Alterations in the Rho pathway contribute to Epstein-Barr virus-induced lymphomagenesis in immunosuppressed environments.

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphomas (EBV+-DLBLs) tend to occur in immunocompromised patients, such as the elderly or those undergoing solid organ transplantation. The pathogenesis and genomic characteristics of EBV+-DLBLs are largely unknown because of the limited availability of human samples and lack of experimental animal models. We observed the development of 25 human EBV+-DLBLs during the engraftment of gastric adenocarcinomas into immunodeficient mice. An integrated genomic analysis of the human-derived EBV+-DLBLs revealed enrichment of mutations in Rho pathway genes, including RHPN2, and Rho pathway transcriptomic activation. Targeting the Rho pathway using a Rho-associated protein kinase (ROCK) inhibitor, fasudil, markedly decreased tumor growth in EBV+-DLBL patient-derived xenograft (PDX) models. Thus, alterations in the Rho pathway appear to contribute to EBV-induced lymphomagenesis in immunosuppressed environments.

Genomic alterations in BCL2L1 and DLC1 contribute to drug sensitivity in gastric cancer.

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. Recent high-throughput analyses of genomic alterations revealed several driver genes and altered pathways in GC. However, therapeutic applications from genomic data are limited, largely as a result of the lack of druggable molecular targets and preclinical models for drug selection. To identify new therapeutic targets for GC, we performed array comparative genomic hybridization (aCGH) of DNA from 103 patients with GC for copy number alteration (CNA) analysis, and whole-exome sequencing from 55 GCs from the same patients for mutation profiling. Pathway analysis showed recurrent alterations in the Wnt signaling [APC, CTNNB1, and DLC1 (deleted in liver cancer 1)], ErbB signaling (ERBB2, PIK3CA, and KRAS), and p53 signaling/apoptosis [TP53 and BCL2L1 (BCL2-like 1)] pathways. In 18.4% of GC cases (19/103), amplification of the antiapoptotic gene BCL2L1 was observed, and subsequently a BCL2L1 inhibitor was shown to markedly decrease cell viability in BCL2L1-amplified cell lines and in similarly altered patient-derived GC xenografts, especially when combined with other chemotherapeutic agents. In 10.9% of cases (6/55), mutations in DLC1 were found and were also shown to confer a growth advantage for these cells via activation of Rho-ROCK signaling, rendering these cells more susceptible to a ROCK inhibitor. Taken together, our study implicates BCL2L1 and DLC1 as potential druggable targets for specific subsets of GC cases.

Clinical effect of omalizumab as an adjuvant treatment to rituximab in patient with refractory bullous pemphigoid.

Patients with refractory bullous pemphigoid (BP) achieve remission after rituximab treatment but require high-dose systemic corticosteroids until the remission. The aim of this retrospective study was to examine the clinical efficacy of omalizumab as an adjuvant treatment to rituximab in patients with refractory BP. Patients with BP receiving treatment with either rituximab monotherapy or rituximab plus omalizumab were considered for the study. The total dose of corticosteroids received for 60 days after administration of rituximab, mortality and relapse rates, and median time to relapse were also investigated. Of 49 patients included in the study, 25 received rituximab monotherapy and 17 received the combination therapy with rituximab and omalizumab. The rituximab plus omalizumab group showed shorter time to disease control with minimal treatment (15 days vs. 67.5 days, p < 0.001) and lower corticosteroid dose for 60 days after administration of rituximab (698.4 mg vs. 1087.4 mg of methylprednisolone, p < 0.001) compared to the rituximab monotherapy group. The results of this study suggest that combination therapy with rituximab and omalizumab can achieve disease control status faster than the rituximab monotherapy, reducing the total dose of corticosteroids.

Targeting antioxidant enzymes enhances the therapeutic efficacy of the BCL-XL inhibitor ABT-263 in KRAS-mutant colorectal cancers.

