Alterations in zonal distribution and plasma membrane localization of hepatocyte bile acid transporters in patients with NAFLD

BACKGROUND

NAFLD is highly prevalent with limited treatment options. Bile acids (BAs) increase in the systemic circulation and liver during NAFLD progression. Changes in plasma membrane localization and zonal distribution of BA transporters can influence transport function and BA homeostasis. However, a thorough characterization of how NAFLD influences these factors is currently lacking. This study aimed to evaluate the impact of NAFLD and the accompanying histologic features on the functional capacity of key hepatocyte BA transporters across zonal regions in human liver biopsies.

METHODS

A novel machine learning image classification approach was used to quantify relative zonal abundance and plasma membrane localization of BA transporters (bile salt export pump [BSEP], sodium-taurocholate cotransporting polypeptide, organic anion transporting polypeptide [OATP] 1B1 and OATP1B3) in non-diseased (n = 10), NAFL (n = 9), and NASH (n = 11) liver biopsies. Based on these data, membrane-localized zonal abundance (MZA) measures were developed to estimate transporter functional capacity.

RESULTS

NAFLD diagnosis and histologic scoring were associated with changes in transporter membrane localization and zonation. Increased periportal BSEPMZA (mean proportional difference compared to non-diseased liver of 0.090) and decreased pericentral BSEPMZA (-0.065) were observed with NASH and also in biopsies with higher histologic scores. Compared to Non-diseased Liver, periportal OATP1B3MZA was increased in NAFL (0.041) and NASH (0.047). Grade 2 steatosis (mean proportional difference of 0.043 when compared to grade 0) and grade 1 lobular inflammation (0.043) were associated with increased periportal OATP1B3MZA.

CONCLUSIONS

These findings provide novel mechanistic insight into specific transporter alterations that impact BA homeostasis in NAFLD. Changes in BSEPMZA likely contribute to altered BA disposition and pericentral microcholestasis previously reported in some patients with NAFLD. BSEPMZA assessment could inform future development and optimization of NASH-related pharmacotherapies.

The clinical significance of adenomatous polyposis coli (APC) and catenin Beta 1 (CTNNB1) genetic aberrations in patients with melanoma

BACKGROUND

Melanoma-intrinsic activated β-catenin pathway, the product of the catenin beta 1 (CTNNB1) gene, has been associated with low/absent tumor-infiltrating lymphocytes, accelerated tumor growth, metastases development, and resistance to anti-PD-L1/anti-CTLA-4 agents in mouse melanoma models. Little is known about the association between the adenomatous polyposis coli (APC) and CTNNB1 gene mutations in stage IV melanoma with immunotherapy response and overall survival (OS).

METHODS

We examined the prognostic significance of somatic APC/CTNNB1 mutations in the Cancer Genome Atlas Project for Skin Cutaneous Melanoma (TCGA-SKCM) database. We assessed APC/CTNNB1 mutations as predictors of response to immunotherapies in a clinicopathologically annotated metastatic patient cohort from three US melanoma centers.

RESULTS

In the TCGA-SKCM patient cohort (n = 434) presence of a somatic APC/CTNNB1 mutation was associated with a worse outcome only in stage IV melanoma (n = 82, median OS of APC/CTNNB1 mutants vs. wild-type was 8.15 vs. 22.8 months; log-rank hazard ratio 4.20, p = 0.011). APC/CTNNB1 mutation did not significantly affect lymphocyte distribution and density. In the 3-melanoma institution cohort, tumor tissues underwent targeted panel sequencing using two standards of care assays. We identified 55 patients with stage IV melanoma and APC/CTNNB1 genetic aberrations (mut) and 169 patients without (wt). At a median follow-up of more than 25 months for both groups, mut compared with wt patients had slightly more frequent (44% vs. 39%) and earlier (66% vs. 45% within six months from original diagnosis of stage IV melanoma) development of brain metastases. Nevertheless, time-to-development of brain metastases was not significantly different between the two groups. Fortunately, mut patients had similar clinical benefits from PD-1 inhibitor-based treatments compared to wt patients (median OS 26.1 months vs. 29.9 months, respectively, log-rank p = 0.23). Less frequent mutations in the NF1, RAC1, and PTEN genes were seen in the mut compared with wt patients from the 3-melanoma institution cohort. Analysis of brain melanoma tumor tissues from a separate craniotomy patient cohort (n = 55) showed that melanoma-specific, activated β-catenin (i.e., nuclear localization) was infrequent (n = 3, 6%) and not prognostic in established brain metastases.

CONCLUSIONS

APC/CTNNB1 mutations are associated with a worse outcome in stage IV melanoma and early brain metastases independent of tumor-infiltrating lymphocyte density. However, PD1 inhibitor-based treatments provide comparable benefits to both mut and wt patients with stage IV melanoma.

Predicting outcomes of surgical management of intrahepatic cholangiocarcinoma: A Gordian Knot

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver malignancy with liver resection with curative intent being the mainstay of treatment related to prolonged survival. Better risk stratification models are needed to optimize patient selection and identify individuals who will benefit the most from an operative approach or alternative treatments due to high incidence of recurrence in patients undergoing resection with curative intent for ICC. Machine learning as well as markers of tumoral biology can generate reliable models that could help in identifying patients at risk of recurrence and worse outcomes. Liver transplantation might have a role in patients with small unresectable tumors.

