Identification of anti‐CD98 antibody mimotopes for inducing antibodies with antitumor activity by mimotope immunization

A mimotope is an antibody‐epitope‐mimicking peptide retrieved from a phage display random peptide library. Immunization with antitumor antibody‐derived mimotopes is promising for inducing antitumor immunity in hosts. In this study, we isolated linear and constrained mimotopes from HBJ127, a tumor‐suppressing anti‐CD98 heavy chain mAb, and determined their abilities for induction of antitumor activity equal to that of the parent antibody. We detected elevated levels of antipeptide responses, but failed to detect reactivity against native CD98‐expressing HeLa cells in sera of immunized mice. Phage display panning and selection of mimotope‐immunized mouse spleen‐derived antibody Fab library showed that HeLa cell‐reactive Fabs were successfully retrieved from the library. This finding indicates that native antigen‐reactive Fab clones represented an undetectable minor population in mimotope‐induced antibody repertoire. Functional and structural analysis of retrieved Fab clones revealed that they were almost identical to the parent antibody. From these results, we confirmed that mimotope immunization was promising for retrieving antitumor antibodies equivalent to the parent antibody, although the co‐administration of adjuvant compounds such as T‐cell epitope peptides and Toll‐like receptor 4 agonist peptides is likely to be necessary for inducing stronger antitumor immunity than mimotope injection alone.     

CD137, an attractive candidate for the immunotherapy of lung cancer

Immunotherapy has become a hotspot in cancer therapy in recent years. Several immune checkpoints inhibitors have been used to treat lung cancer. CD137 is a kind of costimulatory molecule that mediates T cell activation, which regulates the activity of immune cells in a variety of physiological and pathological processes. Targeting CD137 or its ligand (CD137L) has been studied, aiming to enhance anticancer immune responses. Accumulating studies show that anti‐CD137 mAbs alone or combined with other drugs have bright antitumor prospects. In the following, we reviewed the biology of CD137, the antitumor effects of anti‐CD137 Ab monotherapy and the combined therapy in lung cancer.     

ERGIC3, which is regulated by miR‐203a,is a potential biomarker for non‐small cell lung cancer

In a previous study, we found that ERGIC3 was a novel lung cancer‐related gene by screening libraries of differentially expressed genes. In this study, we developed a new murine monoclonal antibody (mAb) against ERGIC3. This avid antibody (6‐C4) is well suited for immunohistochemistry, immunoblotting and solid‐phase immunoassays. Furthermore, we systematically investigated expressions of ERGIC3 in a broad variety of normal human tissues and various types of tumors by immunohistochemistry. In normal human tissues, 6‐C4 reacted only in some epithelial cells, such as hepatocytes, gastrointestinal epithelium, ducts and acini of the pancreas, proximal and distal tubules of the kidney, and mammary epithelial cells; however, most normal human tissues were not stained. Moreover, almost all carcinomas that originated from the epithelial cells were positive for 6‐C4, whereas all sarcomas were negative. Notably, 6‐C4 strongly stained non‐small cell lung cancer (NSCLC) cells but did not react with normal lung tissues. Hence, ERGIC3 mAb could be used in histopathological diagnosis and cytopathological testing to detect early‐stage NSCLC. We also studied the mechanisms of ERGIC3 regulation in vitro and in vivo by means of bioinformatics analysis, luciferase reporter assay, miRNA expression profiling and miRNA transfection. Results showed that miR‐203a downregulation induced ERGIC3 overexpression in NSCLC cells.     

