The impact of single agent PD-1 or PD-L1 inhibition on advanced endometrial cancers: meta-analysis.

BACKGROUND: Immune checkpoint inhibitor (ICI) therapy is an emerging option for advanced endometrial cancer (EC). Mismatch repair (MMR) status is widely regarded as a biomarker predictive of response to ICIs. The predictive value of MMR based on small, single-arm trials, however, is conflicting. In this meta-analysis, we aimed to assess the activity of single-agent ICI in advanced EC, and compared the magnitude of treatment benefit in MMR deficient (dMMR) and MMR proficient (pMMR) EC. METHODS: We carried out an electronic search to identify prospective trials of single-agent ICI in advanced EC. Data on objective response rate (ORR) and progression-free survival (PFS) were extracted and pooled. ORR was estimated using the inverse variance method and subgroup difference by MMR status was examined. PFS difference according to MMR status was summarized using the Kaplan-Meier approach. RESULTS: From eight trials with 492 women, the pooled ORR was 19% [95% confidence interval (CI) 16% to 22%]. ORR was significantly greater in dMMR (n = 281) than pMMR EC (n = 211) (dMMR: 46%, pMMR: 8%; risk ratio 5.74, 95% CI 3.58-9.21; interaction P < 0.001). Complete response was 11% and 0.05% and median PFS was 8.3 and 2.1 months in dMMR and pMMR EC, respectively (hazard ratio PFS 0.58, 95% CI 0.38-0.89; P = 0.01). The 12-month PFS rates were 42.0% and 20.7%, respectively. CONCLUSION: Single-agent ICI is associated with a 5.74 times greater objective response and 42% reduction in risk of disease progression or death in dMMR compared with pMMR EC. MMR status should be determined prospectively and be used as a stratification factor in future trials of advanced EC. Further translational analysis is urgently required to identify the cause of dMMR and allow subclassification of EC into different dMMR molecular subtypes.

ESMO recommendations on predictive biomarker testing for homologous recombination deficiency and PARP inhibitor benefit in ovarian cancer.

BACKGROUND: Homologous recombination repair deficiency (HRD) is a frequent feature of high-grade serous ovarian, fallopian tube and peritoneal carcinoma (HGSC) and is associated with sensitivity to PARP inhibitor (PARPi) therapy. HRD testing provides an opportunity to optimise PARPi use in HGSC but methodologies are diverse and clinical application remains controversial. MATERIALS AND METHODS: To define best practice for HRD testing in HGSC the ESMO Translational Research and Precision Medicine Working Group launched a collaborative project that incorporated a systematic review approach. The main aims were to (i) define the term 'HRD test'; (ii) provide an overview of the biological rationale and the level of evidence supporting currently available HRD tests; (iii) provide recommendations on the clinical utility of HRD tests in clinical management of HGSC. RESULTS: A broad range of repair genes, genomic scars, mutational signatures and functional assays are associated with a history of HRD. Currently, the clinical validity of HRD tests in ovarian cancer is best assessed, not in terms of biological HRD status per se, but in terms of PARPi benefit. Clinical trials evidence supports the use of BRCA mutation testing and two commercially available assays that also incorporate genomic instability for identifying subgroups of HGSCs that derive different magnitudes of benefit from PARPi therapy, albeit with some variation by clinical scenario. These tests can be used to inform treatment selection and scheduling but their use is limited by a failure to consistently identify a subgroup of patients who derive no benefit from PARPis in most studies. Existing tests lack negative predictive value and inadequately address the complex and dynamic nature of the HRD phenotype. CONCLUSIONS: Currently available HRD tests are useful for predicting likely magnitude of benefit from PARPis but better biomarkers are urgently needed to better identify current homologous recombination proficiency status and stratify HGSC management.

ESMO recommendations on predictive biomarker testing for homologous recombination deficiency and PARP inhibitor benefit in ovarian cancer

The European Society for Medical Oncology (ESMO) Translational Research and Precision Medicine Working Group identified that there is currently uncertainty within the oncology community surrounding the different methods for HRD testing in HGSC. To address this, a collaborative project was launched with a number of clinicians and scientists with expertise in the fields of PARPi clinical trials, cancer genomics and DNA repair. The group defined three main aims for the project: (i) Define the term 'HRD test' and recommend how an HRD test's clinical validity is currently best assessed in the context of HGSC, (ii) provide an overview of the biological rationale and the level of evidence supporting currently available HRD tests, and (iii) provide recommendations on the clinical utility of HRD tests in clinical management of HGSC.

