Triple negative breast cancer: Key role of Tumor-Associated Macrophages in regulating the activity of anti-PD-1/PD-L1 agents

Triple-negative breast cancer (TNBC) is associated with a poor prognosis, due to its aggressive behaviour and lack of effective targeted therapies. Immunocheckpoint inhibitors, such as anti-programmed cell death 1 (PD-1) and anti-PD-ligand(L)1 agents, are in course of investigation in TNBC, used alone or in combination with other systemic or local approaches. However, the high cost of these drugs and the lack of validated predictive biomarkers support the development of strategies aimed to overcome resistance and optimize the efficacy of these approaches.Tumor-Associated Macrophages (TAMs) derive from peripheral blood monocytes recruited into the TNBC microenvironment and, in response to several stimuli, undergo M1 (classical) or M2 (alternative) activation. In TNBC, TAMs promote tumor growth and progression by several mechanisms that include the secretion of inhibitory cytokines, the reduction of effector functions of Tumor Infiltrating Lymphocytes (TILs) and the promotion of Regulatory T cell (Treg). Interestingly, TAMs have been shown to directly and indirectly modulate PD-1/PD-L1 expression in tumor environment. On this scenario, several TAM-centered strategies have been proposed, such as the suppression of TAM recruitment, the depletion of their number, the switch of M2 TAMs into antitumor M1 phenotype and the inhibition of TAM-associated molecules. In this review, we will illustrate the activity of TAMs and associated molecules in TNBC, focusing on their role in modulating the expression of PD-1/PD-L1 and on the emerging TAM-tailored strategies for TNBC patients.     

Inhibition of polyamine biosynthesis by dicyclohexylamine in cultured cotyledons of Pinus radiata

Biondi, S., Torrigiani, P., Sansovini, A. and Bagni, N. 1988. Inhibition of polyamine biosynthesis by dicyclohexylamine in cultured cotyledons of Pinus radiata. - Physiol. Plant. 72: 471–476.
The effect of 1 mAf dicyclohexylamine (DCHA) on the synthesis of spermidine and spermine was examined in excised cotyledons of radiata pine ( Pinus radiata D. Don) cultured under shoot-forming (with cytokinin) and non-shoot-forming (minus cytokinin) conditions by incubation with [¹⁴C]-putrescine. In control cotyledons incorporation into spermidine showed a peak at day 2 in the presence and at day 5 in the absence of N⁶-benzyldenine (BA). DCHA-treated cotyledons gave the same labeling pattern, both in the presence and absence of benzyladenine, with a much smaller peak at day 2. The incorporation into spermidine and spermine was insignificant at day 5 and later. The total radioactivity in the trichloroacetic acid supernatant indicated that precursor uptake was strongly reduced by the drug. In addition, the percentage label found in the benzene phase and combined in the 3 polyamines was lower in DCHA-treated cotyledons. Thus, treatment with DCHA not only inhibited the conversion from putrescine to spermidine and spermine, but also reduced its conversion to other benzene-extractable compounds. S-Adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.50) activity, which furnishes the propylamine group to spermidine and spermine synthases (EC 2.5.1.16 and EC 2.5.1.-), was not significantly affected by DCHA and appeared to be independent of the spermidine and spermine synthase reactions, suggesting that spermine synthesis decreased as a result of substrate depletion. The correlation between morphological development and polyamine biosynthesis is discussed.     

Genomic organization of ribosomal DNA and related sequences inTriturus

The ribosomal RNA genes ofTriturus vulgaris meridionalis are clustered at variable and often multiple chromosomal loci. The rDNA repeats exhibit only a limited and discrete length heterogeneity which is accounted for by the non-transcribed spacer (NTS). Interestingly, sequences homologous to the NTS are clustered outside the ribosomal loci. Clones containing such non ribosomal sequences have been isolated from a genomic library ofT. v. meridionalis and analyzed by restriction mapping. These sequences appear to consist mostly of repetitive Bam HI fragments ranging from 500 bp to 1000 bp. The Bam HI fragments are internally repetitious and highly homologous to each other.     

Searching for indole derivatives as potential mushroom tyrosinase inhibitors

Tyrosinase is a copper-containing enzyme widely distributed in nature, involved in the biosynthesis of melanin whose role is to protect the skin from ultraviolet damage. A great interest has been shown on the melanin involvement in malignant melanoma and other carcinogenetic processes. These phenomena have encouraged the research of tyrosinase inhibitors useful in therapeutic field as well as in foods and cosmetics to prevent browning. The idea was to screen our “in house” database to select suitable lead compounds for the discovery of potential drug-inhibiting enzyme. The obtained biological results demonstrated that compounds containing 4-fluorobenzyl moiety at N???1 position of indole system showed the best activity. In addition, the role of the portion linked to the carbonyl group at C???3 was discussed. A Lineweaver–Burk kinetic analysis of the most active indoles, CHI 1043 and derivative 4, showed a mixed-type inhibition in the presence of l-3,4-dihydroxyphenylalanine (l-DOPA) as substrate.     