The sphingosine kinase 2 inhibitor ABC294640 displays anti‐non‐small cell lung cancer activities in vitro and in vivo

Non‐small cell lung cancer (NSCLC) accounts for about 85‐90% of lung cancer cases, and is the number one killer among cancers in the United States. The majorities of lung cancer patients do not respond well to conventional chemo‐ and/or radio‐therapeutic regimens, and have a dismal 5‐year survival rate of ～15%. The recent introduction of targeted therapy and immunotherapy gives new hopes to NSCLC patients, but even with these agents, not all patients respond, and responses are rarely complete. Thus, there is still an urgent need to identify new therapeutic targets in NSCLC and develop novel anti‐cancer agents. Sphingosine kinase 2 (SphK2) is one of the key enzymes in sphingolipid metabolism. SphK2 expression predicts poor survival in NSCLC patients, and is associated with Gefitinib‐resistance. In this study, the anti‐NSCLC activities of ABC294640, the only first‐in‐class orally available inhibitor of SphK2, were explored. The results obtained indicate that ABC294640 treatment causes significant NSCLC cell apoptosis, cell cycle arrest and suppression of tumor growth in vitro and in vivo. Moreover, lipidomics analyses revealed the complete signature of ceramide and dihydro(dh)‐ceramide species in the NSCLC cell‐lines with or without ABC294640 treatment. These findings indicate that sphingolipid metabolism targeted therapy may be developed as a promising strategy against NSCLC.     

Immunological features of a lung cancer patient achieving an objective response with anti‐programmed death‐1 blockade therapy

The role of immune checkpoint inhibitors in metastatic lung cancer has been established in recent years and the pretherapeutic profiles of the tumor microenvironment in responders have been increasingly reported. The role of salvage surgery and the immune profiles of the posttherapeutic specimens in patients achieving an objective response have rarely been studied. We report a case of metastatic lung cancer treated by anti‐programmed death‐1 Ab followed by surgical resection. The immune status of the tumor was assessed, showing germinal center formation, memory B cell infiltration, and a high frequency of interferon gamma ‐secreting T cells.     

Concurrent end‐phase boost high‐dose radiation therapy for non‐small‐cell lung cancer with or without cisplatin chemotherapy*

The aim of this study was to audit the results of a high‐dose, combined‐modality prospective protocol for non‐small‐cell lung cancer in terms of survival, disease‐specific survival and toxicity. One hundred and twenty‐one patients with non‐small‐cell lung cancer were treated with a concurrent, end‐phase, boost, high‐dose radiotherapy protocol with 65 Gy in 35 fractions for more than 5 weeks. Sixty‐six patients received radiotherapy alone (group 1), 29 received concurrent chemoradiation (group 2) and 26 received neoadjuvant and concurrent chemotherapy (group 3). Thirty‐four patients had stage I disease, six had stage II and 81 had stage III. Overall median survival was 23 months: 75% at 1 year and 23% at 5 years. Median survivals for patients with stage I and stages II and III disease were 43 and 19 months, respectively. For stages II and III patients by groups 1–3, median survivals were 18, 25 and 18 months, respectively, and 2‐year survivals were 36, 52 and 38%, respectively. Toxicity was acceptable. Overall, 9% had symptomatic pneumonitis and 7% had grades 3 and 4 oesophagitis. For those who had the mediastinum included in the volume, grade ≥3 oesophagitis occurred in 0, 11 and 22% (n = 110, P = 0.001), respectively, for treatment groups 1–3. Overall treatment‐related mortality was 3%, consisting of two septic deaths, one pneumonitis and possibly one late cardiac event, all occurring in patients who had chemotherapy (7% of 55 patients). Treatment‐related mortality declined over the study period. Accelerated radiotherapy was well tolerated, with only moderate increased acute toxicity when combined with concurrent platinum chemotherapy. Toxicity was enhanced by induction chemotherapy. Overall survival outcomes were excellent for this condition. Continued use of this radiotherapy schedule is recommended as the platform for assessment of other chemotherapy schedules.     

