Factors associated with high exclusive breastfeeding rates among preterm infants under 34 weeks of gestation in Da Nang, Vietnam: A retrospective cohort study.

Background: Preterm infants have higher mortality than full-term infants. While breastfeeding dramatically reduces preterm death, it is limited by biological and practice barriers, particularly for babies born before 34 weeks gestational age. Da Nang Hospital for Women and Children developed a quality improvement approach to improve breastfeeding of preterm infants by strengthening feeding support, non-separation, and kangaroo mother care (KMC). Methods: To determine breastfeeding outcomes following discharge and explore factors associated with improved feeding, mothers of infants under 34 weeks gestational age born October 2021 to March 2022 and discharged alive were interviewed at six months and their medical records were reviewed. Results: Out of 104 preterm infants included, all were exclusively breastfed at discharge and one month, 86.5% at three months, and 63.5% at six months; 47.1% received immediate skin-to-skin contact, 31.7% immediate and continuous KMC, and the remaining 68.3% continuous KMC beginning at a median of three days. Exclusive breastfeeding at six months was associated with the mother antenatally seeking breastfeeding information (odds ratio (OR) = 14.5; 95% confidence interval (CI) = 1.2-173.6), avoiding bottle-feeding at home (OR = 7.7; 95% CI = 1.7-33.7) and reduced with each day delay between birth and full breastfeeding (OR = 0.8; 95% CI = 0.6-0.9). Conclusions: Hospital environments that limit mother-baby separations and feeding delays, including rooming-in of mothers and infants, KMC, and breastfeeding support from birth, enabled 100% of preterm infants born before 34 weeks gestational age to breastfeed exclusively with continued rates higher than previously reported. Addressing antenatal and post-natal factors limiting practice can further improve longer-term breastfeeding outcomes. The approach can be adapted to achieve high exclusive breastfeeding rates, regardless of gestational age.

Sulindac sulfide as a non-immune suppressive γ-secretase modulator to target triple-negative breast cancer.

Introduction: Triple-negative breast cancer (TNBC) comprises a heterogeneous group of clinically aggressive tumors with high risk of recurrence and metastasis. Current pharmacological treatment options remain largely limited to chemotherapy. Despite promising results, the efficacy of immunotherapy and chemo-immunotherapy in TNBC remains limited. There is strong evidence supporting the involvement of Notch signaling in TNBC progression. Expression of Notch1 and its ligand Jagged1 correlate with poor prognosis. Notch inhibitors, including g-secretase inhibitors (GSIs), are quite effective in preclinical models of TNBC. However, the success of GSIs in clinical trials has been limited by their intestinal toxicity and potential for adverse immunological effects, since Notch plays key roles in T-cell activation, including CD8 T-cells in tumors. Our overarching goal is to replace GSIs with agents that lack their systemic toxicity and ideally, do not affect tumor immunity. We identified sulindac sulfide (SS), the active metabolite of FDA-approved NSAID sulindac, as a potential candidate to replace GSIs. Methods: We investigated the pharmacological and immunotherapeutic properties of SS in TNBC models in vitro, ex-vivo and in vivo. Results: We confirmed that SS, a known γ-secretase modulator (GSM), inhibits Notch1 cleavage in TNBC cells. SS significantly inhibited mammosphere growth in all human and murine TNBC models tested. In a transplantable mouse TNBC tumor model (C0321), SS had remarkable single-agent anti-tumor activity and eliminated Notch1 protein expression in tumors. Importantly, SS did not inhibit Notch cleavage in T- cells, and the anti-tumor effects of SS were significantly enhanced when combined with a-PD1 immunotherapy in our TNBC organoids and in vivo. Discussion: Our data support further investigation of SS for the treatment of TNBC, in conjunction with chemo- or -chemo-immunotherapy. Repurposing an FDA-approved, safe agent for the treatment of TNBC may be a cost-effective, rapidly deployable therapeutic option for a patient population in need of more effective therapies.

