Integrative multi-omics characterization of hepatocellular carcinoma in Hispanic patients

Background

The incidence and mortality rates of hepatocellular carcinoma (HCC) among Hispanics in the United States are much higher than those of non-Hispanic whites. We conducted comprehensive multi-omics analyses to understand molecular alterations in HCC among Hispanic patients.

Methods

Paired tumor and adjacent non-tumor samples were collected from 31 Hispanic HCC in South Texas (STX-Hispanic) for genomic, transcriptomic, proteomic, and metabolomic profiling. Additionally, serum lipids were profiled in 40 Hispanic and non-Hispanic patients with or without clinically diagnosed HCC.

Results

Exome sequencing revealed high mutation frequencies of AXIN2 and CTNNB1 in STX Hispanic HCCs, suggesting a predominant activation of the Wnt/β-catenin pathway. The TERT promoter mutation frequency was also remarkably high in the Hispanic cohort. Cell cycles and liver functions were identified as positively- and negatively-enriched, respectively, with gene set enrichment analysis. Gene sets representing specific liver metabolic pathways were associated with dysregulation of corresponding metabolites. Negative enrichment of liver adipogenesis and lipid metabolism corroborated with a significant reduction in most lipids in the serum samples of HCC patients. Two HCC subtypes from our Hispanic cohort were identified and validated with the TCGA liver cancer cohort. The subtype with better overall survival showed higher activity of immune and angiogenesis signatures, and lower activity of liver function-related gene signatures. It also had higher levels of immune checkpoint and immune exhaustion markers.

Conclusions

Our study revealed some specific molecular features of Hispanic HCC and potential biomarkers for therapeutic management of HCC and provides a unique resource for studying Hispanic HCC.

Genome-wide association study identifies high-impact susceptibility loci for HCC in North America

BACKGROUND AND AIMS

Despite the substantial impact of environmental factors, individuals with a family history of liver cancer have an increased risk for HCC. However, genetic factors have not been studied systematically by genome-wide approaches in large numbers of individuals from European descent populations (EDP).

APPROACH AND RESULTS

We conducted a 2-stage genome-wide association study (GWAS) on HCC not affected by HBV infections. A total of 1872 HCC cases and 2907 controls were included in the discovery stage, and 1200 HCC cases and 1832 controls in the validation. We analyzed the discovery and validation samples separately and then conducted a meta-analysis. All analyses were conducted in the presence and absence of HCV. The liability-scale heritability was 24.4% for overall HCC. Five regions with significant ORs (95% CI) were identified for nonviral HCC: 3p22.1, MOBP , rs9842969, (0.51, [0.40-0.65]); 5p15.33, TERT , rs2242652, (0.70, (0.62-0.79]); 19q13.11, TM6SF2 , rs58542926, (1.49, [1.29-1.72]); 19p13.11 MAU2 , rs58489806, (1.53, (1.33-1.75]); and 22q13.31, PNPLA3 , rs738409, (1.66, [1.51-1.83]). One region was identified for HCV-induced HCC: 6p21.31, human leukocyte antigen DQ beta 1, rs9275224, (0.79, [0.74-0.84]). A combination of homozygous variants of PNPLA3 and TERT showing a 6.5-fold higher risk for nonviral-related HCC compared to individuals lacking these genotypes. This observation suggests that gene-gene interactions may identify individuals at elevated risk for developing HCC.

CONCLUSIONS

Our GWAS highlights novel genetic susceptibility of nonviral HCC among European descent populations from North America with substantial heritability. Selected genetic influences were observed for HCV-positive HCC. Our findings indicate the importance of genetic susceptibility to HCC development.

Pivoting to telemedicine in a single-day multidisciplinary liver tumor clinic during COVID-19: the Texas Liver Tumor Center experience

Cancer guidelines recommend that all patients with hepatocellular carcinoma (HCC) have an evaluation by a multidisciplinary team to assess liver health, stage the cancer, and discuss treatment and palliative care options. Coronavirus disease 2019 (COVID-19) had a catastrophic impact on patients with cancer resulting in increased disease burden due to late diagnosis and treatment delays. Late diagnosis has highlighted the need for the early intervention of palliative care for patients with HCC. Conversion to telemedicine has been essential to caring for patients with all stages of cancer without added delays. Texas Liver Tumor Center (TLTC) offers patients with liver cancer at any stage a single-day multidisciplinary evaluation with tumor board review facilitating the early integration of treatment and palliative care services. National Comprehensive Cancer Network (NCCN) guidelines support increasing and improving access to palliative care. TLTC allows for the early integration of palliative care within a 1-day clinic model with an incorporated tumor board. This unique model of patient care decreases the burden of separate patient visits, may expedite the time from diagnosis to first treatment, facilitates the early intervention of palliative care specialists, and allows for optimal screening for clinical trials. In this review, we will provide an overview of the current multidisciplinary models of care for HCC and describe the successful pivot of TLTC from a fully in-person single-day multidisciplinary clinic with a multidisciplinary tumor board (MDTB) to a fully virtual experience, thereby maintaining access to this unique clinical model of patient care during the COVID-19 pandemic. The ability to pivot from in-person clinical visits to completely virtual visits increases patient access to care and enables more physicians to participate. Areas for future study include the impact on patient experience, clinical outcomes, and cost-effectiveness of this high-resource model.