Enhanced anti‐angiogenic effect of E7820 in combination with erlotinib in epidermal growth factor receptor–tyrosine kinase inhibitor‐resistant non‐small‐cell lung cancer xenograft models

Most non‐small‐cell lung cancers (NSCLCs) harboring activating mutations in the epidermal growth factor receptor (EGFR) are initially responsive to EGFR tyrosine kinase inhibitors (EGFR‐TKIs); however, they invariably develop resistance to these drugs. E7820 is an angiogenesis inhibitor that decreases integrin‐α2 expression and is currently undergoing clinical trials. We investigated whether E7820 in combination with erlotinib, an EGFR‐TKI, could overcome EGFR‐TKI‐resistance in the NSCLC cell lines A549 (KRAS; G12S), H1975 (EGFR; L858R/T790M), and H1650 (PTEN; loss, EGFR; exon 19 deletion), which are resistant to erlotinib. Immunohistochemical analysis was carried out in xenografted tumors to investigate anti‐angiogenesis activity and endothelial cell apoptosis levels by endothelial cell marker CD31 and TUNEL staining, respectively. Treatment with E7820 (50 mg/kg) with erlotinib (60 mg/kg) showed a synergistic antitumor effect in three xenograft models. Immunohistochemical analysis indicated that combined treatment with E7820 and erlotinib significantly decreased microvessel density and increased apoptosis of tumor‐associated endothelial cells compared with use of only one of the agents. This combination increased apoptosis in HUVECs through activation of both intrinsic and extrinsic apoptosis pathways in vitro. The combination of E7820 with erlotinib is an alternative strategy to overcome erlotinib resistance in NSCLC by enhancement of the anti‐angiogenic activity of E7820.     

Intermittent chemotherapy can retain the therapeutic potential of anti‐CD137 antibody during the late tumor‐bearing state

Immunomodulating monoclonal antibodies (mAb) can evoke antitumor T‐cell responses, which are attenuated by regulatory T cells (Treg) and myeloid‐derived suppressor cells (MDSC). Treatment with cyclophosphamide (CP) and gemcitabine (GEM) can mitigate the immunosuppression by Treg and MDSC, respectively. In the current study, we examined the antitumor effects of a combination of local injection with anti‐CD137 mAb and intermittent low‐dose chemotherapy using CP and GEM in subcutaneously established CT26 colon carcinoma. Although a significant antitumor effect was observed when local anti‐CD137 mAb therapy (5 μg) was started early in the tumor‐bearing stage (day 10), no therapeutic efficacy was observed when the mAb therapy was started at a later tumor‐bearing stage (day 17). Analyses of the tumor‐infiltrating immune cells revealed that the number of Gr‐1^high/low CD11b⁺ MDSC started to increase 13 days after tumor inoculation, whereas injection with low‐dose (50 mg/kg) CP and GEM mitigated this increase. In addition, although intermittent injections with low‐dose CP and GEM on days 10 and 18 suppressed tumor growth significantly, additional local injections of anti‐CD137 mAb on days 19, 21, and 23 further augmented the therapeutic efficacy. Cytotoxic T lymphocytes reactive to CT26 and a tumor antigen peptide were induced successfully from the spleen cells of tumor‐cured or tumor‐stable mice. In a bilateral tumor inoculation model, this combination therapy achieved systemic therapeutic effects and suppressed the growth of mAb‐untreated tumors. These results suggest that intermittent immunochemotherapy using CP and GEM could retain the therapeutic potential of anti‐CD137 mAb that is normally impaired during the late tumor‐bearing stage.     

Anti‐tumor activity of WK88‐1, a novel geldanamycin derivative,in gefitinib‐resistant non‐small cell lung cancers with Met amplification

