DNAJB1-PRKACA fusion protein-regulated LINC00473 promotes tumor growth and alters mitochondrial fitness in fibrolamellar carcinoma.

Fibrolamellar carcinoma (FLC) is a rare liver cancer that disproportionately affects adolescents and young adults. Currently, no standard of care is available and there remains a dire need for new therapeutics. Most patients harbor the fusion oncogene DNAJB1-PRKACA (DP fusion), but clinical inhibitors are not yet developed and it is critical to identify downstream mediators of FLC pathogenesis. Here, we identify long noncoding RNA LINC00473 among the most highly upregulated genes in FLC tumors and determine that it is strongly suppressed by RNAi-mediated inhibition of the DP fusion in FLC tumor epithelial cells. We show by loss- and gain-of-function studies that LINC00473 suppresses apoptosis, increases the expression of FLC marker genes, and promotes FLC growth in cell-based and in vivo disease models. Mechanistically, LINC00473 plays an important role in promoting glycolysis and altering mitochondrial activity. Specifically, LINC00473 knockdown leads to increased spare respiratory capacity, which indicates mitochondrial fitness. Overall, we propose that LINC00473 could be a viable target for this devastating disease.

Tumor hepatitis B virus RNA identifies a clinically and molecularly distinct subset of hepatocellular carcinoma.

Hepatitis B virus (HBV) infection contributes to hepatocellular carcinoma (HCC) initiation and is associated with worse outcomes. Many prior studies of HBV-related HCC have not accounted for potential heterogeneity among HBV-related tumors by assessing whether HBV activity is present in tumor tissue. Here, we measured tumor HBV RNA, a proxy for viral activity, and investigated the association between HBV RNA status and several clinicogenomic characteristics. We obtained clinical, mutation, RNA-Seq and survival data for 439 HCC tumors from The Cancer Genome Atlas and International Cancer Genome Consortium. Tumors were classified as HBV RNA positive if they harbored >1 HBV RNA read per million human reads. We investigated the association between HBV RNA status and nonsynonymous somatic mutations, gene set expression, homologous recombination deficiency (HRD) score and mutation-specific survival. HBV RNA positive status was associated with higher nonsynonymous mutation rates of multiple genes, including TP53 and CDKN2A, while HBV RNA negative status was associated with higher nonsynonymous BAP1 mutation rate. HBV RNA positive status was also associated with increased transcription of genes involved in multiple DNA damage repair pathways, genes upregulated by MYC and mTORC1, and genes overexpressed in several HCC subclasses associated with a proliferative phenotype. Further, HBV RNA positive status was associated with increased three-biomarker HRD score (22.2 for HBV RNA+ vs. 16.0 for HBV RNA-). Finally, HBV RNA status was associated with multiple mutation-specific survival differences, including decreased survival for HBV RNA positive patients with nonsynonymous KEAP1 mutations compared to those without (hazard ratio 4.26). HCC tumors harboring genomic evidence of HBV activity therefore constitute a distinct HCC subset characterized by specific differences in nonsynonymous mutations, gene set expression, three-biomarker HRD score and mutation-specific survival.

A Multicenter Randomized Three-Arm Phase II Study of (1) Everolimus, (2) Estrogen Deprivation Therapy (EDT) with Leuprolide + Letrozole, and (3) Everolimus + EDT in Patients with Unresectable Fibrolamellar Carcinoma.

