HIF-1α inhibition promotes the efficacy of immune checkpoint blockade in the treatment of non-small cell lung cancer.

The response to immune checkpoint inhibitors (ICIs) monotherapy remains unsatisfactory in patients with NSCLC. Thus, combining ICIs with other potential modalities is of great significance to enhance the response of single drug alone. Here, we identified that HIF-1α inhibition was capable of promoting anti-tumor immunity in NSCLC. We applied NSCLC cell lines and mouse models to evaluate the synergy of combined HIF-1α inhibition and PD-1 blockade on tumor growth and the function of tumor infiltrating lymphocytes (TILs). Public datasets were utilized to investigate patients' prognosis based on expressions of HIF-1α and LOXL2 as well as EMT-associated markers and CD8+ TILs. Moreover, we explored the correlation between HIF-1α and LOXL2 levels and CD8+ TILs in tumor samples from patients with NSCLC by immunohistochemistry, as well as their association to patients' survival. In vitro, PX-478, an HIF-1α inhibitor, promoted tumor cell apoptosis induced by T cells when combined with ICIs. Furthermore, mice treated with PX-478 and anti-PD-1 antibodies exhibited a marked delay in tumor growth and prolonged survival, which correlated with increased TILs and granzyme B secretion. Besides, patients with high HIF-1α expression exhibited high levels of EMT-related markers and low TILs, indicating an immunosuppressive phenotype. Mechanistically, we observed that HIF-1α inhibition suppressed the EMT phenotypes induced by hypoxia and further alleviated tumor immunosuppression, which was related to blockage of HIF-1α/LOXL2 signaling pathway. In summary, we identified that HIF-1α inhibition could synergize with anti-PD-1 to impair tumor growth in vitro and in vivo. Our data suggest that HIF-1α inhibitors represent a promising treatment to enhance anti-tumor immunity and provide preclinical rationale to evaluate the combination of ICIs with HIF-1α inhibition clinically in NSCLC.

Inhibiting eEF-2 kinase-mediated autophagy enhanced the cytocidal effect of AKT inhibitor on human nasopharyngeal carcinoma.

AIM: Our previous research showed that AKT inactivation via small molecule inhibitors did not induce significant apoptosis, but rather markedly increased autophagy in nasopharyngeal carcinoma (NPC). The purpose of the current study was to determine whether autophagy inhibition can enhance the anticancer efficacy of an AKT inhibitor (MK-2206). MATERIALS AND METHODS: NPC cell lines CNE-2 (Epstein-Barr virus negative) and C666-1 (Epstein-Barr virus positive) were used to conduct the research. Autophagy induction effects were evaluated via Western blotting. Eukaryotic elongation factor-2 (eEF-2) kinase was specifically and stably knocked down using shRNA. The growth and proliferation of the cells were assessed by Cell Counting Kit-8. In CNE-2 xenograft tumors, the antitumor effects of an AKT inhibitor (MK-2206) combined with an eEF-2 kinase inhibitor (NH125) were tested. RESULTS: MK-2206 induced eEF-2 kinase-dependent autophagy in NPC cell lines. Knockdown of eEF-2 kinase using shRNA blunted the autophagy activated by MK-2206. Compared with treatment with MK-2206 alone, shRNA or NH125 suppressed eEF-2 kinase and increased the growth-inhibitory effect of MK-2206 on the human NPC cell lines. The synergistic effects of eEF-2 kinase inhibition and MK-2206 were similar to those of the combination of hydroxychloroquine and MK-2206. Moreover, NH125 showed good synergistic effects with MK-2206 in vivo. CONCLUSION: eEF-2 kinase-mediated autophagy induced by AKT inhibition played a protective role in NPC cells. Inhibition of eEF-2 kinase may be an effective method for increasing the efficacy of an AKT inhibitor such as MK-2206 in NPC.

The efficacy of first-line chemotherapy in recurrent or metastatic nasopharyngeal carcinoma: a systematic review and meta-analysis.