Integrin alpha 6 is upregulated and drives hepatocellular carcinoma progression through integrin α6β4 complex

Integrin α6 (ITGA6) forms integrin receptors with either integrin β1 (ITGB1) or integrin β4 (ITGB4). How it functions to regulate hepatocellular carcinoma (HCC) progression is not well-elucidated. We found that ITGA6 RNA and protein expression levels are significantly elevated in human HCC tissues in comparison with paired adjacent nontumor tissues by RNA sequencing, RT-qPCR, Western blotting and immunofluorescence staining. Stable knockdown of ITGA6 with different ITGA6 shRNA expression lentivectors significantly inhibited proliferation, migration and anchorage-independent growth of HCC cell lines in vitro, and xenograft tumor growth in vivo. The inhibition of anchorage-dependent and -independent growth of HCC cell lines was also confirmed with anti-ITGA6 antibody. ITGA6 knockdown was shown to induce cell-cycle arrest at G0/G1 phase. Immunoprecipitation assay revealed apparent interaction of ITGA6 with ITGB4, but not ITGB1. Expression studies showed that ITGA6 positively regulates the expression of ITGB4 with no or negative regulation of ITGB1 expression. Finally, while high levels of ITGA6 and ITGB4 together were associated with significantly worse survival of HCC patients in TCGA data set, the association was not significant for high levels of ITGA6 and ITGB1. In conclusion, ITGA6 is upregulated in HCC tumors and has a malignant promoting role in HCC cells through integrin α6β4 complex. Thus, integrin α6β4 may be a therapeutic target for treating patients with HCC.

Abstract 2272: Integration of multi-omics data reveals molecular features of Hispanic hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the major type of liver cancer and one of the few cancers with a steady increase in incidence and mortality rate over the past several decades in the USA. It disproportionately affects Hispanics in the USA with an incidence and mortality rate about two to three times higher in Hispanics than in non-Hispanic whites. To identify molecular features associated with the Hispanic HCC we have generated genome-wide sequencing (i.e., exome-seq, RNA-seq) data and mass spectrometry-based proteomics data from HCC tumor and matched blood and/or adjacent normal tissues of Hispanic patients based in South Texas. The landscape of somatic mutation in HCC tumors revealed the aflatoxin-induced mutational signature (COSMIC) in some patients indicating an association of aflatoxin mediated toxicity in them. Similar to The Cancer Genome Atlas (TCGA) study, with predominant non-Hispanic HCC tumors, we could identify the most frequent somatic mutations in CTNNB1 and TP53. Other frequently (>10%) mutated genes in our patients appear to be mutated at relatively lower rate in the TCGA patients. Mutation(s) in some of the frequently mutated genes might contribute to the significant enrichment of cellular signaling pathways observed from the Gene Set Enrichment Analysis (GSEA) using paired RNA-seq data. Single sample GSEA (ssGSEA) of our RNA-seq and proteomic data sets revealed two clusters of HCC tumors, denoted as H1 and H2 clusters, with striking differences in various signaling pathways and cellular functions. Patients from the H1 cluster and two sub-clusters within the H2 cluster showed a significant difference in their survival rate based on overall survival information from the TCGA study. The transcriptomic data from Hispanic & non-Hispanic HCC identified activated immune evasion mechanisms in H1 patients. Sorafenib treatment was found to be associated with a lower hazard ratio for overall survival in patients from the H1 cluster compared to the H2 cluster. In sum, we have identified genes more frequently mutated in Hispanic HCC than in non-Hispanic HCC, and cellular and tissue functions significantly enriched only in the Hispanic HCC. We also report a novel classification of HCC tumors with significant differences in various cellular signaling pathways and overall survival. Our findings might be used as biomarkers for the early prediction and better therapeutic management of HCC.

Citation Format: Debodipta Das, Xiaojing Wang, Yu-Chiao Chiu, Hakim Bouamar, Yidong Chen, Siyuan Zheng, Francisco G. Cigarroa, Lu-Zhe Sun. Integration of multi-omics data reveals molecular features of Hispanic hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2272.

Abstract 1046: Combination of CDK 4/6 inhibitor Palbociclib with Rapamycin synergistically inhibits the growth of hepatocellular carcinoma cells

Introduction: Aberrant cell-cycle regulation is common in cancer, making it an attractive therapeutic target. The cell cycle inhibitor Palbociclib has been shown to have a cytostatic effect on HCC cells via the induction of quiescence and senescence, though it has limited cytocidal effect. We hypothesized that arrested cells upregulate mTOR signaling to stay metabolically active and investigated the effect of combining Palbociclib with the mTOR inhibitor Rapamycin on HCC cell lines in-vitro.