LESSONS LEARNED: FLC is a complex cancer with many implicated oncogenic pathways. Single or dual targeting does not appear to alter the natural history of the cancer, and novel therapeutics are needed. Estrogen deprivation therapy with letrozole and leuprolide, alone or in combination with the mTOR inhibitor, everolimus, did not demonstrate clinical activity in advanced fibrolamellar carcinoma. The study drugs were well tolerated when administered as single agents or in combination in this patient population. This study demonstrates that, despite the rarity of FLC, multicenter therapeutic clinical trials are feasible and support the value of this consortium. BACKGROUND: Fibrolamellar carcinoma (FLC) is an uncommon malignancy in young people and is sometimes associated with pregnancy and oral contraceptive use. Immunohistochemical staining and genetic profiling of FLC tumor specimens have revealed aromatase overexpression. The overexpression of mTOR and S6 kinase has been noted in 25% of FLC. On the basis of interaction between estrogen and the PI3K/Akt/mTOR pathway, we hypothesized that suppression of estrogen and mTOR signaling could have antineoplastic activity in FLC. METHODS: Patients were randomized to arm A (everolimus), arm B (letrozole/leuprolide; estrogen deprivation therapy [EDT]), or arm C (everolimus/letrozole/leuprolide). Upon disease progression, patients in arm A or B could proceed to part 2 (everolimus/letrozole/leuprolide). The primary endpoint was progression-free survival (PFS) at 6 months (PFS6) assessed using a Simon's minimax two-stage design, hypothesizing an improvement in PFS6 from 40% to 64% with the study regimen. RESULTS: Twenty-eight patients were enrolled. An unplanned analysis was performed because of perceived concern for lack of efficacy. Stable disease was observed in 9 of 26 evaluable patients (35%). PFS6 was 0%. Median overall survival (OS) was 12.4 months (95% confidence interval [CI], 7.4-20.9) for the whole study cohort. Grade 3 adverse events in ≥10% of patients were nausea (11%), vomiting (11%), anemia (11%), elevated aspartate transaminase (AST; 32%), alanine transaminase (ALT; 36%), and alkaline phosphatase (14%). All 28 patients experienced an event for PFS outcome, and four deaths were due to disease progression. CONCLUSION: Neither EDT nor mTOR inhibition improved outcomes in FLC. Other treatment strategies are needed.

Phase II Multicenter, Open-Label Study of Oral ENMD-2076 for the Treatment of Patients with Advanced Fibrolamellar Carcinoma.

LESSONS LEARNED: The fibrolamellar carcinoma-associated DNAJB1-PRKACA gene fusion transcript RNA codes for the catalytic domain of protein kinase A and, thus, overexpression of Aurora kinase A. ENMD-2076 showed a favorable toxicity profile. The limited results, one patient (3%) with a partial response and 57% of patients with stable disease, do not support further evaluation of ENMD-2076 as single agent. Future studies will depend on the simultaneous targeting approach of DNAJB1-PRKACA and the critical downstream components. BACKGROUND: Fibrolamellar carcinoma (FLC) represents approximately 0.85% of liver cancers. The associated DNAJB1-PRKACA gene fusion transcript RNA codes for the catalytic domain of protein kinase A and overexpression of Aurora kinase A (AURKA). ENMD-2076 is a selective anti-AURKA inhibitor. METHODS: Patients aged >12 years with pathologically confirmed incurable FLC, with measurable disease, Eastern Cooperative Oncology Group performance status 0-2 or Lansky 70-100, and adequate organ function were eligible. Patients were prescribed ENMD-2076 based on body surface area. The primary endpoint was overall objective response rate by RECIST v1.1, with a null hypothesis of true response rate of 2% versus one-sided alternative of 15%. Secondary endpoints included 6-month progression-free survival (PFS) rate (Fig. 1), median PFS, time to progression (TTP), and overall survival (OS). Safety was evaluated throughout the study. RESULTS: Of 35 patients who enrolled and received treatment, 1 (3%) had a partial response (PR) and 20 (57%) had stable disease (SD). Median TTP, PFS, and OS were 5, 3.9, and 19 months, respectively. The most frequently reported drug-related serious adverse event was hypertension in three patients. Three deaths were reported on-study-two due to disease progression and one due to pulmonary embolism not related to ENMD-2076. CONCLUSION: The study provided no rationale for further studying ENMD-2076 as a single agent in FLC.

Sampling strategies to capture single-cell heterogeneity.

Advances in single-cell technologies have highlighted the prevalence and biological significance of cellular heterogeneity. A critical question researchers face is how to design experiments that faithfully capture the true range of heterogeneity from samples of cellular populations. Here we develop a data-driven approach, illustrated in the context of image data, that estimates the sampling depth required for prospective investigations of single-cell heterogeneity from an existing collection of samples.