BACKGROUND: The standard first-line chemotherapy for patients with recurrent or metastatic nasopharyngeal carcinoma (R/M NPC) has not been well established. We conducted a pooled meta-analysis to evaluate the efficacy of commonly used first-line chemotherapy in this disease. METHODS: Electronic databases including PubMed, Embase, and Corchrane library were searched for eligible literatures. Objective response rate (ORR), disease control rate (DCR), progression free survival (PFS), and overall survival (OS) were pooled with the 95% confidence interval (CI) using R software. RESULTS: Totally 973 patients were available for analysis from 14 phase II single arm clinical trials and 2 phase III randomized clinical trials. Four regimens were identified including 5-fluorouracil plus platinum (FP), gemcitabine plus platinum (GP), taxanes plus platinum (TP), and triplet combination regimen. Of these four regimens, triplet combination regimen demonstrated best short-term efficacy with a highest ORR (0.74; 95% CI, 0.62-0.87), DCR (0.91; 95% CI, 0.87-0.95), and 6-month PFS rate (0.83; 95% CI, 0.75-0.91), while 1-year OS rate (0.74; 95% CI, 0.61-0.87) was a little lower than TP regimen. Meanwhile, TP regimen showed best prognosis with a highest 1-year OS rate of 0.79 (95% CI, 0.65-0.92) and pretty good short-term efficacy with an ORR of 0.60 (95% CI, 0.48-0.72) and a DCR of 0.92 (95% CI, 0.86-0.98) comparable with triplet combination therapy. FP regimen had the lowest ORR (0.52; 95% CI, 0.38-0.65) and 1-year OS rate (0.63; 95% CI, 0.57-0.69). Efficacy of GP regimen fell between FP and TP regimens with an ORR of 0.54 (95% CI, 0.38-0.65), a DCR of 0.85 (95% CI, 0.71-0.93), a 6-month PFS rate of 0.69 (95% CI, 0.60-0.78) and a 1-year OS rate of 0.71 (95% CI, 0.61-0.80). CONCLUSIONS: Among four commonly used first-line chemotherapy regimens for R/M NPC, triplet combination regimen showed best short-term efficacy but failed to improve prognosis. TP regimen demonstrated fairly good short-term efficacy and best long-term efficacy, followed by GP regimen, while FP regimen was the lowest.

High PD-L1 expression was associated with poor prognosis in 870 Chinese patients with breast cancer.

BACKGROUND: To investigate the role of PD-L1 expression in tumor recurrence and metastasis in Chinese patients with breast cancer. METHODS: Suitable tissue samples were available from 870 patients with breast cancer. Paraffin-embedded tumor sections were stained with PD-L1 antibody. The correlations between PD-L1 expression and clinical characteristics, ER/PR/HER2 status and survival parameters were analyzed. Kaplan-Meier and univariate Cox proportional hazards model analyses were used to compare the survival of patients with high PD-L1 expression and patients with no PD-L1 expression. RESULTS: The median follow-up time was 98 months(range, 17-265 months).The positive rate of PD-L1 expression in breast cancer was 21.7% (189/870). PD-L1 high expression was inversely associated with larger tumor size, higher tumor grade, more positive lymph node number, as well as negative ER and PR status. PD-L1 expression was particularly higher in TNBC compared with non-TNBC, although no statistical significance was observed. Nomogram logistic regression results based on clinical and pathological features showed that the following factors were more likely associated with high PD-L1 expression: patient age younger than 35 years, larger tumor size, lymphovascular invasion and advanced stage. Our data indicated that patients with high PD-L1 expression had poor DFS, DMFS and overall survival compared with those with no PD-L1 expression. Univariate Cox proportional hazards model analysis showed that PD-L1 was an independent prognostic factor for tumor prognosis. CONCLUSIONS: PD-L1 expression is an important indicator of unfavorable prognosis in breast cancer patients.