The development and evaluation of a nationwide training program for oncology health professionals in the provision of genetic testing for ovarian cancer patients.

BACKGROUND: BRCA1/2 mutation status has increasing relevance for ovarian cancer treatments, making traditional coordination of genetic testing by genetic services unsustainable. Consequently alternative models of genetic testing have been developed to improve testing at the initial diagnosis for all eligible women. METHODS: A training module to enable mainstreamed genetic testing by oncology healthcare professionals was developed by genetic health professionals. Oncology healthcare professionals completed questionnaires before and 12 months post-training to assess perceived skills, competence and barriers to their coordinating genetic testing for women with high-grade non-mucinous epithelial ovarian cancer. Genetic health professionals were surveyed 12 months post-training to assess perceived barriers to implementation of mainstreaming. RESULTS: 185 oncology healthcare professionals were trained in 42 workshops at 35 Australasian hospitals. Of the 273 tests ordered by oncology healthcare professionals post-training, 241 (93.1%) met national testing guidelines. The number of tests ordered by genetic health professionals reduced significantly (z = 45.0, p = 0.008). Oncology healthcare professionals' perceived barriers to mainstreamed testing decreased from baseline to follow-up (t = 2.39, p = 0.023), particularly perceived skills, knowledge and attitudes. However, only 58% reported either 'always' or 'nearly always' having ordered BRCA testing for eligible patients at 12 months, suggesting oncology healthcare professionals' perceived barriers were not systematically addressed through training. CONCLUSIONS: Oncology healthcare professionals have demonstrated a willingness to be involved in the provision of genetic testing in a mainstreaming model. If oncology services are to hold responsibility for coordinating genetic testing, their readiness will require understanding of barriers not addressed by training alone to inform future intervention design.

TGFßR signalling controls CD103+CD11b+ dendritic cell development in the intestine.

CD103+CD11b+ dendritic cells (DCs) are unique to the intestine, but the factors governing their differentiation are unclear. Here we show that transforming growth factor receptor 1 (TGFßR1) has an indispensable, cell intrinsic role in the development of these cells. Deletion of Tgfbr1 results in markedly fewer intestinal CD103+CD11b+ DCs and a reciprocal increase in the CD103-CD11b+ dendritic cell subset. Transcriptional profiling identifies markers that define the CD103+CD11b+ DC lineage, including CD101, TREM1 and Siglec-F, and shows that the absence of CD103+CD11b+ DCs in CD11c-Cre.Tgfbr1 fl/fl mice reflects defective differentiation from CD103-CD11b+ intermediaries, rather than an isolated loss of CD103 expression. The defect in CD103+CD11b+ DCs is accompanied by reduced generation of antigen-specific, inducible FoxP3+ regulatory T cells in vitro and in vivo, and by reduced numbers of endogenous Th17 cells in the intestinal mucosa. Thus, TGFßR1-mediated signalling may explain the tissue-specific development of these unique DCs.Developmental cues for the different dendritic cell (DC) subsets in the intestine are yet to be defined. Here the authors show that TGFßR1 signalling is needed for development of CD103+CD11b+ intestinal DCs from CD103-CD11b+ cells and that they contribute to the generation of Th17 and regulatory T cells.

Development of conventional dendritic cells: from common bone marrow progenitors to multiple subsets in peripheral tissues.

Our understanding of conventional dendritic cell (cDC) development and the functional specializations of distinct subsets in the peripheral tissues has increased greatly in recent years. Here, we review cDC development from the distinct progenitors in the bone marrow through to the distinct cDC subsets found in barrier tissues, providing an overview of the different subsets described in each location. In addition, we detail the transcription factors and local signals that have been proposed to control this developmental process. Importantly, despite these significant advances, numerous questions remain to be answered regarding cDC development. For example, it remains unclear whether the different subsets described, such as the CD103+CD11b+ and CD103-CD11b+ cDCs in the intestines, truly represent different populations or rather distinct developmental or activation stages. Furthermore, whether distinct progenitors exist for these cDC subsets remains to be determined. Thus in the last part of this review we discuss what we believe will be the main questions facing the field for the coming years.