Kinome rewiring reveals AURKA limits PI3K-pathway inhibitor efficacy in breast cancer.

Dysregulation of the PI3K-AKT-mTOR signaling network is a prominent feature of breast cancers. However, clinical responses to drugs targeting this pathway have been modest, possibly because of dynamic changes in cellular signaling that drive resistance and limit drug efficacy. Using a quantitative chemoproteomics approach, we mapped kinome dynamics in response to inhibitors of this pathway and identified signaling changes that correlate with drug sensitivity. Maintenance of AURKA after drug treatment was associated with resistance in breast cancer models. Incomplete inhibition of AURKA was a common source of therapy failure, and combinations of PI3K, AKT or mTOR inhibitors with the AURKA inhibitor MLN8237 were highly synergistic and durably suppressed mTOR signaling, resulting in apoptosis and tumor regression in vivo. This signaling map identifies survival factors whose presence limits the efficacy of targeted therapies and reveals new drug combinations that may unlock the full potential of PI3K-AKT-mTOR pathway inhibitors in breast cancer.

Nivolumab in patients with advanced hepatocellular carcinoma and Child-Pugh class B cirrhosis: Safety and clinical outcomes in a retrospective case series.

BACKGROUND: Nivolumab demonstrated durable responses and safety in patients with hepatocellular carcinoma (HCC) with Child-Pugh class A cirrhosis in the CheckMate 040 trial, with rates of hepatotoxicity that were similar to those of non-HCC populations. To the authors' knowledge, the safety and efficacy of nivolumab has not been established in patients with Child-Pugh class B (CPB) cirrhosis, a population with limited therapeutic options and a poor prognosis. METHODS: The authors conducted a retrospective case series of patients with advanced HCC and CPB cirrhosis who were treated with nivolumab and enrolled in the University of California at San Francisco Hepatobiliary Tissue Bank and Registry. Safety endpoints included rates of grade ≥3 adverse events (AEs) (graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.03]) and serious AEs, immune-related AEs (irAE), steroid requirement, and discontinuation. Efficacy endpoints included time on treatment, the objective response rate according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, overall survival, and progression-free survival. RESULTS: A total of 18 patients were included, with 72% of them (13 of 18 patients) previously treated with sorafenib. The majority of patients (94%; 17 of 18 patients) experienced a grade ≥3 AE, with treatment-related grade ≥3 AEs reported in 28% of patients (5 of 18 patients). irAEs were reported to occur in approximately 50% of patients (9 of 18 patients), and 28% (5 of 18 patients) required steroids. Treatment-related AEs required discontinuation in 4 patients (22%). The median time on treatment was 2.3 months (95% CI, 1.9 months to upper bound not estimable). The objective response rate was 17% (3 of 18 patients), including 2 partial responses and 1 complete response. The median overall survival from the time of nivolumab initiation was 5.9 months (95% CI, 3 months to upper bound not estimable), with a median progression-free survival of 1.6 months (95% CI, 1.4-3.5 months). CONCLUSIONS: Patients with CPB HCC experienced high rates of AEs, although the frequency of irAEs was similar to that of patients with Child-Pugh class A HCC in the CheckMate 040 trial. A subset of patients experienced prolonged tumor responses. Nivolumab warrants further study in patients with CPB HCC.

Loss of Fbxw7 synergizes with activated Akt signaling to promote c-Myc dependent cholangiocarcinogenesis.

