Pilot Study of CT-Based Radiomics Model for Early Evaluation of Response to Immunotherapy in Patients With Metastatic Melanoma.

Objective: Determine the performance of a computed tomography (CT) -based radiomics model in predicting early response to immunotherapy in patients with metastatic melanoma. Methods: This retrospective study examined 50 patients with metastatic melanoma who received immunotherapy treatment in our hospital with an anti-programmed cell death-1 (PD-1) agent or an inhibitor of cytotoxic T lymphocyte antigen-4 (CTLA-4). Thirty-four patients who received an anti-PD-1 agent were in the training sample and 16 patients who received a CTLA-4 inhibitor were in the validation sample. Patients with true progressive disease (PD) were in the poor response group, and those with pseudoprogression, complete response (CR), partial response (PR), or stable disease (SD) were in the good response group. CT images were examined at baseline and after the first and second cycles of treatment, and the imaging data were extracted for radiomics modeling. Results: The radiomics model based on pre-treatment, post-treatment, and delta features provided the best results for predicting response to immunotherapy. Receiver operating characteristic (ROC) analysis for good response indicated an area under the curve (AUC) of 0.882 for the training group and an AUC of 0.857 for the validation group. The sensitivity, specificity, and accuracy of model were 85.70% (6/7), 66.70% (6/9), and 75% (12/16) for predicting a good response. Conclusion: A CT-based radiomics model for metastatic melanoma has the potential to predict early response to immunotherapy and to identify pseudoprogression.

ISG15 inhibits cancer cell growth and promotes apoptosis.

Cervical cancer is one of the most common causes of cancer-related mortality in women in developing countries. Interferon (IFN)-α has been widely used in the treatment of various types of cancer, including cervical cancer, and IFN-stimulated gene 15 (ISG15), an ubiquitin-like protein, is upregulated by IFN-α treatment. The anti-virus and antitumor effects of ISG15 have been reported; however, its mechanism of action have not yet been fully elucidated. In this study, HeLa cells were used as a model system to investigate the roles of ISG15 in IFN-α-mediated cancer cell growth inhibition and induction of apoptosis. The results revealed that both p53 and p21 were upregulated in HeLa cells treated with IFN-α or in the HeLa cells overexpressing ISG15. In addition, the expression levels of ubiquitin-like modifier-activating enzyme 7 (UBA7, also known as UBE1L; ISG15 E1-activating enzyme), UBCH8 (ISG15 E2-conjugating enzyme) and HERC5 (ISG15 E3-ligase) were elevated in the HeLa cells treated with IFN-α. The levels of p53 in the HeLa cells were attenuated by transient transfection with small interfering RNA (siRNA) targeting ISG15 (ISG15-siRNA). Cell viability was inhibited by both IFN-α treatment and ISG15 overexpression. However, these effects were significantly diminished when p53 was knocked down, suggesting that the effects of inhibitory effects of ISG15 on HeLa cell growth and the induction of apoptosis were p53-dependent. Taken together, these results suggest the existence of the IFN-α/ISG15/p53 axis in cervical cancer cells and any strategies manipulating the levels of ISG15 may thus prove to be effective in the treatment of cervical cancer.

Theoretical Studies on Palladium-Mediated Enantioselective C-H Iodination.

DFT calculations have been carried out to investigate the reaction mechanism for Pd(II)-mediated enantioselective C-H iodination. Iodination of the aryl ortho C-H bond of benzylamines catalyzed by Pd(II) diacetate complexes in the presence of the L-MPAA ligand experiences three main steps: first, C-H bond activation; second, oxidative addition of iodine on Pd(II) and reductive elimination of iodobenzene; third, catalyst regeneration through ligand exchange. The C-H bond activation is found to be the rate-determining step of the overall iodination due to higher activation energy. The reaction barrier for the formation of iodinated (R)-benzylamine is lower than that of (S)-benzylamine, which confirms the R enantioselectivity in iodination at room temperature. The retainment of the coordination of one acetic acid on Pd(II) and the chelating MPAA ligand during the catalyzed reaction are suggested to give space economy to facilitate the C-H bond activation. The NHTf functional group on the substrate is found to be very important for ortho C-H iodination at ambient condition. Our calculated results are consistent with the experimental observations.

Effects of a Particular Heptapeptide on the IFN-α-Sensitive CML Cells.