BCR-signaling-induced cell death demonstrates dependency on multiple BH3-only proteins in a murine model of B-cell lymphoma.

Genetic recombination during B-cell development regularly results in the generation of autoreactive, potentially pathogenic B-cell receptors (BCRs). Consequently, multiple mechanisms link inappropriate BCR specificity to clonal deletion. Similar pathways remain in malignant B cells, offering the potential for targeting BCR signaling. Recently, small molecule inhibitors have realized this potential and, therefore, a deeper understanding of BCR-induced signaling networks in malignant cells is vital. The BH3-only protein Bim has a key role in BCR-induced apoptosis, but it has long been proposed that additional BH3-only proteins also contribute, although conclusive proof has been lacking. Here, we comprehensively characterized the mechanism of BCR-induced apoptosis in Eµ-Myc murine lymphoma cells. We demonstrate the upregulation of Bim, Bik, and Noxa during BCR signaling in vitro and that intrinsic apoptosis has a prominent role in anti-BCR antibody therapy in vivo. Furthermore, lymphomas deficient in these individual BH3-only proteins display significant protection from BCR-induced cell death, whereas combined loss of Noxa and Bim offers enhanced protection in comparison with loss of Bim alone. Some but not all of these effects were reversed upon inhibition of Syk or MEK. These observations indicate that BCR signaling elicits maximal cell death through upregulation of multiple BH3-only proteins; namely Bim, Bik, and Noxa.

Prioritizing therapeutic targets using patient-derived xenograft models.

Effective systemic treatment of cancer relies on the delivery of agents with optimal therapeutic potential. The molecular age of medicine has provided genomic tools that can identify a large number of potential therapeutic targets in individual patients, heralding the promise of personalized treatment. However, determining which potential targets actually drive tumor growth and should be prioritized for therapy is challenging. Indeed, reliable molecular matches of target and therapeutic agent have been stringently validated in the clinic for only a small number of targets. Patient-derived xenografts (PDXs) are tumor models developed in immunocompromised mice using tumor procured directly from the patient. As patient surrogates, PDX models represent a powerful tool for addressing individualized therapy. Challenges include humanizing the immune system of PDX models and ensuring high quality molecular annotation, in order to maximize insights for the clinic. Importantly, PDX can be sampled repeatedly and in parallel, to reveal clonal evolution, which may predict mechanisms of drug resistance and inform therapeutic strategy design.

Lymph-borne CD8α+ dendritic cells are uniquely able to cross-prime CD8+ T cells with antigen acquired from intestinal epithelial cells.

Cross-presentation of cellular antigens is crucial for priming CD8(+) T cells, and generating immunity to intracellular pathogens--particularly viruses. It is unclear which intestinal phagocytes perform this function in vivo. To address this, we examined dendritic cells (DCs) from the intestinal lymph of IFABP-tOVA 232-4 mice, which express ovalbumin in small intestinal epithelial cells (IECs). Among lymph DCs (LDCs) only CD103(+) CD11b(-) CD8α(+) DCs cross-present IEC-derived ovalbumin to CD8(+) OT-I T cells. Similarly, in the mesenteric lymph nodes (MLNs), cross-presentation of IEC-ovalbumin was limited to the CD11c(+) MHCII(hi) CD8α(+) migratory DCs, but absent from all other subsets, including the resident CD8α(hi) DCs. Crucially, delivery of purified CD8α(+) LDCs, but not other LDC subsets, into the MLN subcapsular lymphatic sinus induced proliferation of ovalbumin-specific, gut-tropic CD8(+) T cells in vivo. Finally, in 232-4 mice treated with R848, CD8α(+) LDCs were uniquely able to cross-prime interferon γ-producing CD8(+) T cells and drive their migration to the intestine. Our results clearly demonstrate that migrating CD8α(+) intestinal DCs are indispensable for cross-presentation of cellular antigens and, in conditions of inflammation, for the initial differentiation of effector CD8(+) T cells. They may therefore represent an important target for the development of antiviral vaccinations.

CCR2(+)CD103(-) intestinal dendritic cells develop from DC-committed precursors and induce interleukin-17 production by T cells.