Methods: We employed single sample gene set enrichment analysis (ssGSEA) of 10 paired RNA-seq and 15 paired proteomic data sets as well as 371 HCC tumors from TCGA to identify commonly altered molecular markers in HCC, including cell cycle related genes. Subsequently, we studied the effect of Palbociclib and Rapamycin on two HCC cell lines, SNU398 and HuH7. We treated the cell lines with increasing doses of Palbociclib and used cell counting to assess growth inhibition, as well as β-galactosidase activity assay to assess induction of senescence. We then treated both cell lines with Palbociclib for ten days followed by Palbociclib plus Rapamycin for 4 days and performed an MTT assay to assess relative viable cell number. We also did a fixed ratio treatment with Palbociclib and Rapamycin, followed by calculation of combination index to determine the nature of their interaction. Finally, we performed Western Blot analysis for various proteins of the cell cycle and mTOR pathways to elucidate the effects of combination treatment.

Results: ssGSEA revealed significant positive enrichment of several cell cycle and mitosis related gene sets. Palbociclib treatment showed a dose-dependent inhibition of growth as well as increase in senescence associated β-galactosidase activity for both SNU398 and HuH7 cell lines. Addition of Rapamycin demonstrated a dose-dependent potentiation of Palbociclib induced growth inhibition, and fixed ratio treatment with the two drugs established a synergistic effect as indicated by a combination index of less than 1. Western blot analysis showed increased levels of intrinsic CDK inhibitors p16, p15, p21 and p27 with Palbociclib treatment. Western blot analysis of proteins of mTOR pathway revealed that Palbociclib treatment caused an increase in levels of p-mTOR as well as its downstream signaling proteins p-4eBP1, p-p70 and p-s6, and addition of Rapamycin suppressed their levels.

Conclusion: HCC cells over-express genes and proteins that drive cell cycle progression. Palbociclib induces senescence in hepatocellular carcinoma cell lines along with an associated upregulation in mTOR signaling, and combination with Rapamycin has a synergistic effect on growth inhibition in-vitro possibly by eliminating senescent cells.

Citation Format: Ankur Tiwari, Araceli Huerta, Hakim Bouamar, Debodipta Das, Francisco G. Cigarroa, LuZhe Sun. Combination of CDK 4/6 inhibitor Palbociclib with Rapamycin synergistically inhibits the growth of hepatocellular carcinoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1046.

Impact of Portable Normothermic Blood-Based Machine Perfusion on Outcomes of Liver Transplant: The OCS Liver PROTECT Randomized Clinical Trial

Question

Can oxygenated portable normothermic perfusion of deceased donor livers for transplant improve outcomes compared with the current standard of care using ischemic cold storage?

Findings

In this multicenter randomized clinical trial of 300 recipients of liver transplants with the donor liver preserved by either normothermic perfusion or conventional ischemic cold storage, normothermic machine perfusion resulted in decreased early liver graft injury and ischemic biliary complications and greater organ utilization.

Meaning

In this study, portable normothermic oxygenated machine perfusion of donor liver grafts resulted in improved outcomes after liver transplant and in more livers being transplanted.

Importance

Ischemic cold storage (ICS) of livers for transplant is associated with serious posttransplant complications and underuse of liver allografts.

Objective

To determine whether portable normothermic machine perfusion preservation of livers obtained from deceased donors using the Organ Care System (OCS) Liver ameliorates early allograft dysfunction (EAD) and ischemic biliary complications (IBCs).

Design, Setting, and Participants

This multicenter randomized clinical trial (International Randomized Trial to Evaluate the Effectiveness of the Portable Organ Care System Liver for Preserving and Assessing Donor Livers for Transplantation) was conducted between November 2016 and October 2019 at 20 US liver transplant programs. The trial compared outcomes for 300 recipients of livers preserved using either OCS (n = 153) or ICS (n = 147). Participants were actively listed for liver transplant on the United Network of Organ Sharing national waiting list.

Interventions

Transplants were performed for recipients randomly assigned to receive donor livers preserved by either conventional ICS or the OCS Liver initiated at the donor hospital.

Main Outcomes and Measures

The primary effectiveness end point was incidence of EAD. Secondary end points included OCS Liver ex vivo assessment capability of donor allografts, extent of reperfusion syndrome, incidence of IBC at 6 and 12 months, and overall recipient survival after transplant. The primary safety end point was the number of liver graft–related severe adverse events within 30 days after transplant.

Results

Of 293 patients in the per-protocol population, the primary analysis population for effectiveness, 151 were in the OCS Liver group (mean [SD] age, 57.1 [10.3] years; 102 [67%] men), and 142 were in the ICS group (mean SD age, 58.6 [10.0] years; 100 [68%] men). The primary effectiveness end point was met by a significant decrease in EAD (27 of 150 [18%] vs 44 of 141 [31%]; P = .01). The OCS Liver preserved livers had significant reduction in histopathologic evidence of ischemia-reperfusion injury after reperfusion (eg, less moderate to severe lobular inflammation: 9 of 150 [6%] for OCS Liver vs 18 of 141 [13%] for ICS; P = .004). The OCS Liver resulted in significantly higher use of livers from donors after cardiac death (28 of 55 [51%] for the OCS Liver vs 13 of 51 [26%] for ICS; P = .007). The OCS Liver was also associated with significant reduction in incidence of IBC 6 months (1.3% vs 8.5%; P = .02) and 12 months (2.6% vs 9.9%; P = .02) after transplant.

