HHLA2 and PD-L1 co-expression predicts poor prognosis in patients with clear cell renal cell carcinoma

Background

Although clear cell renal cell carcinoma (ccRCC) is well known as a highly immunogenic tumor, only a small subset of patients could benefit from current immunotherapy, which might be due to the heterogeneity of immune microenvironment in ccRCC. So, it is meaningful to explore novel immunotherapy or combination therapy for improving therapeutic efficacy. HHLA2, a newly discovered B7 family member, is prevalently expressed in numerous tumors, including ccRCC. This study aimed to investigate the prognostic impact of HHLA2/PD-L1 co-expression and its relationship with tumor-infiltrating lymphocytes (TILs).

Methods

The expression levels of HHLA2, PD-L1, CD8, and CD4 in cancer tissues from cases (206 in the training cohort and 197 in the validation cohort) with surgically resectable primary ccRCC were evaluated by immunohistochemistry.

Results

The positive rates of HHLA2 were much higher than those of PD-L1 in ccRCC tissues. HHLA2-positive expression was significantly associated with necrosis, microvascular invasion, advanced Fuhrman nuclear, and TNM stage and indicated a shorter progression-free survival (PFS) and overall survival (OS) in both cohorts. Moreover, patients with HHLA2/PD-L1 co-expression suffered the highest risk of disease progression and death by a significant margin. Besides, HHLA2/PD-L1 co-expression was significantly associated with a high density of CD8⁺ and CD4⁺ TILs. Notably, a new immune classification, based on HHLA2/PD-L1 co-expression and TILs, successfully stratified PFS and OS, especially in patients with TILs positivity.

Conclusions

The expression of HHLA2 is more frequent than PD-L1 in ccRCC. HHLA2/PD-L1 co-expression had an adverse impact on the prognoses of patients with ccRCC; this finding provides a rationale for combination immunotherapy with anti-HHLA2 and PD-L1 blockage for patients with ccRCC in the future.

The influencing factors and functions of DNA G-quadruplexes

G‐quadruplexes form folded structures because of tandem repeats of guanine sequences in DNA or RNA. They adopt a variety of conformations, depending on many factors, including the type of loops and cations, the nucleotide strand number, and the main strand polarity of the G‐quadruplex. Meanwhile, the different conformations of G‐quadruplexes have certain influences on their biological functions, such as the inhibition of transcription, translation, and DNA replication. In addition, G‐quadruplex binding proteins also affect the structure and function of G‐quadruplexes. Some chemically synthesized G‐quadruplex sequences have been shown to have biological activities. For example, bimolecular G‐quadruplexes of AS1411 act as targets of exogenous drugs that inhibit the proliferation of malignant tumours. G‐quadruplexes are also used as vehicles to deliver nanoparticles. Thus, it is important to identify the factors that influence G‐quadruplex structures and maintain the stability of G‐quadruplexes. Herein, we mainly discuss the factors influencing G‐quadruplexes and the synthetic G‐quadruplex, AS1411.

Significance of the study

This review summarizes the factors that influence G‐quadruplexes and the functions of the synthetic G‐quadruplex, AS1411. It also discusses the use of G‐quadruplexes for drug delivery in tumour therapy.

Quantitative image analysis for evaluation of tumor response in clinical oncology

The objective, accurate, and standardized evaluation of tumor response to treatment is an indispensable procedure in clinical oncology. Compared to manual measurement, computer-assisted linear measurement can significantly improve the accuracy and reproducibility of tumor burden quantification. For irregular-shaped and infiltrating or diffuse tumors, which are difficult to quantify by linear measurement, computer-assisted volumetric measurement may provide a more objective and sensitive quantification to evaluate tumor response to treatment than linear measurement does. In the evaluation of tumor response to novel oncologic treatments such as targeted therapy, changes in overall tumor size do not necessarily reflect tumor response to therapy due to the presence of internal necrosis or hemorrhages. This leads to a new generation of imaging biomarkers to evaluate tumor response by using texture analysis methods, also called radiomics. Computer-assisted texture analysis technology offers a more comprehensive and in-depth imaging biomarker to evaluate tumor response. The application of computer-assisted quantitative imaging analysis techniques not only reduces the inaccuracy and improves the reliability in tumor burden quantification, but facilitates the development of more comprehensive and intelligent approaches to evaluate treatment response, and hence promotes precision imaging in the evaluation of tumor response in clinical oncology. This article summarizes the state-of-the-art technical developments and clinical applications of quantitative imaging analysis in evaluation of tumor response in clinical oncology.

