Preclinical evaluation of a novel EGFR&c-Met bispecific near infrared probe for visualization of esophageal cancer and metastatic lymph nodes.

PURPOSE: This study aimed to establish a near infrared fluorescent (NIRF) probe based on an EGFR&c-Met bispecific antibody for visualization of esophageal cancer (EC) and metastatic lymph nodes (mLNs). METHODS: EGFR and c-Met expression were assessed by immunohistochemistry. EGFR&c-Met bispecific antibody EMB01 was labeled with IRDye800cw. The binding of EMB01-IR800 was assessed by enzyme linked immunosorbent assay, flow cytometry, and immunofluorescence. Subcutaneous tumors, orthotopic tumors, and patient-derived xenograft (PDX) were established for in vivo fluorescent imaging. PDX models using lymph nodes with or without metastasis were constructed to assess the performance of EMB01-IR800 in differential diagnosis of lymph nodes. RESULTS: The prevalence of overexpressing EGFR or c-Met was significantly higher than single marker either in EC or corresponding mLNs. The bispecific probe EMB01-IR800 was successfully synthesized, with strong binding affinity. EMB01-IR800 showed strong cellular binding to both Kyse30 (EGFR overexpressing) and OE33 (c-Met overexpressing) cells. In vivo fluorescent imaging showed prominent EMB01-IR800 uptake in either Kyse30 or OE33 subcutaneous tumors. Likewise, EMB01-IR800 exhibited superior tumor enrichment in both thoracic orthotopic esophageal squamous cell carcinoma and abdominal orthotopic esophageal adenocarcinoma models. Moreover, EMB01-IR800 produced significantly higher fluorescence in patient-derived mLNs than in benign lymph nodes. CONCLUSION: This study demonstrated the complementary overexpression of EGFR and c-Met in EC. Compared to single-target probes, the EGFR&c-Met bispecific NIRF probe can efficiently depict heterogeneous esophageal tumors and mLNs, which greatly increased the sensitivity of tumor and mLN identification.

Identification of a CEACAM5 targeted nanobody for positron emission tomography imaging and near-infrared fluorescence imaging of colorectal cancer.

PURPOSE: Here, we aim to identify a CEACAM5-targeted nanobody and demonstrate its application in positron emission tomography (PET) imaging and near-infrared (NIR) fluorescence imaging in colorectal cancer (CRC). METHODS: Immunohistochemistry was applied to verify CEACAM5 expression in CRC and metastatic lymph nodes (mLNs). CEACAM5-targeted nanobodies were obtained by immunization of human CEACAM5 protein in a dromedary, followed by several rounds of phage screenings. Immunofluorescence staining and flow cytometry was carried out to determine the binding affinity of the nanobodies. The nanobodies were radiolabeled by coupling 18F-SFB for PET imaging of CRC subcutaneous xenografts and lymph node metastasis (LNM). IRDye800CW (IR800) were conjugated to form NIR probes for NIR imaging in CRC subcutaneous models. RESULTS: CEACAM5 was overexpressed in either human CRC tissues or mLNs. A CEACAM5 targeted nanobody, Nb41 was successfully generated, with excellent in vitro binding properties. Incorporation of albumin binding domain (ABD) did not affect the affinity of Nb41. In vivo imaging showed that both 18F-FB-Nb41 and 18F-FB-Nb41-ABD showed obvious accumulation in the tumor. Due to the longer retention in the blood, 18F-FB-Nb41-ABD enrichment in tumors was significantly delayed but higher compared to 18F-FB-Nb41. Both 18F-FB-Nb41 and 18F-FB-Nb41-ABD showed prominent LNM enrichment. Similarly, the IR800-conjugated nanobodies Nb41-IR800 and Nb41-ABD-IR800 exhibited superior imaging effects in subcutaneous models, while Nb41-ABD-IR800 exhibited higher fluorescence intensity in the tumor accompanied with a remarkedly delay compared to Nb41-IR800. CONCLUSION: Collectively, we presented the identification and in vivo validation of a CEACAM5-targeted nanobody and a fused nanobody with an ABD, which enabled to the non-invasive visualization of malignancy of CRC using PET imaging and NIR imaging in subcutaneous models as well as LNM models.

NIR-II Navigation with an EGFR-Targeted Probe Improves Imaging Resolution and Sensitivity of Detecting Micrometastases in Esophageal Squamous Cell Carcinoma Xenograft Models.

