T-cell engineered with a fully humanized B-cell maturation antigen-specific T-cell antigen coupler receptor effectively target multiple myeloma

B-cell maturation antigen (BCMA) is a clinically validated target for multiple myeloma. T-cell engineered with chimeric antigen receptors (CARs) directed against BCMA have demonstrated robust therapeutic activity in clinical trials, but toxicities remain a significant concern for a subset of patients, supporting continued investigation of other engineered T-cell platforms that may offer equal efficacy with an improved toxicity profile. The authors recently described a BCMA-specific, T-cell-centric synthetic antigen receptor, the T-cell antigen coupler (TAC) receptor, that can be used to engineer T-cell with robust anti-myeloma activity. Here the authors describe the creation of a fully humanized BCMA-specific TAC receptor. Single-chain variable fragments (scFvs) were developed from BCMA-specific F(ab)s that were identified in a fully human phage display library. Twenty-four configurations of the F(ab)s were evaluated in a medium-throughput screening using primary T-cell, and a single F(ab), TRAC 3625, emerged as the most robust following in vitro and in vivo evaluation. An optimized BCMA-specific TAC receptor was developed through iterations of the BCMA-TAC design that evaluated a next-generation TAC scaffold sequence, different domains connecting the TAC to the 3625 scFv and different orientations of the TRAC 3625 heavy and light variable regions.

Manufacturing T cells in hollow fiber membrane bioreactors changes their programming and enhances their potency

Engineered T cell therapies have revolutionized modern oncology, however processes for manufacturing T cell therapies vary and the impact of manufacturing processes On the cell product is poorly understood. Herein, we have used a commercially available hollow fiber membrane bioreactor (HFMBR) operated in a novel mode to demonstrate that T cells can be engineered with lentiviruses, grown to very high densities, and washed and harvested in a single, small volume bioreactor that is readily amenable to automation. Manufacturing within the HFMBR dramatically changed the programming of the T cells and yielded a product with greater therapeutic potency than T cells produced using the standard manual method. This change in programming was associated with increased resistance to cryopreservation, which is beneficial as T cell products are typically cryopreserved prior to administration to the patient. Transcriptional profiling of the T cells revealed a shift toward a glycolytic metabolism, which may protect cells from oxidative stress offering an explanation for the improved resistance to cryopreservation. This study reveals that the choice of bioreactor fundamentally impacts the engineered T cell product and must be carefully considered. Furthermore, these data challenge the premise that glycolytic metabolism is detrimental to T cell therapies.

Development of a B-cell maturation antigen-specific T-cell antigen coupler receptor for multiple myeloma

BACKGROUND AIMS

T cells engineered with synthetic receptors have delivered powerful therapeutic results for patients with relapsed/refractory hematologic malignancies. The authors have recently described the T-cell antigen coupler (TAC) receptor, which co-opts the endogenous T-cell receptor (TCR) and activates engineered T cells in an HLA-independent manner. Here the authors describe the evolution of a next-generation TAC receptor with a focus on developing a TAC-engineered T cell for multiple myeloma.

METHODS

To optimize the TAC scaffold, the authors employed a bona fide antigen-binding domain derived from the B-cell maturation antigen-specific monoclonal antibody C11D5.3, which has been used successfully in the clinic. The authors first tested humanized versions of the UCHT1 domain, which is used by the TAC to co-opt the TCR. The authors further discovered that the signal peptide affected surface expression of the TAC receptor. Higher density of the TAC receptor enhanced target binding in vitro, which translated into higher levels of Lck at the immunological synapse and stronger proliferation when only receptor-ligand interactions were present.

RESULTS

The authors observed that the humanized UCHT1 improved surface expression and in vivo efficacy. Using TAC T cells derived from both healthy donors and multiple myeloma patients, the authors determined that despite the influence of receptor density on early activation events and effector function, receptor density did not impact late effector functions in vitro, nor did the receptor density affect in vivo efficacy.

CONCLUSIONS

The modifications to the TAC scaffold described herein represent an important step in the evolution of this technology, which tolerates a range of expression levels without impacting therapeutic efficacy.

Antagonists of the serotonin receptor 5A target human breast tumor initiating cells

Background

Breast tumor initiating cells (BTIC) are stem-like cells that initiate and sustain tumor growth, and drive disease recurrence. Identifying therapies targeting BTIC has been hindered due primarily to their scarcity in tumors. We previously reported that BTIC frequency ranges between 15% and 50% in multiple mammary tumors of 3 different transgenic mouse models of breast cancer and that this frequency is maintained in tumor cell populations cultured in serum-free, chemically defined media as non-adherent tumorspheres. The latter enabled high-throughput screening of small molecules for their capacity to affect BTIC survival. Antagonists of several serotonin receptors (5-HTRs) were among the hit compounds. The most potent compound we identified, SB-699551, selectively binds to 5-HT5A, a Gα_i/o protein coupled receptor (GPCR).