The identification of intestinal macrophages (mφs) and dendritic cells (DCs) is a matter of intense debate. Although CD103(+) mononuclear phagocytes (MPs) appear to be genuine DCs, the nature and origins of CD103(-) MPs remain controversial. We show here that intestinal CD103(-)CD11b(+) MPs can be separated clearly into DCs and mφs based on phenotype, gene profile, and kinetics. CD64(-)CD103(-)CD11b(+) MPs are classical DCs, being derived from Flt3 ligand-dependent, DC-committed precursors, not Ly6C(hi) monocytes. Surprisingly, a significant proportion of these CD103(-)CD11b(+) DCs express CCR2 and there is a selective decrease in CD103(-)CD11b(+) DCs in mice lacking this chemokine receptor. CCR2(+)CD103(-) DCs are present in both the murine and human intestine, drive interleukin (IL)-17a production by T cells in vitro, and show constitutive expression of IL-12/IL-23p40. These data highlight the heterogeneity of intestinal DCs and reveal a bona fide population of CCR2(+) DCs that is involved in priming mucosal T helper type 17 (Th17) responses.

Interleukin-22 binding protein (IL-22BP) is constitutively expressed by a subset of conventional dendritic cells and is strongly induced by retinoic acid.

Interleukin-22 (IL-22) is mainly produced at barrier surfaces by T cells and innate lymphoid cells and is crucial to maintain epithelial integrity. However, dysregulated IL-22 action leads to deleterious inflammation and is involved in diseases such as psoriasis, intestinal inflammation, and cancer. IL-22 binding protein (IL-22BP) is a soluble inhibitory IL-22 receptor and may represent a crucial regulator of IL-22. We show both in rats and mice that, in the steady state, the main source of IL-22BP is constituted by a subset of conventional dendritic cells (DCs) in lymphoid and non-lymphoid tissues. In mouse intestine, IL-22BP was specifically expressed in lamina propria CD103(+)CD11b(+) DC. In humans, IL-22BP was expressed in immature monocyte-derived DC and strongly induced by retinoic acid but dramatically reduced upon maturation. Our data suggest that a subset of immature DCs may actively participate in the regulation of IL-22 activity in the gut by producing high levels of IL-22BP.

Intestinal CD103(-) dendritic cells migrate in lymph and prime effector T cells.

Intestinal dendritic cells (DCs) continuously migrate through lymphatics to mesenteric lymph nodes where they initiate immunity or tolerance. Recent research has focused on populations of intestinal DCs expressing CD103. Here we demonstrate, for the first time, the presence of two distinct CD103(-) DC subsets in intestinal lymph. Similar to CD103(+) DCs, these intestine-derived CD103(-) DCs are responsive to Flt3 and they efficiently prime and confer a gut-homing phenotype to naive T cells. However, uniquely among intestinal DCs, CD103(-) CD11b(+) CX(3)CR1(int) lymph DCs induce the differentiation of both interferon-γ and interleukin-17-producing effector T cells, even in the absence of overt stimulation. Priming by CD103(-) CD11b(+) DCs represents a novel mechanism for the rapid generation of effector T-cell responses in the gut. Therefore, these cells may prove to be valuable targets for the treatment of intestinal inflammation or in the development of effective oral vaccines.

Resident and pro-inflammatory macrophages in the colon represent alternative context-dependent fates of the same Ly6Chi monocyte precursors.

Macrophages (mφ) are essential for intestinal homeostasis and the pathology of inflammatory bowel disease (IBD), but it is unclear whether discrete mφ populations carry out these distinct functions or if resident mφ change during inflammation. We show here that most resident mφ in resting mouse colon express very high levels of CX3CR1, are avidly phagocytic and MHCII(hi), but are resistant to Toll-like receptor (TLR) stimulation, produce interleukin 10 constitutively, and express CD163 and CD206. A smaller population of CX3CR1(int) cells is present in resting colon and it expands during experimental colitis. Ly6C(hi)CCR2(+) monocytes can give rise to all mφ subsets in both healthy and inflamed colon and we show that the CX3CR1(int) pool represents a continuum in which newly arrived, recently divided monocytes develop into resident CX3CR1(hi) mφ. This process is arrested during experimental colitis, resulting in the accumulation of TLR-responsive pro-inflammatory mφ. Phenotypic analysis of human intestinal mφ indicates that analogous processes occur in the normal and Crohn's disease ileum. These studies show for the first time that resident and inflammatory mφ in the intestine represent alternative differentiation outcomes of the same precursor and targeting these events could offer routes for therapeutic intervention in IBD.

