Combined effects of microplastics and cadmium on the soil-plant system: Phytotoxicity, Cd accumulation and microbial activity.

Microplastics (MPs), an emerging pollutant of concern, widely cooccurred with heavy metals in soil, however, little is known about the combined effects of the interactions of MPs and cadmium (Cd) on the soil-plant system. In this study, the combined effects of several types of MPs and soil Cd contamination on Brassica juncea growth, Cd uptake, and soil microbial carbon metabolism were investigated in a 50-day pot experiment. Aged polyethylene (PE), aged polypropylene (PP), biodegradable polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA) displayed moderate phytotoxicity, with reductions in leaf chlorophyll content and shoot biomass. Compared with the control treatment without MPs or B. juncea, B. juncea growth significantly increased the soil pH by 0.3 pH units, and the growth of B. juncea in the presence of biodegradable PBAT or PLA MPs increased the soil pH by an additional 0.4 or 0.6 pH units, respectively. The presence of PBAT or PLA MPs greatly reduced soil diethylenetriamine pentaacetic acid (DTPA)-extractable Cd concentrations and plant Cd accumulation. The Cd bioconcentration factor was higher in roots than shoots in all treatments except the treatment containing PBAT MPs. The average well color development (AWCD), an indicator of metabolic activity, was highest in the treatment with B. juncea alone and was reduced by both biodegradable and conventional MPs. The microbial utilization efficiency of esters and alcohols was enhanced in the treatment with PBAT MPs, whereas carboxylic acids were preferentially utilized in the treatment with PLA MPs. These findings indicate that co-exposure to MPs and Cd may alter soil microenvironmental characteristics such as soil pH, leading to changes in Cd bioavailability, plant growth and Cd accumulation, and the microbial community's capacity to metabolize carbon. These effects of MPs in soil warrant further exploration.

A TMVP1-modified near-infrared nanoprobe: molecular imaging for tumor metastasis in sentinel lymph node and targeted enhanced photothermal therapy.

BACKGROUND: TMVP1 is a novel tumor targeting polypeptide screened by our laboratory with a core sequence of five amino acids LARGR. It specially binds to vascular endothelial growth factor receptor-3 (VEGFR-3), which is mainly expressed on neo-lymphatic vessels in sentinel lymph node (SLN) with tumor metastasis in adults. Here, we prepared a targeted nanoprobe using TMVP1-modified nanomaterials for tumor metastasis SLN imaging. RESULTS: In this study, TMVP1-modified polymer nanomaterials were loaded with the near-infrared (NIR) fluorescent dye, indocyanine green (ICG), to prepare a molecular imaging TMVP1-ICG nanoparticles (NPs) to identify tumor metastasis in SLN at molecular level. TMVP1-ICG-NPs were successfully prepared using the nano-precipitation method. The particle diameter, morphology, drug encapsulation efficiency, UV absorption spectrum, cytotoxicity, safety, and pharmacokinetic properties were determined. The TMVP1-ICG-NPs had a diameter of approximately 130 nm and an ICG loading rate of 70%. In vitro cell experiments and in vivo mouse experiments confirmed that TMVP1-ICG-NPs have good targeting ability to tumors in situ and to SLN with tumor metastasis by binding to VEGFR-3. Effective photothermal therapy (PTT) with TMVP1-ICG-NPs was confirmed in vitro and in vivo. As expected, TMVP1-ICG-NPs improved ICG blood stability, targeted tumor metastasis to SLN, and enhanced PTT/photodynamic (PDT) therapy, without obvious cytotoxicity, making it a promising theranostic nanomedicine. CONCLUSION: TMVP1-ICG-NPs identified SLN with tumor metastasis and were used to perform imaging-guided PTT, which makes it a promising strategy for providing real-time NIR fluorescence imaging and intraoperative PTT for patients with SLN metastasis.

