium in H&E stained odontogenic cysts

An algorithm for the automated segmentation of epithelial tissue in digital images of histologic tissue sections of odontogenic cysts (cysts originating from residual odontogenic epithelium) is presented. The algorithm features an image standardization process that greatly reduces variation in luminance and chrominance between images due to variations in sample preparation. Segmentation of the epithelial regions of images uses an algorithm based on binary graph cuts where graph weights depend on probabilities obtained from colour histogram models of epithelium and stroma image regions. Algorithm training used a data set of 38 images of four types of odontogenic cyst and was tested using a separate data set of 35 images of the same four cyst types. The best parameters for the segmentation algorithm were determined using a response-surface optimizer. The best parameter set resulted in an overall mean (± std. dev.) sensitivity of 91.5 ± 17% and overall mean specificity of 85.1 ± 18.6% on the training set. Particularly good results were obtained for dentigerous and odontogenic keratocysts for which the mean sensitivities/specificities were 91.9 ± 6.15%/97.4 ± 2.15% and 96.1 ± 1.98%/98.7 ± 3.16%, respectively. Our method is potentially applicable to many pathological conditions in similar tissues, such as skin and mucous membranes where there is a clear microscopic distinction between epithelium and connective tissues.

A study of primary dental enamel from preterm and full-term children using light and scanning electron microscopy

PURPOSE

The aim of this study was to examine the enamel thickness of the maxillary primary incisors of preterm children with very low birth weight (< 1,500 g) compared to full-term children with normal birth weight.

METHODS

A total of 90 exfoliated maxillary primary central incisors were investigated using light microscopy and scanning electron microscopy (SEM). Three serial buccolingual ground sections of each tooth were examined under light microscopy, and maximum dimensions of the prenatally and postnatally formed enamel were measured.

RESULTS

The enamel of preterm teeth was approximately 20% thinner than that for full-term teeth. Most of the reduction was observed in the prenatally formed enamel. This was 5 to 13 times thinner than that for full-term children (P<.001). The "catch-up" thickness of postnatally formed enamel did not compensate fully for the decrease in prenatal enamel (P<.001). Although none of the teeth used in this study had enamel defects visible to the naked eye, 52% of preterm teeth showed enamel hypoplasia under SEM, compared with only 16% found on full-term teeth (P<.001). These defects were present as pits or irregular, shallow areas of missing enamel.

CONCLUSIONS

Preterm primary dental enamel is abnormal in surface quality, and is significantly thinner compared to full-term enamel. The thinner enamel is due mainly to reduced prenatal growth and results in smaller dimensions of the primary dentition.

Association of the Q576R polymorphism in the interleukin-4 receptor alpha chain with indolent mastocytosis limited to the skin

Gain-of-function mutations in c-kit, which appear to contribute to mast cell hyperplasia, have been detected in both limited and aggressive forms of mastocytosis, suggesting that other mutations or polymorphisms may contribute to the clinical phenotype. Because addition of interleukin-4 (IL-4) to mast cell cultures is reported to induce apoptosis, the hypothesis was considered that individuals carrying the gain-of-function polymorphism Q576R in the cytoplasmic domain of the alpha-subunit of the IL-4 receptor (IL-4R) might be relatively resistant to the gain-of-function mutation in c-kit. To assess this possibility, 36 patients with either cutaneous or systemic mastocytosis were studied for association with the Q576R polymorphism. The Q576R polymorphism was found more frequently in those with disease limited to skin and who exhibited lower levels of surrogate disease markers. These data suggest that the Q576R IL-4R alpha- chain polymorphism may mitigate disease expression and confer a better prognosis in patients with mastocytosis. (Blood. 2001;98:880-882)

Distribution and synthesis of elastin in porcine gingiva and alveolar mucosa

Histologically, there are variations in the distribution of the types of elastic fibers within the tissues of the masticatory mucosa. For example, the alveolar mucosa has heavy deposits of elastin which decrease in quantity and size as it merges with the attached gingiva. These differences in elastin content may result from the tissues' different physiological workload modulating the expression of tropoelastin mRNA. Alternatively, these differences could be due to the presence of phenotypically different fibroblasts that have different basal levels of tropoelastin mRNA expression. The aim of this study was to determine whether the differences in the distribution of elastin between alveolar mucosa and attached gingiva could be due to phenotypic differences between fibroblasts derived from these tissues. Histochemical (Miller's elastin stain) and immunohistochemical staining were used to localize elastin within these tissues. Elastin production by cultured fibroblasts derived from alveolar mucosa and attached gingiva was assessed by Western blot analyses, and Northern blot analyses were used to detect levels of elastin mRNA by these cells. The results from this study have confirmed that elastin is richly expressed in oral mucosa and poorly expressed in attached gingiva. In vitro, the cells demonstrated a capacity to synthesize and secrete tropoelastin, however this was not found to differ between cells from the two different sources. These findings indicate that while some heterogeneity in fibroblast populations may exist within various tissues of the periodontium, other factors, such as functional requirements of the tissues in which they reside, may also play an important role in the phenotypic expression of these cells.