BACKGROUND & AIMS: The ubiquitin ligase F-box and WD repeat domain-containing 7 (FBXW7) is recognized as a tumor suppressor in many cancer types due to its ability to promote the degradation of numerous oncogenic target proteins. Herein, we aimed to elucidate its role in intrahepatic cholangiocarcinoma (iCCA). METHODS: Herein, we first confirmed that FBXW7 gene expression was reduced in human iCCA specimens. To identify the molecular mechanisms by which FBXW7 dysfunction promotes cholangiocarcinogenesis, we generated a mouse model by hydrodynamic tail vein injection of Fbxw7ΔF, a dominant negative form of Fbxw7, either alone or in association with an activated/myristylated form of AKT (myr-AKT). We then confirmed the role of c-MYC in human iCCA cell lines and its relationship to FBXW7 expression in human iCCA specimens. RESULTS: FBXW7 mRNA expression is almost ubiquitously downregulated in human iCCA specimens. While forced overexpression of Fbxw7ΔF alone did not induce any appreciable abnormality in the mouse liver, co-expression with AKT triggered cholangiocarcinogenesis and mice had to be euthanized by 15 weeks post-injection. At the molecular level, a strong induction of Fbxw7 canonical targets, including Yap, Notch2, and c-Myc oncoproteins, was detected. However, only c-MYC was consistently confirmed as a FBXW7 target in human CCA cell lines. Most importantly, selected ablation of c-Myc completely impaired iCCA formation in AKT/Fbxw7ΔF mice, whereas deletion of either Yap or Notch2 only delayed tumorigenesis in the same model. In human iCCA specimens, an inverse correlation between the expression levels of FBXW7 and c-MYC transcriptional activity was observed. CONCLUSIONS: Downregulation of FBXW7 is ubiquitous in human iCCA and cooperates with AKT to induce cholangiocarcinogenesis in mice via c-Myc-dependent mechanisms. Targeting c-MYC might represent an innovative therapy against iCCA exhibiting low FBXW7 expression. LAY SUMMARY: There is mounting evidence that FBXW7 functions as a tumor suppressor in many cancer types, including intrahepatic cholangiocarcinoma, through its ability to promote the degradation of numerous oncoproteins. Herein, we have shown that the low expression of FBXW7 is ubiquitous in human cholangiocarcinoma specimens. This low expression is correlated with increased c-MYC activity, leading to tumorigenesis. Our findings suggest that targeting c-MYC might be an effective treatment for intrahepatic cholangiocarcinoma.

An Optimized Chromatographic Strategy for Multiplexing In Parallel Reaction Monitoring Mass Spectrometry: Insights from Quantitation of Activated Kinases.

Reliable quantitation of protein abundances in defined sets of cellular proteins is critical to numerous biological applications. Traditional immunodetection-based methods are limited by the quality and availability of specific antibodies, especially for site-specific post-translational modifications. Targeted proteomic methods, including the recently developed parallel reaction monitoring (PRM) mass spectrometry, have enabled accurate quantitative measurements of up to a few hundred specific target peptides. However, the degree of practical multiplexing in label-free PRM workflows remains a significant limitation for the technique. Here we present a strategy for significantly increasing multiplexing in label-free PRM that takes advantage of the superior separation characteristics and retention time stability of meter-scale monolithic silica-C18 column-based chromatography. We show the utility of the approach in quantifying kinase abundances downstream of previously developed active kinase enrichment methodology based on multidrug inhibitor beads. We examine kinase activation dynamics in response to three different MAP kinase inhibitors in colorectal carcinoma cells and demonstrate reliable quantitation of over 800 target peptides from over 150 kinases in a single label-free PRM run. The kinase activity profiles obtained from these analyses reveal compensatory activation of TGF-ß family receptors as a response to MAPK blockade. The gains achieved using this label-free PRM multiplexing strategy will benefit a wide array of biological applications.

Hybrid Capture-Based Tumor Sequencing and Copy Number Analysis to Confirm Origin of Metachronous Metastases in BRCA1-Mutant Cholangiocarcinoma Harboring a Novel YWHAZ-BRAF Fusion.