Treatment with Recombinant Trichinella spiralis Cathepsin B-like Protein Ameliorates Intestinal Ischemia/Reperfusion Injury in Mice by Promoting a Switch from M1 to M2 Macrophages.

Intestinal ischemia/reperfusion (I/R) injury, in which macrophages play a key role, can cause high morbidity and mortality. The switch from classically (M1) to alternatively (M2) activated macrophages, which is dependent on the activation of STAT6 signaling, has been shown to protect organs from I/R injuries. In the current study, the effects of recombinant Trichinella spiralis cathepsin B-like protein (rTsCPB) on intestinal I/R injury and the potential mechanism related to macrophage phenotypes switch were investigated. In a mouse I/R model undergoing 60-min intestinal ischemia followed by 2-h or 7-d reperfusion, we demonstrated that intestinal I/R caused significant intestinal injury and induced a switch from M2 to M1 macrophages, evidenced by a decrease in levels of M2 markers (arginase-1 and found in inflammatory zone protein), an increase in levels of M1 markers (inducible NO synthase and CCR7), and a decrease in the ratio of M2/M1 macrophages. RTsCPB reversed intestinal I/R-induced M2-M1 transition and promoted M1-M2 phenotype switch evidenced by a significant decrease in M1 markers, an increase in M2 markers, and the ratio of M2/M1 macrophages. Meanwhile, rTsCPB significantly ameliorated intestinal injury and improved intestinal function and survival rate of animals, accompanied by a decrease in neutrophil infiltration and an increase in cell proliferation in the intestine. However, a selective STAT6 inhibitor, AS1517499, reversed the protective effects of rTsCPB by inhibiting M1 to M2 transition. These findings suggest that intestinal I/R injury causes a switch from M2 to M1 macrophages and that rTsCPB ameliorates intestinal injury by promoting STAT6-dependent M1 to M2 transition.

Roles of immunohistochemical staining in diagnosing pulmonary squamous cell carcinoma.

BACKGROUND: Differentiating morphologic features based on hematoxylin-eosin (HE) staining is the most common method to classify pathological subtypes of non-small-cell lung cancer (NSCLC). However, its accuracy and inter-observer reproducibility in pathological diagnosis of poorly differentiated NSCLC remained to be improved. MATERIALS AND METHODS: We attempted to explore the role of immunohistochemistry (IHC) staining in diagnosing pulmonary squamous cell carcinoma (SQCC) with poorly differentiated features by HE staining or with elevated serum adenocarcinoma-specific tumor markers (AD-TMs). We also compared the difference of epidermal growth factor receptor (EGFR) mutation rate between patients with confirmed SQCC and those with revised pathological subtype. Logistic regression analyses were used to test the association between different factors and diagnostic accuracy. RESULTS: A total of 132 patients who met the eligible criteria and had adequate specimens for IHC confirmation were included. Pathological revised cases in poor differentiated subgroup, biopsy samples and high-level AD-TMs cases were more than those with high/moderate differentiation, surgical specimens and normal-level AD-TMs. Moreover, biopsy sample was a significant factor decreasing diagnostic accuracy of pathological subtype (OR, 4.037; 95% CI 1.446-11.267, p=0.008). Additionally, EGFR mutation rate was higher in patients with pathological diagnostic changes than those with confirmed SQCC (16.7% vs 4.4%, p=0.157). CONCLUSIONS: Diagnosis based on HE staining only might cause pathological misinterpretation in NSCLC patients with poor differentiation or high-level AD-TMs, especially those with biopsy samples. HE staining and IHC should be combined as pathological diagnostic standard. The occurrence of EGFR mutations in pulmonary SQCC might be overestimated.

[The effect of bone marrow mesenchymal stem cells engraftment on lung tissue at early stage of smoke inhalation injury in rabbits].

