Aim
Much attention has been paid to conversion therapy for stage IV gastric cancer, however, its operative comorbidities and survival benefit have not yet been clarified. CONVO‐GC‐1, an international ...retrospective cohort study, was designed to investigate the role of conversion surgery in Japan, Korea, and China.
Methods
The rate of operative complications was the primary endpoint and the overall survival (OS), according to the four‐category criteria previously published (Gastric Cancer:19; 2016), was analyzed as the secondary endpoint.
Results
A total of 1206 patients underwent surgery after chemotherapy with curative intent. Operative complications were observed in 290 (24.0%) patients in all grades, including pancreatic fistula and surgical site infection. The median survival time (MST) of all resected patients was 36.7 mo (M) and those of R0, R1, and R2 resection were 56.6 M, 25.8 M, and 21.7 M, respectively. Moreover, the MST of R0 patients were 47.8 M, 116.7 M, 44.8 M in categories 1, 2, and 3, respectively, and not reached in category 4. Interestingly, the MST of P1 patients was as favorable as that of P0CY1 patients if R0 resection was achieved. The MST of patients with liver metastasis was also favorable regardless of the number of lesions, and the MST of patients with para‐aortic lymph node (LN) No 16a1/b2 metastasis was not inferior to that of patients with para‐aortic LN No 16a2/b1 metastasis.
Conclusion
Conversion therapy for stage IV gastric cancer is safe and could be a new therapeutic strategy to improve the survival of patients, especially those with R0 resection.
R0 resection of conversion therapy can be a new strategy for gastric cancer.
The phosphatidylinositol 3‐kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway plays a vital role in cell proliferation, apoptosis, metabolism, and angiogenesis in various human cancers, ...including head and neck squamous cell carcinoma (HNSCC). In the present study, we aimed to clarify the role of AKT, which is a major downstream effector of the PI3K‐AKT‐mTOR pathway, in HNSCC. We first investigated the mRNA expression of AKT isoforms using RNA‐sequencing data from The Cancer Genome Atlas database. We observed a specific elevation of AKT3 expression in HNSCC tissues when compared with that in normal tissues. Furthermore, AKT3 expression correlated with genes related to the immunosuppressive microenvironment more than the other AKT isoforms and PIK3CA. Accordingly, we focused on AKT3 and performed a knockdown approach using an HNSCC cell line. AKT3 knockdown cells exhibited impaired proliferation, a shift in the cell cycle from G2/M to G1/G0 phase, an increase in apoptotic cells, and downregulation of gene expression related to immunosuppression, as well as the knockdown of its upstream regulator PIK3CA. We also performed immunohistochemistry for both AKT3 and PIK3CA using surgical specimens from 72 patients with HNSCC. AKT3 expression in tumor cells correlated with immune cell infiltration and unfavorable prognosis when compared with PIK3CA. These findings suggested that AKT3 expression is a potential biomarker for predicting the immunoreactivity and prognosis of HNSCC. Furthermore, the isoform‐specific inhibition of AKT3 could be developed as a novel cancer therapy that efficiently suppresses the PI3K‐AKT‐mTOR pathway.
This research work demonstrated that AKT3 is a key regulator that modulates the proliferative and immunosuppressive functions of HNSCC. AKT3 is a potential candidate for a novel biomarker of the immunosuppressive microenvironment and shorter survival. The isoform‐specific inhibition of AKT3 could be developed as a novel cancer therapy that efficiently suppresses the PI3K‐AKT‐mTOR pathway.
Synergistic effects among multiple gene mutations are involved in cancer development and progression. However, developing genetically modified mouse models to analyze various combinations of ...mutations is extremely labor‐intensive and time‐consuming. To address these problems, we developed a novel method for in vivo multiplexed genome editing of the murine uterus to model human endometrial carcinoma (EMC). To do this, we injected a CRISPR‐Cas9 ribonucleoprotein complex into the uterine cavity of adult female mice, followed by electroporation. Evaluation of reporter mice demonstrated that genome editing occurred specifically in uterine epithelial cells, which are the origin of EMCs. Simultaneous targeting of Pten/Trp53/Lkb1, or targeting of Pten/Lkb1 along with the Ctnnb1ΔEx3 mutation, resulted in efficient generation of invasive tumors in wild‐type females within 3 months. This novel method will enable rapid and easy validation of many combinations of gene mutations that lead to endometrial carcinogenesis.
What's new?
Synergy among multiple mutations influences the development of human endometrial carcinoma. Assessing combinations of mutations in conventional mouse models, however, is costly and time consuming. In the present study, to more feasibly reproduce multiple cancer mutations in mice, the authors experimented with in vivo genome editing via introduction of Cas9 ribonucleoproteins into the murine uterus. In wild‐type female mice, invasive tumors developed within 3 months of simultaneous introduction of mutations in Pten/Trp53/Lkb1 or Pten/Lkb1 and Ctnnb1 via genome editing. The novel method reported here enables rapid and simple validation of various combinations of mutations responsible for endometrial carcinogenesis.
