Gemcitabine promotes autophagy and lysosomal function through ERK- and TFEB-dependent mechanisms.

Gemcitabine is a first-line treatment agent for pancreatic ductal adenocarcinoma (PDAC). Contributing to its cytotoxicity, this chemotherapeutic agent is primarily a DNA replication inhibitor that also induces DNA damage. However, its therapeutic effects are limited owing to chemoresistance. Evidence in the literature points to a role for autophagy in restricting the efficacy of gemcitabine. Autophagy is a catabolic process in which intracellular components are delivered to degradative organelles lysosomes. Interfering with this process sensitizes PDAC cells to gemcitabine. It is consequently inferred that autophagy and lysosomal function need to be tightly regulated to maintain homeostasis and provide resistance to environmental stress, such as those imposed by chemotherapeutic drugs. However, the mechanism(s) through which gemcitabine promotes autophagy remains elusive, and the impact of gemcitabine on lysosomal function remains largely unexplored. Therefore, we applied complementary approaches to define the mechanisms triggered by gemcitabine that support autophagy and lysosome function. We found that gemcitabine elicited ERK-dependent autophagy in PDAC cells, but did not stimulate ERK activity or autophagy in non-tumoral human pancreatic epithelial cells. Gemcitabine also promoted transcription factor EB (TFEB)-dependent lysosomal function in PDAC cells. Indeed, treating PDAC cells with gemcitabine caused expansion of the lysosomal network, as revealed by Lysosome associated membrane protein-1 (LAMP1) and LysoTracker staining. More specific approaches have shown that gemcitabine promotes the activity of cathepsin B (CTSB), a cysteine protease playing an active role in lysosomal degradation. We showed that lysosomal function induced by gemcitabine depends on TFEB, the master regulator of autophagy and lysosomal biogenesis. Interfering with TFEB function considerably limited the clonogenic growth of PDAC cells and hindered the capacity of TFEB-depleted PDAC cells to develop orthotopic tumors.

A diet rich in docosahexaenoic acid enhances reactive astrogliosis and ramified microglia morphology in apolipoprotein E epsilon 4-targeted replacement mice.

Docosahexaenoic acid (DHA) consumption reduces spatial memory impairment in mice carrying the human apolipoprotein E ε4 (APOE4) allele. The current study evaluated whether astrocyte and microglia morphology contribute to the mechanism of this result. APOE3 and APOE4 mice were fed either a DHA-enriched diet or a control diet from 4 to 12 months of age. Coronal brain sections were immunostained for GFAP, Iba1, and NeuN. Astrocytes from APOE4 mice exhibited signs of reactive astrogliosis compared to APOE3 mice. Consumption of DHA exacerbated reactive astrocyte morphology in APOE4 carriers. Microglia from APOE4-control mice exhibited characteristics of amoeboid morphology and other characteristics of ramified morphology (more processes, greater process complexity, and greater distance between neighboring microglia). DHA enhanced ramified microglia morphology in APOE4 mice. In addition, APOE4 mice fed the DHA diet had lower hippocampal concentrations of interleukin-7, lipopolysaccharide-induced CXC chemokine and monocyte chemoattractant protein 1, and higher concentration of interferon-gamma compared to APOE4-control mice. Our results indicate that a diet rich in DHA enhances reactive astrogliosis and ramified microglia morphology in APOE4 mice.

Bilateral Recurrent Laryngeal Nerve Palsy following Total Thyroidectomy in Triple A Syndrome, an Unexpected but Critical Complication.

INTRODUCTION: Triple "A" syndrome (TAS) is a rare autosomal recessive disorder that presents in childhood with achalasia cardia, alacrima, ACTH-resistant adrenal insufficiency, with sensorimotor and autonomic polyneuropathy developing later in the course of the disease. Case Presentation. An adult white male affected by this syndrome underwent an uneventful total thyroidectomy for malignancy and suffered delayed bilateral recurrent laryngeal nerve palsy in the early postoperative hours. The palsy spontaneously resolved after a five-week course. CONCLUSION: Given the rarity of this severe condition and the absence of surgical or medical causes identifiable, there is possibility that it is the neurological involvement caused by TAS that predisposed the patient to this adverse outcome, precipitated by standard manipulations during surgery.

Sentinel Lymph Node Biopsy in High-Risk Cutaneous Squamous Cell Carcinoma: Analysis of a Large Size Retrospective Series.

BACKGROUND: One of the most important prognostic factors for mortality in cutaneous squamous cell carcinoma (cSCC) is the development of nodal metastasis. There is no consensus regarding which patient with cSCC should be offered sentinel lymph node biopsy (SLNB). OBJECTIVE: This study aimed to establish the rate of positive SLNBs among patients with high-risk cSCCs and to identify which high-risk features are associated with a positive SLNB. METHODS: Five-year retrospective case series in an academic tertiary care center reviewing 93 SLNBs. RESULTS: Of the 93 SLNBs performed, 5 (5.4%) were positive. Three patients (3/5) had neck dissection and one (1/5) had radiation therapy, with no recurrence at the time of last follow-up. A tumor diameter ≥2 cm, a tumor depth >6 mm or below subcutaneous fat, perineural invasion of nerves with a diameter ≥0.1 mm, moderate or poor histological differentiation, lymphovascular invasion, and immunosuppression were associated with a positive SLNB. All tumors with a positive SLNB were classified as T2b according to the Brigham and Women's Hospital (BWH) tumor staging. LIMITATIONS: Retrospective study and absence of a control group. CONCLUSION: Sentinel lymph node biopsy can be considered for BWH T2b and T3 tumors. However, more randomized controlled studies are needed.

Association of bifid epiglottis and laryngeal web with Bardet-Biedl syndrome: A case report.

Bardet-Biedl syndrome (BBS) is a rare autosomal-recessive disease characterized by rod-cone dystrophy, obesity, postaxial polydactyly, cognitive impairment, hypogonadism and renal abnormalities. Bifid epiglottis and anterior laryngeal web are rare congenital anomalies and are often constituent of polymalformation syndromes. We report a case of a 9-month-old patient initially referred in otolaryngology (ENT) for dysphonia and recurrent respiratory infections. Physical exam and fiberoptic nasopharyngolaryngoscopy showed bifid epiglottis and laryngeal web associated with BBS. Those laryngeals anomalies may be underdiagnosed in BBS and this case supports the importance of upper airway evaluation by an ENT team, especially with respiratory symptoms or dysphagia.