OBJECTIVE: To explore the effect of bone marrow mesenchymal stem cells (MSCs) engraftment on lung tissue at early stage of smoke inhalation injury in rabbits. METHODS: MSCs were proliferated by the method of whole marrow culture and identified by flow cytometry. Forty-eight rabbits were randomly divided into smoke inhalation group (S group) and MSCs group (M group) after reproduction of rabbit smoke inhalation injury model. 10 ml of phosphate buffer saline (PBS) containing 1×10(7)/ml MSCs was intravenously injected in M group, meanwhile 10 ml PBS was injected intravenously in S group. Eight rabbits were sacrificed at 2, 6 and 24 hours after intervention, and the lung tissue was harvested for morphological and pathological observation, and lung injury score was used to evaluate smoke inhalation injury. RESULTS: Cultured cells were confirmed to be MSCs with flow cytometry. Lung injury in rabbits of M group was less serious in morphology and histopathology than that in S group. Though there was no significance in lung injury score between M group and S group at 2 hours after injury (4.0±0.7 vs. 4.5±0.6, P>0.05), the lung injury scores in M group at 6 hours and 24 hours after injury were significantly lower than those in S group (6 hours: 6.1±0.9 vs. 8.2±0.9, 24 hours: 4.6±0.9 vs. 10.4±0.8, both P<0.01). CONCLUSION: Intravenous engraftment of MSCs could ameliorate lung injury induced by smoke inhalation, and improve lung injury score significantly.

[Effect of bone marrow mesenchymal stem cells engraftment on secretion of inflammatory cytokine in the early stages of smoke inhalation injury in rabbits].

OBJECTIVE: To explore the effect of bone marrow mesenchymal stem cells (MSCs) engraftment on secretion of tumor necrosis factor-α (TNF-α), interleukins (IL-1ß, IL-6, IL-10) in peripheral blood and lung homogenates in the early stages of smoke inhalation injury. METHODS: MSCs were proliferated by the method of whole marrow culture and identified by flow cytometry. Fifty-six healthy New Zealand rabbits were randomly divided into control group (C group, n=8), smoke inhalation injury group (S group, n=24) and smoke inhalation injury+MSCs engraftment group (M group, n=24). The latter two groups were subdivided into 2, 4, 6 hours after injury subgroups, with 8 rabbits in each group. The levels of TNF-α, IL-1ß, IL-6 and IL-10 in peripheral blood and lung homogenates were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Compared with C group, concent of pro-inflammatory and anti-inflammatory cytokines in peripheral blood at each time point in S group were increased significantly. The concent of pro-inflammatory cytokines in lung homogenate at each time point in S group was significantly higher than those in C group, and that of anti-inflammatory cytokines showed no significant changes. Compared with the S group, concent of pro-inflammatory cytokines in peripheral blood in M group was decreased significantly, and that of anti-inflammatory cytokines was increased significantly [6 hours TNF-α (µg/L): 1.7±1.7 vs. 4.1±1.6, IL-1ß (ng/L): 9.9±1.7 vs. 21.2±2.6, IL-6 (µg/L): 1.0±0.3 vs. 1.3±0.2, IL-10 (ng/L): 15.2±4.4 vs. 7.9±3.5, all P<0.05]. Concent of pro-inflammatory cytokines at each time point in M group was decreased significantly when compared with S group in lung homogenate, while only anti-inflammatory cytokine at 4 hours and 6 hours was increased significantly [6 hours TNF-α (ng/L): 503.0±156.4 vs. 587.7±171.2, IL-1ß (ng/L): 0.4±0.2 vs. 0.6±0.2, IL-6 (ng/L): 155.2±13.7 vs. 350.2±20.3, IL-10 (ng/L): 23.3±5.4 vs. 11.0±5.6, all P<0.05]. CONCLUSION: MSCs engraftment could decrease pro-inflammatory cytokines and increase anti-inflammatory cytokines in the early stages of smoke inhalation injury, thus ameliorates inflammatory response, which confers protective effect on smoke inhalation injury.