Conclusions and Relevance

This multicenter randomized clinical trial provides the first indication, to our knowledge, that normothermic machine perfusion preservation of deceased donor livers reduces both posttransplant EAD and IBC. Use of the OCS Liver also resulted in increased use of livers from donors after cardiac death. Together these findings indicate that OCS Liver preservation is associated with superior posttransplant outcomes and increased donor liver use.

Trial Registration

ClinicalTrials.gov Identifier: NCT02522871

The pediatric solid organ transplant experience with COVID-19: An initial multi-center, multi-organ case series

The clinical course of COVID-19 in pediatric solid organ transplant recipients remains ambiguous. Though preliminary experiences with adult transplant recipients have been published, literature centered on the pediatric population is limited. We herein report a multi-center, multi-organ cohort analysis of COVID-19-positive transplant recipients ≤ 18 years at time of transplant. Data were collected via institutions' respective electronic medical record systems. Local review boards approved this cross-institutional study. Among 5 transplant centers, 26 patients (62% male) were reviewed with a median age of 8 years. Six were heart recipients, 8 kidney, 10 liver, and 2 lung. Presenting symptoms included cough (n = 12 (46%)), fever (n = 9 (35%)), dry/sore throat (n = 3 (12%)), rhinorrhea (n = 3 (12%)), anosmia (n = 2 (8%)), chest pain (n = 2 (8%)), diarrhea (n = 2 (8%)), dyspnea (n = 1 (4%)), and headache (n = 1 (4%)). Six patients (23%) were asymptomatic. No patient required supplemental oxygen, intubation, or ECMO. Eight patients (31%) were hospitalized at time of diagnosis, 3 of whom were already admitted for unrelated problems. Post-transplant immunosuppression was reduced for only 2 patients (8%). All symptomatic patients recovered within 7 days. Our multi-institutional experience suggests the prognoses of pediatric transplant recipients infected with COVID-19 may mirror those of immunocompetent children, with infrequent hospitalization and minimal treatment, if any, required.

An ancestry informative marker panel design for individual ancestry estimation of Hispanic population using whole exome sequencing data

Background

Europeans and American Indians were major genetic ancestry of Hispanics in the U.S. These ancestral groups have markedly different incidence rates and outcomes in many types of cancers. Therefore, the genetic admixture may cause biased genetic association study with cancer susceptibility variants specifically in Hispanics. For example, the incidence rate of liver cancer has been shown with substantial disparity between Hispanic, Asian and non-Hispanic white populations. Currently, ancestry informative marker (AIM) panels have been widely utilized with up to a few hundred ancestry-informative single nucleotide polymorphisms (SNPs) to infer ancestry admixture. Notably, current available AIMs are predominantly located in intron and intergenic regions, while the whole exome sequencing (WES) protocols commonly used in translational research and clinical practice do not cover these markers. Thus, it remains challenging to accurately determine a patient’s admixture proportion without additional DNA testing.

Results

In this study we designed an unique AIM panel that infers 3-way genetic admixture from three distinct and selective continental populations (African (AFR), European (EUR), and East Asian (EAS)) within evolutionarily conserved exonic regions. Initially, about 1 million exonic SNPs from selective three populations in the 1000 Genomes Project were trimmed by their linkage disequilibrium (LD), restricted to biallelic variants, and finally we optimized to an AIM panel with 250 SNP markers, or the UT-AIM250 panel, using their ancestral informativeness statistics. Comparing to published AIM panels, UT-AIM250 performed better accuracy when we tested with three ancestral populations (accuracy: 0.995 ± 0.012 for AFR, 0.997 ± 0.007 for EUR, and 0.994 ± 0.012 for EAS). We further demonstrated the performance of the UT-AIM250 panel to admixed American (AMR) samples of the 1000 Genomes Project and obtained similar results (AFR, 0.085 ± 0.098; EUR, 0.665 ± 0.182; and EAS, 0.250 ± 0.205) to previously published AIM panels (Phillips-AIM34: AFR, 0.096 ± 0.127, EUR, 0.575 ± 0.290, and EAS, 0.330 ± 0.315; Wei-AIM278: AFR, 0.070 ± 0.096, EUR, 0.537 ± 0.267, and EAS, 0.393 ± 0.300). Subsequently, we applied the UT-AIM250 panel to a clinical dataset of 26 self-reported Hispanic patients in South Texas with hepatocellular carcinoma (HCC). We estimated the admixture proportions using WES data of adjacent non-cancer liver tissues (AFR, 0.065 ± 0.043; EUR, 0.594 ± 0.150; and EAS, 0.341 ± 0.160). Similar admixture proportions were identified from corresponding tumor tissues. In addition, we estimated admixture proportions of The Cancer Genome Atlas (TCGA) collection of hepatocellular carcinoma (TCGA-LIHC) samples (376 patients) using the UT-AIM250 panel. The panel obtained consistent admixture proportions from tumor and matched normal tissues, identified 3 possible incorrectly reported race/ethnicity, and/or provided race/ethnicity determination if necessary.