Biliary tract cancers such as cholangiocarcinoma represent a heterogeneous group of cancers that can be difficult to diagnose. Recent comprehensive genomic analyses in large cholangiocarcinoma cohorts have defined important molecular subgroups within cholangiocarcinoma that may relate to anatomic location and etiology [1], [2], [3], [4] and may predict responsiveness to targeted therapies in development [5], [6], [7]. These emerging data highlight the potential for tumor genomics to inform diagnosis and treatment options in this challenging tumor type. We report the case of a patient with a germline BRCA1 mutation who presented with a cholangiocarcinoma driven by the novel YWHAZ-BRAF fusion. Hybrid capture-based DNA sequencing and copy number analysis performed as part of clinical care demonstrated that two later-occurring tumors were clonally derived from the primary cholangiocarcinoma rather than distinct new primaries, revealing an unusual pattern of late metachronous metastasis. We discuss the clinical significance of these genetic alterations and their relevance to therapeutic strategies. KEY POINTS: Hybrid capture-based next-generation DNA sequencing assays can provide diagnostic clarity in patients with unusual patterns of metastasis and recurrence in which the pathologic diagnosis is ambiguous.To our knowledge, this is the first reported case of a YWHAZ-BRAF fusion in pancreaticobiliary cancer, and a very rare case of cholangiocarcinoma in the setting of a germline BRCA1 mutation.The patient's BRCA1 mutation and YWHAZ-BRAF fusion constitute potential targets for future therapy.

Identification of Chemical Inhibitors of ß-Catenin-Driven Liver Tumorigenesis in Zebrafish.

Hepatocellular carcinoma (HCC) is one of the most lethal human cancers. The search for targeted treatments has been hampered by the lack of relevant animal models for the genetically diverse subsets of HCC, including the 20-40% of HCCs that are defined by activating mutations in the gene encoding ß-catenin. To address this chemotherapeutic challenge, we created and characterized transgenic zebrafish expressing hepatocyte-specific activated ß-catenin. By 2 months post fertilization (mpf), 33% of transgenic zebrafish developed HCC in their livers, and 78% and 80% of transgenic zebrafish showed HCC at 6 and 12 mpf, respectively. As expected for a malignant process, transgenic zebrafish showed significantly decreased mean adult survival compared to non-transgenic control siblings. Using this novel transgenic model, we screened for druggable pathways that mediate ß-catenin-induced liver growth and identified two c-Jun N-terminal kinase (JNK) inhibitors and two antidepressants (one tricyclic antidepressant, amitriptyline, and one selective serotonin reuptake inhibitor) that suppressed this phenotype. We further found that activated ß-catenin was associated with JNK pathway hyperactivation in zebrafish and in human HCC. In zebrafish larvae, JNK inhibition decreased liver size specifically in the presence of activated ß-catenin. The ß-catenin-specific growth-inhibitory effect of targeting JNK was conserved in human liver cancer cells. Our other class of hits, antidepressants, has been used in patient treatment for decades, raising the exciting possibility that these drugs could potentially be repurposed for cancer treatment. In support of this proposal, we found that amitriptyline decreased tumor burden in a mouse HCC model. Our studies implicate JNK inhibitors and antidepressants as potential therapeutics for ß-catenin-induced liver tumors.

Pan-mTOR inhibitor MLN0128 is effective against intrahepatic cholangiocarcinoma in mice.