Oral bowenoid lesions: differential diagnosis and pathogenetic insights

OBJECTIVE

To determine if oral lesions exhibiting bowenoid features reflect the diverse microscopic appearance and biologic behaviour of Bowen's disease and bowenoid papulosis of the skin and genitalia.

STUDY DESIGN

Seven cases of oral bowenoid lesions (6 with follow-up data) were assessed for differences in histologic features, human papillomavirus (HPV) viral status, and selected immunohistochemically detectable cell cycling proteins (p53, WAF-1, Cyclin D1, Bcl-2) and were correlated with available follow-up data.

RESULTS

Two histologic subsets were identified. One, which was believed to correspond to Bowen's disease, exhibited large numbers of transepithelial apoptotic bodies, dyskeratotic cells and mitoses (bowenoid elements), poor differentiation of background epithelial cells, and consistent HPV-16/18 positivity. The other, believed to correspond to bowenoid papulosis, exhibited few bowenoid elements, good background differentiation, and inconsistent HPV-16/18 positivity. One of the aggressive cases exhibited repeated recurrences despite apparent total clinical excision, whereas none of the other group recurred.

CONCLUSION

Although a small number of cases are in this study, results suggest that oral bowenoid lesions may exhibit histopathologic and behavioral variations ranging from oral Bowen's disease to oral bowenoid papulosis. Studies on more cases are needed to confirm this initial impression.

An immunohistochemical study of matrix molecules associated with barrier membrane-mediated periodontal wound healing

Guided tissue regeneration (GTR) is a clinical procedure developed to facilitate periodontal regeneration by using barrier membranes to selectively promote the repopulation of a periodontal defect by periodontal ligament and bone cells at the expense of epithelial and gingival connective tissue cells. The aim of this study was to gain insight into the biological events occurring during membrane mediated periodontal wound healing by examining the immunohistochemical expression of a number of extracellular matrix components in tissues treated via the GTR technique. Experimental periodontal defects were created around the second premolar tooth in 4 dogs and wound closure was achieved by application of expanded polytetrafluoroethylene membranes around each tooth and flap positioning coronal to the cementoenamel junction. The dogs were sacrificed after a 4-wk healing period, block dissections of the part of the mandible containing the experimental tooth were obtained and paraffin sections were prepared. Using standard immunohistochemical techniques, the sections were stained with a monoclonal antibody against bone morphogenetic proteins 2 and 4 (BMP-2 and -4) and polyclonal antibodies against collagen I, collagen II, decorin, biglycan, bone sialoprotein, osteopontin and osteocalcin. Collagen I was predominantly localized within the regenerating bone, whereas collagen III staining was more abundant in the soft connective tissues of the defect. Decorin and biglycan staining was faint within the extracellular matrix of the regenerating defect, although both proteoglycans exhibited intense intracellular localization within some of the cells inhabiting the defect. The staining for BMP-2 and -4 was weak within the bone but strong within the extracellular matrix of the regenerating soft tissue. Osteopontin and bone sialoprotein were strongly localized in the regenerating bone and cementum found within the defect. Osteocalcin staining was present in both the regenerating and mature cementum and associated cementoblasts, and it was relatively weaker in the regenerating bone compared to the mature bone. The observed pattern of immunolocalization of the extracellular matrix macromolecules suggests that the heterogeneous cell population filling the GTR wound had created an environment that was conducive to periodontal regeneration.

Acquired tufted angioma of the lower lip mucosa

The acquired tufted angioma is a unique, dusky red, vascular proliferation previously reported in the skin, usually developing in childhood or in young adults, which exhibits a distinctive microscopic appearance. Clinically, the condition enlarges at a variable rate, becomes stable and may regress spontaneously. A small, long-standing, vascular lesion of the mucosa of the lower lip, exhibiting microscopic and immunohistochemical features resembling those of acquired tufted angioma, is reported. The differential diagnosis, including pyogenic granuloma, capillary hemangioma and hemangiopericytoma, is discussed.

High frequency of allelic loss in dysplastic lichenoid lesions

Oral lichen planus (OLP) is a common mucosal condition that is considered premalignant by some, whereas others argue that only lichenoid lesions with epithelial dysplasia are at risk of progressing into oral carcinoma. A recent study from this laboratory used microsatellite analysis to evaluate OLP for loss of heterozygosity (LOH) at loci on three chromosomal arms (3p, 9p, and 17p) (Am J Path 1997;Vol151:Page323-Page327). Loss on these arms is a common event in oral epithelial dysplasia and has been associated with risk of progression of oral leukoplakia to cancer. The data showed that, although dysplastic epithelium demonstrated a high frequency of LOH (40% for mild dysplasia), a significantly lower frequency of LOH was noted in OLP (6%), which is even lower than that in hyperplasia (14%). Such results do not support OLP as a lesion at risk for malignant transformation. As a second step of the research, we determined LOH frequencies in 61 dysplastic lichenoid lesions (mild 35; moderate 19; severe 7) using the same microsatellite markers and compared these results with data obtained from the first study and from 13 normal mucosal specimens. Dysplastic lichenoid lesions showed a high frequency of loss (54% for lichenoid lesions with mild dysplasia), but values did not differ significantly from those observed in dysplasia of similar degree without lichenoid appearance. None of the normal mucosa demonstrated LOH. Epithelial dysplasia is a sign of malignant risk, independent of lichenoid changes. Such results suggest that pathologists should search for dysplasia carefully in lesions that otherwise qualify as OLP and that caution should be used when discounting dysplasia as being merely a reactive condition in lichenoid lesions.