Using the phage display biopanning technique, we have previously identified a heptapeptide KLWVIPQ which specifically binds to the surface of the IFN-α-sensitive but not the IFN-α-resistant CML cells. The effects of this heptapeptide on the IFN-α-sensitive CML cells were investigated in the present study. IFN-α-sensitive KT-1/A3 and IFN-α-resistant KT-1/A3R CML cells were transfected by pEGFP-KLWVIPQ expression vector and/or induced by IFN-α. WST-1 cell proliferation assay, flow cytometry, and western blotting were performed to determine the effects of this heptapeptide and/or IFN-α on CML cells. The viability of the KT-1/A3 cells was inhibited and apoptosis was induced by either expression of the heptapeptide KLWVIPQ or IFN-α treatment with concurrent upregulation of P53 and downregulation of P210(bcr/abl). However, these effects were not observed in the IFN-α-resistant KT-1/A3R cells. These results suggest that the heptapeptide KLWVIPQ shares a similar mechanism with IFN-α in the regulation of CML cell growth and apoptosis, implying that the heptapeptide KLWVIPQ could be a novel target to go further into mechanisms of IFN-α sensitivity and/or resistance in CML.

Ubiquitination involved enzymes and cancer.

Ubiquitination is a post-translational modification process that regulates multiple cell functions. It also plays important roles in the development of cancer. Mechanistically, ubiquitination is a complex process that is comprised of a series of events involving ubiquitin-activating enzymes, ubiquitin-conjugating enzymes and ubiquitin ligases. In general, covalent attachment of ubiquitin to the target proteins marks them for degradation. Dysregulation of the ubiquitination process may cause carcinogenesis. In this review, we summarize recent developments in understanding the relationship between ubiquitination enzymes and carcinogenesis.

Polymorphisms of DNA repair genes XPD, XRCC1, and OGG1, and lung adenocarcinoma susceptibility in Chinese population.

Lung adenocarcinoma (ADC) is one of the major histological types of lung cancer. Genetic polymorphism in DNA repair genes and lung ADC susceptibility is well documented. In this case-control study, the association between the polymorphic sites of DNA repair genes XPD-751, XRCC1-399, and OGG1-326, and lung ADC susceptibility in ethnic Han Chinese population has been investigated. Genomic DNA was isolated from the peripheral blood of 201 healthy controls and 82 lung ADC patients from the people of Hunan Province, China. Polymorphisms of the investigated genes were analyzed by using polymerase chain reaction-restriction fragment length polymorphism. There was no significant difference between the samples from lung ADC patients and healthy controls about the genotype frequencies of XPD-751, XRCC1-399, and OGG1-326 sites. However, multifactor dimensionality reduction analysis showed that the genetic polymorphisms of the three-loci models of DNA repair genes (XPD-751/XRCC1-399/OGG1-326) are associated with lung ADC. Thus, this study reveals that a three-order interaction among the polymorphic sites of XPD-751, XRCC1-399, and OGG1-326 is associated with lung ADC risk in the studied population, although polymorphism in individual gene was not associated.

Differential responses to UVB irradiation in human keratinocytes and epidermoid carcinoma cells.

OBJECTIVE: To examine UVB-induced responses in normal human keratinocytes (HaCaT) and epidermoid carcinoma cells (A431) at the cellular and molecular level, and investigated the protective effect of salidroside. METHODS: Cells irradiated by UVB at various dosage and their viability was assessed by MTT assays, cell cycle was analysed by flow cytometry. The expression of NF-κB, BCL-2, and CDK6 after 50 J/m(2) UVB irradiation were detected by RT-PCR and western blotting. RESULTS: Our results confirmed greater tolerance of A341 cells to UVB-induced damage such as cell viability and cell cycle arrest, which was accompanied by differential expression changes in NF-κB, BCL-2, and CDK6. UVB exposure resulted in HaCaT cells undergoing G(1)-S phase arrest. When treated with salidroside, HaCaT survival was significantly enhanced following exposure to UVB, suggesting great therapeutic potential for this compound. CONCLUSION: Taken together, our study suggests that A431 respond differently to UVB than normal HaCaT cells, and supports a role for NF-κB, CDK6, and BCL-2 in UVB-induced cell G(1)-S phase arrest. Furthermore, salidroside can effectively protect HaCaT from UVB irradiation.

[Mechanisms of ultraviolet B irradiation-induced injuries in 16HBE cells].

OBJECTIVE: To investigate the biological effects of ultraviolet B (UVB) irradiation on human bronchial epithelial cells (16HBE cells) and explore the possible mechanism. METHODS: The survival rates of 16HBE cells were detected by MTT assay at 12 h after UVB irradiation at different doses (0, 10, 30, 50, 70, and 100 J/m(2)) or at 50 J/m(2) for different durations (2, 4, 8, 12, and 24 h). The DNA ladder was detected by agarose gel electrophoresis, the cell cycle changes were analyzed by flow cytometry, and the expression of nuclear factor-κB (NF-κB)/p65 protein was assayed by Western blotting following the exposures. RESULTS: UVB irradiation of the cells resulted in lowered cell survival rates, DNA fragmentation, S phase arrest and up-regulation of NF-κB/p65 protein expression. CONCLUSIONS: UVB irradiation can induce growth inhibition and apoptosis of 16HBE cells, in which process NF-κB protein may play a key role.