Transforming growth factor (TGF)-β superfamily proteins have many important biological functions, including regulation of tissue differentiation, cell proliferation, and migration in both normal and ...cancer cells. Many studies have reported that TGF-β signaling is associated with disease progression and therapeutic resistance in several cancers. Similarly, TGF-β-induced protein (TGFBI)-a downstream component of the TGF-β signaling pathway-has been shown to promote and/or inhibit cancer. Here, we review the state of basic and clinical research on the roles of TGF-β and TGFBI in gastrointestinal cancers.
Background
Gain-of-function mutations in
CACNA1C
encoding Cav1.2 cause syndromic or non-syndromic type-8 long QT syndrome (LQTS) (sLQT8 or nsLQT8). The cytoplasmic domain (D)Ⅰ-Ⅱ linker in Cav1.2 ...plays a pivotal role in calcium channel inactivation, and mutations in this site have been associated with sLQT8 (such as Timothy syndrome) but not nsLQT8.
Objective
Since we identified a novel
CACNA1C
mutation, located in the DⅠ-Ⅱ linker, associated with nsLQTS, we sought to reveal its biophysical defects.
Methods
Target panel sequencing was employed in 24 genotype-negative nsLQTS probands (after Sanger sequencing) and three family members. Wild-type (WT) or R511Q Cav1.2 was transiently expressed in tsA201 cells, then whole-cell Ca
2+
or Ba
2+
currents (I
Ca
or I
Ba
) were recorded using whole-cell patch-clamp techniques.
Results
We identified two
CACNA1C
mutations, a previously reported R858H mutation and a novel R511Q mutation located in the DⅠ-Ⅱ linker. Four members of one nsLQTS family harbored the
CACNA1C
R511Q mutation. The current density and steady-state activation were comparable to those of WT-I
Ca
. However, persistent currents in R511Q-I
Ca
were significantly larger than those of WT-I
Ca
(WT at +20 mV: 3.3±0.3%, R511Q: 10.8±0.8%, P<0.01). The steady-state inactivation of R511Q-I
Ca
was weak in comparison to that of WT-I
Ca
at higher prepulse potentials, resulting in increased window currents in R511Q-I
Ca
. Slow component of inactivation of R511Q-I
Ca
was significantly delayed compared to that of WT-I
Ca
(WT-tau at +20 mV: 81.3±3.3 ms, R511Q-tau: 125.1±5.0 ms, P<0.01). Inactivation of R511Q-I
Ba
was still slower than that of WT-I
Ba
, indicating that voltage-dependent inactivation (VDI) of R511Q-I
Ca
was predominantly delayed.
Conclusions
Delayed VDI, increased persistent currents, and increased window currents of R511Q-I
Ca
cause nsLQT8. Our data provide novel insights into the structure-function relationships of Cav1.2 and the pathophysiological roles of the DⅠ-Ⅱ linker in phenotypic manifestations.
Hypoxia-inducible factor-2α (HIF-2α, or EPAS1) is important for cancer progression, and is a putative biomarker for poor prognosis for non-small cell lung cancer (NSCLC). However, molecular ...mechanisms underlying the EPAS1 overexpression are not still fully understood. We explored a role of a single nucleotide polymorphism (SNP), rs13419896 located within intron 1 of the EPAS1 gene in regulation of its expression. Bioinformatic analyses suggested that a region including the rs13419896 SNP plays a role in regulation of the EPAS1 gene expression and the SNP alters the binding activity of transcription factors. In vitro analyses demonstrated that a fragment containing the SNP locus function as a regulatory region and that a fragment with A allele showed higher transactivation activity than one with G, especially in the presence of overexpressed c-Fos or c-Jun. Moreover, NSCLC patients with the A allele showed poorer prognosis than those with G at the SNP even after adjustment with various variables. In conclusion, the genetic polymorphism of the EPAS1 gene may lead to variation of its gene expression levels to drive progression of the cancer and serve as a prognostic marker for NSCLC.