BACKGROUND & AIMS: Intrahepatic cholangiocarcinoma (ICC) is a lethal malignancy without effective treatment options. MLN0128, a second generation pan-mTOR inhibitor, shows efficacy for multiple tumor types. We evaluated the therapeutic potential of MLN0128 vs. gemcitabine/oxaliplatin in a novel ICC mouse model. METHODS: We established a novel ICC mouse model via hydrodynamic transfection of activated forms of AKT (myr-AKT) and Yap (YapS127A) protooncogenes (that will be referred to as AKT/YapS127A). Genetic approaches were applied to study the requirement of mTORC1 and mTORC2 in mediating AKT/YapS127A driven tumorigenesis. Gemcitabine/oxaliplatin and MLN0128 were administered in AKT/YapS127A tumor-bearing mice to study their anti-tumor efficacy in vivo. Multiple human ICC cell lines were used for in vitro experiments. Hematoxylin and eosin staining, immunohistochemistry and immunoblotting were applied for the characterization and mechanistic study. RESULTS: Co-expression of myr-AKT and YapS127A promoted ICC development in mice. Both mTORC1 and mTORC2 complexes were required for AKT/YapS127A ICC development. Gemcitabine/oxaliplatin had limited efficacy in treating late stage AKT/YapS127A ICC. In contrast, partial tumor regression was achieved when MLN0128 was applied in the late stage of AKT/YapS127A cholangiocarcinogenesis. Furthermore, when MLN0128 was administered in the early stage of AKT/YapS127A carcinogenesis, it led to disease stabilization. Mechanistically, MLN0128 efficiently inhibited AKT/mTOR signaling both in vivo and in vitro, inducing strong ICC cell apoptosis and only marginally affecting proliferation. CONCLUSIONS: This study suggests that mTOR kinase inhibitors may be beneficial for the treatment of ICC, even in tumors that are resistant to standard of care chemotherapeutics, such as gemcitabine/oxaliplatin-based regimens, especially in the subset of tumors exhibiting activated AKT/mTOR cascade. Lay summary: We established a novel mouse model of intrahepatic cholangiocarcinoma (ICC). Using this new preclinical model, we evaluated the therapeutic potential of mTOR inhibitor MLN0128 vs. gemcitabine/oxaliplatin (the standard chemotherapy for ICC treatment). Our study shows the anti-neoplastic potential of MLN0128, suggesting that it may be superior to gemcitabine/oxaliplatin-based chemotherapy for the treatment of ICC, especially in the tumors exhibiting activated AKT/mTOR cascade.

HIF and c-Myc: sibling rivals for control of cancer cell metabolism and proliferation.

O(2) deprivation (hypoxia) and cellular proliferation engage opposite cellular pathways, yet often coexist during tumor growth. The ability of cells to grow during hypoxia results in part from crosstalk between hypoxia-inducible factors (HIFs) and the proto-oncogene c-Myc. Acting alone, HIF and c-Myc partially regulate complex adaptations undertaken by tumor cells growing in low O(2). However, acting in concert these transcription factors reprogram metabolism, protein synthesis, and cell cycle progression, to "fine tune" adaptive responses to hypoxic environments.

HIF-2alpha promotes hypoxic cell proliferation by enhancing c-myc transcriptional activity.

HIF-2alpha promotes von Hippel-Lindau (VHL)-deficient renal clear cell carcinoma (RCC) tumorigenesis, while HIF-1alpha inhibits RCC growth. As HIF-1alpha antagonizes c-Myc function, we hypothesized that HIF-2alpha might enhance c-Myc activity. We demonstrate here that HIF-2alpha promotes cell-cycle progression in hypoxic RCCs and multiple other cell lines. This correlates with enhanced c-Myc promoter binding, transcriptional effects on both activated and repressed target genes, and interactions with Sp1, Miz1, and Max. Finally, HIF-2alpha augments c-Myc transformation of primary mouse embryo fibroblasts (MEFs). Enhanced c-Myc activity likely contributes to HIF-2alpha-mediated neoplastic progression following loss of the VHL tumor suppressor and influences the behavior of hypoxic tumor cells.

Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma.

The DNAJ-PKAc fusion kinase is a defining feature of fibrolamellar carcinoma (FLC). FLC tumors are notoriously resistant to standard chemotherapies, with aberrant kinase activity assumed to be a contributing factor. By combining proximity proteomics, biochemical analyses, and live-cell photoactivation microscopy, we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates, including proteins involved in translation and the anti-apoptotic factor Bcl-2-associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Tissue samples from patients with FLC exhibit increased levels of BAG2 in primary and metastatic tumors. Furthermore, drug studies implicate the DNAJ-PKAc/Hsp70/BAG2 axis in potentiating chemotherapeutic resistance. We find that the Bcl-2 inhibitor navitoclax enhances sensitivity to etoposide-induced apoptosis in cells expressing DNAJ-PKAc. Thus, our work indicates BAG2 as a marker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.