An assessment of the osteoinductive potential of commercial demineralized freeze-dried bone in the murine thigh muscle implantation model

Early studies have demonstrated that implantation of laboratory preparations of demineralized freeze dried bone (DFDB) into the thigh muscle of mice induces ectopic osteoinduction. However, with the development of commercial preparations of DFDB for clinical use, concerns have been raised as to the osteoinductive properties of such preparations. The aim of this study was to investigate the osteoinductive potential of some commercial preparations of DFDB compared to a newly developed product which incorporates DFDB into a collagen sponge. Commercial preparations of DFDB or the DFDB/collagen sponge were inserted into the thigh muscles of 60 adult Swiss CD-1 mice. At the completion of each experimental period (7, 14, 30, 90 and 180 days), the animals were sacrificed, and the hindquarters of the mice were radiographed. The area where each graft had been placed was then excised, processed for light microscopy, and stained with hematoxylin and eosin or von Kossa's stain. Histological analysis of the DFDB/collagen sponges demonstrated significant remineralization which increased with time. Remineralization of the DFDB/collagen sponges was verified by radiographs which showed a significant increase in radiopacity over time. There was no radiographic evidence of mineralized tissue formation or remineralization in any of the commercial DFDB samples studied. At all time points studied, histological analyses failed to show evidence of bone formation for any of the preparations. The results suggest that commercially available DFDB is not osteoinductive in the murine model and question the use of such materials in clinical periodontics. The results found for the DFDB/collagen sponge indicate a different mechanism of activity from DFDB as evidenced by its rapid remineralization. The role this remineralization process has in osteoinduction is unknown and requires further study.

Oral squamous cell carcinoma: new insights

Squamous cell carcinoma is the most common form of oral cancer, and causes more deaths than any other oral disease. Dentists and dental auxiliaries must know the clinical, etiologic, pathogenetic and prognostic features of squamous cell carcinoma to ensure appropriate screening and diagnosis of the patient. It is now recognized that cancers are genetic diseases, which arise from inherited genetic factors and exposure to exogenous carcinogens that alter the DNA of cells. Increasingly, the genetic events that contribute to the development of cancers at many sites within the body are being identified, and the complex series of genetic steps required for fully-developed neoplasia to arise in the oral cavity are being better characterized. This article reviews recent advances in the understanding of the etiology and pathogenesis of oral carcinoma, including the involvement of various oncogenes, tumor suppressor genes and viruses.

Osteosarcoma and fibrous dysplasia: radiographic features in the differential diagnosis: a case report

A case of osteosarcoma misdiagnosed as fibrous dysplasia is presented to demonstrate the importance of an integrated diagnostic approach to oral lesions. The clinical and radiographic differences between fibrous dysplasia and osteosarcoma are reviewed.

Pathology of intraoral sebaceous glands

Large clinical studies have shown that intraoral sebaceous glands are present in 70 to 95% of the population. In many individuals these small white to yellow macules and papules are so numerous that they dominate the buccal mucosa. Despite their prevalence, pathological changes of these glands are considered uncommon. This paper reviews the pathologic spectrum of intraoral sebaceous glands including Demodex infestation, cystic lesions, sebaceous hyperplasia and neoplastic lesions. New data is presented on the true sebaceous cyst and the second reported case of intraoral steatocystoma simplex is documented.

Dental abnormalities associated with a chromosome 2 deletion

This case report describes the dental and physical anomalies observed in a young female patient who had a chromosome abnormality involving deletion of the q 33-q 35 region of chromosome 2. The dental dysplasia observed in this patient is proposed to be of genetic origin but the complication of anoxia at birth makes it difficult to assign the intellectual and physical impairments solely to the genetic deletion.

Dilaceration of a primary maxillary incisor associated with neonatal laryngoscopy

Neonatal laryngoscopy and endotracheal intubation often are required for prematurely born, low birthweight children. Previous studies have shown that these procedures are associated with a high prevalence of enamel hypoplasia of the maxillary anterior teeth. The present case report, which describes dilaceration of a left maxillary primary central incisor probably resulting from laryngoscopy, strongly supports the hypothesis that irreversible trauma to the dentition may result from endotracheal intubation.

S-100 protein content of dermal and oral mucosal blue nevi

Three common blue nevi from skin of the trunk and upper extremities, and 5 from oral mucosae were studied using an immunoperoxidase stain for S-100 protein. The skin lesions were uniformly negative whereas all of the oral mucosal lesions contained numerous positively stained dendritic cells. This difference may, in part, be explained by the different embryologic origins of the connective tissue stromas; the connective tissues of the head and neck are thought to be of neural crest origin whereas the connective tissues in the rest of the body are of mesodermal origin. These findings strengthen and refine the association between S-100 protein content and neural crest derivation.