54 research outputs found

    Sodium-coupled Monocarboxylate Transporters in Normal Tissues and in Cancer

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    SLC5A8 and SLC5A12 are sodium-coupled monocarboxylate transporters (SMCTs), the former being a high-affinity type and the latter a low-affinity type. Both transport a variety of monocarboxylates in a Na+-coupled manner. They are expressed in the gastrointestinal tract, kidney, thyroid, brain, and retina. SLC5A8 is localized to the apical membrane of epithelial cells lining the intestinal tract and proximal tubule. In the brain and retina, its expression is restricted to neurons and the retinal pigment epithelium. The physiologic functions of SLC5A8 include absorption of short-chain fatty acids in the colon and small intestine, reabsorption of lactate and pyruvate in the kidney, and cellular uptake of lactate and ketone bodies in neurons. It also transports the B-complex vitamin nicotinate. SLC5A12 is also localized to the apical membrane of epithelial cells lining the intestinal tract and proximal tubule. In the brain and retina, its expression is restricted to astrocytes and Müller cells. SLC5A8 also functions as a tumor suppressor; its expression is silenced in tumors of colon, thyroid, stomach, kidney, and brain. The tumor-suppressive function is related to its ability to mediate concentrative uptake of butyrate, propionate, and pyruvate, all of which are inhibitors of histone deacetylases. SLC5A8 can also transport a variety of pharmacologically relevant monocarboxylates, including salicylates, benzoate, and γ-hydroxybutyrate. Non-steroidal anti-inflammatory drugs such as ibuprofen, ketoprofen, and fenoprofen, also interact with SLC5A8. These drugs are not transportable substrates for SLC5A8, but instead function as blockers of the transporter. Relatively less is known on the role of SLC5A12 in drug transport

    Zinc Sensing Receptor Signaling, Mediated by GPR39, Reduces Butyrate-Induced Cell Death in HT29 Colonocytes via Upregulation of Clusterin

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    Zinc enhances epithelial proliferation, protects the digestive epithelial layer and has profound antiulcerative and antidiarrheal roles in the colon. Despite the clinical significance of this ion, the mechanisms linking zinc to these cellular processes are poorly understood. We have previously identified an extracellular Zn2+ sensing G-protein coupled receptor (ZnR) that activates Ca2+ signaling in colonocytes, but its molecular identity as well as its effects on colonocytes' survival remained elusive. Here, we show that Zn2+, by activation of the ZnR, protects HT29 colonocytes from butyrate induced cell death. Silencing of the G-protein coupled receptor GPR39 expression abolished ZnR-dependent Ca2+ release and Zn2+-dependent survival of butyrate-treated colonocytes. Importantly, GPR39 also mediated ZnR-dependent upregulation of Na+/H+ exchange activity as this activity was found in native colon tissue but not in tissue obtained from GPR39 knock-out mice. Although ZnR-dependent upregulation of Na+/H+ exchange reduced the cellular acid load induced by butyrate, it did not rescue HT29 cells from butyrate induced cell death. ZnR/GPR39 activation however, increased the expression of the anti-apoptotic protein clusterin in butyrate-treated cells. Furthermore, silencing of clusterin abolished the Zn2+-dependent survival of HT29 cells. Altogether, our results demonstrate that extracellular Zn2+, acting through ZnR, regulates intracellular pH and clusterin expression thereby enhancing survival of HT29 colonocytes. Moreover, we identify GPR39 as the molecular moiety of ZnR in HT29 and native colonocytes

    Expression of the Na(+)/l(- )symporter (NIS) is markedly decreased or absent in gastric cancer and intestinal metaplastic mucosa of Barrett esophagus

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    BACKGROUND: The sodium/iodide symporter (NIS) is a plasma membrane glycoprotein that mediates iodide (I(-)) transport in the thyroid, lactating breast, salivary glands, and stomach. Whereas NIS expression and regulation have been extensively investigated in healthy and neoplastic thyroid and breast tissues, little is known about NIS expression and function along the healthy and diseased gastrointestinal tract. METHODS: Thus, we investigated NIS expression by immunohistochemical analysis in 155 gastrointestinal tissue samples and by immunoblot analysis in 17 gastric tumors from 83 patients. RESULTS: Regarding the healthy Gl tract, we observed NIS expression exclusively in the basolateral region of the gastric mucin-producing epithelial cells. In gastritis, positive NIS staining was observed in these cells both in the presence and absence of Helicobacter pylori. Significantly, NIS expression was absent in gastric cancer, independently of its histological type. Only focal faint NIS expression was detected in the direct vicinity of gastric tumors, i.e., in the histologically intact mucosa, the expression becoming gradually stronger and linear farther away from the tumor. Barrett mucosa with junctional and fundic-type columnar metaplasia displayed positive NIS staining, whereas Barrett mucosa with intestinal metaplasia was negative. NIS staining was also absent in intestinalized gastric polyps. CONCLUSION: That NIS expression is markedly decreased or absent in case of intestinalization or malignant transformation of the gastric mucosa suggests that NIS may prove to be a significant tumor marker in the diagnosis and prognosis of gastric malignancies and also precancerous lesions such as Barrett mucosa, thus extending the medical significance of NIS beyond thyroid disease

