New immune cell engagers for cancer immunotherapy.

There have been major advances in the immunotherapy of cancer in recent years, including the development of T cell engagers - antibodies engineered to redirect T cells to recognize and kill cancer cells - for the treatment of haematological malignancies. However, the field still faces several challenges to develop agents that are consistently effective in a majority of patients and cancer types, such as optimizing drug dose, overcoming treatment resistance and improving efficacy in solid tumours. A new generation of T cell-targeted molecules was developed to tackle these issues that are potentially more effective and safer. In addition, agents designed to engage the antitumour activities of other immune cells, including natural killer cells and myeloid cells, are showing promise and have the potential to treat a broader range of cancers.

Control of acute myeloid leukemia by a trifunctional NKp46-CD16a-NK cell engager targeting CD123.

CD123, the alpha chain of the IL-3 receptor, is an attractive target for acute myeloid leukemia (AML) treatment. However, cytotoxic antibodies or T cell engagers targeting CD123 had insufficient efficacy or safety in clinical trials. We show that expression of CD64, the high-affinity receptor for human IgG, on AML blasts confers resistance to anti-CD123 antibody-dependent cell cytotoxicity (ADCC) in vitro. We engineer a trifunctional natural killer cell engager (NKCE) that targets CD123 on AML blasts and NKp46 and CD16a on NK cells (CD123-NKCE). CD123-NKCE has potent antitumor activity against primary AML blasts regardless of CD64 expression and induces NK cell activation and cytokine secretion only in the presence of AML cells. Its antitumor activity in a mouse CD123+ tumor model exceeds that of the benchmark ADCC-enhanced antibody. In nonhuman primates, it had prolonged pharmacodynamic effects, depleting CD123+ cells for more than 10 days with no signs of toxicity and very low inflammatory cytokine induction over a large dose range. These results support clinical development of CD123-NKCE.

Antitumor immunity induced by antibody-based natural killer cell engager therapeutics armed with not-alpha IL-2 variant.

Harnessing innate immunity is emerging as a promising therapeutic approach in cancer. We report here the design of tetraspecific molecules engaging natural killer (NK) cell-activating receptors NKp46 and CD16a, the ß-chain of the interleukin-2 receptor (IL-2R), and a tumor-associated antigen (TAA). In vitro, these tetraspecific antibody-based natural killer cell engager therapeutics (ANKETs) induce a preferential activation and proliferation of NK cells, and the binding to the targeted TAA triggers NK cell cytotoxicity and cytokine and chemokine production. In vivo, tetraspecific ANKETs induce NK cell proliferation and their accumulation at the tumor bed, as well as the control of local and disseminated tumors. Treatment of non-human primates with CD20-directed tetraspecific ANKET leads to CD20+ circulating B cell depletion, with minimal systemic cytokine release and no sign of toxicity. Tetraspecific ANKETs, thus, constitute a technological platform for harnessing NK cells as next-generation cancer immunotherapies.

Exploiting Natural Killer Cell Engagers to Control Pediatric B-cell Precursor Acute Lymphoblastic Leukemia.

Natural killer (NK) cells represent a promising cell type in antitumor immunotherapy for efficacy and safety, particularly in the treatment of hematologic malignancies. NK cells have been shown to exert antileukemia activity in the context of haploidentical hematopoietic stem cell transplantation (haplo-HSCT). Products have been developed to boost the activation of NK cells only when cross-linked by tumor cells, avoiding any off-target effect. Here, we tested the in vitro effect of different NK-cell engagers (NKCE), which trigger either NKp46 or NKp30 together with CD16A, and target either CD19 or CD20 to induce killing of pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Target cells were NALM-16 and MHH-CALL-4 cell lines and four primary leukemias, while effector cells were resting NK cells derived from healthy donors and pediatric patients with leukemia after αßT/B-depleted haplo-HSCT. The NK cell-resistant MHH-CALL-4 was efficiently killed using all NKCEs. Boosting of NK activity against MHH-CALL-4 was also evident by degranulation and IFNγ production. Because of the lack of CD20 and high expression of CD19 on primary BCP-ALL, we focused on NKCEs targeting CD19. NKp46- and NKp30-based NKCEs displayed similar potency at inducing NK-cell activity, even when challenged with primary BCP-ALL blasts. Their efficacy was shown also using NK cells derived from transplanted patients. NKCE-induced activation against BCP-ALL can override HLA-specific inhibitory interactions, although the strongest response was observed by the alloreactive NK-cell subset. These data support the therapeutic use of NKp46/CD16A/CD19-NKCE to fight refractory/relapsed leukemia in pretransplantation or posttransplantation settings.

