Early prediction of response to cetuximab and radiotherapy by FDG-PET/CT for the treatment of a locoregionally advanced squamous cell carcinoma of the hypopharynx

Cetuximab (CTX) is used for the concurrent treatment with radiotherapy (RT) in squamous cell carcinoma of head and neck (HNSCC). There are no reliable clinical predictive markers of effectiveness of CTX at yet. We describe the clinical case of patient who received a CTX/RT to cure locoregionally advanced hypopharyngeal SCC. 2-Deoxy-2-[18F]fluoro-d-glucose positron emission tomography and computed tomography (18FDG-PET/CT) was performed before the treatment and repeated 10 days after CTX induction dose. A repeated 18FDG-PET/CT scan showed dramatic decrease of metabolic parameters. Patient had a complete response after treatment and is still alive and cured after 5 years

Acute radiation dermatitis evaluation with reflectance confocal microscopy: a prospective study /

BACKGROUND: During radiotherapy (RT), most breast cancer patients experience ionizing radiation (IR)-induced skin injury-acute radiation dermatitis (ARD). The severity of ARD is determined by a physician according to CTCAE or RTOG scales, which are subjective. Reflectance confocal microscopy (RCM) is a noninvasive skin imaging technique offering cellular resolution. Digital dermoscopy (DD) performed in conjugation with RCM can provide more information regarding skin toxicity. The purpose of this study is to create an RCM and DD features-based ARD assessment scale, to assess the association with CTCAE scale and possible predictive value. METHODS: One hundred and three breast cancer patients during RT were recruited; every week, clinical symptoms of ARD (CTCAE scale) were evaluated and RCM, together with digital dermoscopy (DD), was performed. RESULTS: According to RCM; after 2 RT weeks, exocytosis and/or spongiosis were present in 94% of patients; after 3 weeks, mild contrast cells (MMCs) were detected in 45%; disarrayed epidermis (DE) was present in 66% of patients after 4 weeks and in 93% after 5 weeks; abnormal dermal papillae (ADP) were present in 68% of patients after 5 weeks. The coefficients of RCM features (RCMcoef) alone and together with dermoscopically determined erythema (RCM-ERYcoef) were significantly associated with ARD severity grade. RCMcoef is a significant predictive factor for the clinical manifestation of ARD. CONCLUSIONS: RCM features of irradiated skin appear earlier than clinical symptoms, have a characteristic course, and allow the severity of ARD to be predicted

Individual radiosensitivity as a risk factor for the radiation-induced acute radiodermatitis

Background: Up to 95% of irradiated patients suffer from ionizing radiation (IR) induced early skin reaction, acute radiation dermatitis (ARD). Some experts think that additional skin hydra-tion can reduce acute skin reactions. Individual radiosensitivity (IRS) determined from lymphocytes may help to predict acute radiation toxicity. The purpose of this study is to evaluate the clinical manifestation of ARD in different skincare groups during whole breast radiotherapy depending on IRS and other risk factors. Methods: A total of 108 early-stage breast cancer patients were randomized into best supportive care (BSC) and additional skincare (ASC) groups. IRS was evaluated using a G2 assay modified with caffeine-induced G2 checkpoint arrest. All patients received a 50 Gy dose to the breast planning target volume (PTV). Clinical assessment of ARD symptoms according to the CTCAE grading scale was performed once a week. Results: IRS was successfully determined for 91 out of 108 patients. A total of 10 patients (11%) had normal IRS, 47 patients (52%) were categorized as radiosensitive, and 34 (37%) as highly radiosensitive. There was no significant difference in the manifestation of ARD between patient groups by skincare or IRS. According to logistic regression, patients with bigger breasts were prone to more severe ARD (p = 0.002). Conclusions: The additional skincare did not improve skin condition during RT. A total of 89% of patients had increased radiosensitivity. IRS determined before RT did not show the predictive value for the manifestation of ARD. Logistic regression revealed that breast volume was the most significant risk factor for the manifestation of ARD

The missing part: the Archaeoglobus fulgidus Argonaute forms a functional heterodimer with an N-L1-L2 domain protein /

Argonaute (Ago) proteins are present in all three domains of life (bacteria, archaea and eukaryotes). They use small (15–30 nucleotides) oligonucleotide guides to bind complementary nucleic acid targets and are responsible for gene expression regulation, mobile genome element silencing, and defence against viruses or plasmids. According to their domain organization, Agos are divided into long and short Agos. Long Agos found in prokaryotes (long-A and long-B pAgos) and eukaryotes (eAgos) comprise four major functional domains (N, PAZ, MID and PIWI) and two structural linker domains L1 and L2. The majority (∼60%) of pAgos are short pAgos, containing only the MID and inactive PIWI domains. Here we focus on the prokaryotic Argonaute AfAgo from Archaeoglobus fulgidus DSM4304. Although phylogenetically classified as a long-B pAgo, AfAgo contains only MID and catalytically inactive PIWI domains, akin to short pAgos. We show that AfAgo forms a heterodimeric complex with a protein encoded upstream in the same operon, which is a structural equivalent of the N-L1-L2 domains of long pAgos. This complex, structurally equivalent to a long PAZ-less pAgo, outperforms standalone AfAgo in guide RNA-mediated target DNA binding. Our findings provide a missing piece to one of the first and the most studied pAgos

Short prokaryotic Argonautes provide defence against incoming mobile genetic elements through NAD+ depletion

Argonaute (Ago) proteins are found in all three domains of life. The so-called long Agos are composed of four major domains (N, PAZ, MID and PIWI) and contribute to RNA silencing in eukaryotes (eAgos) or defence against invading mobile genetic elements in prokaryotes (pAgos). The majority (~60%) of pAgos identified bioinformatically are shorter (comprising only MID and PIWI domains) and are typically associated with Sir2, Mrr or TIR domain-containing proteins. The cellular function and mechanism of short pAgos remain enigmatic. Here we show that Geobacter sulfurreducens short pAgo and the NAD$^+$-bound Sir2 protein form a stable heterodimeric complex. The GsSir2/Ago complex presumably recognizes invading plasmid or phage DNA and activates the Sir2 subunit, which triggers endogenous NAD$^+$ depletion and cell death, and prevents the propagation of invading DNA. We reconstituted NAD$^+$ depletion activity in vitro and showed that activated GsSir2/Ago complex functions as a NADase that hydrolyses NAD$^+$ to ADPR. Thus, short Sir2-associated pAgos provide defence against phages and plasmids, underscoring the diversity of mechanisms of prokaryotic Agos