Long-term complete response in metastatic poorly-differentiated neuroendocrine rectal carcinoma with a multimodal approach: A case report

BACKGROUNDNeuroendocrine gastrointestinal tumors (NETs) are rare and have different natural behaviors. Surgery is the gold standard treatment for local disease while radiotherapy has been demonstrated to be ineffective. Poorly differentiated neuroendocrine carcinomas (NECs) represent only 5%-10% of digestive NETS. Due to aggressive growth and rapid metastatic diffusion, early diagnosis and a multidisciplinary approach are mandatory. The role of surgery and radiotherapy in this setting is still debated, and chemotherapy remains the treatment of choice.CASE SUMMARYA 42-year-old male with an ulcerated bleeding rectal lesion was diagnosed with a NEC G3 (Ki67 index > 90%) on May 2015 and initially treated with 3 cycles of first-line chemotherapy, but showed early local progressive disease at 3 mo and underwent sphincter-sparing open anterior low rectal resection. In September 2015, the first post-surgery total-body computed tomography (CT) scan showed an early pelvic disease relapse. Therefore, systemic chemotherapy with FOLFIRI was started and the patient obtained only a partial response. This was followed by pelvic radiotherapy (50 Gy). On April 2016, a CT scan and 18F-fluorodeoxyglucose positron emission tomography imaging showed a complete response (CR) of the pelvic lesion, but pathological abdominal inter-aortocaval lymph nodes were observed. Due to disease progression of abdominal malignant nodes, the patient received radiotherapy at 45 Gy, and finally obtained a CR. As of January 2021, the patient has no symptoms of relapse and no late toxicity after chemotherapy or radiotherapy.CONCLUSIONThis case demonstrates how a multimodal approach can be successful in obtaining long-term CR in metastatic sites in patients with high grade digestive NECs.     

Direct interaction with filamins modulates the stability and plasma membrane expression of CFTR

The role of the cystic fibrosis transmembrane conductance regulator (CFTR) as a cAMP-dependent chloride channel on the apical membrane of epithelia is well established. However, the processes by which CFTR is regulated on the cell surface are not clear. Here we report the identification of a protein-protein interaction between CFTR and the cytoskeletal filamin proteins. Using proteomic approaches, we identified filamins as proteins that associate with the extreme CFTR N terminus. Furthermore, we identified a disease-causing missense mutation in CFTR, serine 13 to phenylalanine (S13F), which disrupted this interaction. In cells, filamins tethered plasma membrane CFTR to the underlying actin network. This interaction stabilized CFTR at the cell surface and regulated the plasma membrane dynamics and confinement of the channel. In the absence of filamin binding, CFTR was internalized from the cell surface, where it prematurely accumulated in lysosomes and was ultimately degraded. Our data demonstrate what we believe to be a previously unrecognized role for the CFTR N terminus in the regulation of the plasma membrane stability and metabolic stability of CFTR. In addition, we elucidate the molecular defect associated with the S13F mutation.     

The development of a quantitative ELISA for antibodies against human platelet antigen type 1a

BACKGROUND: Severe neonatal alloimmune thrombocytopenia is often due to antibodies against human platelet antigen type 1a (HPA-1a). The aim of this study was to develop a quantitative ELISA for the measurement of antibodies against HPA-1a. STUDY DESIGN AND METHODS: HPA-1a glycoprotein (GP) IIb-IIIa was immobilized and mixed with recalcified anti-HPA-1a-positive plasma overnight at 4 degrees C. The beads were washed, the antibodies against HPA-1a were eluted, and the eluate pH level was promptly adjusted. The purified antibodies were dialyzed and used for the development of an ELISA incorporating HPA-1a-coated plates. RESULTS: Serial doubling dilutions of the purified antibodies resulted in consistent sigmoid standard curves with a sensitivity of 0.5 microg per mL. To determine the reproducibility of the ELISA, antibodies against HPA-1a in five plasma samples (Samples A-E) were measured at serial doubling dilutions in four separate assays. Three of the samples (Samples A-C) contained antibodies against HPA-1a. The mean amounts in microg per mL (+/- SD, percentage of CV) obtained in the four assays were as follows: Sample A, 133 (9.4, 7.1%); Sample B, 16.5 (1.7, 10%); and Sample C, 8 (0.8, 10%). The amounts in the two antibody-negative controls (Samples D and E) were consistently less than 0.2 microg per mL. CONCLUSION: Using immobilized HPA-1a1a, antibodies against HPA-1a has been purified, and a quick and simple quantitative assay has been developed.     