Sulfur enhances cadmium bioaccumulation in Cichorium intybus by altering soil properties, heavy metal availability and microbial community in contaminated alkaline soil.

Cadmium (Cd) contamination seriously threatens the soil health and food safety. Combination of amendment and accumulator plant is a green and effective technique to improve phytoremediation of Cd-contaminated alkaline soil. In this study, a potting experiment was conducted to investigate the effect of sulfur on Cd phytoextraction by Cichorium intybus (chicory). Soil chemical and microbial properties were determined to reveal the mechanism of sulfur-assisting Cd phytoremediation by chicory. Soil pH decreased from 7.77 to the lowest 7.30 with sulfur addition (0.6, 0.9 and 1.2 g kg-1, LS, MS and HS treatment); Electric conductivity, sulfate anion and available cadmium concentration increased gradually with increasing sulfur doses. Cd concentration of shoot and root significantly increased from 1.47 to 4.43 mg kg-1, 6.15 to 20.16 mg kg-1 by sulfur treatment relative to CK, which were attributed to increased available Cd concentration induced by decreased pH. Sulfur treatments significantly increased the Cd bioconcentration factor by 64.1%, 118.6%, 201.0% for shoot, 76.3%, 145.6% and 227.7% for root under LS, MS and HS relative to CK treatment, respectively (P < 0.05). However, only MS treatment significantly improved the Cd removal efficiency by 82.9% in comparison of CK treatment (P < 0.05). Microbial community diversity measured by 16SrRNA showed that Thiobacillus and Actinobacteria were the key and dominant strains of soil microbial communities after sulfur addition, which played a pivotal role in the process of sulfur oxidation involved in decrease of soil pH and the transformation of Cd forms. Correlation analysis and path analysis by structural equation model indicated that soil sulfate anion and Thiobacillus directly affected Cd removal efficiency by chicory in Cd-contaminated alkaline soil. This suggests that combination of sulfur and chicory may provide a way to promote Cd bioaccumulation for phytoremediation of Cd-contaminated alkaline soil.

The exon 12-containing LHX6 isoforms promote cervical cancer cell proliferation by regulating the MAPK signaling pathway.

LIM homeobox 6 (LHX6) has been reported to be downregulated and inhibits cell proliferation in various cancers. Alternative splicing of LHX6 leads to six annotated isoforms, which can be found in the NCBI database. However, the expression patterns and potential roles of these isoforms remain poorly characterized in cervical cancer. Here, we demonstrated that the LHX6 isoforms containing exon 12 (LHX6EX(+12) group) and isoforms lacking exon 12 (LHX6EX(-12) group) were differentially expressed in cervical tissue by qRT-PCR. The mRNA expression level of LHX6EX(+12) group was higher than that of LHX6EX(-12) group in cervical cancer tissue. Knockdown of LHX6EX(+12) group and all LHX6 isoforms (LHX6All group) inhibited cell growth, increased cell apoptosis, and induced cell cycle arrest from G0/G1 phase to S phase in vitro. Consistently, overexpression of the LHX6EX(+12) group promoted cervical cancer cell proliferation in vitro. In contrast, no significant differences in cell proliferation were found between LHX6EX(-12) isoform knockdown group and its control. RNA-sequencing suggested that the LHX6EX(+12) isoform group might exert its cancer-promoting effects in cervical cancer via regulating MAPK signaling pathway. Downregulation of the LHX6EX(+12) group significantly suppressed the phosphorylation of MRK, ERK, JNK, and P38 at the protein level. We also identified some unique biological processes and signaling pathways in which each isoform group might be involved. In summary, our results indicated that LHX6EX(+12) isoform group was the dominant oncogenic type of LHX6 in cervical cancer, which may be a new biomarker and a potential precise therapeutic target for cervical cancer in the future.

A novel ICG-labeled cyclic TMTP1 peptide dimer for sensitive tumor imaging and enhanced photothermal therapy in vivo.