Cancer research is increasingly dependent of patient-derived xenograft model (PDX). However, a major point of concern regarding the PDX model remains the replacement of the human stroma with murine ...counterpart. In the present work we aimed at clarifying the significance of the human-to-murine stromal replacement for the fidelity of colorectal cancer (CRC) and liver metastasis (CRC-LM) PDX model. We have conducted a comparative metabolic analysis between 6 patient tumors and corresponding PDX across 4 generations. Metabolic signatures of cancer cells and stroma were measured separately by MALDI-imaging, while metabolite changes in entire tumors were quantified using mass spectrometry approach. Measurement of glucose metabolism was also conducted in vivo using
F-fluorodeoxyglucose (FDG) and positron emission tomography (PET). In CRC/CRC-LM PDX model, human stroma was entirely replaced at the second generation. Despite this change, MALDI-imaging demonstrated that the metabolic profiles of both stromal and cancer cells remained stable for at least four generations in comparison to the original patient material. On the tumor level, profiles of 86 water-soluble metabolites as well as 93 lipid mediators underlined the functional stability of the PDX model. In vivo PET measurement of glucose uptake (reflecting tumor glucose metabolism) supported the ex vivo observations. Our data show for the first time that CRC/CRC-LM PDX model maintains the functional stability at the metabolic level despite the early replacement of the human stroma by murine cells. The findings demonstrate that human cancer cells actively educate murine stromal cells during PDX development to adopt the human-like phenotype.
Abstract
Castration-resistant prostate cancer shows resistance to not only androgen deprivation therapy (ADT) but also X-ray therapy. On the other hand, carbon ion beams have a high biological effect ...and are used for various cancers showing resistance to X-ray therapy. The purposes of this study are to clarify the difference in the sensitivity of Castration-resistant prostate cancer to X-ray and carbon ion beams and to elucidate the mechanism. The androgen-insensitive prostate cancer cell line LNCaP-LA established by culturing the androgen-sensitive prostate cancer cell line LNCaP for 2 years in androgen-free medium was used for this study. First, colony formation assays were performed to investigate its sensitivity to X-ray and carbon ion beams. Next, DNA mutation analysis on 409 cancer-related genes and comprehensive transcriptome analysis (RNA-seq) were performed with a next-generation sequencer. Lethal dose 50 values of X-rays for LNCaP and LNCaP-LA were 1.4 Gy and 2.8 Gy, respectively (P < 0.01). The Lethal dose 50 values of carbon ion beams were 0.9 Gy and 0.7 Gy, respectively (P = 0.09). On DNA mutation analysis, AR mutation was observed specifically in LNCaP-LA. From RNA-seq, 181 genes were identified as differentially expressed genes (DEGs; FDR <0.10, P < 0.00076) between LNCaP and LNCaP-LA. Function analysis suggested that cell death was suppressed in LNCaP-LA, and pathway analysis suggested that the NRF2-pathway involved in intracellular oxidative stress prevention was activated in LNCaP-LA. LNCaP-LA showed X-ray resistance compared to LNCaP and sensitivity to carbon ion beams. The AR mutation and the NRF2-pathway were suggested as causes of resistance.
While a KCND3 V392I mutation uniquely displays a mixed electrophysiological phenotype of Kv4.3, only limited clinical information on the mutation carriers is available. We report two teenage siblings ...exhibiting both cardiac (early repolarization syndrome and paroxysmal atrial fibrillation) and cerebral phenotypes (epilepsy and intellectual disability), in whom we identified the KCND3 V392I mutation. We propose a link between the KCND3 mutation with a mixed electrophysiological phenotype and cardiocerebral phenotypes, which may be defined as a novel cardiocerebral channelopathy.
Purpose
L-type amino acid transporter 1 (LAT1) is linked to tumor cell proliferation, angiogenesis, and survival in various human cancers. Although the expression of LAT1 was identified as a ...significant prognostic predictor after surgery in patients with pancreatic ductal adenocarcinoma (PDAC), little is known about the clinical significance of LAT1 as a chemotherapeutic resistance factor in PDAC.
Methods
A total of 110 patients with surgically resected PDAC were retrospectively reviewed as the training set. Immunohistochemical staining of resected tumor specimens was assessed using anti-LAT1 antibodies. In vitro analysis of chemotherapy resistance and LAT1 function using PDAC cell lines was also performed.
Results
The rate of high expression of LAT1 was 64.1% (71/110). The high expression of LAT1 protein was significantly associated with tumor differentiation, tumor depth (T factor), lymph node metastasis, venous invasion, recurrence, and clinical response. By multivariate analysis, LAT1 was validated as an independent prognostic factor for predicting worse survival after surgery. We analyzed the TCGA data set and obtained similar results that the survival rates of SLC7A5 high expression group were poorer than that of low expression group. LAT1 could successfully predict the outcome of patients who received adjuvant chemotherapy after surgery (
n
= 88) and systemic chemotherapy after recurrence (
n
= 56). All patients with high LAT1 expression were non-responders, whereas approximately 30% of the patients with low LAT1 expression responders (
p
= 0.0002). By analyzing the TCGA online database, it was found that LAT1 closely correlated with hypoxia-induced genes, such as
PTGES, PYGL
, and
KPNA2
.
Conclusion
LAT1 as an independent prognostic marker is a potential molecular targeting gene to reduce chemoresistance and tumor growth in patients with PDAC, supported by our in vitro study.
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