Neither loss of Bik alone, nor combined loss of Bik and Noxa, accelerate murine lymphoma development or render lymphoma cells resistant to DNA damaging drugs.

The pro-apoptotic BH3-only protein, BIK, is widely expressed and although many critical functions in developmental or stress-induced death have been ascribed to this protein, mice lacking Bik display no overt abnormalities. It has been postulated that Bik can serve as a tumour suppressor, on the basis that its deficiency and loss of apoptotic function have been reported in many human cancers, including lymphoid malignancies. Evasion of apoptosis is a major factor contributing to c-Myc-induced tumour development, but despite this, we found that Bik deficiency did not accelerate Eµ-Myc-induced lymphomagenesis. Co-operation between BIK and NOXA, another BH3-only protein, has been previously described, and was attributed to their complementary binding specificities to distinct subsets of pro-survival BCL-2 family proteins. Nevertheless, combined deficiency of Bik and Noxa did not alter the onset of Eµ-Myc transgene induced lymphoma development. Moreover, although p53-mediated induction of Bik has been reported, neither Eµ-Myc/Bik(-/-) nor Eµ-Myc/Bik(-/-)Noxa(-/-) lymphomas were more resistant than control Eµ-Myc lymphomas to killing by DNA damaging drugs, either in vitro or in vivo. These results suggest that Bik, even in combination with Noxa, is not a potent suppressor of c-Myc-driven tumourigenesis or critical for chemotherapeutic drug-induced killing of Myc-driven tumours.

The primordial follicle reserve is not renewed after chemical or γ-irradiation mediated depletion.

Reports indicate that germ-line stem cells present in adult mice can rapidly generate new oocytes and contribute to the primordial follicle reserve following conditions of ovotoxic stress. We further investigated the hypothesis that adult mice have the capacity to generate new oocytes by monitoring primordial follicle numbers throughout postnatal life and following depletion of the primordial follicle reserve by exposure to doxorubicin (DXR), trichostatin A (TSA), or whole-body γ-irradiation. We show that primordial follicle number remains stable in adult C57BL/6 mice between the ages of 25 and 100 days. However, within 2 days of treatment with DXR or TSA, primordial follicle numbers had declined to 65 and 51% respectively (P<0.05-0.01 when compared to untreated controls), with no restoration of follicle numbers evident after 7 days for either treatment. Furthermore, ovaries from mice subjected to sterilizing doses of γ-irradiation (0.45 or 4.5 Gy) revealed complete ablation of all primordial follicles 5 days after treatment, with no indication of follicular renewal. We conclude that neo-folliculogenesis does not occur following chemical or γ-irradiation mediated depletion of the primordial follicle reserve.

Consensus statement by hospital based dentists providing dental treatment for patients with inherited bleeding disorders.

Avoidance of dental care and neglect of oral health may occur in patients with inherited bleeding disorders because of concerns about perioperative and postoperative bleeding, but this is likely to result in the need for crisis care, and more complex and high-risk procedures. Most routine dental care in this special needs group can be safely managed in the general dental setting following consultation with the patient's haematologist and adherence to simple protocols. Many of the current protocols for dental treatment of patients with inherited bleeding disorders were devised many years ago and now need revision. There is increasing evidence that the amount of factor cover previously recommended for dental procedures can now be safely reduced or may no longer be required in many cases. There is still a need for close cooperation and discussion between the patient's haematologist and dental surgeon before any invasive treatment is performed. A group of hospital based dentists from centres where patients with inherited bleeding disorders are treated met and, after discussions, a management protocol for dental treatment was formulated.

Control of HIF-1{alpha} and vascular signaling in fetal lung involves cross talk between mTORC1 and the FGF-10/FGFR2b/Spry2 airway branching periodicity clock.