TMTP1 is a polypeptide independently screened in our laboratory, which can target tumors in situ and metastases. In previous work, we have successfully developed a near-infrared (NIR) probe TMTP1-PEG4-ICG for tumor imaging. However, the limited ability to target tumor micrometastases hinders its further clinical application. Multimerization of peptides has been extensively demonstrated as an effective strategy to increase receptor binding affinity due to "multivalent effect" or "apparent cooperative affinity". In this study, a novel TMTP1 homodimer-directed NIR probe (TMTP1-PEG4)2-ICG was successfully constructed and synthesized. The cyclic TMTP1 peptides were bridged by two PEG4 linkers and then labeled with ICG-NHS for tumor imaging and photothermal therapy. In vivo biodistribution were assessed in normal BALB/c mice, and tumor targeting abilities of (TMTP1-PEG4)2-ICG and its monomer were evaluated and compared in 4T1-bearing subcutaneous tumor and lymph node metastasis model mice. Biodistribution analysis in vivo revealed that (TMTP1-PEG4)2-ICG was cleared mainly in both liver and kidney dependent way. Comparing with free ICG dye or TMTP1-PEG4-ICG probe, this improved (TMTP1-PEG4)2-ICG dimer showed more sensitive tumor imaging and could clearly identify tumors at a minimum volume of 10 mm3. Additionally, when compared to its monomer, lymph node (LN) metastases could also be apparently visualized and easily distinguished from normal LN by the novel dimer at 24 h post-injection. The blocking study revealed that the tumor accumulation of this probe was specifically medicated by receptor-ligand interaction. Furthermore, with the increase in stability and tumor targeting ability of ICG in vivo, the probe could also be an attractive photothermal agent to significantly inhibit tumor growth under 808 nm NIR laser irradiation. In conclusion, our work revealed that the novel (TMTP1-PEG4)2-ICG dimer could be a promising theranostic agent for sensitive tumor imaging and imaging-guided photothermal therapy, indicating its broad prospects for further clinical transformation.

TMTP1-Modified, Tumor Microenvironment Responsive Nanoparticles Co-Deliver Cisplatin and Paclitaxel Prodrugs for Effective Cervical Cancer Therapy.

BACKGROUND AND PURPOSE: Cisplatin-paclitaxel (TP) combination chemotherapy as the first-line therapy for numerous cancers is hindered by its inadequate accumulation in tumors and severe side effects resulting from non-specific distribution. The aim of this study is to explore whether TMTP1-modified, cisplatin and paclitaxel prodrugs co-loaded nanodrug could improve cervical cancer chemotherapy and relieve its side effects through active and passive tumor targeting accumulation and controlled drug release. METHODS: TDNP, with capacities of active targeting for tumors and controlled drug release, was prepared to co-deliver cisplatin and paclitaxel prodrugs. The characteristics were investigated, including the diameter, surface zeta potential, stability and tumor microenvironment (TME) dependent drug release profiles. Cellular uptake, cytotoxicity, drug accumulation in tumors, antitumor effects and safety analysis were evaluated in vitro and in vivo. RESULTS: The oxidized cisplatin and the paclitaxel linked to the polymer achieved a high loading effciency of over 80% and TME-dependent sustained drug release. Moreover, TMTP1 modification enhanced cellular uptake of TDNP and further improved the cytotoxicity of TDNP in vitro. In vivo, TDNP showed an extended blood circulation and increased accumulation in SiHa xenograft models with the aid of TMTP1. More importantly, TDNP controlled tumor growth without life-threatening side effects. CONCLUSION: Our study provided a novel TP co-delivery platform for targeted chemotherapy of cervical cancer, which was promising to improve the therapeutic effcacy of TP and may also have application in other tumors.

TMTP1-modified Indocyanine Green-loaded Polymeric Micelles for Targeted Imaging of Cervical Cancer and Metastasis Sentinel Lymph Node in vivo.