Conclusions

Here we demonstrated the feasibility of using evolutionarily conserved exonic regions to infer admixture proportions and provided a robust and reliable control for sample collection or patient stratification for genetic analysis. R implementation of UT-AIM250 is available at https://github.com/chenlabgccri/UT-AIM250.

Abstract 4642: RNA interference reveals tumor promoting roles of integrin alpha 6 (ITGA6) in hepatocellular carcinoma

Introduction: Hepatocellular carcinoma (HCC) is the sixth most common malignancy worldwide and the third leading cause of cancer related mortality. The incidence and mortality rates of HCC are two times higher in Latinos than in the general population in the US and are the highest in Latinos from the South Texas region. The genetic and epigenetic events associated with the increased incidence of HCC in this population are still unclear. Increasing evidence suggests that integrins are one of the most important receptors for cell metastasis including integrin α6β1 and α6β4. However, few studies have focused on the function of integrin alpha 6 (ITGA6) in the tumorigenesis and progression of HCC. We aim to investigate the expression and potential roles of ITGA6 in HCC.

Materials and Methods: Paired HCC tissues and adjacent non-tumor tissues were collected for RNA sequencing. ITGA6 RNA and protein expression levels were evaluated by RNA sequencing, RT-qPCR, Western blot and immunohistochemistry. HCC cell lines (SNU398 and Huh7) were transiently transfected with two ITGA6siRNAs and stably transfected with an ITGA6 shRNA lentivector. These cell lines were used for assays testing the effects of ITGA6 knockdown on HCC cell proliferation, migration and anchorage independent growth.

Results: Analysis of RNA sequencing data indicated that the expression of ITGA6 increased 4-fold in HCC tumor tissues compared to adjacent non-tumor tissues, which was validated by RT-qPCR. Western blotting also confirmed increased expression of ITGA6 in the tumor tissues. The knockdown of ITGA6 by siRNAs and shRNA was confirmed with Western blot and qRT-PCR. ITGA6 knockdown significantly decreased proliferation, migration and anchorage independent growth of HCC cell lines.

Conclusions: ITGA6 is upregulated in HCC tumors in Latinos patients. ITGA6 may play a malignant-promoting role in HCC cells. Our studies provided new insights into the molecular mechanisms that drive HCC progression and potential therapeutic targets for treating patients with HCC including South Texas Latino patients.

Citation Format: Guixi Zheng, Carla Zeballos, Hakim Bouamar, Matyas Cserhati, Francisco G Cigarroa, Lu-zhe Sun. RNA interference reveals tumor promoting roles of integrin alpha 6 (ITGA6) in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4642.

Abstract 2424: Hepatocellular carcinoma in the South Texas Latino population: Implications of STEAP2

Introduction: Hepatocellular carcinoma (HCC) is the most common type of liver cancer in adults and the third most common cause of cancer death worldwide; while incidence and mortality rates are two times higher in Latinos, incidence rates are the highest among Latinos in the South Texas region. The genetic and epigenetic events associated with the increased incidence of HCC in this population are largely unknown. We performed whole genome RNA sequencing in paired HCC tumor and adjacent non-tumor tissue total RNA from nine South Texas Latino patients. Analysis of differentially expressed genes revealed significant alterations in pathways associated with oxidative stress; most importantly, we found that the expression of STEAP2 (Six Transmembrane Epithelial Antigen of the Prostate 2) is increased five-fold in HCC tumor tissue compared to adjacent non-tumor tissue. In comparison to a non-Latino population, this finding was unique to South Texas Latinos. STEAP2 is a metalloreductase of iron and copper; reduced iron and copper ions can mediate the production of hydroxyl radicals resulting in increased oxidative stress, which can cause DNA damage and lipid peroxidation. We aim to prove that STEAP2 through regulation of iron and copper homeostasis, and an increase in oxidative stress, will lead to malignant transformation of hepatocytes resulting in tumor progression of HCC, including in obese hosts.

Material and Methods: Latino paired HCC and adjacent non-tumor tissues were collected for RNA sequencing, metal ion measurement and oxidative stress markers. STEAP2 RNA and protein expression levels in Latino and Caucasian samples were evaluated by RT-PCR, Western blot, and immunohistochemistry. HCC cell lines (SNU398 and HUH7) with knockdown (KD) and overexpression (OE) of STEAP2 were created to examine the proliferation, migration, anchorage independent growth, and oxidative stress in vitro.