Cancer chemotherapeutic drugs exert cytotoxic effects by modulating intracellular reactive oxygen species (ROS) levels. However, whether ROS modulates the efficacy of targeted therapeutics remains poorly understood. Previously, we reported that upregulation of the anti-apoptotic protein, BCL-XL, by KRAS activating mutations was a potential target for KRAS-mutant colorectal cancer (CRC) treatment. Here, we demonstrated that the BCL-XL targeting agent, ABT-263, increased intracellular ROS levels and targeting antioxidant pathways augmented the therapeutic efficacy of this BH3 mimetic. ABT-263 induced expression of genes associated with ROS response and increased intracellular ROS levels by enhancing mitochondrial superoxide generation. The superoxide dismutase inhibitor, 2-methoxyestradiol (2-ME), exhibited synergism with ABT-263 in KRAS-mutant CRC cell lines. This synergistic effect was attributed to the inhibition of mTOR-dependent translation of the anti-apoptotic MCL-1 protein via caspase 3-mediated cleavage of AKT and S6K. In addition, combination treatment of ABT-263 and 2-ME demonstrated a synergistic effect in in vivo patient-derived xenografts harboring KRAS mutations. Our data suggest a novel role for ROS in BH3 mimetic-based targeted therapy and provide a novel strategy for treatment of CRC patients with KRAS mutations.

CRISPR screens identify a novel combination treatment targeting BCL-XL and WNT signaling for KRAS/BRAF-mutated colorectal cancers.

Metastatic or recurrent colorectal cancer (CRC) patients require systemic chemotherapy, but the therapeutic options of targeted agents remain limited. CRC patients with KRAS or BRAF gene mutations exhibit a worse prognosis and are resistant to anti-EGFR treatment. Previous studies have shown that the expression of anti-apoptotic protein BCL-XL is increased in CRC patients with KRAS/BRAF mutations, suggesting BCL-XL as a therapeutic target for this subgroup. Here, we performed genome-wide CRISPR/Cas9 screens of cell lines with KRAS mutations to investigate the factors required for sensitivity to BCL-XL inhibitor ABT-263 using single-guide RNAs (sgRNAs) that induce loss-of-function mutations. In the presence of ABT-263, sgRNAs targeting negative regulators of WNT signaling (resulting in WNT activation) were enriched, whereas sgRNAs targeting positive regulators of WNT signaling (resulting in WNT inhibition) were depleted in ABT-263-resistant cells. The activation of WNT signaling was highly associated with an increased expression ratio of anti- to pro-apoptotic BCL-2 family genes in CRC samples. Genetic and pharmacologic inhibition of WNT signaling using ß-catenin short hairpin RNA or TNIK inhibitor NCB-0846, respectively, augmented ABT-263-induced cell death in KRAS/BRAF-mutated cells. Inhibition of WNT signaling resulted in transcriptional repression of the anti-apoptotic BCL-2 family member, MCL1, via the functional inhibition of the ß-catenin-containing complex at the MCL1 promoter. In addition, the combination of ABT-263 and NCB-0846 exhibited synergistic effects in in vivo patient-derived xenograft (PDX) models with KRAS mutations. Our data provide a novel targeted combination treatment strategy for the CRC patient subgroup with KRAS or BRAF mutations.

Predictive biomarkers for 5-fluorouracil and oxaliplatin-based chemotherapy in gastric cancers via profiling of patient-derived xenografts.

Gastric cancer (GC) is commonly treated by chemotherapy using 5-fluorouracil (5-FU) derivatives and platinum combination, but predictive biomarker remains lacking. We develop patient-derived xenografts (PDXs) from 31 GC patients and treat with a combination of 5-FU and oxaliplatin, to determine biomarkers associated with responsiveness. When the PDXs are defined as either responders or non-responders according to tumor volume change after treatment, the responsiveness of PDXs is significantly consistent with the respective clinical outcomes of the patients. An integrative genomic and transcriptomic analysis of PDXs reveals that pathways associated with cell-to-cell and cell-to-extracellular matrix interactions enriched among the non-responders in both cancer cells and the tumor microenvironment (TME). We develop a 30-gene prediction model to determine the responsiveness to 5-FU and oxaliplatin-based chemotherapy and confirm the significant poor survival outcomes among cases classified as non-responder-like in three independent GC cohorts. Our study may inform clinical decision-making when designing treatment strategies.