Promotion of a synthetic degradation of activated STAT6 by PARP-1 inhibition: roles of poly(ADP-ribosyl)ation, calpains and autophagy.

BACKGROUND: We reported that PARP-1 regulates genes whose products are crucial for asthma, in part, by controlling STAT6 integrity speculatively through a calpain-dependent mechanism. We wished to decipher the PARP-1/STAT6 relationship in the context of intracellular trafficking and promoter occupancy of the transcription factor on target genes, its integrity in the presence of calpains, and its connection to autophagy. METHODS: This study was conducted using primary splenocytes or fibroblasts derived from wild-type or PARP-1-/- mice and Jurkat T cells to mimic Th2 inflammation. RESULTS: We show that the role for PARP-1 in expression of IL-4-induced genes (e.g. gata-3) in splenocytes did not involve effects on STAT6 phosphorylation or its subcellular trafficking, rather, it influenced its occupancy of gata-3 proximal and distal promoters in the early stages of IL-4 stimulation. At later stages, PARP-1 was crucial for STAT6 integrity as its inhibition, pharmacologically or by gene knockout, compromised the fate of the transcription factor. Calpain-1 appeared to preferentially degrade JAK-phosphorylated-STAT6, which was blocked by calpastatin-mediated inhibition or by genetic knockout in mouse fibroblasts. The STAT6/PARP-1 relationship entailed physical interaction and modification by poly(ADP-ribosyl)ation independently of double-strand-DNA breaks. Poly(ADP-ribosyl)ation protected phosphorylated-STAT6 against calpain-1-mediated degradation. Additionally, our results show that STAT6 is a bonafide substrate for chaperone-mediated autophagy in a selective and calpain-dependent manner in the human Jurkat cell-line. The effects were partially blocked by IL-4 treatment and PARP-1 inhibition. CONCLUSIONS: The results demonstrate that poly(ADP-ribosyl)ation plays a critical role in protecting activated STAT6 during Th2 inflammation, which may be synthetically targeted for degradation by inhibiting PARP-1.

Differential effects of poly(ADP ribose) polymerase inhibitor-based metronomic therapy on programmed death-ligand 1 and matrix-associated factors in human myeloid cells.

We recently showed that while partial poly(ADP-ribose) polymerase (PARP)-1 inhibition with a low metronomic sub-half-maximal inhibitory concentration/dose (IC50) of olaparib provides superior protection against colon cancer in mice compared to complete inhibition by blocking the suppressive function of myeloid-derived suppressor cells (MDSCs) and synergizing with anti-program cell death (PD)-1-based immunotherapy. Here, we examined whether PARP inhibitors (PARPi) exert effects on human myeloid cells that alter T cell function (e.g. PD-ligand (L)1) or metastasis/tumor microenvironment-associated factors (e.g. tissue inhibitor of matrix metalloproteinases (MMPs) (TIMP)-2 and MMPs activity). We show that olaparib-based metronomic therapy induced a marginal increase in PD-L1 expression in MDSCs-enriched cells, decreased its expression in dendritic cells (DCs)-enriched cells, and caused little to no effect on macrophage-enriched cells. Interestingly, MDSCs-enriched cells also expressed low levels of PARP-1 while dendritic cells and macrophages expressed high levels of the protein. Bone marrow progenitors expressed no PD-L1; however, when differentiated into MDSCs, the expression was high displaying higher glycosylation levels compared to those observed in peripheral blood mononuclear cells (PBMCs)-derived cells. Contrary to reported effects on cancer cells, the sub-IC50 or moderate olaparib concentration caused substantial decrease in PD-L1. A sub-IC50 concentration of other clinically used PARPi (rucaparib, niraparib, and talazoparib) as well as the failed PARPi, iniparib, exerted similar effects. Furthermore, PARPi-based metronomic therapy reprogramed myeloid cells with the potential to stabilize intratumoral matrix by increasing secreted-TIMP-2 with a differential reduction in MMP-2/MMP-9 activity. Thus, PARPi-based metronomic therapy may promote functional changes in myeloid cells that provide an additional rationale for combining it with immunotherapy. Our results also provide new opportunities for iniparib in cancer therapy.