The survival rate of esophageal squamous carcinoma (ESCC) after surgical resection is estimated to be only 30.3% due to the difficulty in identifying microinfiltration and subtle metastases. In this study, we explored the value of near-infrared fluorescence in the second window (NIR-II) using an epidermal growth factor receptor (EGFR)-targeted probe (cetuximab-IR800) for the intraoperative navigation of ESCC in xenograft mouse models. Immunohistochemical results showed that EGFR was aberrantly expressed in 94.49% (120/127) of ESCC tissues and 90.63% (58/64) of metastatic lymph nodes. Western blot results demonstrated that EGFR protein was highly expressed in ESCC cell lines. Flow cytometry data revealed that cetuximab-IR800 showed a stronger binding specificity in EGFR-positive KYSE-30 cells than in A2780 control cells (P < 0.01). In vivo imaging data showed that the ratio of mean fluorescent intensity (MFI) and tumor to background (TBR) was significantly higher in KYSE-30 subcutaneous tumors with the infusion of cetuximab-IR800 than in those with the infusion of IgG1-IR800 (P < 0.05). Surgical navigation with NIR-II imaging showed that the TBR in orthotopic ESCC was significantly higher than that of NIR in the first window (NIR-I) (2.11 ± 0.46 vs 1.58 ± 0.31, P < 0.05), and NIR-II was more sensitive than NIR-I in detecting subcentimeter metastases (94.87% (37/39) vs 58.97% (23/39), P < 0.001). In conclusion, cetuximab-IR800 with high specificity for ESCC was first used in NIR-II surgical navigation. This probe showed better imaging resolution and higher sensitivity in detecting subtle metastases derived from an orthotopic ESCC model than NIR-I, which indicates that NIR-II has promise in guiding precise surgery for ESCC patients.

SRXN1 stimulates hepatocellular carcinoma tumorigenesis and metastasis through modulating ROS/p65/BTG2 signalling.

Sulfiredoxin 1 (SRXN1) is a pivotal regulator of the antioxidant response in eukaryotic cells. However, the role of SRXN1 in hepatocellular carcinoma (HCC) is far from clear. The present study aims to elucidate whether SRXN1 participates in tumorigenesis and metastasis of HCC and to determine the molecular mechanisms. We found that SRXN1 expression was up-regulated in HCC tissue samples and correlated with poor prognosis in HCC patients. We also observed that SRXN1 knockdown by transient siRNA transfection inhibited HCC cell proliferation, migration and invasion. Overexpression of SRXN1 increased HCC cell migration and invasion. B-cell translocation gene 2 (BTG2) was identified as a downstream target of SRXN1. Mechanistic studies revealed that SRXN1-depleted reactive oxygen species (ROS) modulated migration and invasion of HCC cells. In addition, the ROS/p65/BTG2 signalling hub was found to regulate the epithelial-mesenchymal transition (EMT), which mediates the pro-metastasis role of SRXN1 in HCC cells. In vivo experiments showed SRXN1 promotes HCC tumour growth and metastasis in mouse subcutaneous xenograft and metastasis models. Collectively, our results revealed a novel pro-tumorigenic and pro-metastatic function of SRXN1 in HCC. These findings demonstrate a rationale to exploit SRXN1 as a therapeutic target effectively preventing metastasis of HCC.

Inhibition of JNK/c-Jun-ATF2 Overcomes Cisplatin Resistance in Liver Cancer through down-Regulating Galectin-1.

Due to drug resistance, the clinical response to cisplatin (CDDP) from patients with liver cancer is unsatisfactory. The alleviation or overcoming of CDDP resistance is an urgent problem to be solved in clinics. Tumor cells rapidly change signal pathways to mediate drug resistance under drug exposure. Here, multiple phosphor-kinase assays were performed and c-Jun N-terminal kinase (JNK) was activated in liver cancer cells treated with CDDP. The high activity of the JNK promotes poor progression and mediates cisplatin resistance in liver cancer, leading to a poor prognosis of liver cancer. Mechanistically, the highly activated JNK phosphorylated c-Jun and ATF2 formed a heterodimer to upregulate the expression of Galectin-1, leading to promoting cisplatin resistance in liver cancer. Importantly, we simulated the clinical evolution of drug resistance in liver cancer by continuous CDDP administration in vivo. In vivo bioluminescence imaging showed the activity of JNK gradually increased during this process. Moreover, the inhibition of JNK activity by small molecular or genetic inhibitors enhanced DNA damage and overcame CDDP resistance in vitro and in vivo. Collectively, our results underline that the high activity of JNK/c-Jun-ATF2/Galectin-1 mediates cisplatin resistance in liver cancer and provides an optional scheme for dynamic monitoring of molecular activity in vivo.