Although epidermal growth factor receptor‐tyrosine kinase inhibitors (EGFR‐TKIs) have been introduced for the treatment of non‐small cell lung cancer (NSCLC), the emergence of secondary T790M mutation in EGFR or amplification of the Met proto‐oncogene restrain the clinical success of EGFR‐TKIs. Since heat shock protein‐90 (Hsp90) stabilizes various oncoproteins including EGFR and c‐Met, the inhibition of Hsp90 activity appears as a rational strategy to develop anticancer drugs. Despite preclinical efficacy of geldanamycin‐anasamycin (GA)‐derivatives containing benzoquinone moiety as Hsp90 inhibitors, the hepatotoxicity of these GA‐derivatives restricts their therapeutic benefit. We have prepared WK‐88 series of GA‐derivatives, which lack the benzoquinone moiety. In this study, we have examined the anticancer effects of WK88‐1 in Met‐amplified‐ and gefitinib‐resistant (HCC827GR) NSCLC cells and its parental HCC827 cells. Treatment with WK88‐1 reduced the cell viability in both HCC827 and HCC827GR cells, which was associated with marked decrease in the constitutive expression of Hsp90 client proteins, such as EGFR, ErbB2, ErbB3, Met and Akt. Moreover, WK88‐1 attenuated phosphorylation of these Hsp90 client proteins and reduced the anchorage‐independent growth of HCC827GR cells. Administration of WK88‐1 did not cause hepatotoxicity in animals and significantly reduced the growth of HCC827GR cells xenograft tumors in nude mice. Our study provides evidence that ErbB3 might be a client for Hsp90 in Met‐amplified NSCLCs. In conclusion, we demonstrate that inhibition of Hsp90 dampens the activation of EGFR‐ or c‐Met‐mediated survival of Met‐amplified NSCLCs and that WK88‐1 as a Hsp90 inhibitor alleviates gefitinib resistance in HCC827GR cells.     

Phase I study of salazosulfapyridine in combination with cisplatin and pemetrexed for advanced non‐small‐cell lung cancer

Spliced variant isoforms of CD44 (CD44v) are a marker of cancer stem cells in solid tumors. They stabilize the xCT subunit of the transporter system xc(–) and thereby promote synthesis of the antioxidant glutathione. Salazosulfapyridine (SASP) is an inhibitor of xCT and suppresses the proliferation of CD44v‐positive cancer cells. Chemotherapy‐naïve patients with advanced non‐squamous non‐small‐cell lung cancer were enrolled in a dose‐escalation study (standard 3 + 3 design) of SASP in combination with cisplatin and pemetrexed. The primary end‐point was the percentage of patients who experience dose‐limiting toxicity. Fifteen patients were enrolled in the study. Dose‐limiting toxicity was observed in one of six patients at a SASP dose of 1.5 g/day (elevation of aspartate and alanine aminotransferase levels, each of grade 3), two of five patients at 3 g/day (hypotension or pneumonitis, each of grade 3), and two of three patients at 4.5 g/day (anorexia of grade 3). The maximum tolerated dose was thus 3 g/day, and the recommended dose was 1.5 g/day. The overall response rate was 26.7% and median progression‐free survival was 11.7 months, much longer than that for cisplatin–pemetrexed alone in previous studies. Exposure to SASP varied markedly among individuals according to ABCG2 and NAT2 genotypes. The serum concentration of free CD44v protein was increased after the first cycle of treatment, possibly reflecting death of cancer stem cells. Salazosulfapyridine was thus given safely in combination with cisplatin–pemetrexed, with the addition of SASP tending to prolong progression‐free survival. This trial is registered in the UMIN Clinical Trials Registry as UMIN000017854.     

Validation for histology‐driven diagnosis in non‐small cell lung cancer using hsa‐miR‐205 and hsa‐miR‐21 expression by two different normalization strategies