Differential expression profiles of microRNAs in NIH3T3 cells in response to UVB irradiation.

MicroRNAs (miRNAs) are known as a kind of small, noncoding RNA, which play an important role in mediating many biological processes such as development, cell proliferation and differentiation in plants and animals. Here we report the differential expression profiles of miRNAs and characterized putative target genes in NIH3T3 cells at a series of different time points after UVB irradiation (compared with no UVB irradiation). The relative expression of mature miRNA genes was determined by miRNA microarray technique and the results were confirmed by real-time reverse transcriptase polymerase chain reaction (qRT-PCR). Potential target genes of these miRNAs were classified into different function categories with the GOstat software (http://gostat.wehi.edu.au/cgi-bin/goStat.pl). Several miRNAs in this study expressed highly at different time points, especially mmu-miR-365 and mmu-miR-21. Three miRNAs were lowly expressed, of which mmu-miR-465 showed low levels of expression at all time points, whereas after 50 J m(-2) UVB irradiation mmu-miR-296 and mmu-miR-376c showed low levels of expression at 6 and 12 h, respectively. Our study provided a basis for the global characterization of UV-regulated miRNA expression.

[Effects of radiation injury on peripheral blood and liver NO concentration in mice].

OBJECTIVE: To study the effect of radiation injury on nitric oxide (NO) concentration in mouse peripheral blood and liver. METHODS: NIH mice were subjected to gamma-ray exposure at 9.0 Gy and transferred immediately in room temperature condition. NO concentrations in the liver and peripheral blood were examined before and at different time points after the exposure. RESULTS: Compared to that before exposure, NO concentration in the peripheral blood and liver significantly increased after gamma-ray exposure. NO concentration in the peripheral blood began to increase 3 h after the exposure, but that in the liver increased till 6 h after the exposure. CONCLUSION: Radiation can cause the increase of NO concentration in the peripheral blood and liver, but different tissues may exhibit different response intensities to radiation.

[Roles of p38 and ERK signaling pathway in cell apoptosis induced by UVB irradiation].

OBJECTIVE: To explore the involvement of p38 and ERK signal transduction pathways in UVB-induced cell apoptosis. METHODS: HaCat cells were exposed to UVB irradiation for 1, 3, 5, 10, and 15 min, respectively, after which the cell survival was assessed using MTT assay, and the cell apoptosis observed under fluorescent microscope with Hoechst staining. Western blotting was used to examine the possible signal transduction pathway involved in the cell apoptosis following the exposures. RESULTS: For the same incubation time following the exposure, the cell survival rate decreased gradually with the increase of UVB irradiation dose. At a fixed UVB irradiation dose, prolonged cell incubation following the exposure resulted in decreased cell survival rate, which, however, began to increase after the minimum rate was reached. At different UVB doses, cell exposure for 5 min caused the highest cell apoptosis rate, which peaked at 12 h during the post-irradiation incubation. The expressions of p38 and p53 were significantly decreased while p44/42 expression remained unchanged in the exposed cells. CONCLUSION: UVB irradiation can induce growth inhibition and apoptosis of HaCat cells in a dose- and time-dependent manner, and p38 pathway other than ERK pathway is probably involved in UVB-induced cell apoptosis.

Downregulation of HBx mRNA in HepG2.2.15 cells by small interfering RNA.

OBJECTIVE: Hepatitis B virus (HBV) infection is one of the most prevalent viral infectious diseases in humans. And it is still a challenge for the development of an effective therapy for HBV infection. Recently, the progress in RNA interference (RNAi) has shed some light on the inhibition of HBV expression and replication by RNAi specific for the various genes of the HBV genome. Some prior researches suggests that the HBV x protein (HBx) plays an important role in viral transcription, cell growth, and apoptotic cell death. METHODS: In the present study, we designed three siRNAs based on the X-protein of HBV sequences and tested their effects on the expression of HBx gene following sorting of siRNA-positive cells. The interference effect was tested in 24, 48, and 72 h. HBsAg in cultured media was assayed using western blot at various days post-transfection. The amount of HBx mRNA was quantitated by Real-time reverse-transcript PCR (RT-PCR). RESULTS: There was a decrease in the levels of HBV mRNA and HBsAg from the the transfected cells. Among these three siRNAs, siRNA-2 was found to be the most effective at suppressing HBV gene expression.