[Regulatory effect of bone marrow mesenchymal stem cells on polarization of macrophages]

Objective: To examine the regulatory effect of bone marrow mesenchymal stem cells (BM-MSCs) on the polarization of bone marrow-derived macrophages, and to provide a theoretical support for the application of mesenchymal stem cells in the treatment of liver fibrosis. Methods: MSCs and macrophages were first isolated from the bone marrow of mice. Macrophages were polarized to M1 macrophages with lipopolysaccharide (LPS) and interferon-γ (IFN-γ), and to M2 macrophages with interleukin-4 (IL-4). The macrophages were then co-cultured with BM-MSCs in a Transwell for 24 h, and changes in the percentages of M1 and M2 macrophages were examined using flow cytometry. The mRNA levels of the M1 macrophage-associated cytokines, tumor necrosis factor-α (TNF-α) and interleukin-23a (IL-23a), and M2 macrophage-associated molecules, arginase-1 (Arg-1) and CD163, were measured by real-time quantitative PCR. The two samples were compared using the t test, and P < 0.05 was considered as statistically significant. Results: Flow cytometry showed that the percentage of M1 macrophages was significantly lower in the (macrophage + LPS + IFN-γ + BM-MSC) co-culture group than in the (macrophage + LPS + IFN-γ) group (62.5% ± 4.6% vs 86.6% ± 6.9%, t = 5.034, P = 0.0073). In addition, the relative mRNA expression of TNF-α and IL-23a was also significantly reduced in the co-culture group compared with those in the macrophage control group as measured by RT-qPCR (t = 11.57 and 10.57, respectively, P < 0.05). Compared with that in the macrophage control group, the percentage of M2 macrophages in the (macrophage+BM-MSC) co-culture group was significantly increased (89.5% ± 5.8% vs 70.1% ± 6.3%, t = 3.924, P = 0.0172), along with significantly elevated relative mRNA expression of Arg1 (14.35±1.05 vs 1.00±0.03, t = 21.96, P < 0.05) and CD163 (3.04 ± 0.27 vs 1.00 ± 0.03, t = 13.14, P < 0.05). Conclusion: BM-MSCs can inhibit LPS + IFN-γ-induced polarization to M1 macrophages and promote polarization to M2 macrophages through the release of paracrine factors.

Preliminary Study of MR and Fluorescence Dual-mode Imaging: Combined Macrophage-Targeted and Superparamagnetic Polymeric Micelles

Purpose: To establish small-sized superparamagnetic polymeric micelles for magnetic resonance and fluorescent dual-modal imaging, we investigated the feasibility of MR imaging (MRI) and macrophage-targeted in vitro. Methods: A new class of superparamagnetic iron oxide nanoparticles (SPIONs) and Nile red-co-loaded mPEG-Lys3-CA4-NR/SPION polymeric micelles was synthesized to label Raw264.7 cells. The physical characteristics of the polymeric micelles were assessed, the T2 relaxation rate was calculated, and the effect of labeling on the cell viability and cytotoxicity was also determined in vitro. In addition, further evaluation of the application potential of the micelles was conducted via in vitro MRI. Results: The diameter of the mPEG-Lys3-CA4-NR/SPION polymeric micelles was 33.8 ± 5.8 nm on average. Compared with the hydrophilic SPIO, mPEG-Lys3-CA4-NR/SPION micelles increased transversely (r2), leading to a notably high r2 from 1.908 µg/mL-1S-1 up to 5.032 µg/mL-1S-1, making the mPEG-Lys3-CA4-NR/SPION micelles a highly sensitive MRI T2 contrast agent, as further demonstrated by in vitro MRI. The results of Confocal Laser Scanning Microscopy (CLSM) and Prussian blue staining of Raw264.7 after incubation with micelle-containing medium indicated that the cellular uptake efficiency is high. Conclusion: We successfully synthesized dual-modal MR and fluorescence imaging mPEG-Lys3-CA4-NR/SPION polymeric micelles with an ultra-small size and high MRI sensitivity, which were effectively and quickly uptaken into Raw 264.7 cells. mPEG-Lys3-CA4-NR/SPION polymeric micelles might become a new MR lymphography contrast agent, with high effectiveness and high MRI sensitivity.