Systemic Therapy for Advanced Hepatocellular Carcinoma: ASCO Guideline Update.

PURPOSE: To update an evidence-based guideline to assist in clinical decision-making for patients with advanced hepatocellular carcinoma (HCC). METHODS: ASCO convened an Expert Panel to update the 2020 guideline on systemic therapy for HCC. The panel updated the systematic review to include randomized controlled trials (RCTs) published through October 2023 and updated recommendations. RESULTS: Ten new RCTs met the inclusion criteria and were added to the evidence base. RECOMMENDATIONS: Atezolizumab + bevacizumab (atezo + bev) or durvalumab + tremelimumab (durva + treme) may be offered first-line for patients with advanced HCC, Child-Pugh class A liver disease, and Eastern Cooperative Oncology Group performance status 0-1. Where there are contraindications to these therapies, sorafenib, lenvatinib, or durvalumab may be offered first-line. Following first-line treatment with atezo + bev, second-line therapy with a tyrosine kinase inhibitor (TKI), ramucirumab (for patients with alpha-fetoprotein [AFP] ≥400 ng/mL), durva + treme, or nivolumab + ipilimumab (nivo + ipi) may be recommended for appropriate candidates. Following first-line therapy with durva + treme, second-line therapy with a TKI is recommended. Following first-line treatment with sorafenib or lenvatinib, second-line therapy options include cabozantinib, regorafenib for patients who previously tolerated sorafenib, ramucirumab (AFP ≥400 ng/mL), nivo + ipi, or durvalumab; atezo + bev or durva + treme may be considered for patients who did not have access to these therapies in the first-line setting, and do not have contraindications. Pembrolizumab or nivolumab are also options for appropriate patients following sorafenib or lenvatinib. Third-line therapy may be considered in Child-Pugh class A patients with good PS, using one of the agents listed previously that has a nonidentical mechanism of action with previously received therapy. A cautious approach to systemic therapy is recommended for patients with Child-Pugh class B advanced HCC. Further guidance on choosing between options is included within the guideline.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

New Opportunities to Individualize Frontline Therapy in Advanced Stages of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is a leading cause of cancer death globally and is rising in incidence. Until recently, treatment options for patients with advanced stages of HCC have been limited to antiangiogenic therapies with modest improvements in overall survival. The emerging role of immunotherapy with immune checkpoint inhibitors (ICI) in oncology has led to a rapid expansion in treatment options and improvements in outcomes for patients with advanced stages of HCC. Recent clinical trials have shown meaningful survival improvement in patients treated with the combination of bevacizumab and atezolizumab, as well as with the combination of tremelimumab with durvalumab, resulting in regulatory approvals of these regimens as frontline therapy. Beyond improvements in overall survival, ICI-based combination regimens achieve higher rates of durable treatment response than multikinase inhibitors and have favorable side effect profiles. With the emergence of doublet anti-angiogenic and immune checkpoint inhibitor (ICI) and dual ICI combinations, individualized therapy is now possible for patients based on co-morbidity profiles and other factors. These more potent systemic therapies are also being tested in earlier stages of disease and in combination with loco-regional therapies such as trans-arterial chemoembolization and stereotactic body radiotherapy. We summarize these advances and emerging therapeutic combinations currently in clinical trials.

Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma.