Vitamin D3 improves the effects of low dose Der p 2 allergoid treatment in Der p 2 sensitized BALB/c mice

Background

Airborne allergens can induce an immunological chronic disease characterized by airway hyper responsiveness and inflammation, mediated by exaggerated Th2 immune response. Allergen-specific immunotherapy (AIT) is effective for treating this condition because it is able to modify its natural course by opposing the underlying pathogenic mechanisms and determining immune suppression, immune deviation and tolerance. The rational for the present study was to investigate the possibility of improving allergoid-based IT in terms of efficacy and safety. Recently, 1α,25-dihydroxyvitamin D₃ (VD₃), the active metabolite of vitamin D₃, was described to be a potent inducer of T regulatory cells and to be a good adjuvant in AIT settings.

Methods

We investigated whether the co-administration of VD₃ could potentiate the effect of AIT even when added to a low dose of chemically-modified monomeric allergoid of Der p 2 (d2-OID), in a Derp p 2 (d2)-sensitized BALB/c mice model. Control groups where treated with sham, VD₃ alone or d2-OID only.

Results

The d2-OID alone was not fully successful, as expected for a low dose. VD₃ administration was associated with some valuable, although limited, changes in the immunological parameters in the lung. On the contrary, the VD₃ adjuvated allergoid vaccine induced the most prominent reduction of airway eosinophilia and Th2 cytokines and concomitant increase of T regulatory cells and IL-10 in the lung and Der p 2-specific IgG2a in the serum.

Conclusions

The addition of VD₃ to a conventional AIT protocol would allow the reduction of allergoid dose needed and therefore, the production costs. Moreover, beneficial immunomodulatory effects have been achieved by the oral administration which might favour the management of the therapy by the patients and their adherence, possibly enhancing the efficacy of the treatment.

     

AKT1E17K Is Oncogenic in Mouse Lung and Cooperates with Chemical Carcinogens in Inducing Lung Cancer

The hotspot AKT1^E17K mutation in the pleckstrin homology domain of AKT1 occurs in approximately 0.6–2% of human lung cancers. Recently, we have demonstrated that AKT1^E17K transforms immortalized human bronchial cells. Here by use of a transgenic Cre-inducible murine strain in the wild type Rosa26 (R26) locus (R26-AKT1^E17K mice) we demonstrate that AKT1^E17K is a bona-fide oncogene and plays a role in the development of lung cancer in vivo. In fact, we report that mutant AKT1^E17K induces bronchial and/or bronchiolar hyperplastic lesions in murine lung epithelium, which progress to frank carcinoma at very low frequency, and accelerates tumor formation induced by chemical carcinogens. In conclusion, AKT1^E17K induces hyperplasia of mouse lung epithelium in vivo and cooperates with urethane to induce the fully malignant phenotype.     

Detrimental effects of melanocortin‐1 receptor (MC1R) variants on the clinical outcomes of BRAF V600 metastatic melanoma patients treated with BRAF inhibitors

Melanocortin‐1 receptor (MC1R) plays a key role in skin pigmentation, and its variants are linked with a higher melanoma risk. The influence of MC1R variants on the outcomes of patients with metastatic melanoma (MM) treated with BRAF inhibitors (BRAFi) is unknown. We studied the MC1R status in a cohort of 53 consecutive BRAF‐mutated patients with MM treated with BRAFi. We also evaluated the effect of vemurafenib in four ^V600BRAF melanoma cell lines with/without MC1R variants. We found a significant correlation between the presence of MC1R variants and worse outcomes in terms of both overall response rate (ORR; 59% versus 95%, P = 0.011 univariate, P = 0.028 multivariate analysis) and progression‐free survival (PFS) shorter than 6 months (72% versus 33%, P = 0.012 univariate, P = 0.027 multivariate analysis). No difference in overall survival (OS) was reported, probably due to subsequent treatments. Data in vitro showed a significant different phosphorylation of Erk1/2 and p38 MAPK during treatment, associated with a greater increase in vemurafenib IC50 in MC1R variant cell lines.     

Exploring the Role of Killer Cell Immunoglobulin-Like Receptors and Their HLA Class I Ligands in Autoimmune Hepatitis

Background

Natural killer cells are involved in the complex mechanisms underlying autoimmune diseases but few studies have investigated their role in autoimmune hepatitis. Killer immunoglobulin-like receptors are key regulators of natural killer cell-mediated immune responses.

Methods and Findings

KIR gene frequencies, KIR haplotypes, KIR ligands and combinations of KIRs and their HLA Class I ligands were investigated in 114 patients diagnosed with type 1 autoimmune hepatitis and compared with a group of 221 healthy controls. HLA Class I and Class II antigen frequencies were compared to those of 551 healthy unrelated families representative of the Sardinian population. In our cohort, type 1 autoimmune hepatitis was strongly associated with the HLA-B18, Cw5, DR3 haplotype. The KIR2DS1 activating KIR gene and the high affinity HLA-C2 ligands were significantly higher in patients compared to controls. Patients also had a reduced frequency of HLA-Bw4 ligands for KIR3DL1 and HLA-C1 ligands for KIR2DL3. Age at onset was significantly associated with the KIR2DS1 activating gene but not with HLA-C1 or HLA-C2 ligand groups.

Conclusions

The activating KIR gene KIR2DS1 resulted to have an important predictive potential for early onset of type 1 autoimmune hepatitis. Additionally, the low frequency of the KIR-ligand combinations KIR3DL1/HLA-Bw4 and KIR2DL3/HLA-C1 coupled to the high frequency of the HLA-C2 high affinity ligands for KIR2DS1 could contribute to unwanted NK cell autoreactivity in AIH-1.