Genetic variation in the invasive weed Mikania micrantha (Asteraceae) suggests highways as corridors for its dispersal in southern China

BACKGROUND AND AIMS

Roads as corridors of seed or fruit spatial dispersal have major impacts on the establishment and spread of invasive species, but their precise role in population genetic variation remains poorly understood. The South American weed Mikania micrantha has spread rapidly across southern China since its introduction to the Shenzhen area in 1984. This study investigated how its genetic diversity is distributed along highways, and whether highways have acted as corridors for the rapid expansion of M. micrantha METHODS: Twenty-seven roadside populations were sampled along four highways in southern China, and 787 samples were examined using 12 microsatellite markers. Variation in genetic diversity among populations was quantified and patterns of genetic differentiation were analysed.

KEY RESULTS

A high level of genetic diversity was found at both the species and the population levels in this self-incompatible plant (expected heterozygosity = 0·497 and 0·477, respectively; allelic richness = 2·580 and 2·521, respectively). The Wright F-statistic value among populations (0·044, P < 0·01) and the analysis of molecular variance (91 % of genetic variation residing within populations, 9 % among populations within highways and 0 % among the four highways) showed a relatively low level of genetic differentiation among populations, while the principal coordinate and cluster analyses also indicated a lack of clear geographical genetic structure among populations. The calculated N_m value of 5·5 signifies strong gene flow.

CONCLUSIONS

The pattern of genetic variation is consistent with facilitated dispersal along highways. The genetic admixtures among the roadside populations imply the occurrence of multiple population introductions during colonization. The long-distance dispersal of seeds associated with vehicular transportation on highways may have played important roles in shaping the genetic variation. This finding highlights the importance of highways as corridors for the spread of M. micrantha in southern China.

Pilot study on efficacy of reduced cathartic bowel preparation with polyethylene glycol and bisacodyl

AIM: To evaluate the efficacy of reduced cathartic bowel preparation with 2 L polyethylene glycol (PEG)-4000 electrolyte solution and 10 mg bisacodyl enteric-coated tablets for computed tomographic colonography (CTC).

METHODS: Sixty subjects who gave informed consent were randomly assigned to study group A, study group B or the control group. On the day prior to CTC, subjects in study group A were given 20 mL 40% wt/vol barium sulfate suspension before 3 mealtimes, 60 mL 60% diatrizoate meglumine diluted in 250 mL water after supper, and 10 mg bisacodyl enteric-coated tablets 1 h before oral administration of 2 L PEG-4000 electrolyte solution. Subjects in study group B were treated identically to those in study group A, with the exception of bisacodyl which was given 1 h after oral PEG-4000. Subjects in the control group were managed using the same strategy as the subjects in study group A, but without administration of bisacodyl. Residual stool and fluid scores, the attenuation value of residual fluid, and discomfort during bowel preparation in the three groups were analyzed statistically.

RESULTS: The mean scores for residual stool and fluid in study group A were lower than those in study group B, but the differences were not statistically significant. Subjects in study group A showed greater stool and fluid cleansing ability than the subjects in study group B. The mean scores for residual stool and fluid in study groups A and B were lower than those in the control group, and were significantly different. There was no significant difference in the mean attenuation value of residual fluid between study group A, study group B and the control group. The total discomfort index during bowel preparation was 46, 45 and 45 in the three groups, respectively, with no significant difference.

CONCLUSION: Administration of 10 mg bisacodyl enteric-coated tablets prior to or after oral administration of 2 L PEG-4000 electrolyte solution enhances stool and fluid cleansing ability, and has no impact on the attenuation value of residual fluid or the discomfort index. The former is an excellent alternative for CTC colorectum cleansing