Methods

We evaluated the activity of structurally unrelated selective 5-HT5A antagonists using multiple orthogonal assays of BTIC frequency. Thereafter we used a phosphoproteomic approach to uncover the mechanism of action of SB-699551. To validate the molecular target of the antagonists, we used the CRISPR-Cas9 gene editing technology to conditionally knockout HTR5A in a breast tumor cell line.

Results

We found that selective antagonists of 5-HT5A reduced the frequency of tumorsphere initiating cells residing in breast tumor cell lines and those of patient-derived xenografts (PDXs) that we established. The most potent compound among those tested, SB-699551, reduced the frequency of BTIC in ex vivo assays and acted in concert with chemotherapy to shrink human breast tumor xenografts in vivo. Our phosphoproteomic experiments established that exposure of breast tumor cells to SB-699551 elicited signaling changes in the canonical Gα_i/o-coupled pathway and the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) axis. Moreover, conditional mutation of the HTR5A gene resulted in the loss of tumorsphere initiating cells and BTIC thus mimicking the effect of SB-699551.

Conclusions

Our data provide genetic, pharmacological and phosphoproteomic evidence consistent with the on-target activity of SB-699551. The use of such agents in combination with cytotoxic chemotherapy provides a novel therapeutic approach to treat breast cancer.

A Cross-Reactive Small Protein Binding Domain Provides a Model to Study Off-Tumor CAR-T Cell Toxicity

Tumor-targeted chimeric antigen receptor (CAR)-engineered T lymphocytes (CAR-T cells) have demonstrated striking clinical success, but their use has been associated with a constellation of toxicities. A better understanding of the pathogenesis of these toxicities is required to improve the safety profile of CAR-T cells. Herein, we describe a xenograft model of off-tumor CAR-T cell-associated toxicity. Human CAR-T cells targeted against HER2 using a small-protein binding domain induced acute, dose-dependent toxicities in mice. The inclusion of a CD28 or 4-1BB co-stimulatory domain in the CAR was required to produce toxicity; however, co-stimulation through CD28 was most toxic on a per-cell basis. CAR-T cell activation in the lungs and heart was associated with a systemic cytokine storm. The severity of observed toxicities was dependent upon the peripheral blood mononuclear cell (PBMC) donor used as a T cell source and paralleled the CD4⁺-to-CD8⁺ T cell ratio in the adoptive transfer product. CD4⁺ CAR-T cells were determined to be the primary contributors to CAR-T cell-associated toxicity. However, donor-specific differences persisted after infusion of a purified CD4⁺ CAR-T cell product, indicating a role for additional variables. This work highlights the contributions of CAR-T cell-intrinsic variables to the pathogenesis of off-tumor toxicity.

The chimeric TAC receptor co-opts the T cell receptor yielding robust anti-tumor activity without toxicity

Engineering T cells with chimeric antigen receptors (CARs) is an effective method for directing T cells to attack tumors, but may cause adverse side effects such as the potentially lethal cytokine release syndrome. Here the authors show that the T cell antigen coupler (TAC), a chimeric receptor that co-opts the endogenous TCR, induces more efficient anti-tumor responses and reduced toxicity when compared with past-generation CARs. TAC-engineered T cells induce robust and antigen-specific cytokine production and cytotoxicity in vitro, and strong anti-tumor activity in a variety of xenograft models including solid and liquid tumors. In a solid tumor model, TAC-T cells outperform CD28-based CAR-T cells with increased anti-tumor efficacy, reduced toxicity, and faster tumor infiltration. Intratumoral TAC-T cells are enriched for Ki-67+ CD8+ T cells, demonstrating local expansion. These results indicate that TAC-T cells may have a superior therapeutic index relative to CAR-T cells.

