It is generally accepted that recurrent chromosome translocations play a major role in the molecular pathogenesis of hematological malignancies but not of solid tumors. However, chromosome ...translocations involving the e26 transformation‐specific sequence transcription factor loci have been demonstrated recently in many prostate cancer cases. Furthermore, through a functional screening with retroviral cDNA expression libraries, we have discovered the fusion‐type protein tyrosine kinase echinoderm microtubule‐associated protein like‐4 (EML4)–anaplastic lymphoma kinase (ALK) in non‐small cell lung cancer (NSCLC) specimens. A recurrent chromosome translocation, inv(2)(p21p23), in NSCLC generates fused mRNA encoding the amino‐terminal half of EML4 ligated to the intracellular region of the receptor‐type protein tyrosine kinase ALK. EML4–ALK oligomerizes constitutively in cells through the coiled coil domain within the EML4 region, and becomes activated to exert a marked oncogenicity both in vitro and in vivo. Break and fusion points within the EML4 locus may diverge in NSCLC cells to generate various isoforms of EML4–ALK, which may constitute ~5% of NSCLC cases, at least in the Asian ethnic group. In the present review I summarize how detection of EML4–ALK cDNA may become a sensitive diagnostic means for NSCLC cases that are positive for the fusion gene, and discuss whether suppression of ALK enzymatic activity could be an effective treatment strategy against this intractable disorder. (Cancer Sci 2008; 99: 2349–2355)
Cancer genomic medicine in Japan MANO, Hiroyuki
Proceedings of the Japan Academy, Series B,
07/2020, Volume:
96, Issue:
7
Journal Article
Peer reviewed
Open access
Advances in cancer research have revolutionized the way cancer is diagnosed and treated. Any cancer is now known to be an amalgamation of many subtypes, each carrying its specific cancer-causing gene ...or oncogene. It is also evident that a given oncogene is often present across a wide range of cancer subtypes, albeit at different frequencies. These lines of information have brought cancer genomic medicine (CGM) to the clinic, where genetic information is used to optimize therapeutic intervention. In 2017, the Expert Meeting for Cancer Genomic Medicine Promotion Consortium in the Ministry of Health, Labour and Welfare (MHLW) of Japan submitted a blueprint for the CGM platform in Japan. Accordingly, the MHLW designated a total of 206 hospitals that conduct cancer gene panel testing under the national health insurance system and established the Center for Cancer Genomics and Advanced Therapeutics to store genomic/clinical information of cancer patients. Since June 2019, the CGM officially started in Japan.
Targeting of essential growth drivers represents an ideal approach to cancer treatment. To identify such molecules in clinical specimens, we developed a highly sensitive functional screening system ...based on the preparation of retroviral cDNA expression libraries. By screening such a library of lung adenocarcinoma with a focus formation assay, we discovered the EML4-ALK fusion-type oncogene. A small chromosomal inversion thus leads to fusion of the amino-terminal portion of the microtubule-associated protein EML4 to the intracellular kinase domain of ALK, a receptor-type protein tyrosine kinase. Constitutive dimerization of EML4-ALK mediated by a dimerization motif of EML4 results in kinase activation. Specific inhibitors of the kinase activity of ALK have been developed as therapeutic drugs for EML4-ALK–positive lung cancer, three of which (crizotinib, ceritinib, and alectinib) have already been approved for clinical use. An overall clinical response rate of 93.5% for alectinib has shown that agents that target essential growth drivers can become magic bullets for cancer treatment.
Immune checkpoint blockade has provided a paradigm shift in cancer therapy, but the success of this approach is very variable; therefore, biomarkers predictive of clinical efficacy are urgently ...required. Here, we show that the frequency of PD-1
CD8
T cells relative to that of PD-1
regulatory T (T
) cells in the tumor microenvironment can predict the clinical efficacy of programmed cell death protein 1 (PD-1) blockade therapies and is superior to other predictors, including PD ligand 1 (PD-L1) expression or tumor mutational burden. PD-1 expression by CD8
T cells and T
cells negatively impacts effector and immunosuppressive functions, respectively. PD-1 blockade induces both recovery of dysfunctional PD-1
CD8
T cells and enhanced PD-1
T
cell-mediated immunosuppression. A profound reactivation of effector PD-1
CD8
T cells rather than PD-1
T
cells by PD-1 blockade is necessary for tumor regression. These findings provide a promising predictive biomarker for PD-1 blockade therapies.