Metastasis is one of the most threatening aspects of cervical cancer. We developed a method to intraoperatively map the primary tumor, metastasis and metastatic sentinel lymph nodes (SLNs), providing real-time intraoperative guidance in cervical cancer. Methods: TMTP1, a tumor metastasis targeting peptide, was employed to modify the indocyanine green (ICG)-loaded poly (ethylene glycol)- poly (lactic-co-glycolic acid) (PEG-PLGA) micelles. The cervical cancer subcutaneous tumor model and lung metastasis model were established to determine the active targeting of ICG-loaded TMTP1-PEG-PLGA micelles (ITM) for the primary tumor and occult metastasis of cervical cancer. Human cervical cancer HeLa cells engineered by firefly luciferase were injected into the right hocks of BALB/c nude mice to develop the SLN metastasis model. The ITM and control ICG-loaded PEG-PLGA micelles (IM) were injected into the right hind footpads in the SLN metastasis model, and the migration and retention of micelles were recorded under near-infrared fluorescence. K14-HPV16 transgenic mice were also used to detect the image capability of ITM to target cancerous lesions. Results: ITM could actively target imaging of the primary tumor and cervical cancer metastasis. ITM quickly diffused from the injection site to SLNs along lymphatic capillaries and remained in the SLNs for 12 h. Moreover, ITM specifically accumulated in the tumor metastatic SLNs (T-SLNs), which could be successfully distinguished from normal SLNs (N-SLNs). Conclusion: ITM could achieve active targeting of the primary tumor, metastasis and T-SLNs, providing precise and real-time intraoperative guidance for cervical cancer.

Bradykinin promotes proliferation, migration, and invasion of cervical cancer cells through STAT3 signaling pathways.

It has been reported recently that bradykinin (BK) is involved in the regulation of various processes in cancer cells. However, its role and underlying mechanism of action in cervical cancer (CC) are still unknown. In the present study, it was revealed that BK promoted proliferation, migration, and invasion of CC cells, whereas bradykinin B2 receptor antagonist HOE140 had the inverse effect. Furthermore, it was confirmed that overexpression of bradykinin B2 receptor (B2R) facilitated the proliferation, migration, and invasion of BK­treated CC cells, while knockdown of B2R had the opposite effect. Mechanistically, the present results revealed that the BK/B2R­induced biological function of CC cells occured by activating STAT3 signaling pathways, and that knockdown of B2R or B2R antagonist had the opposite effects. Moreover, it was demonstrated that BK/B2R facilitated CC cell migration and invasion by upregulating the expression of the STAT3­regulated products MMP2 and MMP9, while downregulating the expression of the pro­apoptotic protein cleaved caspase­9. Thus, the present findings revealed that BK promoted CC cell proliferation, migration, and invasion by binding to B2R via STAT3 signaling pathways.

Targeted co-delivery of Trp-2 polypeptide and monophosphoryl lipid A by pH-sensitive poly (ß-amino ester) nano-vaccines for melanoma.

Dendritic cell (DC)-targeted vaccines based on nanotechnology are a promising strategy to efficiently induce potent immune responses. We synthesized and manufactured a mannose-modified poly (ß-amino ester) (PBAE) nano-vaccines with easily tuneable and pH-sensitive characteristics to co-deliver the tumor-associated antigen polypeptide Trp-2 and the TLR4 agonist monophosphoryl lipid A (MPLA). To reduce immunosuppression in the tumor microenvironment, an immune checkpoint inhibitor, PD-L1 antagonist, was administrated along with PBAE nano-vaccines to delay melanoma development. We found that mannosylated Trp-2 and MPLA-loaded PBAE nano-vaccines can target and mature DCs, consequently boosting antigen-specific cytotoxic T lymphocyte activity against melanoma. The prophylactic study indicates that combination therapy with PD-L1 antagonist further enhanced anti-tumor efficacy by 3.7-fold and prolonged median survival time by 1.6-fold more than free Trp-2/MPLA inoculation. DC-targeting PBAE polymers have a great potential as a nanotechnology platform to design vaccines and achieve synergistic anti-tumor effects with immune checkpoint therapy.