New polynomial regression formula to improve second-eye refractive outcomes in sequential bilateral cataract surgery.

PURPOSE: To assess a new polynomial regression formula integrating the refractive prediction error of the first-operated eye to improve the intraocular lens power calculation of the second eye in cataract surgery. SETTING: Centre Hospitalier Universitaire, Toulouse, France. DESIGN: Retrospective multicentric dataset study. METHODS: A polynomial regression formula, WeOptimeye2nd (WO2nd), was developed using a machine-learning algorithm trained on a dataset of 534 patients who underwent sequential bilateral cataract surgery. A separate multicentric dataset was used to retrospectively calculate predicted refraction with WO2nd, SRK/T and Barrett Universal II formulas, and 3 other methods of constant factors (CFs) second-eye refinement (CF0.38, CF0.35, and CF0.5). Mean absolute errors (MAEs) and percentage of eyes within ±0.25, ±0.5, and ±1.0 diopter (D) from predicted spherical equivalent were compared between formulas. RESULTS: The study comprised data on 722 patients. In the overall population, WO2nd had the lowest MAE: 0.339 vs 0.347 (P = .137), 0.340 (P = .956), 0.350 (P = .066), 0.399 (P < .001), and 0.410 (P < .001), with CF0.38, CF0.5, and CF0.35, Barrett II, and SRK/T, respectively. WO2nd had the highest percentage of eyes within ±0.5 D of the predicted refraction, and the difference was statistically significant vs SRK/T and Barrett II formulas but not vs CF0.38, CF0.5, and CF0.35. WO2nd performed the best in axial length (AL) < 22 mm with the lowest MAE and a statistically significant difference vs any other formula. CONCLUSIONS: WO2nd improved the refractive outcome of the second-operated eye and performed well in extreme AL and mean keratometry subgroups.

Increase in lamin B1 promotes telomere instability by disrupting the shelterin complex in human cells.

Telomere maintenance is essential to preserve genomic stability and involves telomere-specific proteins, DNA replication and repair proteins. Lamins are key components of the nuclear envelope and play numerous roles, including maintenance of the nuclear integrity, regulation of transcription, and DNA replication. Elevated levels of lamin B1, one of the major lamins, have been observed in some human pathologies and several cancers. Yet, the effect of lamin B1 dysregulation on telomere maintenance remains unknown. Here, we unveil that lamin B1 overexpression drives telomere instability through the disruption of the shelterin complex. Indeed, lamin B1 dysregulation leads to an increase in telomere dysfunction-induced foci, telomeric fusions and telomere losses in human cells. Telomere aberrations were preceded by mislocalizations of TRF2 and its binding partner RAP1. Interestingly, we identified new interactions between lamin B1 and these shelterin proteins, which are strongly enhanced at the nuclear periphery upon lamin B1 overexpression. Importantly, chromosomal fusions induced by lamin B1 in excess were rescued by TRF2 overexpression. These data indicated that lamin B1 overexpression triggers telomere instability through a mislocalization of TRF2. Altogether our results point to lamin B1 as a new interacting partner of TRF2, that is involved in telomere stability.

Natural killer cell engagers in cancer immunotherapy: Next generation of immuno-oncology treatments.

Immuno-oncology is revolutionizing the treatment of cancers, by inducing the recognition and elimination of tumor cells by the immune system. Recent advances have focused on generating or unleashing tumor antigen-specific T-cell responses, leading to alternative treatment paradigms for many cancers. Despite these successes, the clinical benefit has been limited to a subset of patients and certain tumor types, highlighting the need for alternative strategies. One innovative approach is to broaden and amplify antitumoral immune responses by targeting innate immunity. Particularly, the aim has been to develop new antibody formats capable of stimulating the antitumor activity of innate immune cells, boosting not only their direct role in tumor elimination, but also their function in eliciting multicellular immune responses ultimately resulting in long-lasting tumor control by adaptive immunity. This review covers the development of a new class of synthetic molecules, natural killer cell engagers (NKCEs), which are built from fragments of monoclonal antibodies (mAbs) and are designed to harness the immune functions of NK cells in cancer. As currently shown in preclinical studies and clinical trials, NKCEs are promising candidates for the next generation of tumor immunotherapies.