Results: Analysis of RNA sequencing data demonstrated the overexpression of STEAP2 in HCC tumors in Latino patients, which were validated by RT-PCR and Western blot data. Lipid peroxidation product, 4-hydroxynonenal, and copper levels were higher in HCC tumor vs. adjacent tissue. KD of STEAP2 in the HCC cell lines decreased proliferation, migration and anchorage independent growth, while OE of STEAP2 increase migration and anchorage independent growth but not proliferation.

Conclusions: STEAP2 is specifically overexpressed in HCC tumors in Latinos in comparison to HCC tumors in non-Latino whites and appears to play a malignant-promoting role in HCC cells. Further studies on the role of STEAP2 as a novel tumor promoter in HCC and the mechanisms by which it promotes carcinogenesis are underway. The proposed studies will likely yield mechanistic insights into the molecular mechanisms that drive HCC development and progression in South Texas Latinos and potential therapeutic targets.

Citation Format: Carla Zeballos, Hakim Bouamar, Guixi Zheng, Xiang Gu, Yidong Chen, Francisco G. Cigarroa, Lu-Zhe Sun. Hepatocellular carcinoma in the South Texas Latino population: Implications of STEAP2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2424.

Abstract 5425: The role of six transmembrane epithelial antigen of the prostate 2 in hepatocellular carcinoma

Introduction: The incidence of hepatocellular carcinoma (HCC) in Hispanics is three times higher than non-Hispanic whites, and even higher in South Texas (STX) Hispanics. This is attributed to a higher prevalence of hepatitis C, diabetes, obesity and perhaps genetic and epigenetic alterations. Knowledge regarding genetic alterations in Hispanics is sparse as demonstrated by the lack of Hispanics with HCC in The Cancer Genome Atlas (TCGA). Therefore, our group sequenced paired adjacent liver and HCC tumor samples from STX Hispanics, which highlighted a gene over-expressed in tumors of Hispanics, called the Six Transmembrane Epithelial Antigen of the Prostate 2 (STEAP2). STEAP2 is a metalloreductase of iron and copper and is implicated in increased iron and reactive oxygen species in the liver which can lead to the progression of inflammation and cirrhosis. STEAP2 may play an important oncogenic role in HCC, especially in the setting of obesity. We propose to test the hypothesis that overexpression of STEAP2 will lead to malignant property in HCC cells resulting in enhanced proliferation, survival, invasiveness, and eventually development of HCC, especially in obese hosts.

Methods: Hispanic paired tissue continues to be collected from our institution for RNA sequencing and establishment of Hispanic HCC cell lines. STEAP2 RNA and protein expression levels in Hispanic paired samples versus Caucasian paired samples were evaluated by RT-PCR, Western blot, and immunohistochemistry. Knockdown and overexpression of STEAP2 were established in HCC cell lines and in primary Hispanic HCC cell lines to examine the effects on iron levels, oxidative stress, proliferation, invasiveness, apoptosis and cell cycle in vitro.

Results: Hispanic HCC RNA sequencing data compared to TCGA HCC RNA sequencing data (no Hispanics) demonstrated the overexpression of STEAP2 in HCC tumors in Hispanic patients, which were validated by RT-PCR data and Western blot data. Lipid peroxidation product, 4-hydroxynonenal, and copper levels were higher in HCC tumor versus adjacent tissue. Iron levels were higher in adjacent tissue versus tumor tissue in Hispanics. Knockdown of STEAP2 in SNU398 cells decreased proliferation and migration, while in HUH7 cells STEAP2 knockdown only decreased migration.

Conclusions: STEAP2 is specifically overexpressed in HCC tumors in Hispanics in comparison to HCC tumors in non-Hispanic whites and appears to play a malignant-promoting role in HCC cells. Further studies to establish the role of STEAP2 as a tumor promoter in HCC and the mechanisms by which it promotes carcinogenesis are underway. The proposed studies will likely yield mechanistic insights into the molecular mechanisms that drive HCC development and progression in South Texas Hispanics and potential therapeutic targets involving STEAP2-mediated metal ion metabolism and oxidative stress.

Citation Format: Carla R. Zeballos, Hakim Bouamar, Xiang Gu, Yidong Chen, Francisco G. Cigarroa, LuZhe Sun. The role of six transmembrane epithelial antigen of the prostate 2 in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5425. doi:10.1158/1538-7445.AM2017-5425

Leading an academic health center in the 21st century: a pediatric surgeon's perspective

PURPOSE

At present, there is a gathering storm that is threatening the very practice of the art of medicine for future generations as never before. This article gives successful examples and calls for approaches that support improvements in education and health care for low-income and minority populations.

METHODS

To address this problem, the University of Texas Health Science Center at San Antonio established the Regional Academic Health Center (RAHC) along the Texas/Mexico border, which provides educational opportunities, clinical partnerships, and facilities to attract faculty to research and examine the health problems that are common in the Hispanic population.