Unstable Genome and Transcriptome Dynamics during Tumor Metastasis Contribute to Therapeutic Heterogeneity in Colorectal Cancers.

PURPOSE: Genomic and transcriptomic alterations during metastasis are considered to affect clinical outcome of colorectal cancers, but detailed clinical implications of metastatic alterations are not fully uncovered. We aimed to investigate the effect of metastatic evolution on in vivo treatment outcome, and identify genomic and transcriptomic alterations associated with drug responsiveness. EXPERIMENTAL DESIGN: We developed and analyzed patient-derived xenograft (PDX) models from 35 patients with colorectal cancer including 5 patients with multiple organ metastases (MOMs). We performed whole-exome, DNA methylation, and RNA sequencing for patient and PDX tumors. With samples from patients with MOMs, we conducted phylogenetic and subclonal analysis and in vivo drug efficacy test on the corresponding PDX models. RESULTS: Phylogenetic analysis using mutation, expression, and DNA methylation data in patients with MOMs showed that mutational alterations were closely connected with transcriptomic and epigenomic changes during the tumor evolution. Subclonal analysis revealed that initial primary tumors with larger number of subclones exhibited more dynamic changes in subclonal architecture according to metastasis, and loco-regional and distant metastases occurred in a parallel or independent fashion. The PDX models from MOMs demonstrated therapeutic heterogeneity for targeted treatment, due to subclonal acquisition of additional mutations or transcriptomic activation of bypass signaling pathway during tumor evolution. CONCLUSIONS: This study demonstrated in vivo therapeutic heterogeneity of colorectal cancers using PDX models, and suggests that acquired subclonal alterations in mutations or gene expression profiles during tumor metastatic processes can be associated with the development of drug resistance and therapeutic heterogeneity of colorectal cancers.

Grape Seed Proanthocyanidin Inhibits Mucin Synthesis and Viral Replication by Suppression of AP-1 and NF-κB via p38 MAPKs/JNK Signaling Pathways in Respiratory Syncytial Virus-Infected A549 Cells.

Airway epithelial cells are often infected by respiratory syncytial virus (RSV), one of the most common causes of asthma, bronchiolitis, chronic obstructive pulmonary disease, and pneumonia. During the infection process, excessive mucins instigate airway inflammation. However, the mechanism underlying RSV-induced airway hyper-responsiveness and inflammation is poorly understood. Furthermore, no reliable vaccines or drugs for antiviral therapy are available. In this study, the effect of the natural compound grape seed proanthocyanidin (GSP) on RSV-infected human airway epithelial cells A549 was evaluated. After pretreatment of the cells with or without exposure to RSV with 5-10 µg GSP/mL, the expression of various mucins (MUC1, MUC2, MUC5AC, MUC5B, and MUC8) was evaluated by real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blotting, as well as confocal microscopy. We found that GSP significantly decreased RSV-induced mucin synthesis at the mRNA and protein levels. In addition, GSP suppressed the RSV-induced signaling pathways, including extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38, together with nuclear factor kappa B (NF-κB) and activating protein-1 family members (c-Jun and c-Fos). Concomitantly, GSP inhibited the replication of RSV within A549 cells. Taken together, all our results suggest that GSP could be a potent therapeutic agent to suppress excessive mucus production and viral replication in RSV-induced airway inflammatory disorders.

Grape seed proanthocyanidin inhibits inflammatory responses in hepatic stellate cells by modulating the MAPK, Akt and NF-κB signaling pathways.