Targeting MICA/B with cytotoxic therapeutic antibodies leads to tumor control.

Background: MICA and MICB are tightly regulated stress-induced proteins that trigger the immune system by binding to the activating receptor NKG2D on cytotoxic lymphocytes. MICA and MICB are highly polymorphic molecules with prevalent expression on several types of solid tumors and limited expression in normal/healthy tissues, making them attractive targets for therapeutic intervention. Methods: We have generated a series of anti-MICA and MICB cross-reactive antibodies with the unique feature of binding to the most prevalent isoforms of both these molecules. Results: The anti-MICA and MICB antibody MICAB1, a human IgG1 Fc-engineered monoclonal antibody (mAb), displayed potent antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) of MICA/B-expressing tumor cells in vitro. However, it showed insufficient efficiency against solid tumors in vivo, which prompted the development of antibody-drug conjugates (ADC). Indeed, optimal tumor control was achieved with MICAB1-ADC format in several solid tumor models, including patient-derived xenografts (PDX) and carcinogen-induced tumors in immunocompetent MICAgen transgenic mice. Conclusions: These data indicate that MICA and MICB are promising targets for cytotoxic immunotherapy.

The HIF1α/JMY pathway promotes glioblastoma stem-like cell invasiveness after irradiation.

Human glioblastoma (GBM) is the most common primary malignant brain tumor. A minor subpopulation of cancer cells, known as glioma stem-like cells (GSCs), are thought to play a major role in tumor relapse due to their stem cell-like properties, their high resistance to conventional treatments and their high invasion capacity. We show that ionizing radiation specifically enhances the motility and invasiveness of human GSCs through the stabilization and nuclear accumulation of the hypoxia-inducible factor 1α (HIF1α), which in turn transcriptionally activates the Junction-mediating and regulatory protein (JMY). Finally, JMY accumulates in the cytoplasm where it stimulates GSC migration via its actin nucleation-promoting activity. Targeting JMY could thus open the way to the development of new therapeutic strategies to improve the efficacy of radiotherapy and prevent glioma recurrence.

Boosting Cytotoxic Antibodies against Cancer.

Monoclonal antibodies (mAbs) targeting antigens expressed at the surface of tumor cells are widely used for cancer control in clinics, but these treatments need to be improved. Chew et al. show how an old drug, prochlorperazine, could be repurposed to enhance the efficacy of anti-tumor mAbs by increasing the cell-surface expression of tumor antigens.

Multifunctional Natural Killer Cell Engagers Targeting NKp46 Trigger Protective Tumor Immunity.

Over the last decade, various new therapies have been developed to promote anti-tumor immunity. Despite interesting clinical results in hematological malignancies, the development of bispecific killer-cell-engager antibody formats directed against tumor cells and stimulating anti-tumor T cell immunity has proved challenging, mostly due to toxicity problems. We report here the generation of trifunctional natural killer (NK) cell engagers (NKCEs), targeting two activating receptors, NKp46 and CD16, on NK cells and a tumor antigen on cancer cells. Trifunctional NKCEs were more potent in vitro than clinical therapeutic antibodies targeting the same tumor antigen. They had similar in vivo pharmacokinetics to full IgG antibodies and no off-target effects and efficiently controlled tumor growth in mouse models of solid and invasive tumors. Trifunctional NKCEs thus constitute a new generation of molecules for fighting cancer. VIDEO ABSTRACT.

Blocking Antibodies Targeting the CD39/CD73 Immunosuppressive Pathway Unleash Immune Responses in Combination Cancer Therapies.