Serotonergic system antagonists target breast tumor initiating cells and synergize with chemotherapy to shrink human breast tumor xenografts

Breast tumors comprise an infrequent tumor cell population, termed breast tumor initiating cells (BTIC), which sustain tumor growth, seed metastases and resist cytotoxic therapies. Hence therapies are needed to target BTIC to provide more durable breast cancer remissions than are currently achieved. We previously reported that serotonergic system antagonists abrogated the activity of mouse BTIC resident in the mammary tumors of a HER2-overexpressing model of breast cancer. Here we report that antagonists of serotonin (5-hydroxytryptamine; 5-HT) biosynthesis and activity, including US Federal Food and Drug Administration (FDA)-approved antidepressants, targeted BTIC resident in numerous breast tumor cell lines regardless of their clinical or molecular subtype. Notably, inhibitors of tryptophan hydroxylase 1 (TPH1), required for 5-HT biosynthesis in select non-neuronal cells, the serotonin reuptake transporter (SERT) and several 5-HT receptors compromised BTIC activity as assessed by functional sphere-forming assays. Consistent with these findings, human breast tumor cells express TPH1, 5-HT and SERT independent of their molecular or clinical subtype. Exposure of breast tumor cells ex vivo to sertraline (Zoloft), a selective serotonin reuptake inhibitor (SSRI), reduced BTIC frequency as determined by transplanting drug-treated tumor cells into immune-compromised mice. Moreover, another SSRI (vilazodone; Viibryd) synergized with chemotherapy to shrink breast tumor xenografts in immune-compromised mice by inhibiting tumor cell proliferation and inducing their apoptosis. Collectively our data suggest that antidepressants in combination with cytotoxic anticancer therapies may be an appropriate treatment regimen for testing in clinical trials.

Asparaginase inhibits the lectin pathway of complement activation

Oncological treatment has been associated with an increased risk of infection, most often related to therapy-induced pancytopenia. However, limited research has been conducted on the effect of oncological therapy on the complement system, being part of the non-cellular innate immune system. This became the rationale for an observational clinical study (C2012) in which we have investigated the prevalence of transient complement defects. Once we had observed such defects, a correlation of the complement defects to specific clinical parameters or to specific therapeutic regimens was investigated. A prominent defect observed in C2012 was the inhibition of the lectin pathway (LP) of complement activation during the treatment of acute lymphoblastic leukemia (ALL), which we could directly associate to the use of asparaginase (ASNase). Ex-vivo experiments confirmed a direct dose-dependent inhibitory effect of ASNase on the LP functionality.

Ex vivo expanded natural killer cells from breast cancer patients and healthy donors are highly cytotoxic against breast cancer cell lines and patient-derived tumours

BACKGROUND

Natural killer (NK) cells play a critical role in cancer immunosurveillance. Recent developments in NK cell ex-vivo expansion makes it possible to generate millions of activated NK cells from a small volume of peripheral blood. We tested the functionality of ex vivo expanded NK cells in vitro against breast cancer cell lines and in vivo using a xenograft mouse model. The study aim was to assess functionality and phenotype of expanded NK cells from breast cancer patients against breast cancer cell lines and autologous primary tumours.

METHODS

We used a well-established NK cell co-culture system to expand NK cells ex vivo from healthy donors and breast cancer patients and examined their surface marker expression. Moreover, we tested the ability of expanded NK cells to lyse the triple negative breast cancer and HER2-positive breast cancer cell lines MDA-MB-231 and MDA-MB-453, respectively. We also tested their ability to prevent tumour growth in vivo using a xenograft mouse model. Finally, we tested the cytotoxicity of expanded NK cells against autologous and allogeneic primary breast cancer tumours in vitro.

RESULTS

After 3 weeks of culture we observed over 1000-fold expansion of NK cells isolated from either breast cancer patients or healthy donors. We also showed that the phenotype of expanded NK cells is comparable between those from healthy donors and cancer patients. Moreover, our results confirm the ability of ex vivo expanded NK cells to lyse tumour cell lines in vitro. While the cell lines examined had differential sensitivity to NK cell killing we found this was correlated with level of major histocompatibility complex (MHC) class I expression. In our in vivo model, NK cells prevented tumour establishment and growth in immunocompromised mice. Finally, we showed that NK cells expanded from the peripheral blood of breast cancer patients show high cytotoxicity against allogeneic and autologous patient-derived tumour cells in vitro.

CONCLUSION

NK cells from breast cancer patients can be expanded similarly to those from healthy donors, have a high cytotoxic ability against breast cancer cell lines and patient-derived tumour cells, and can be compatible with current cancer treatments to restore NK cell function in cancer patients.