    Congenital cardiac liver cirrhosis with combined hepatocellular-cholangiocarcinoma-a case report

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    Background: Cardiac liver cirrhosis secondary to Fontan procedure has been associated with hepatocellular carcinoma at a younger age. However, Fontan associated liver disease and combined hepatocellular-cholangiocarcinoma has not been previously reported. Combined hepatocellular-cholangiocarcinoma is a rare cancer that accounts for 2-5% of primary liver tumors and poses significant diagnostic and treatment challenges. This case highlights these needs and potential screening and treatment considerations. Herein we describe a case of combined hepatocellular-cholangiocarcinoma in a patient with autism, congenital heart disease, and Fontan procedure. Case Description: The patient is a 27-year-old male who presented with a liver mass detected on MRI performed in the context of a rising alpha-fetoprotein during a screening visit. Biopsy of the mass revealed a combined hepatocellular-cholangiocarcinoma which was staged as localized. Due to the COVID-19 pandemic and subsequent halt of all elective surgeries, the patient received local therapy with chemoembolization followed by pembrolizumab. The disease progressed though, and therapy was changed to gemcitabine plus cisplatin. Patient received 2 cycles of therapy, after which he and his family decided to transfer medical care to Memorial Sloan Kettering. Next generation sequencing of the tumor revealed TP53 and FGFR2 mutations. By then patient was also found to have lung metastasis. To help address the hepatocellular carcinoma, lenvatinib was added. Patient had sustainable disease control for about a year, yet eventually developed thrombocytopenia complicated by an episode of gastrointestinal bleeding. With a worsening performance status, adverse events of the treatment, and recurrent hospitalizations, a goals of care discussion with his family led to the discontinuation of active cancer therapy and patient was started on best supportive care. Patient remained in active follow-up until the time of this report and passed away less than a year from initiating best supportive care alone. Conclusions: This challenging case raises awareness towards screening and monitoring all patients with Fontan procedure for Fontan associated liver disease and liver cancers, including combined hepatocellular-cholangiocarcinoma. To the best of our knowledge, this is the first description of combined hepatocellular-cholangiocarcinoma occurring in the context of cardiac cirrhosis. The management difficulties that led to altering the goals of care, is another reminder of the dynamic nature of the care oncologists would provide. © Journal of Gastrointestinal Oncology. All rights reserved

    Hepatoid esophagogastric adenocarcinoma and tumoral heterogeneity: A case report

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    Hepatoid adenocarcinoma of the stomach is an uncommon subtype of gastric cancer remarkably similar to hepatocellular carcinoma in histopathological analysis. It is also commonly associated with high serum alfa-fetoprotein and a poorer prognosis, despite the emergence of new therapeutic options. In recent years, next generation sequencing (NGS) technology has made it possible to identify and describe the genes and molecular alterations common to gastric cancer thereby contributing to the advancement of targeted therapies. A 62-year-old patient, with no prior risk factor for hepatocellular carcinoma (HCC), presented to the emergency room with dysphagia for solids, abdominal pain and weight loss of about 3 kilograms over 3 months. Histopathological analysis presented with disparities regarding HER2 and programmed death-ligand 1 (PD-L1) status in the primary and metastatic sites. We describe a case of a de novo metastatic, human epidermal growth factor receptor 2 (HER2) positive esophagogastric junction hepatoid adenocarcinoma. Although this is a rare subgroup of gastric cancer, treatment strategies were based in recent studies in immunotherapy and guided therapy, taking into consideration the molecular findings from the patient’s tumor NGS analysis. Data about HER2 and PDL1 heterogeneity were also reviewed. Despite the aggressiveness and rarity of this histology, the patient had a good response to treatment. © Journal of Gastrointestinal Oncology. All rights reserved

    Implications of CAR‐T

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