Pathways and role of MALAT1 in esophageal and gastric cancer

Esophageal cancer (EC) and gastric cancer (GC) often have an unfavorable prognosis. Therefore, research is being conducted to identify the molecular mechanisms underlying the tumorigenesis and progression of GC and EC, and to indicate novel therapeutic targets and clinically applicable biomarkers. The dysregulations and roles of long non-coding RNAs (lncRNAs) have been widely reported, and current published literature has shown that lncRNAs play important regulatory roles in the carcinogenesis and progression of EC and GC. The lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been investigated in a number of studies with regard to its pathogenic pathways and association with the prognosis of gastric and esophageal malignancies. As literature on the topic of MALAT1 in EC and GC continues to emerge, the present review aims to summarize all current knowledge on the association between MALAT1 expression and esophagogastric malignancies and to describe the pathogenic pathways and possible prognostic role of MALAT1 in esophagogastric cancer. As research studies on MALAT1 pathways in esophagogastric malignancies are ongoing, new possibilities for the diagnosis, prognosis and therapy of GC and EC are likely to be identified.

Novel therapies are changing treatment paradigms in metastatic prostate cancer

Metastatic castration-resistant prostate cancer (mCRPC) remains a terminal diagnosis with an aggressive disease course despite currently approved therapeutics. The recent successful development of poly ADP-ribose polymerase (PARP) inhibitors for patients with mCRPC and mutations in DNA damage repair genes has added to the treatment armamentarium and improved personalized treatments for prostate cancer. Other promising therapeutic agents currently in clinical development include the radiotherapeutic 177-lutetium-prostate-specific membrane antigen (PSMA)-617 targeting PSMA-expressing prostate cancer and combinations of immunotherapy with currently effective treatment options for prostate cancer. Herein, we have highlighted the progress in systemic treatments for mCRPC and the promising agents currently in ongoing clinical trials.

Insulinomas: from diagnosis to treatment. A review of the literature

Insulinoma is the most common pancreatic neuroendocrine tumor (NET). Insulinomas are most commonly benign, well-differentiated NETs, whereas malignant neoplasms account for approximately 5-10% of all cases. Management includes conservative treatment with drugs targeting insulin-induced hypoglycemia, non-operative invasive procedures, as well as curative open or laparoscopic tumor resection. The current review aimed to summarize the current literature evidence on insulinoma and investigate the advantages and complications of available treatments.

High incidence of brain metastases (BrM) in patients with metastatic cutaneous melanoma (MCM) and mutations in the APC/β-catenin (CTNNB1)

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Background: Activation of the WNT/β-catenin pathway is associated with low/absent tumor-infiltrating lymphocytes (TILs) and resistance to anti-PD-L1/anti-CTLA-4 agents in mouse melanoma models. We aimed to investigate if APC/CTNNB1 mutations in melanoma pts are associated with TIL status, prediction of response to immunotherapy (IT), and overall survival (OS). Methods: Pts with CM and APC or CTNNB1 mutations identified in melanoma tumors using the TruSight Tumor 26 Illumina assay were enrolled. Demographics, clinical (stage, treatment response, follow-up), pathologic (TIL status), and molecular (BRAF/NRAS, C→T (i.e. UV signature) nucleotide transition, functional significance by IMPACT, mutant allele frequency (MAF) corrected from the % tumor) characteristics were investigated. Results: We identified a total of 25 pts (13 males; age at original diagnosis (median 61 yrs, range 22-78 yrs). CTNNB1 and APC mutations were mutually exclusive. 48% (12/25) had APC mutations and 52% (13/25) had CTNNB1 mutations; of which (i.e. CTNNB1 mutations) 69% (9/13) had absent TILs. 88% (22/25) of APC/CTNNB1 mutations had moderate functional significance, 64% (16/25) of the mutations had a C→T nucleotide change, 36% (9/25) had BRAFV600, and 20% (5/25) NRASQ61 mutations. 64% (14/22) of pts with stage II-III progressed to stage IV; of these 14 pts, 8 (57%) developed parenchymal BrM. 13 of the stage II-III 22 pts who progressed to stage IV received IT; of these 13 pts, 7 (53%) had absent TILs. APC/CTNNB1 mutations did not influence response to IT, irrespective of the MAF of the mutations. Of the 12 pts with MCM and measurable disease who received IT 9/12 had absent TILs and 7/12 responded. The median OS from the time of diagnosis of distant MCM (N = 17; 14 pts who progressed from initial stage II-III and 3 pts who were originally diagnosed with stage IV) was 18.8 months (range, 2.4-48.0 months). Conclusions: APC & CTNNB1 mutations are mutually exclusive. CTNNB1 mutations are more frequently associated with absent TILs. Pts with MCM had relatively shorter OS (18.8 months) in part due to development of BrM. In this small cohort APC/CTNNB1 mutations did not seem to impair response to immunotherapy.