Targeting PARP-1 with metronomic therapy modulates MDSC suppressive function and enhances anti-PD-1 immunotherapy in colon cancer.

BACKGROUND: Poly(ADP-ribose) polymerase (PARP) inhibitors (eg, olaparib) are effective against BRCA-mutated cancers at/near maximum tolerated doses by trapping PARP-1 on damaged chromatin, benefitting only small patient proportions. The benefits of targeting non-DNA repair aspects of PARP with metronomic doses remain unexplored. METHODS: Colon epithelial cells or mouse or human bone marrow (BM)-derived-myeloid-derived suppressor cells (MDSCs) were stimulated to assess the effect of partial PARP-1 inhibition on inflammatory gene expression or immune suppression. Mice treated with azoxymethane/four dextran-sulfate-sodium cycles or APCMin/+ mice bred into PARP-1+/- or treated with olaparib were used to examine the role of PARP-1 in colitis-induced or spontaneous colon cancer, respectively. Syngeneic MC-38 cell-based (microsatellite instability, MSIhigh) or CT-26 cell-based (microsatellite stable, MSS) tumor models were used to assess the effects of PARP inhibition on host responses and synergy with anti-Programmed cell Death protein (PD)-1 immunotherapy. RESULTS: Partial PARP-1 inhibition, via gene heterozygosity or a moderate dose of olaparib, protected against colitis-mediated/APCMin -mediated intestinal tumorigenesis and APCMin -associated cachexia, while extensive inhibition, via gene knockout or a high dose of olaparib, was ineffective or aggravating. A sub-IC50-olaparib dose or PARP-1 heterozygosity was sufficient to block tumorigenesis in a syngeneic colon cancer model by modulating the suppressive function, but not intratumoral migration or differentiation, of MDSCs, with concomitant increases in intratumoral T cell function and cytotoxicity, as assessed by granzyme-B/interferon-γ levels. Adoptive transfer of WT-BM-MDSCs abolished the protective effects of PARP-1 heterozygosity. The mechanism of MDSC modulation involved a reduction in arginase-1/inducible nitric oxide synthase/cyclo-oxygenase-2, but independent of PARP-1 trapping on chromatin. Although a high-concentration olaparib or the high-trapping PARP inhibitor, talazoparib, activated stimulator of interferon gene (STING) in BRCA-proficient cells and induced DNA damage, sub-IC50 concentrations of either drug failed to induce activation of the dsDNA break sensor. STING expression appeared dispensable for MDSC suppressive function and was not strictly required for olaparib-mediated effects. Ironically, STING activation blocked human and mouse MDSC function with no additive effects with olaparib. A metronomic dose of olaparib was highly synergistic with anti-PD-1-based immunotherapy, leading to eradication of MSIhigh or reduction of MSS tumors in mice. CONCLUSIONS: These results support a paradigm-shifting concept that expands the utility of PARP inhibitor and encourage testing metronomic dosing of PARP inhibitor to enhance the efficacy of checkpoint inhibitor-based immunotherapies in cancer.

PARP-1 Is Critical for Recruitment of Dendritic Cells to the Lung in a Mouse Model of Asthma but Dispensable for Their Differentiation and Function.