Malacia, inflammation and bronchoalveolar lavage culture in children with persistent respiratory symptoms

In children with persistent respiratory symptoms despite regular anti-asthma inhalation treatment, diagnostic investigations to exclude underlying disease are warranted. 124 children were prospectively enrolled, and 24-h oesophageal pH measurement and fibreoptic bronchoscopy with bronchoalveolar lavage (BAL) were performed. BAL fluid (BALF) was processed for neutrophil counting and bacterial culture. Inflammation of the respiratory mucosa was assessed. A structural abnormality of the central airways was found in 47% of subjects (40% females). In 19% of subjects, neither anatomical anomalies nor inflamed respiratory mucosa were observed, whereas in 64%, definite macroscopic mucosal inflammation was observed. Inflammation of the respiratory mucosa was associated with a significantly higher percentage of neutrophils in the BALF: median (interquartile range) 48 (14-82)% compared with 7 (0-16)% (p<0.025). A positive BALF culture was found in 62% of the infants with mucosal inflammation compared with 25% in the group without inflammation (p<0.016). 56% of the BALF samples were positive for bacterial culture. In children with persistent respiratory symptoms, nearly half have anatomical anomalies of the central airways. In 62% of the children with mucosal inflammation, a positive BAL culture and a significantly higher percentage of BALF neutrophils were detected.

Enabling nursing students to focus on the Ottawa Charter and the nurses role in tackling inequalities in health through international exchange

Student nurses in a transatlantic exchange program explored the role of registered nurses in five countries' public health systems. The Ottawa Charter provided a framework for students to examine the nurse's responsibilities in public health. Students took practice placements in geographically rural a reason another continent and explored inequalities in health care. If nurses are to understand their role in the health care system then they must be taught the scope of their practice including their role in health promotion,public health practice and community development. For this project nursing instructors developed an assignment relevant to the aims and suitable for students in all five nursing programs. Only three of 48 students offered an assignment which focused on building healthy public policy. Nurse educators need to explore this further to ensure nurses of the future are aware of their role and responsibilities in this area and have skills to work effectively to influence and build healthy policy. The international student exchange supported the students' developing understanding of the breadth of initiatives around the globe where nurses are actively engaged in addressing inequalities of health. Findings from an analysis of their assignments are presented in this evaluative report.

Duration of breastfeeding and breastfeeding problems in relation to length of postpartum stay: a longitudinal cohort study of a national Swedish sample

AIM

To investigate the association between length of postpartum stay and duration of breastfeeding and breastfeeding problems, with special focus on early hospital discharge.

METHODS

Swedish-speaking women were recruited from all antenatal clinics in Sweden during 3 wk evenly spread over 1 y in 1999 to 2000. In total, 3293 women (71% of those who were eligible) consented to participate in the study. Data were collected by questionnaires in early pregnancy, 2 mo and 1 y postpartum, and from the Swedish Medical Birth Register. For the purpose of this study, only data from the 2709 women (82%) who filled in the question about length of stay in the 2-mo questionnaire were analysed. Women were divided into six groups according to length of postpartum stay (day 1: < 24 h to day 6: > or = 120 h).

RESULTS

The median duration of any breastfeeding was 7 mo in women discharged on day 1, and 8 mo in women discharged on any of the following days; a non-significant difference (p = 0.66). Besides hospital policies regarding length of stay (residential area) and number of domiciliary visits, early discharge was associated with the following maternal characteristics, which could be divided into three categories: (1) older, multipara, many children; (2) positive experience of the first breastfeeding after birth; (3) low education, economic problems, smoking, lack of support from partner. Late discharge was associated with operative delivery, preterm birth and low infant birthweight. When these factors were controlled for by Cox regression analysis, no statistical differences were found between the six groups in the relative risk of discontinuing to breastfeed. Breastfeeding problems, such as engorgement and mastitis, did not differ, but women discharged on day 6 or later had fewer problems with sore or cracked nipples during the first week and more problems 4-8 wk postpartum.

CONCLUSION

Maternal characteristics may be more important predictors of the duration of breastfeeding than length of stay in hospital after the birth. The effect of domiciliary support needs further research.

Growth under privileged conditions of healthy Swedish infants exclusively breastfed from birth to 4-6 months: a longitudinal prospective study based on daily records of feeding

AIM

In most studies the methodology used to study growth in relation to breastfeeding patterns cannot ensure that exclusive breastfeeding has in fact occurred since birth. The aim of this study was to investigate the growth of healthy infants in Sweden in whom exclusive breastfeeding for the first 4-6 mo was ascertained through daily feeding records and to compare the results with the World Health Organization (WHO) "12-month breastfed pooled data set" and the Euro-Growth references for exclusively breastfed infants, as well as with the National Center for Health Statistics (NCHS)/WHO reference.

METHODS

147 exclusively breastfed infants and 325 non-exclusively breastfed Swedish infants, with a birthweight of > or = 3 kg, were included. The mothers had previous breastfed at least one infant for at least 4 mo. Weight was recorded fortnightly and length monthly.