Targeted therapy of non‐small cell lung cancer (NSCLC) demands a more accurate tumor classification that is crucial for patient selection in personalized treatment. MicroRNAs constitute a promising class of biomarkers and a helpful tool for the distinction between lung adenocarcinoma (AC) and squamous cell lung carcinoma (SCC). The aim of this study was to evaluate the impact of two different normalization strategies, using U6 snRNA and hsa‐miR‐103 as reference genes, on hsa‐miR‐205 and hsa‐miR‐21 expression levels, in terms of the classification of subtypes of NSCLC. By means of a quantitative real‐time polymerase chain reaction (qRT‐PCR) microRNA expression levels were evaluated in a classification set of 98 surgically resected NSCLC fresh‐frozen samples, and validated findings in an independent set of 42 NSCLC samples. The microRNA expression levels were exploited to develop a diagnostic test using two data normalization strategies. The performance of microRNA profiling in different normalization methods was compared. We revealed the microRNA‐based qRT‐PCR tests to be appropriate measures for distinguishing between AC and SCC (the concordance of histologic diagnoses and molecular methods greater than 88%). Performance evaluation of microRNA tests, based on the two normalization strategies, showed that the procedure using hsa‐miR‐103 as reference target has a slight advantage (sensitivity 83.33 and 100% in classification and validation set, respectively) compared to U6 snRNA. Molecular tests based on microRNA expression allow a reliable classification of subtypes for NSCLC and can constitute a useful diagnostic strategy in patient selection for targeted therapy.     

Clinical development of anti‐CD19 chimeric antigen receptor T‐cell therapy for B‐cell non‐Hodgkin lymphoma

B‐cell non‐Hodgkin lymphoma (B‐NHL) is the most frequent hematological malignancy. Although refined chemotherapy regimens and several new therapeutics including rituximab, a chimeric anti‐CD20 monoclonal antibody, have improved its prognosis in recent decades, there are still a substantial number of patients with chemorefractory B‐NHL. Anti‐CD19 chimeric antigen receptor (CAR) T‐cell therapy is expected to be an effective adoptive cell treatment and has the potential to overcome the chemorefractoriness of B‐cell leukemia and lymphoma. Recently, several clinical trials have shown remarkable efficacy of anti‐CD19 CAR T‐cell therapy, not only in B‐acute lymphoblastic leukemia but also in B‐NHL. Nonetheless, there are several challenges to overcome before introduction into clinical practice, such as: (i) further refinement of the manufacturing process, (ii) further improvement of efficacy, (iii) finding the optimal infusion cell dose, (iv) optimization of lymphocyte‐depleting chemotherapy, (v) identification of the best CAR structure, and (vi) optimization of toxicity management including cytokine release syndrome, neurologic toxicity, and on‐target off‐tumor toxicity. Several ways to solve these problems are currently under study. In this review, we describe the updated clinical data regarding anti‐CD19 CAR T‐cell therapy, with a focus on B‐NHL, and discuss the clinical implications and perspectives of CAR T‐cell therapy.     

Spontaneous antibody, and CD4 and CD8 T-cell responses against XAGE-1b (GAGED2a) in non-small cell lung cancer patients

The spontaneous immune responses against XAGE-1b (GAGED2a) were analyzed in non-small cell lung cancer (NSCLC) patients. An antibody response against XAGE-1b (GAGED2a) was observed in 10% (20/200) of NSCLC patients and in 19% (13/69) of stage IIIB/IV lung adenocarcinoma patients. A CD4 T-cell response was detected in 88% (14/16) and a CD8 T-cell response in 67% (6/9) in the XAGE-1b (GAGED2a) antibody-positive patients examined. Frequent antibody responses and CD4 and CD8 T-cell responses in XAGE-1b (GAGED2a) antibody-positive patients indicate the strong immunogenicity of the XAGE-1b (GAGED2a) antigen in NSCLC patients. We established T-cell clones from PBMCs of antibody-positive patients and determined the DRB1*04:05-restricted XAGE-1b (GAGED2a) 18-31 peptide (14-mer) as a CD4 T cell epitope and the A*02:06-restricted XAGE-1b (GAGED2a) 21-29 peptide (9-mer) as a CD8 T cell epitope. As for peptide recognition, CD4 and CD8 T-cell clones responded to naturally processed antigen. The CD4 T-cell clone recognized DCs pulsed with the synthetic protein or a lysate from XAGE-1b-transfected 293T cells. The CD8 T-cell clone showed cytotoxicity against a tumor expressing XAGE-1b (GAGED2a) and the appropriate HLA class I allele. These findings establish XAGE-1b (GAGED2a) as a promising target for a lung cancer vaccine.     