Divergent role of heme oxygenase inhibition in the pathogenesis of sepsis

The reduction of neutrophil migration to an infectious focus is associated with a high mortality in severe sepsis. Previously, we showed that heme oxygenase (HO) products downregulate neutrophil recruitment in a noninfectious inflammatory model. The present study was designed to determine the role of HO in sepsis induced by cecal ligation and puncture (CLP) model. We demonstrated that pretreatment, but not the combination of pretreatment plus posttreatment with zinc protoporphyrin IX (ZnPP IX), an HO inhibitor, prevented the reduction of CXCR2 on circulating neutrophils and the failure of intraperitoneal neutrophil migration to the site of infection. Consequently, bacterial dissemination, systemic inflammatory response, and organ injury were prevented. In addition, pretreatment with the HO inhibitor avoided hypotension and consequently increased survival. Moreover, in mice subjected to severe CLP, the pretreatment, but not the combination of pretreatment plus posttreatment with ZnPP IX, prevented the increase of plasmatic free heme observed in nontreated severe CLP. The administration of exogenous hemin to mice subjected to moderate sepsis consistently increased the mortality rate. Furthermore, hemin resulted in a reduction of neutrophil migration both in vivo and in vitro. Altogether, our results demonstrated that pretreatment with the HO inhibitor prevents the pathological findings in severe CLP. However, the combination of pretreatment plus posttreatment with ZnPP IX enhances sepsis severity because of an increase in circulating levels of heme, which is deleterious to the host tissues and also inhibits neutrophil migration.     

A simple and robust quantitative PCR assay to determine CYP21A2 gene dose in the diagnosis of 21-hydroxylase deficiency

BACKGROUND: Correct diagnosis of 21-hydroxylase deficiency (21OHD) requires the identification of CYP21A2 gene deletions and CYP21A1P/CYP21A2 chimeric genes, which are disease-causing alleles, and gene duplications, which can lead to false-positive 21OHD allele results. Because lack of suitable CYP21A2 dosage assessment methods hampers correct 21OHD diagnosis, we developed a new assay based on the relative quantification of the CYP21A2 gene using the DSP gene as a reference. METHODS: The assay to determine CYP21A2 copy number is based on real-time PCR. The method also detects the presence of the CYP21A1P/CYP21A2 chimeric gene. We used a duplex PCR to coamplify the DSP gene, included as an internal control, along with CYP21A2. The difference in threshold cycles between CYP21A2 and DSP genes (DeltaCt) was used to assess CYP21A2 copy number. RESULTS: The DeltaCt values obtained from 24 samples used to set up the method clearly differentiated 3 nonoverlapping intervals, which corresponded to the number of CYP21A2 copies: -1.35 to -0.25 defined 2 gene copies, +0.20 to +2.00 defined 1 copy, and -2.50 to -1.50 defined 3 copies. With these intervals we were able to assess the gene copy number in 24 additional samples. CONCLUSIONS: This new method for gene copy assessment detects homozygous and heterozygous CYP21A2 gene deletions, CYP21A1P/CYP21A2 chimeric genes, and gene duplications. Moreover, the method is robust, fast, and easy to use in a molecular diagnosis laboratory. This method together with CYP21A2 gene sequencing can provide a definitive system for the detection of almost all, common as well as rare, 21OHD alleles.