RESULTS

Infants exclusively breastfed since birth showed similar growth in weight and height to that of the non-exclusively breastfed infants. During the first 6 mo of life the growth of exclusively breastfed infants was also similar to that of the infants regularly receiving formula at 12-16 wk of age, mostly in addition to breast milk. The monthly growth increments were fairly similar to those of the "WHO pooled breastfed data set" and the Euro-Growth references for exclusively breastfed infants.

CONCLUSION

In an affluent society truly exclusively breastfed infants seem to have the same growth during the first half year of life as non-exclusively breastfed infants with a high breastfeeding rate.

How exclusive is exclusive breastfeeding? A comparison of data since birth with current status data

BACKGROUND

There is no accepted and widely used indicator for exclusive breastfeeding since birth. Indeed, the difference between 'current status' data on exclusive breastfeeding and data on 'exclusive breastfeeding since birth' is rarely recognized. We used data from a longitudinal study to examine this issue.

METHODS

A descriptive longitudinal, prospective study design was used in which 506 mother-infant pairs were included. The mothers completed daily recordings on infant feeding during the first nine months after birth. A research assistant conducted fortnightly home visits with structured interviews. The resulting data on breastfeeding patterns are presented in two different ways: analysis of 'current status' data based on a single 24-hour recording of infant feeding at 2, 4 and 6 months of age, and analysis of data 'since birth', i.e. data on infant feeding for every day, starting from birth until the ages of 2, 4 and 6 months.

RESULTS

A wide discrepancy between the results obtained from the two analyses was found. The difference in the exclusive breastfeeding rate was over 40 percentage points at both 2 and 4 months of age (92% versus 51% at 2 months and 73% versus 30% at 4 months) and 9 percentage points at 6 months (11% versus 1.8%).

CONCLUSIONS

Current status indicators based on a 24-hour period may be inadequate and even misleading for many purposes. We propose that in many studies an indicator called 'exclusive breastfeeding since birth' could be added.

Breastfeeding patterns in relation to thumb sucking and pacifier use

OBJECTIVES

To analyze the influence of thumb sucking and pacifier use on breastfeeding patterns in exclusively breastfed infants, on the duration of exclusive breastfeeding, and on the total breastfeeding duration.

STUDY DESIGN

Descriptive, longitudinal, prospective study.

SETTING

The subjects were recruited from a population of 15 189 infants born in the maternity ward at the University Hospital, Uppsala, Sweden between May 1989 and December 1992.

STUDY POPULATION

506 mother-infant pairs.

METHODS

Daily recordings by the mothers on infant feeding from the first week after delivery through the duration of the study. Fortnightly home visits with structured interviews by a research assistant.

RESULTS

Pacifier use was associated with fewer feeds and shorter suckling duration per 24 hours, shorter duration of exclusive breastfeeding, and shorter total breastfeeding duration compared with no pacifier use. These associations were not found for thumb sucking. The possible negative effects of pacifiers on breastfeeding seemed to be related to the frequency of their use. Maternal age and education only slightly modified the association between pacifier use and breastfeeding duration.

CONCLUSIONS

More frequent use of a pacifier was associated with shorter breastfeeding duration, even among a group of mothers who were highly motivated to breastfeed. breastfeeding duration, breastfeeding pattern, exclusive breastfeeding, pacifier use, thumb sucking.

Breastfeeding patterns in exclusively breastfed infants: a longitudinal prospective study in Uppsala, Sweden

Exclusive breastfeeding was studied among 506 infants in Uppsala, Sweden, based on daily recordings during the first 6 mo. The mothers had previously breastfed at least one infant for at least 4 mo. Most of the mothers considered that they breastfed on demand. Wide variations in breastfeeding frequency and suckling duration were found both between different infants and in the individual infant over time. At 2 wk, the mean frequency of daytime feeds (based on one 13-d record) between different infants ranged from 2.9 to 10.8 and night-time feeds from 1.0 to 5.1. The daytime suckling duration (based on one 24-h record) ranged from 20 min to 4h 35 min and night-time duration from 0 to 2h 8 min. At any given age, a maximum of only 2% of the infants were not breastfed during the night. At 4 mo, 95% of the infants were breastfeeding and 40% were exclusively breastfed at this age. Longer breastfeeding duration and longer duration of exclusive breastfeeding were both associated with higher frequency of breastfeeds, longer breastfeeding of the previous child and higher education. No gender differences were found. Maternal smoking was associated with shorter duration of exclusive breastfeeding, and pacifier use was associated with shorter duration of both exclusive breastfeeding and total breastfeeding. This study confirms that every mother-infant pair needs to be understood as a unique dyad throughout lactation. These data demonstrate a wide range of patterns among women who are exclusively breastfeeding and indicate that it would be inappropriate to put pressure on individual families to adopt preconceived patterns of infant feeding.