Cell cycle‐related and expression‐elevated protein in tumor overexpression is associated with proliferation behaviors and poor prognosis in non‐small‐cell lung cancer

The cell cycle‐related and expression‐elevated protein in tumor (CREPT) is overexpressed in several human malignancies. However, the clinical relevance of CREPT expression and its biological role in non‐small‐cell lung cancer (NSCLC) remains unclear. In this study, we detected the expression of CREPT in both NSCLC tissues and cell lines by immunohistochemistry, Western blot analysis, and RT‐PCR. The correlation between CREPT expression and clinicopathologic features was analyzed in 271 NSCLC patients. The prognostic value of CREPT expression was evaluated by Kaplan–Meier analysis and Cox regression analysis. CREPT was overexpressed in Calu‐1 cell lines by using plasmid vector and its biological function was explored both in vitro and in vivo. We found that CREPT was significantly overexpressed in NSCLC compared with paired adjacent non‐tumor tissues, and the expression level of CREPT was correlated with tumor differentiation, lymph node metastasis, and clinical stage. Kaplan–Meier analysis showed that the recurrence‐free survival and overall survival of high CREPT expression groups were significantly shorter than those of the low CREPT expression group. Multivariate analysis identified that CREPT might be an independent biomarker for the prediction of NSCLC prognosis. Overexpression of CREPT increased cell proliferation and enhanced the migration and invasion ability of Calu‐1 cells (a human NSCLC cell line with relative low CRPET expression) in vitro. Moreover, CREPT overexpression promoted tumor growth in a nude mice model. These results suggest that CREPT is closely relevant to the proliferation of NSCLC cells and it might be a potential prognostic marker in NSCLC patients.     

CD24在非小细胞肺癌中的表达及其临床意义

目的：探讨CD24在非小细胞肺癌中的表达及其预后意义.方法：采用免疫组织化学方法检测CD24在73例非小细胞肺癌和10例正常肺组织中的表达,分析CD24表达与非小细胞肺癌临床病理参数的关系及其对患者预后评估价值.结果：非小细胞肺癌患者和正常肺对照组中CD 24的阳性表达率分别为82.2%和30%,两者差异显著（p=0.001）.CD24的表达在各个临床病理参数之间不存在显著差异（P〉0.05）.CD24高表达患者的死亡风险较低表达者明显升高（RR=2.20,95%CI=1.023-4.731,P=0.044）,累积生存率显著降低（P=0.036）,多因素预后分析显示CD24的表达是非小细胞肺癌的独立预后因素（P=0.015）.结论：CD24在非小细胞肺癌中表达增高,其表达对判断非小细胞肺癌的发展及预后具有一定的临床意义,为靶向治疗提供了潜在靶点.     

Knockdown of G‐protein‐signaling modulator 2 promotes metastasis of non‐small‐cell lung cancer by inducing the expression of Snail

Non‐small‐cell lung cancer (NSCLC) is the leading global cause of cancer‐related death. Due to the lack of reliable diagnostic or prognostic biomarkers, the prognosis of NSCLC remains poor. Consequently, there is an urgent need to explore the mechanisms underlying this condition in order to identify effective biomarkers. G‐protein‐signaling modulator 2 (GPSM2) is widely recognized as a determinant of mitotic spindle orientation. However, its role in cancer, especially NSCLC, remains uncertain. In this study, we found that GPSM2 was downregulated in NSCLC tissues and was correlated with a poor prognosis. Furthermore, the knockdown of GPSM2 promoted NSCLC cell metastasis in vitro and in vivo and accelerated the process of epithelial‐mesenchymal transition (EMT). Mechanistically, we showed that silencing GPSM2 induced cell metastasis and EMT through the ERK/glycogen synthase kinase‐3β/Snail pathway. These results confirm that GPSM2 plays an important role in NSCLC. Moreover, GPSM2, as an independent prognostic factor, could be a potential prognostic biomarker and drug target for NSCLC.