Dendritic cells (DCs) are critical in asthma and many other immune diseases. We previously demonstrated a role for PARP-1 in asthma. Evidence on PARP-1 playing a role in Th2-associated DC function is not clear. In this study, we examined whether PARP-1 is critical for DC differentiation and function using bone marrow progenitors and their migration to the lung in an ovalbumin-based mouse model of asthma. Results show that changes in PARP-1 levels during GM-CSF-induced DC differentiation from bone marrow progenitors were cyclic and appear to be part of an array of changes that included STAT3/STAT5/STAT6/GRAIL/RAD51. Interestingly, PARP-1 gene deletion affected primarily STAT6 and γH2AX. PARP-1 inhibition significantly reduced the migration of DCs to the lungs of ovalbumin-challenged mice, which was associated with a concomitant reduction in lung levels of the adhesion molecule VCAM-1. The requirement of PARP-1 for VCAM-1 expression was confirmed using endothelial and lung smooth muscle cells. PARP-1 expression and activity were also required for VCAM-1 in differentiated DCs. An assessment of CD11b+/CD11c+/MHCIIhigh DCs in spleens and lymph nodes of OVA-sensitized mice revealed that PARP-1 inhibition genetically or by olaparib exerted little to no effect on DC differentiation, percentage of CD80+/CD86+/CD40+-expressing cells, or their capacity to promote proliferation of ovalbumin-primed (OTII) CD4+ T cells. These findings were corroborated using GM-CSF-induced differentiation of DCs from the bone marrow. Surprisingly, the PARP-1-/- DCs exhibited a higher intrinsic capacity to induce OTII CD4+ T cell proliferation in the absence of ovalbumin. Overall, our results show that PARP-1 plays little to no role in DC differentiation and function and that the protective effect of PARP-1 inhibition against asthma is associated with a prevention of DC migration to the lung through a reduction in VCAM-1 expression. Given the current use of PARP inhibitors (e.g., olaparib) in the clinic, the present results may be of interest for the relevant therapies.

Sulfated non-anticoagulant heparin blocks Th2-induced asthma by modulating the IL-4/signal transducer and activator of transcription 6/Janus kinase 1 pathway.

BACKGROUND: The efficacy of heparins and low-MW-heparins (LMWH) against human asthma has been known for decades. However, the clinical utility of these compounds has been hampered by their anticoagulant properties. Much effort has been put into harnessing the anti-inflammatory properties of LMWH but none have been used as therapy for asthma. Sulfated-non-anticoagulant heparin (S-NACH) is an ultra-LMWH with no systemic anticoagulant effects. OBJECTIVE: The present study explored the potential of S-NACH in blocking allergic asthma and examined the potential mechanism by which it exerts its effects. METHODS: Acute and chronic ovalbumin-based mouse models of asthma, splenocytes, and a lung epithelial cell line were used. Mice were challenged with aerosolized ovalbumin and administered S-NACH or saline 30 min after each ovalbumin challenge. RESULTS: Sulfated-non-anticoagulant heparin administration in mice promoted a robust reduction in airway eosinophilia, mucus production, and airway hyperresponsiveness even after chronic repeated challenges with ovalbumin. Such effects were linked to suppression of Th2 cytokines IL-4/IL-5/IL-13/GM-CSF and ovalbumin-specific IgE without any effect on IFN-γ. S-NACH also reduced lung fibrosis in mice that were chronically-exposed to ovalbumin. These protective effects of S-NACH may be attributed to modulation of the IL-4/JAK1 signal transduction pathway through an inhibition of STAT6 phosphorylation and a subsequent inhibition of GATA-3 and inducible NO synthase expression. The effect of the drug on STAT6 phosphorylation coincided with a reduction in JAK1 phosphorylation upon IL-4 treatment. The protective effects of S-NACH treatment was associated with reduction of the basal expression of the two isoforms of arginase ARG1 and ARG2 in lung epithelial cells. CONCLUSIONS: Our study demonstrates that S-NACH constitutes an opportunity to benefit from the well-known anti-asthma properties of heparins/LMWH while bypassing the risk of bleeding. Our results show, for the first time, that such anti-asthma effects may be associated with reduction of the IL-4/JAK1/STAT6 pathway.