The DNAJ-PKAc fusion kinase is a defining feature of the adolescent liver cancer fibrolamellar carcinoma (FLC). A single lesion on chromosome 19 generates this mutant kinase by creating a fused gene encoding the chaperonin binding domain of Hsp40 (DNAJ) in frame with the catalytic core of protein kinase A (PKAc). FLC tumors are notoriously resistant to standard chemotherapies. Aberrant kinase activity is assumed to be a contributing factor. Yet recruitment of binding partners, such as the chaperone Hsp70, implies that the scaffolding function of DNAJ- PKAc may also underlie pathogenesis. By combining proximity proteomics with biochemical analyses and photoactivation live-cell imaging we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates. One validated DNAJ-PKAc target is the Bcl-2 associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Immunoblot and immunohistochemical analyses of FLC patient samples correlate increased levels of BAG2 with advanced disease and metastatic recurrences. BAG2 is linked to Bcl-2, an anti-apoptotic factor that delays cell death. Pharmacological approaches tested if the DNAJ- PKAc/Hsp70/BAG2 axis contributes to chemotherapeutic resistance in AML12 DNAJ-PKAc hepatocyte cell lines using the DNA damaging agent etoposide and the Bcl-2 inhibitor navitoclax. Wildtype AML12 cells were susceptible to each drug alone and in combination. In contrast, AML12 DNAJ-PKAc cells were moderately affected by etoposide, resistant to navitoclax, but markedly susceptible to the drug combination. These studies implicate BAG2 as a biomarker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.

Defining incidence and complications of fibrolamellar liver cancer through tiered computational analysis of clinical data.

The incidence and biochemical consequences of rare tumor subtypes are often hard to study. Fibrolamellar liver cancer (FLC) is a rare malignancy affecting adolescents and young adults. To better characterize the incidence and biochemical consequences of this disease, we combined a comprehensive analysis of the electronic medical record and national payer data and found that FLC incidence is likely five to eight times higher than previous estimates. By employing unsupervised learning on clinical laboratory data from patients with hyperammonemia, we find that FLC-associated hyperammonemia mirrors metabolic dysregulation in urea cycle disorders. Our findings demonstrate that advanced computational analysis of rich clinical datasets can provide key clinical and biochemical insights into rare cancers.

Preclinical evidence for anaplastic lymphoma kinase inhibitors as novel therapeutic treatments for cholangiocarcinoma.

Introduction: Bile duct cancer (cholangiocarcinoma, CCA) has a poor prognosis for patients, and despite recent advances in targeted therapies for other cancer types, it is still treated with standard chemotherapy. Anaplastic lymphoma kinase (ALK) has been shown to be a primary driver of disease progression in lung cancer, and ALK inhibitors are effective therapeutics in aberrant ALK-expressing tumors. Aberrant ALK expression has been documented in CCA, but the use of ALK inhibitors has not been investigated. Using CCA cell lines and close-to-patient primary cholangiocarcinoma cells, we investigated the potential for ALK inhibitors in CCA. Methods: ALK, cMET, and ROS1 expression was determined in CCA patient tissue by immunohistochemistry and digital droplet polymerase chain reaction, and that in cell lines was determined by immunoblot and immunofluorescence. The effect on cell viability and mechanism of action of ALK, cMet, and ROS1 inhibitors was determined in CCA cell lines. To determine whether ceritinib could affect primary CCA cells, tissue was taken from four patients with biliary tract cancer, without ALK rearrangement, mutation, or overexpression, and grown in three-dimensional tumor growth assays in the presence or absence of humanized mesenchymal cells. Results: ALK and cMet but not ROS were both upregulated in CCA tissues and cell lines. Cell survival was inhibited by crizotinib, a c-met/ALK/ROS inhibitor. To determine the mechanism of this effect, we tested c-Met-specific and ALK/ROS-specific inhibitors, capmatinib and ceritinib, respectively. Whereas capmatinib did not affect cell survival, ceritinib dose-dependently inhibited survival in all cell lines, with IC50 ranging from 1 to 9 µM and co-treatments with gemcitabine and cisplatin further sensitized cells, with IC50 ranging from IC50 0.60 to 2.32 µM. Ceritinib did not inhibit cMet phosphorylation but did inhibit ALK phosphorylation. ALK was not mutated in any of these cell lines. Only ceritinib inhibited 3D growth of all four patient samples below mean peak serum concentration, in the presence and absence of mesenchymal cells, whereas crizotinib and capmatinib failed to do this. Ceritinib appeared to exert its effect more through autophagy than apoptosis. Discussion: These results indicate that ceritinib or other ALK/ROS inhibitors could be therapeutically useful in cholangiocarcinoma even in the absence of aberrant ALK/ROS1 expression.