The development of tyrosine kinase inhibitors (TKIs) has improved the treatment of non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. The current research ...priority is to provide viable treatments for patients who have drug-resistant EGFR mutations. We evaluated the drug sensitivity of various EGFR mutants to monotherapies and combination therapies of EGFR-TKIs. In vitro, the transforming potential and drug sensitivity of 357 EGFR variants were assessed. In vivo, we tested the sensitivity of EGFR variants to different regimens of EGFR-TKIs by examining changes in the proportion of each variant within the tumor. Out of 357 variants thoroughly examined for transforming activities, 144 (40.3%) and 282 (79.0%) transformed 3T3 and Ba/F3 cells, respectively. Among the latter variants, 50 (17.7%) were found to be resistant or only partly resistant to osimertinib or afatinib. Four of 25 afatinib-resistant variants (16%) were sensitive to osimertinib, whereas 25 of 46 osimertinib-resistant variants (54.3%) were sensitive to afatinib. Despite the lack of a synergistic impact, TKI combination treatment effectively reduced in vivo the heterogeneous tumors composed of 3T3 cells with different EGFR variants. Regimens starting with afatinib and subsequently switched to osimertinib suppressed tumor development more efficiently than the opposite combination. Combination EGFR-TKI treatment may decrease tumor growth and prevent the development of resistant variants. This work created an experimental model of a heterogeneous tumor to find the best combination therapy regimen and proposes a basic notion of EGFR-TKI combination therapy to enhance the prognosis of NSCLC patients.
Macroautophagy is an intracellular degradation process that requires multiple autophagy-related (
) genes. In this study, we performed a genome-wide screen using the autophagic flux reporter ...GFP-LC3-RFP and identified
as a novel
gene. TMEM41B is a multispanning membrane protein localized in the endoplasmic reticulum (ER). It has a conserved domain also found in vacuole membrane protein 1 (VMP1), another ER multispanning membrane protein essential for autophagy, yeast Tvp38, and the bacterial DedA family of putative half-transporters. Deletion of
blocked the formation of autophagosomes at an early step, causing accumulation of ATG proteins and small vesicles but not elongating autophagosome-like structures. Furthermore, lipid droplets accumulated in
-knockout (KO) cells. The phenotype of
-KO cells resembled those of
-KO cells. Indeed, TMEM41B and VMP1 formed a complex in vivo and in vitro, and overexpression of VMP1 restored autophagic flux in
-KO cells. These results suggest that TMEM41B and VMP1 function together at an early step of autophagosome formation.
Through an integrated molecular- and histopathology-based screening system, we performed a screening for fusions of anaplastic lymphoma kinase (ALK) and c-ros oncogene 1, receptor tyrosine kinase ...(ROS1) in 1,529 lung cancers and identified 44 ALK-fusion-positive and 13 ROS1-fusion-positive adenocarcinomas, including for unidentified fusion partners for ROS1. In addition, we discovered previously unidentified kinase fusions that may be promising for molecular-targeted therapy, kinesin family member 5B (KIF5B)-ret proto-oncogene (RET) and coiled-coil domain containing 6 (CCDC6)-RET, in 14 adenocarcinomas. A multivariate analysis of 1,116 adenocarcinomas containing these 71 kinase-fusion-positive adenocarcinomas identified four independent factors that are indicators of poor prognosis: age ≥ 50 years, male sex, high pathological stage and negative kinase-fusion status.
Numerous nontruncating missense variants of the BRCA2 gene have been identified, but there is a lack of convincing evidence, such as familial data, demonstrating their clinical relevance and they ...thus remain unactionable. To assess the pathogenicity of variants of unknown significance (VUSs) within BRCA2, here we develop a method, the MANO-B method, for high-throughput functional evaluation utilizing BRCA2-deficient cells and poly (ADP-ribose) polymerase (PARP) inhibitors. The estimated sensitivity and specificity of this assay compared to those of the International Agency for Research on Cancer classification system is 95% and 95% (95% confidence intervals: 77-100% and 82-99%), respectively. We classify the functional impact of 186 BRCA2 VUSs with our computational pipeline, resulting in the classification of 126 variants as normal/likely normal, 23 as intermediate, and 37 as abnormal/likely abnormal. We further describe a simplified, on-demand annotation system that could be used as a companion diagnostic for PARP inhibitors in patients with unknown BRCA2 VUSs.
Tumor microenvironment plays a pivotal role in cancer progression; however, little is known regarding how differences in the microenvironment affect characteristics of cancer cells. Here, we ...investigated the effects of tumor microenvironment on cancer cells by using mouse tumor models. After three cycles of inoculation and extraction of human pancreatic cancer cells, including SUIT-2 and Panc-1 cells, from tumors, distinct cancer cell lines were established: 3P cells from the pancreas obtained using the orthotopic tumor model and 3sc cells from subcutaneous tissue obtained using the subcutaneous tumor model. On re-inoculation of these cells, the 3sc cells and, more prominently, the 3P cells, exhibited higher tumorigenic activity than the parental cells. The 3P cells specifically exhibited low E-cadherin expression and high invasiveness, suggesting that they were endowed with the highest malignant characteristics. RNA-sequence analysis demonstrated that distinct signaling pathways were activated in each cell line and that the 3P cells acquired a cancer stem cell-like phenotype. Among cancer stem cell-related genes, those specifically expressed in the 3P cells, including NES, may be potential new targets for cancer therapy. The mechanisms underlying the development of highly malignant cancer cell lines were investigated. Individual cell clones within the parental cells varied in tumor-forming ability, indicating the presence of cellular heterogeneity. Moreover, the tumor-forming ability and the gene expression profile of each cell clone were altered after serial orthotopic inoculations. The present study thus suggests that both selection and education processes by tumor microenvironment are involved in the development of highly malignant cancer cells.
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