Membrane-Bound IL-21 Promotes Sustained Ex Vivo Proliferation of Human Natural Killer Cells

NK cells have therapeutic potential for a wide variety of human malignancies. However, because NK cells expand poorly in vitro, have limited life spans in vivo, and represent a small fraction of peripheral white blood cells, obtaining sufficient cell numbers is the major obstacle for NK-cell immunotherapy. Genetically-engineered artificial antigen-presenting cells (aAPCs) expressing membrane-bound IL-15 (mbIL15) have been used to propagate clinical-grade NK cells for human trials of adoptive immunotherapy, but ex vivo proliferation has been limited by telomere shortening. We developed K562-based aAPCs with membrane-bound IL-21 (mbIL21) and assessed their ability to support human NK-cell proliferation. In contrast to mbIL15, mbIL21-expressing aAPCs promoted log-phase NK cell expansion without evidence of senescence for up to 6 weeks of culture. By day 21, parallel expansion of NK cells from 22 donors demonstrated a mean 47,967-fold expansion (median 31,747) when co-cultured with aAPCs expressing mbIL21 compared to 825-fold expansion (median 325) with mbIL15. Despite the significant increase in proliferation, mbIL21-expanded NK cells also showed a significant increase in telomere length compared to freshly obtained NK cells, suggesting a possible mechanism for their sustained proliferation. NK cells expanded with mbIL21 were similar in phenotype and cytotoxicity to those expanded with mbIL15, with retained donor KIR repertoires and high expression of NCRs, CD16, and NKG2D, but had superior cytokine secretion. The mbIL21-expanded NK cells showed increased transcription of the activating receptor CD160, but otherwise had remarkably similar mRNA expression profiles of the 96 genes assessed. mbIL21-expanded NK cells had significant cytotoxicity against all tumor cell lines tested, retained responsiveness to inhibitory KIR ligands, and demonstrated enhanced killing via antibody-dependent cell cytotoxicity. Thus, aAPCs expressing mbIL21 promote improved proliferation of human NK cells with longer telomeres and less senescence, supporting their clinical use in propagating NK cells for adoptive immunotherapy

Contemporary Management of Locally Advanced and Recurrent Rectal Cancer: Views from the PelvEx Collaborative

Pelvic exenteration is a complex operation performed for locally advanced and recurrent pelvic cancers. The goal of surgery is to achieve clear margins, therefore identifying adjacent or involved organs, bone, muscle, nerves and/or vascular structures that may need resection. While these extensive resections are potentially curative, they can be associated with substantial morbidity. Recently, there has been a move to centralize care to specialized units, as this facilitates better multi-disciplinary care input. Advancements in pelvic oncology and surgical innovation have redefined the boundaries of pelvic exenterative surgery. Combined with improved neoadjuvant therapies, advances in diagnostics, and better reconstructive techniques have provided quicker recovery and better quality of life outcomes, with improved survival This article provides highlights of the current management of advanced pelvic cancers in terms of surgical strategy and potential future developments

Patients’ Initial Doubts, Reservations and Objections to the ABC’s of REBT and their Application

This exploratory research set out to develop an initial framework and categorization scheme for understanding patients’ initial doubts, reservations and objections to the ABC’s of REBT and their application. 60 patients were asked to write down their doubts following a pre-therapy ‘‘Introduction to REBT’’ session. Subsequently, an emergent content analysis was carried out to identify main themes. The content analysis revealed five general categories, of which the two largest ones concerned theoretical doubts about the ABC model, and doubts about putting the ABC model into practice. Further sub-categorization revealed a variety of concerns that related to these categories. For example, a large proportion of doubts about putting the ABC model into practice were sub-categorized as concerning the perceived difficulty of doing so. In turn, this sub-category contained further sub-categories of difficulty-related beliefs

Gene expression in NK cells stimulated with mbIL15 or mbIL21 as assessed using the nCounter platform.

<p>Paired aliquots of purified NK cells from 4 donors were stimulated for one week with either Clone 4 (mbIL15) or Clone 9.mbIL21. Total RNA was purified and equal quantities hybridized for detection of expression of 96 genes. Gene expression was normalized to LDH (mean 6,076 copies detected), and the remaining data for each gene plotted as mean +/− SEM for each expansion condition. Genes with detection below background (set at ≤10 detected copies) were excluded as not biologically significant (grey box). The ten highest-expressed genes in addition to LDH are labeled, as are genes that are differentially expressed by >2 fold (red) or <0.5 fold (blue) in mbIL21-expanded cells. Differentially expressed genes were replotted (inset) for comparison, and two-tailed <i>t-</i>test applied.</p