Immune checkpoint inhibitors have revolutionized cancer treatment. However, many cancers are resistant to ICIs, and the targeting of additional inhibitory signals is crucial for limiting tumor evasion. The production of adenosine via the sequential activity of CD39 and CD73 ectoenzymes participates to the generation of an immunosuppressive tumor microenvironment. In order to disrupt the adenosine pathway, we generated two antibodies, IPH5201 and IPH5301, targeting human membrane-associated and soluble forms of CD39 and CD73, respectively, and efficiently blocking the hydrolysis of immunogenic ATP into immunosuppressive adenosine. These antibodies promoted antitumor immunity by stimulating dendritic cells and macrophages and by restoring the activation of T cells isolated from cancer patients. In a human CD39 knockin mouse preclinical model, IPH5201 increased the anti-tumor activity of the ATP-inducing chemotherapeutic drug oxaliplatin. These results support the use of anti-CD39 and anti-CD73 monoclonal antibodies and their combination with immune checkpoint inhibitors and chemotherapies in cancer.

ALT cancer cells are specifically sensitive to lysine acetyl transferase inhibition.

Some cancer cells elongate their telomeres through the ALT (alternative lengthening of telomeres) pathway, which is based on homologous recombination for the addition of telomere repeats without telomerase activity. General control non-derepressible 5 (GCN5) and P300/CBP-associated factor (PCAF), two homologous lysine acetyltransferases, exert opposite effects on the ALT pathway, inhibiting or favoring it respectively. Here we show that ALT cells are particularly sensitive to the inhibition of acetyltransferases activities using Anacardic Acid (AA). AA treatment recapitulates the effect of PCAF knockdown on several ALT features, suggesting that AA decreased the ALT mechanism through the inhibition of lysine transferase activity of PCAF, but not that of GCN5. Furthermore, AA specifically sensitizes human ALT cells to radiation as compared to telomerase-positive cells suggesting that the inhibition of lysine acetyltransferases activity may be used to increase the radiotherapy efficiency against ALT cancers.

[Natural killer cells: promising targets in cancer therapy]. / Les cellules natural killer : des cibles prometteuses dans la thérapie contre le cancer.

TITLE: Les cellules natural killer : des cibles prometteuses dans la thérapie contre le cancer. ABSTRACT: L'immuno-oncologie est une approche d'immunothérapie novatrice qui change le traitement des cancers en stimulant la capacité du système immunitaire à reconnaître et éliminer les cellules tumorales. Cette approche a pour but de mettre en place une immuno-surveillance anti-tumorale durable chez des patients pour lesquels les thérapies conventionnelles ont échoué.

PARP3, a new therapeutic target to alter Rictor/mTORC2 signaling and tumor progression in BRCA1-associated cancers.

PARP3 has been shown to be a key driver of TGFß-induced epithelial-to-mesenchymal transition (EMT) and stemness in breast cancer cells, emerging as an attractive therapeutic target. Nevertheless, the therapeutic value of PARP3 inhibition has not yet been assessed. Here we investigated the impact of the absence of PARP3 or its inhibition on the tumorigenicity of BRCA1-proficient versus BRCA1-deficient breast cancer cell lines, focusing on the triple-negative breast cancer subtype (TNBC). We show that PARP3 knockdown exacerbates centrosome amplification and genome instability and reduces survival of BRCA1-deficient TNBC cells. Furthermore, we engineered PARP3-/- BRCA1-deficient or BRCA1-proficient TNBC cell lines using the CRISPR/nCas9D10A gene editing technology and demonstrate that the absence of PARP3 selectively suppresses the growth, survival and in vivo tumorigenicity of BRCA1-deficient TNBC cells, mechanistically via effects associated with an altered Rictor/mTORC2 signaling complex resulting from enhanced ubiquitination of Rictor. Accordingly, PARP3 interacts with and ADP-ribosylates GSK3ß, a positive regulator of Rictor ubiquitination and degradation. Importantly, these phenotypes were rescued by re-expression of a wild-type PARP3 but not by a catalytic mutant, demonstrating the importance of PARP3's catalytic activity. Accordingly, reduced survival and compromised Rictor/mTORC2 signaling were also observed using a cell-permeable PARP3-specific inhibitor. We conclude that PARP3 and BRCA1 are synthetic lethal and that targeting PARP3's catalytic activity is a promising therapeutic strategy for BRCA1-associated cancers via the Rictor/mTORC2 signaling pathway.

