A new strategy to target regulatory T cells in solid tumors

Combination therapy: Future directions of immunotherapy in small cell lung cancer

Small cell lung cancer (SCLC), an aggressive and devastating malignancy, is characterized by rapid growth and early metastasis. Although most patients respond to first-line chemotherapy, the majority of patients rapidly relapse and have a relatively poor prognosis. Fortunately, immunotherapy, mainly including antibodies that target the cytotoxic T lymphocyte antigen-4 (CTLA-4), checkpoints programmed death-1 (PD-1), and programmed death-ligand 1 (PD-L1) to block immune regulatory checkpoints on tumor cells, immune cells, fibroblasts cells and endothelial cells, has achieved the milestone in several solid tumors, such as melanoma and non-small-cell lung carcinomas (NSCLC). In recent years, immunotherapy has made progress in the treatment of patients with SCLC, while its response rate is relatively low to monotherapy. Interestingly, the combination of immunotherapy with other therapy, such as chemotherapy, radiotherapy, and targeted therapy, preliminarily achieve greater therapeutic effects for treating SCLC. Combining different immunotherapy drugs may act synergistically because of the complementary effects of the two immune checkpoint pathways (CTLA-4 and PD-1/PD-L1 pathways). The incorporation of chemoradiotherapy in immunotherapy may augment antitumor immune responses because chemoradiotherapy can enhance tumor cell immunogenicity by rapidly inducing tumor lysis and releasing tumor antigens. In addition, since immunotherapy drugs and the molecular targets drugs act on different targets and cells, the combination of these drugs may achieve greater therapeutic effects in the treatment of SCLC. In this review, we focused on the completed and ongoing trials of the combination therapy for immunotherapy of SCLC to find out the rational combination strategies which may improve the outcomes for SCLC.

Effects of Arsenic Trioxide on Minor Progressive High-Grade Osteosarcoma of the Extremities Metastatic to the Lung: Results of 39 Patients Treated in a Single Institution

Patients who mildly progressed after first-line chemotherapy were administered arsenic trioxide (ATO) 5–10 mg intravenously daily. Thirty-nine patients were finally enrolled in the study, of whom 19 patients received first-line chemotherapy with ATO infusion while 20 patients did not. Progression-free survival at 4 months was 89.2 and 62.7% (p = 0.043) for the ATO group and the control group, respectively, while the 2-year overall survival was 61 and 16.4% (p = 0.032).

Trial Watch: Radioimmunotherapy for oncological indications

During the past two decades, it has become increasingly clear that the antineoplastic effects of radiation therapy do not simply reflect the ability of X-, β- and γ-rays to damage transformed cells and directly cause their permanent proliferative arrest or demise, but also involve cancer cell-extrinsic mechanisms. Indeed, among other activities, radiotherapy has been shown to favor the establishment of tumor-specific immune responses that operate systemically, underpinning the so-called 'out-of-field' or 'abscopal' effect. Thus, ionizing rays appear to elicit immunogenic cell death, a functionally peculiar variant of apoptosis associated with the emission of a particularly immunostimulatory combination of damage-associated molecular patterns. In line with this notion, radiation therapy fosters, and thus exacerbates, the antineoplastic effects of various treatment modalities, including surgery, chemotherapy and various immunotherapeutic agents. Here, we summarize recent advances in the use of ionizing rays as a means to induce or potentiate therapeutically relevant anticancer immune responses. In addition, we present clinical trials initiated during the past 12 months to test the actual benefit of radioimmunotherapy in cancer patients.

Arsenic trioxide inhibits DNA methyltransferase and restores TMS1 gene expression in K562 cells

BACKGROUND

Gene silencing associated with aberrant methylation of promoter region CpG islands is an acquired epigenetic alteration that serves as an alternative to genetic defects in the inactivation of tumor suppressor genes in human cancers. The demethylating, dose-dependent effect of arsenic trioxide (As2O3) on several tumor-related genes has already been postulated. However, whether such a demethylating effect also applies to the TMS1 gene in chronic myeloid leukemia cell line K562 cells has not been studied so far. The aim of the present study was to detect the methylation status of the TMS1 gene in K562 cells and the demethylation effect of As2O3 on TMS1 as well as TMS1 apoptosis-associated protein Bcl-2/Bax and DNA methyltransferase (DNMT) expression.

METHODS

TMS1 mRNA expression in K562 cells and normal bone marrow was determined by reverse transcription (RT) polymerase chain reaction (PCR), and the DNA methylation status of the TMS1 promoter in K562 cells treated with different concentrations of As2O3 for 48 h was determined by methylation-specific PCR. RT-PCR and Western blot were used to detect TMS1 and DNMT expression. We also assessed TMS1-associated apoptosis protein Bcl-2/Bax expression by Western blot and apoptosis rates by flow cytometry using annexin V/propidium iodide double staining.

RESULTS

In K562 cells, TMS1 was completely methylated and both TMS1 mRNA and protein showed a low expression, but 2 μmol/l As2O3 could significantly restore the expression of the TMS1 gene both at mRNA and protein level (p < 0.01) by fully reversing DNA methylation. As2O3 decreased mRNA and protein expression of DNMT1 (p < 0.05) in a dose-dependent manner. Flow cytometry showed that in the experimental group (2 μmol/l As2O3), cell apoptosis was significantly increased compared with the control group (no As2O3; p < 0.05). In the experimental group, Western blot showed that the expression of the anti-apoptotic protein Bcl-2 was significantly decreased; however, the proapoptotic protein Bax was markedly increased and the Bcl-2/Bax ratio was markedly reduced (p < 0.01).

CONCLUSIONS

As2O3 could restore the expression of TMS1 by inhibiting DNMT to reverse the hypermethylation and induced apoptosis of K562 cells by downregulation of Bcl-2/Bax expression.