In the present study, we aimed to investigate the molecular mechanisms and prophylactic effects of grape seed proanthocyanidin (GSP) on lipopolysaccharide (LPS)-stimulated human hepatic stellate cells (HSCs). Cell counting and MTT assays were used to assess cell viability in the absence or presence of GSP. Reverse transcription-quantitative PCR (RT-qPCR) was performed for several inflammation-related genes (NOD1, NOD2, TLR2, TLR4, IL-1 ß, IL-6, IL-8, iNOS and COX-2). The expression of anti-inflammatory cell signaling molecules, including c-Jun N-terminal kinase (JNK), p38, extracellular signal regulated kinase (ERK), Akt, nuclear factor-κB (NF-κB), inhibitory-κBα (IκBα), iNOS and COX-2, was evaluated by western blot analysis. Finally, IL-8 levels in the culture supernatant of HSCs were measured by ELISA. Pretreatment with GSP before LPS treatment significantly suppressed the mRNA expression of pro-inflammatory cytokines such as IL-1ß, IL-6 and IL-8. GSP inhibited mRNA expression of LPS-induced TLR4, NOD2 and COX-2, in addition to inhibiting the expression of iNOS. GSP also inhibited LPS-induced NF-κB activation and IκBα phosphorylation. Concomitantly, GSP dose-dependently suppressed the activation of MAP kinases (JNK, ERK and p38) and Akt in LPS-stimulated HSCs. These data suggest that GSP inhibits inflammatory responses in HSCs by inactivating the NF-κB signaling pathway via MAP kinases. Thus, GSP may be considered as a novel drug for the treatment of hepatic inflammation, infectious diseases and fibrosis.

A Novel Combination Treatment Targeting BCL-XL and MCL1 for KRAS/BRAF-mutated and BCL2L1-amplified Colorectal Cancers.

Colorectal cancer is the third most commonly diagnosed cancer in the world, and exhibits heterogeneous characteristics in terms of genomic alterations, expression signature, and drug responsiveness. Although there have been considerable efforts to classify this disease based on high-throughput sequencing techniques, targeted treatments for specific subgroups have been limited. KRAS and BRAF mutations are prevalent genetic alterations in colorectal cancers, and patients with mutations in either of these genes have a worse prognosis and are resistant to anti-EGFR treatments. In this study, we have found that a subgroup of colorectal cancers, defined by having either KRAS or BRAF (KRAS/BRAF) mutations and BCL2L1 (encoding BCL-XL) amplification, can be effectively targeted by simultaneous inhibition of BCL-XL (with ABT-263) and MCL1 (with YM-155). This combination treatment of ABT-263 and YM-155 was shown to have a synergistic effect in vitro as well as in in vivo patient-derived xenograft models. Our data suggest that combined inhibition of BCL-XL and MCL1 provides a promising treatment strategy for this genomically defined colorectal cancer subgroup. Mol Cancer Ther; 16(10); 2178-90. ©2017 AACR.

An Integrative Approach to Precision Cancer Medicine Using Patient-Derived Xenografts.

Cancer is a heterogeneous disease caused by diverse genomic alterations in oncogenes and tumor suppressor genes. Despite recent advances in high-throughput sequencing technologies and development of targeted therapies, novel cancer drug development is limited due to the high attrition rate from clinical studies. Patient-derived xenografts (PDX), which are established by the transfer of patient tumors into immunodeficient mice, serve as a platform for co-clinical trials by enabling the integration of clinical data, genomic profiles, and drug responsiveness data to determine precisely targeted therapies. PDX models retain many of the key characteristics of patients' tumors including histology, genomic signature, cellular heterogeneity, and drug responsiveness. These models can also be applied to the development of biomarkers for drug responsiveness and personalized drug selection. This review summarizes our current knowledge of this field, including methodologic aspects, applications in drug development, challenges and limitations, and utilization for precision cancer medicine.