Cloning and functional study of a novel aromatic-ring-hydroxylating dioxygenase gene.

The aromatic-ring-hydroxylating dioxygenase is a key enzyme that initiates the biodegradation of polycyclic aromatic hydrocarbons in bacteria. In the present study, a novel dioxygenase sequence was cloned from Terrabacter sp. FLO using a genome walking method. The dioxygenase was cloned into pET17 and actively expressed in E.coli BL21 (DE3) in co-expression with electron transfer chain proteins. The recombinant dioxygenase was found to transform phenanthrene, fluorene, pyrene and fluoranthene into the cis-dihydrodiol metabolites.

[Specific small interfering RNAs inhibit replication of hepatitis B virus].

OBJECTIVE: To obtain specific small interfering RNAs (siRNA) for hepatitis B virus (HBV) and evaluate their interfering effect. METHODS: Three siRNAs were transfected into HepG2.2.15 cells, and the amount of HBV mRNA in the cell culture medium was quantified with real-time fluorescence quantitative RT-PCR. HBsAg in the culture media was assayed with Western blotting at different time points after transfection. RESULTS: The cells transfected with specific siRNAs showed decreased levels of HBV mRNA and HBsAg (P<0.05), but those with nonspecific siRNA transfection as the negative control did not show such changes (P>0.05). CONCLUSION: Specific siRNA can significantly inhibit protein expression and mRNA synthesis of HBV in HepG2.2.15 cells in vitro.

[Positron emission tomography with L-[S-methyl-11C]-methioine and its biodistribution].

OBJECTIVE: To study the biodistribution of L-[S-methyl-(11)C]-methioine ((11)C-MET) and explore its clinical application in positron emission tomography (PET) for brain tumor detection. METHODS: Twenty-four Wistar rats and divided into 6 equal groups and injected with (11)C-MET through the tail vein and killed by decollation at 5, 10, 20, 30 and 40 min after injection, respectively. The liver, brain, blood, heart, lung, kidney, and spleen were harvested to measure the radioactivity and calculate the biodistribution of (11)C-MET. PET imaging with (11)C-MET was performed in 6 normal volunteers and 30 patients with pathologically confirmed brain gliomas. RESULTS AND CONCLUSION: (11)C-MET showed high blood uptake and a long retention in the tumor mass, therefore can be a valuable tracer for PET imaging of brain tumor and the hypophysis.

[Effect of hot and humid environment on bone marrow and spleen of mice exposed to gamma irradiation].

OBJECTIVE: To study the effect of hot and humid environment (HHE) on the bone marrow and spleen in mouse exposed to gamma irradiation. METHODS: After exposure to gamma irradiation at the dosage of 6.5 Gy, the mice were subjected to treatment in HHE for 1 h or at room temperature (RT) respectively. After exposure to HHE, the mice in HHE group were kept at RT. The bone marrow and spleen of the mice in both RT and HHE groups were examined at 1, 3, 5, 9 and 15 days after irradiation for bone marrow cellularity, DNA content in the bone marrow cells, and spleen/body weight ratio. RESULTS: Compared with the RT group, mice in the HEE group showed aggravation of decreases in bone marrow cells, DNA content and spleen/body weight ratio. CONCLUSIONS: HHE aggravates radiation injury of the bone marrow and spleen in mice.

Survival of mice with gamma-ray irradiation in hot and humid environments.

OBJECTIVE: To study the survival of the mice with gamma-ray irradiation in hot and humid environments (HHE) and determine the median lethal dose in 30 days (LD50/30). METHODS: One hundred mice were randomly divided into 2 groups (n=50 each) to receive gamma-ray irradiation at the dosage of either 7 or 9 Gy, and were then immediately transferred to the chambers simulating HHE for treatment for 30, 60, 90 or 120 min respectively, leaving one group at room temperature (n=10 in each group). The death rates of the mice within 30 days were observed. For LD50/30 determination, another 180 mice in 3 equal groups were subjected to irradiation at 5, 7 or 9 Gy, respectively and after further division of each group into 3 equal subgroups, the mice underwent treatment in HHE for 60 or 90 min respectively or at room temperature to observe their death rates within 30 days and calculate the LD50/30. RESULTS: Compared to the mice treated at room temperature, earlier onset and more cases of infections with much severity were observed in all the HHE groups, with reduced average survival time and obviously shortened median survival time (P<0.05), and LD50/30 tended to also decrease in the HHE groups. CONCLUSION: The survival indexes of irradiated mice are significantly decreased in hot and humid environments.