Serum bradykinin levels as a diagnostic marker in cervical cancer with a potential mechanism to promote VEGF expression via BDKRB2.

Bradykinin (BK) is one of the kinin peptides and preferentially binds to bradykinin B2 receptor (BDKRB2). A recent study indicated that BK played an important role in the occurrence and progression of cancer. In this study, we evaluated the serum BK levels in 130 cervical cancer (CC) cases (including 65 cases with pre­ and post­surgery paired samples, another 65 cases with only pre­surgery samples), 35 cervical intraepithelial neoplasia (CIN) cases (pre­ and post­surgery paired) and 35 control cases. We found that BK was overexpressed in patients with CC compared to patients with CIN and the control group. When combined with squamous cell carcinoma­related antigen (SCCA), the diagnostic efficacy of BK was prominently enhanced. Moreover, we detected the expression level of the BK receptor BDKRB2 in CC, CIN and normal cervical tissues and observed a higher expression in the CC and CIN tissues than in the normal cervix. We then explored the possible mechanisms of action of BK in promoting the progression of CC. When BK was added to the cell culture medium, human umbilical vein endothelial cell (HUVEC) angiogenesis increased and vascular endothelial growth factor (VEGF) expression in CC cell lines was also elevated. The BK antagonist, HOE140, exerted an opposite effect. The knockdown or the overexpression of BDKRB2 in CC cell lines further confirmed its oncogenic role in angiogenesis. Taken together, the findings of this study suggest that BK may be a diagnostic biomarker for CC and may notably improve the diagnostic efficacy when combined with SCCA. BK promotes the progression of CC by upregulating the expression of VEGF via BDKRB2 and subsequently facilitating angiogenesis.

Mechanical cues modulate cellular uptake of nanoparticles in cancer via clathrin-mediated and caveolae-mediated endocytosis pathways.

AIM: To investigate the influence of tissue mechanics on the cellular uptake efficiency of nanoparticles (NPs) in cancer. MATERIALS & METHODS: Collagen-coated polyacrylamide gels were prepared as model substrates. Coumarin 6-loaded poly(lactic-co-glycolic) acid micelles (C6-NPs) were prepared to investigate the cellular uptake of NPs. RESULTS: We demonstrated that substrate stiffness modulated the cellular uptake of NPs of cancer. Mechanistically, mechanical cues exerted influence on the clathrin-mediated endocytosis and caveolae-mediated endocytosis pathways, which mediated stiffness-regulated cellular uptake of NPs. CONCLUSION: Our findings shed light on the regulatory role of the mechanical cues on the cellular uptake of NPs and will facilitate the selection of clinical patients who might benefit from a given nanotherapy.

A Novel Near-Infrared Fluorescent Probe TMTP1-PEG4-ICG for in Vivo Tumor Imaging.

Molecular imaging agents are considered to be promising tracers for tumor imaging and guided therapy. TMTP1 was screened through the FliTrx bacterial peptide display system in our laboratory previously and shown to specifically target to primary tumors and metastatic foci. In this study, small peptide TMTP1 was designed to conjugate to a near-infrared fluorescent agent ICG derivative ICG-OSu through PEG4, forming the novel probe TMTP1-PEG4-ICG. It was successfully synthesized and certified. CCK-8 assay showed that it was nontoxic to normal cells and cancerous cells. Dynamics study indicated that the probe was cleared through the liver-intestine and kidney-bladder pathway. Tumor targeting capability of this probe in vitro was evaluated on 4T1, SiHa, HeLa, S12, and HaCaT cells by flow cytometry. In vivo imaging of 4T1 and HeLa tumor-bearing mice further identified the tumor homing ability. As we had expected, the probe showed excellent affinity to cancer cells not only in vitro but also in vivo, whether in murine tumor or humanized tumor. In conclusion, TMTP1-PEG4-ICG demonstrated ideal imaging effects on tumor-bearing mice model, providing new opportunities for tumor diagnostic or guiding resection.