RESULTS

In less than 4 years at the RAHC, nearly 100 medical students have been educated and 60% of residents are staying in the border area to practice. The creation of the RAHC has also has stimulated interest in students who are largely Hispanic to pursue health professional education. The University of Texas Health Science Center at San Antonio is now the number one public medical school graduating the most Hispanics in the nation.

CONCLUSIONS

The concept of the RAHC is an important means of addressing access to health care while serving as a catalyst to increase opportunities for students of all backgrounds to pursue health professional education.

Radiofrequency tissue ablation: effect of hepatic blood flow occlusion on thermal injuries produced in cirrhotic livers

BACKGROUND

Radiofrequency thermal ablation has been used as a treatment for several types of hepatic malignancies. Many of these lesions exist in the presence of cirrhosis. Limitations exist to the size of the ablations and, subsequently, the efficacy of treatment. Hepatic vascular inflow occlusion has been advocated as an adjunctive measure to increase the efficacy of the ablation. We present a model in the human cirrhotic liver that demonstrates the advantage of blood flow occlusion during radiofrequency ablation.

METHODS

Five patients with advanced endstage liver disease scheduled to have orthotopic liver transplantation were enrolled in this study. After laparotomy and before hepatectomy, radiofrequency ablation was performed without and with hepatic blood flow occlusion. After hepatectomy, the liver was sectioned, the area of ablation was measured in three dimensions, and the volume of ablation calculated.

RESULTS

Three of the patients had had previously placed transjugular intrahepatic portosystemic shunt. The mean volume of the ablation without blood flow occlusion was 22.5 +/- 7.4 cm(3) and that with blood flow occlusion was 48.4 +/- 24.0 cm(3) (P =.05).

CONCLUSIONS

Ablation area is increased significantly with hepatic blood flow occlusion in the human cirrhotic liver. This result may have application in the treatment of larger (>3 cm) hepatic malignancies.

Sonographically observed echogenic response during intraoperative radiofrequency ablation of cirrhotic livers: pathologic correlation

OBJECTIVE

We performed a study to determine the correlation between the diameter of the echogenic response observed with intraoperative sonography during radiofrequency ablation of the cirrhotic liver and the mean diameter of tissue necrosis.

SUBJECTS AND METHODS

A total of 22 intraoperative radiofrequency ablations were created in 11 cirrhotic livers. The largest diameter of the sonographically observed echogenic response surrounding and perpendicular to the radiofrequency probe was measured. The subsequent zone of necrosis observed at pathology in the hepatectomy specimens after liver transplantation was measured in three planes and compared with the measured diameter of the echogenic response.

RESULTS

During all except three ablations, a hyperechoic region was visualized surrounding the radiofrequency probe. The diameter of the echogenic response correlated significantly with the mean diameter of necrosis (correlation coefficient, 0.84). However, the echogenic response overestimated the minimal diameter of necrosis (mean difference, 0.8 +/- 0.4 cm) in 18 of 22 ablations and underestimated the maximum diameter of necrosis (mean difference, 0.9 +/- 0.8 cm) in 16 of 22 ablations.

CONCLUSION

The diameter of the echogenic response observed with intraoperative sonography during radiofrequency ablation of the cirrhotic liver correlates closely with the mean diameter of the subsequent area of tissue necrosis. However, the solitary diameter of the echogenic response as measured in our study was often greater than the smallest diameter and less than the largest diameter of the area of tissue necrosis. Therefore, the echogenic response associated with radiofrequency ablation of the cirrhotic liver should be viewed only as a rough approximation of the area of induced tissue necrosis; the final assessment of the adequacy of ablation should be deferred to an alternative imaging technique.

Transplantation of single and paired pediatric kidneys into adult recipients

BACKGROUND

The transplantation of kidneys from cadaveric donors < or = 5 years of age into adult recipients is controversial. The large disparity between donor renal mass and recipient body mass is feared to be problematic. Controversy also exists whether to transplant kidneys from these young donors individually or as a pair into a single recipient.

STUDY DESIGN

We retrospectively reviewed our experience from January 1991 to January 1995 with 22 adult renal transplantations using kidneys from cadaveric donors < or = 5 years of age. Ten patients received single allografts. Twelve received organs paired en bloc. Fifty-two adult recipients from cadaveric donors aged 18-55 years served as controls. All patients received cyclosporine-based immunosuppression. Recipient characteristics did not differ significantly between the groups.

RESULTS

Actuarial patient and graft survival rates were similar for the two groups. The incidence of urinary complications was higher in the recipients of pediatric kidneys than in the adult-donor group (18.2% versus 3.8%, respectively, p = not significant). No grafts were lost from urinary complications. Renal function, as determined by the calculated creatinine clearance, was significantly greater in the pediatric group (76.1 +/- 4.0 versus 61.4 +/- 23.2 mL/min, p = 0.035) by 6 months after transplantation. Recipients of paired pediatric kidneys initially had better renal function (63.9 +/- 21.4 mL/min) than those receiving single pediatric kidneys (38.2 +/- 11.6 mL/min) (p = 0.004), but by 6 months, no significant difference existed. At 2 years, renal function in the pediatric-donor group remained significantly better than in the adult-donor group. Hematocrit levels as a measure of erythropoiesis were similar for single pediatric, paired pediatric, and adult-donor recipients.