Lung development requires coordinated signaling between airway and vascular growth, but the link between these processes remains unclear. Mammalian target of rapamycin complex-1 (mTORC1) can amplify hypoxia-inducible factor-1α (HIF-1α) vasculogenic activity through an NH(2)-terminal mTOR binding (TOS) motif. We hypothesized that this mechanism coordinates vasculogenesis with the fibroblast growth factor (FGF)-10/FGF-receptor2b/Spry2 regulator of airway branching. First, we tested if the HIF-1α TOS motif participated in epithelial-mesenchymal vascular signaling. mTORC1 activation by insulin significantly amplified HIF-1α activity at fetal Po(2) (23 mmHg) in human bronchial epithelium (16HBE14o-) and induced vascular traits (Flk1, sprouting) in cocultured human embryonic lung mesenchyme (HEL-12469). This enhanced activation of HIF-1α by mTORC1 was abolished on expression of a HIF-1α (F99A) TOS-mutant and also suppressed vascular differentiation of HEL-12469 cocultures. Next, we determined if vasculogenesis in fetal lung involved regulation of mTORC1 by the FGF-10/FGFR2b/Spry2 pathway. Fetal airway epithelium displayed distinct mTORC1 activity in situ, and its hyperactivation by TSC1(-/-) knockout induced widespread VEGF expression and disaggregation of Tie2-positive vascular bundles. FGF-10-coated beads grafted into fetal lung explants from Tie2-LacZ transgenic mice induced localized vascular differentiation in the peripheral mesenchyme. In rat fetal distal lung epithelial (FDLE) cells cultured at fetal Po(2), FGF-10 induced mTORC1 and amplified HIF-1α activity and VEGF secretion without induction of ERK1/2. This was accompanied by the formation of a complex between Spry2, the cCBL ubiquitin ligase, and the mTOR repressor, TSC2, which abolished GTPase activity directed against Rheb, the G protein inducer of mTORC1. Thus, mTORC1 links HIF-1α-driven vasculogenesis with the FGF-10/FGFR2b/Spry2 airway branching periodicity regulator.

Puma and to a lesser extent Noxa are suppressors of Myc-induced lymphomagenesis.

Evasion of apoptosis contributes importantly to c-Myc-induced tumorigenesis. The BH3-only Bcl-2 family members Puma and Noxa are critical pro-apoptotic transcriptional targets of p53, a major mediator of Myc-induced apoptosis and suppressor of Myc-induced tumorigenesis. Hence, we have explored the impact of their individual or combined loss on myc-driven lymphomagenesis. Notably, Puma deficiency both increased B-lineage cells and accelerated the development of B lymphoma, accompanied by leukaemia, but not of pre-B lymphoma. Noxa deficiency alone also increased B-lineage cells but did not accelerate lymphomagenesis. However, its deficiency combined with loss of one puma allele produced more rapid onset of both pre-B and B lymphomas than did loss of a single puma allele alone. Nevertheless, the acceleration evoked by loss of both genes was not as marked as that caused by p53 heterozygosity. These results show that Puma imposes a significant, and Noxa a minor barrier to c-Myc-driven lymphomagenesis. They also indicate that additional BH3-only proteins probably also drive Myc-induced apoptosis and that non-apoptotic functions of p53 may contribute substantially to its tumour suppressor role.

Analysis of the apoptotic and therapeutic activities of histone deacetylase inhibitors by using a mouse model of B cell lymphoma.

Histone deacetylase inhibitors (HDACi) can elicit a range of biological responses that affect tumor growth and survival, including inhibition of cell cycle progression, induction of tumor cell-selective apoptosis, suppression of angiogenesis, and modulation of immune responses, and show promising activity against hematological malignancies in clinical trials. Using the Emu-myc model of B cell lymphoma, we screened tumors with defined genetic alterations in apoptotic pathways for therapeutic responsiveness to the HDACi vorinostat. We demonstrated a direct correlation between induction of tumor cell apoptosis in vivo and therapeutic efficacy. Vorinostat did not require p53 activity or a functional death receptor pathway to kill Emu-myc lymphomas and mediate a therapeutic response but depended on activation of the intrinsic apoptotic pathway with the proapoptotic BH3-only proteins Bid and Bim playing an important role. Our studies provide important information regarding the mechanisms of action of HDACi that have broad implications regarding stratification of patients receiving HDACi therapy alone or in combination with other anticancer agents.