Anti-NKG2A mAb Is a Checkpoint Inhibitor that Promotes Anti-tumor Immunity by Unleashing Both T and NK Cells.

Checkpoint inhibitors have revolutionized cancer treatment. However, only a minority of patients respond to these immunotherapies. Here, we report that blocking the inhibitory NKG2A receptor enhances tumor immunity by promoting both natural killer (NK) and CD8+ T cell effector functions in mice and humans. Monalizumab, a humanized anti-NKG2A antibody, enhanced NK cell activity against various tumor cells and rescued CD8+ T cell function in combination with PD-x axis blockade. Monalizumab also stimulated NK cell activity against antibody-coated target cells. Interim results of a phase II trial of monalizumab plus cetuximab in previously treated squamous cell carcinoma of the head and neck showed a 31% objective response rate. Most common adverse events were fatigue (17%), pyrexia (13%), and headache (10%). NKG2A targeting with monalizumab is thus a novel checkpoint inhibitory mechanism promoting anti-tumor immunity by enhancing the activity of both T and NK cells, which may complement first-generation immunotherapies against cancer.

Primary sulcus implantation of a diffractive multifocal pseudophakic piggyback intraocular lens.

PURPOSE: To evaluate the efficacy and safety of the combined implantation of a monofocal intraocular lens (IOL) in the capsular bag with a diffractive multifocal IOL designed for sulcus placement (Reverso). SETTING: Purpan Hospital, Toulouse, and Helios Clinic, Saint-Jean-de-Luz, France. DESIGN: Prospective case series. METHODS: The multifocal IOL piggyback IOL was implanted in the sulcus during cataract surgery. Visual acuity, defocus curve, contrast sensitivity, IOL positioning, and patient satisfaction were assessed with 1-year follow-ups. RESULTS: Fifty-four eyes of 27 patients were included. At 1-month, monocular uncorrected distance (UDVA) and near (UNVA) visual acuities were 0.13 logarithm of the minimum angle of resolution (logMAR) ± 0.18 (SD) and 0.20 ± 0.16 logMAR, respectively. Binocular UDVA and UNVA were 0.03 ± 0.06 and 0.12 ± 0.08 logMAR, respectively. At 1 year, the mean monocular logMAR UDVA, corrected distance visual acuity, UNVA, and corrected near visual acuity were 0.10 ± 0.11, 0.02 ± 0.06, 0.18 ± 0.12, and 0.13 ± 0.08, respectively. The defocus curve and contrast sensitivity values were comparable to those obtained with other multifocal IOLs. On Scheimpflug imaging, the mean distance between the sulcus multifocal IOL and the monofocal IOL was 517 ± 141 µm. At 1 year, ultrasound biomicroscopy showed an annular fibrosis of the anterior capsule in 94.4% of the eyes. Complications included 1 posttraumatic IOL decentration and 1 slight corectopia. Eighty-nine percent of patients reported satisfaction. CONCLUSIONS: The piggyback implantation of this multifocal IOL seemed to be safe and effective. It might provide similar results as a primary in-the-bag multifocal IOL, with the advantage of reversibility that might extend primary or secondary implantation.

Neonicotinoid pesticides can reduce honeybee colony genetic diversity.

Neonicotinoid insecticides can cause a variety of adverse sub-lethal effects in bees. In social species such as the honeybee, Apis mellifera, queens are essential for reproduction and colony functioning. Therefore, any negative effect of these agricultural chemicals on the mating success of queens may have serious consequences for the fitness of the entire colony. Queens were exposed to the common neonicotinoid pesticides thiamethoxam and clothianidin during their developmental stage. After mating, their spermathecae were dissected to count the number of stored spermatozoa. Furthermore, their worker offspring were genotyped with DNA microsatellites to determine the number of matings and the genotypic composition of the colony. Colonies providing the male mating partners were also inferred. Both neonicotinoid and control queens mated with drones originating from the same drone source colonies, and stored similar number of spermatozoa. However, queens reared in colonies exposed to both neonicotinoids experienced fewer matings. This resulted in a reduction of the genetic diversity in their colonies (i.e. higher intracolonial relatedness). As decreased genetic diversity among worker bees is known to negatively affect colony vitality, neonicotinoids may have a cryptic effect on colony health by reducing the mating frequency of queens.