CONCLUSIONS

Kidneys from cadaveric donors < or = 5 years of age are suitable for transplantation into adults. Pediatric kidneys provide excellent renal function despite an initially tremendous disparity between renal mass and recipient body mass. Rapid true renal growth probably occurs. No appreciable advantage is achieved by using two pediatric kidneys for a single recipient.

Liver transplantation in infants younger than 1 year of age

OBJECTIVE

The authors report on experience with liver transplantation for infants younger than 1 year of age.

SUMMARY BACKGROUND DATA

Over the last 15 years, orthotopic liver transplant has become the only lifesaving procedure available for infants with end-stage liver disease. Many transplant centers initially required infants to reach a specific weight or age to minimize morbidity and mortality. Size-appropriate infant donors also were uncommon. As a result, many children, in the first few years of life, died of their disease. The availability of reduced-size cadaveric and living-related liver transplants has offered the ability to transplant the young infant with liver failure.

METHODS

The authors instituted a program to aggressively transplant infants with liver failure in the first year of life using both cadaveric and living-related liver donors.

RESULTS

Between June 1991 and January 1995, 13 infants were transplanted for rapidly progressive liver failure. Infant age ranged from 4 to 11 months (mean, 7.5 months). The cause of liver failure included biliary atresia (11), alpha 1-antitrypsin deficiency (1), and liver failure secondary to echovirus 7 (1). The United Network for Organ Sharing status at the time of transplant ranged from status 4, intensive care unit bound (4 patients); status 3, hospitalized (4 patients); or status 2, failing at home (5 patients). Six patients (46%) received cadaveric whole organ (2) or segmental transplants (4). Seven patients (54%) received left lateral segment living-related transplants from parental donors. After operation, patients received cyclosporine or FK506-based immunosuppression. Three patients (23%) required four retransplants (two cadaveric for primary nonfunction; one living-related for graft thrombosis in the face of fungal infection and bile leak). Postoperative complications included primary nonfunction (15%), rejection (85%), graft vascular thrombosis (15%, two of three revascularized successfully), bacterial and fungal infections (77%), and viral infections (46%). Epstein-Barr virus-associated lymphoproliferative developed in two patients (15%). Intestinal perforation requiring reoperation developed in two patients (15%). Bile leaks requiring reoperation or transhepatic stinting or both developed in three patients (23%). Two patients died in the perioperative period (< 1 month) from a combination of primary nonfunction or graft thrombosis and sepsis. Overall survival was 85%, ranging from 11.0 months to 4.5 years.

CONCLUSIONS

Orthotopic liver transplantation in infants younger than 1 year of age poses significant challenges from technical and infectious complications. Despite these barriers, overall patient survival is comparable to that of older children and adults.

Laparoscopic live donor nephrectomy

A laparoscopic live-donor nephrectomy was performed on a 40-year-old man. The kidney was removed intact via a 9-cm infraumbilical midline incision. Warm ischemia was limited to less than 5 min. Immediately upon revascularization, the allograft produced urine. By the second postoperative day, the recipient's serum creatinine had decreased to 0.7 mg/dl. The donor's postoperative course was uneventful. He experienced minimal discomfort and was discharged home on the first postoperative day. We conclude that laparoscopic donor nephrectomy is feasible. It can be performed without apparent deleterious effects to either the donor or the recipient. The limited discomfort and rapid convalescence enjoyed by our patient indicate that this technique may prove to be advantageous.

Recombinant human müllerian inhibiting substance inhibits epidermal growth factor receptor tyrosine kinase

Autophosphorylation of the epidermal growth factor (EGF) receptor in A-431 cells and plasma membrane fractions was inhibited by partially purified recombinant human Müllerian Inhibiting Substance (MIS). Immunoprecipitation of the EFG receptor using anti-EGF receptor or anti-phosphotyrosine antibodies, and phosphoamino acid analysis of this receptor, demonstrated that MIS specifically inhibited EGF-induced tyrosine phosphorylation. Inhibition of EGF receptor autophosphorylation by MIS in membrane preparations was not affected by increasing concentrations of EGF, manganese or [gamma-(32)P] ATP. Thus, it is unlikely that MIS competes for EGF binding sites or sequesters substrate. Immunoabsorption of MIS with anti-human MIS antibody blocked the MIS inhibition of EGF receptor autophosphorylation, indicating that the inhibition was due to MIS. Our data suggest that MIS regulates the activity of the EGF receptor tyrosine kinase in A-431 cells.

Imperforate anus with long but apparent low fistula in females

Despite the low entry of the rectum into the vagina in some females with imperforate anus, the fistula may be deceivingly long. This variation should alert the surgeon to measure the fistula prior to anoplasty. During surgery, biopsies of the mobilized segment should also be done to assure that cloacal-transitional lined structures have been removed and rectal mucosa anastamosed to the perineum.