MMP26: A potential biomarker for prostate cancer.

The application of prostate-specific antigen (PSA) in the screening and diagnosis of prostate cancer (PCa) has improved the clinical management of PCa patients. However, the PSA assay has been faced with criticism due to its potential association with over-diagnosis and subsequent overtreatment of indolent patients. Matrix metalloproteinase-26 (MMP26) is a member of matrix metalloproteinases (MMPs) and has been reported to be highly expressed in many cancers. This investigation evaluated the potential of serum MMP26 as a biomarker for PCa. The level of serum MMP26 was measured by enzyme-linked immunosorbent assay (ELISA) in 160 subjects including PCa group (n=80), benign prostatic hyperplasia (BPH) group (n=40) and control group (n=40). Furthermore, we evaluated the expression of MMP26 in tissues by immunohistochemistry. The results showed the serum MMP26 levels were significantly higher in PCa group than in BPH group and control group. Similarly, the MMP26 protein was positive in PCa tissues and negative in BPH tissues and control tissues. In conclusion, these results suggested MMP26 could be used as a potential serum biomarker in the diagnosis of PCa.

Human CAFs promote lymphangiogenesis in ovarian cancer via the Hh-VEGF-C signaling axis.

Cancer-associated fibroblasts (CAFs) play a pivotal role in the development and progression of many human cancers. Recent studies have shown that Hedgehog (Hh) signalling modulates the stromal microenvironment and prepares a suitable niche for tumour metastasis. However, the detailed molecular mechanisms underlying CAF-mediated lymphangiogenesis have not been fully elucidated. Therefore, our goal is to illustrate whether Hh ligands can activate Hh signalling in CAFs in a paracrine fashion and elucidate the effect of CAFs on lymphangiogenesis. We determined here that Sonic Hedgehog (SHH) secreted by ovarian cancer (OC) cells activated Hh signalling in CAFs and promoted the proliferation of CAFs. Moreover, we co-injected SHH-overexpressing OC cells and CAFs in a xenograft model and found that the CAFs accelerated tumourigenesis and lymphangiogenesis in OC. Mechanistically, we found that SHH secreted by the OC cells induced VEGF-C expression in CAFs. Inhibition of Hh signalling in CAFs decreased VEGF-C expression and diminished the positive role of CAFs in supporting tumourigenesis and lymphangiogenesis in a murine xenograft model. Our results demonstrate that CAFs constitute a supportive niche for cancer lymphangiogenesis via the Hh/VEGF-C signalling axis and provide evidence for the clinical application of Hh inhibitors in the treatment of OC.

XPNPEP2 is overexpressed in cervical cancer and promotes cervical cancer metastasis.

XPNPEP2 is a proline hydrolytic enzyme that hydrolyzes several biologically active peptides and causes a loss of substrate activity. However, its function in cancer is still unknown. Our study showed that XPNPEP2 expression was significantly upregulated in cervical cancer tissues compared with normal cervical tissues and cervical intraepithelial neoplasm tissues. Statistical analysis showed that XPNPEP2 expression was associated with the International Federation of Gynecology and Obstetrics stage and lymph node metastasis. Overexpression of XPNPEP2 in SiHa and HeLa cells promoted cell invasion and migration without affecting cell proliferation and apoptosis. Mechanistically, we found that XPNPEP2 facilitated cervical cancer cell invasion and migration by inducing epithelial-mesenchymal transition. Furthermore, we demonstrated that XPNPEP2 had significant effects on the metastasis of xenografted tumors in vivo. Collectively, our findings identify the novel function of XPNPEP2 in the metastasis of cervical cancer and suggest that XPNPEP2 could be a novel potential therapeutic target for the treatment of cervical cancer.