Arsenic-Loaded Biomimetic Iron Oxide Nanoparticles for Enhanced Ferroptosis-Inducing Therapy of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) has a poor response to most available systemic therapies due to intrinsic or acquired resistance to apoptosis. Ferroptosis-based therapy is expected to circumvent those limitations. Therefore, the rational design of ferroptosis-based therapies with targeted delivery of ferroptosis inducers for HCC is in need. In this study, we found that arsenic trioxide (ATO) can efficiently induce ferroptosis in HCC cells, and this effect could be reversed by the iron chelator deferoxamine. On this basis, a drug delivery system was constructed to enhance the therapeutic efficacy of ATO by camouflaging ATO-loaded magnetic nanoparticles (Fe3O4) with HCC cell membranes, termed AFN@CM. After AFN@CM treatment, glutathione peroxidase 4 was strongly inhibited and intracellular lipid peroxide species were significantly increased in HCC cells. In addition, enhanced ferroptosis and tumor suppression were observed both in vitro and in vivo. The bio-safety of AFN@CM was also demonstrated by the in vivo toxicity evaluation. In addition, benefiting from the cell membrane coating, AFN@CM showed enhanced accumulation at tumor sites and achieved continuous tumor elimination in the mouse model. In conclusion, AFN@CM exhibited satisfactory therapeutic efficacy in the treatment of HCC and provided a desirable ferroptosis-based strategy for safe and reliable HCC therapeutics.

Lu3+-based nanoprobe for virtual non-contrast CT imaging of hepatocellular carcinoma.

Transcatheter arterial chemoembolization (TACE), the mainstream treatment for hepatocellular carcinoma (HCC), is a method of blocking tumor blood vessels with a mixture of lipiodol and chemotherapeutics. And the contrast-enhanced computed tomography (CT) is the commonly used way for follow-up of HCC after TACE. However, it is noteworthy that when lipiodol deposition plays an embolic effect, it also produces high-density artifacts in CT images. These artifacts usually conceal the enhancement effect of iodine contrast agents. As a result, the residual region is difficult to be visualized. To overcome this obstacle, we developed one kind of Lu3+/Gd3+ doped fluoride nanoprobe modified with Dp-PEG2000 to realize CT/MRI dual-modality imaging of HCC. Compared with lipiodol or ioversol, the obtained PEGylated product LG-PEG demonstrated a greater density value in high keV CT images. In vitro experiments showed the lipiodol artifacts can be removed in virtual non-contrast (VNC) imaging, but the density of ioversol was also removed at the same time. However, the LG-PEG synthesized in this work can still maintain a high density in VNC imaging, which indicates that LG-PEG can exploit its advantages to the full in VNC imaging. Furthermore, LG-PEG successfully exerted tumor enhancement effects in the in vivo VNC images of HCC with lipiodol deposition. In addition, LG-PEG exhibited a strong T2 enhancement effect with low biological toxicity and less side-effect on the main organ and blood. Thus, the LG-PEG reported in this research can serve as an effective and safe VNC contrast agent for HCC imaging after TACE.

SARS-CoV-2 spike spurs intestinal inflammation via VEGF production in enterocytes.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) can cause gastrointestinal (GI) symptoms that often correlate with the severity of COVID-19. Here, we explored the pathogenesis underlying the intestinal inflammation in COVID-19. Plasma VEGF level was particularly elevated in patients with GI symptoms and significantly correlated with intestinal edema and disease progression. Through an animal model mimicking intestinal inflammation upon stimulation with SARS-CoV-2 spike protein, we further revealed that VEGF was over-produced in the duodenum prior to its ascent in the circulation. Mechanistically, SARS-CoV-2 spike promoted VEGF production through activating the Ras-Raf-MEK-ERK signaling in enterocytes, but not in endothelium, and inducing permeability and inflammation. Blockage of the ERK/VEGF axis was able to rescue vascular permeability and alleviate intestinal inflammation in vivo. These findings provide a mechanistic explanation and therapeutic targets for the GI symptoms of COVID-19.

Rapid visualizing and pathological grading of bladder tumor tissues by simple nanodiagnostics.

Developing a tissue diagnosis technology to avoid the complicated processes and the usage of expensive reagents while achieving rapid pathological grading diagnosis to provide a better strategy for clinical treatment is an important strategy of tumor diagnose. Herein, we selected the integrin αvß3 as target based on the analysis of clinical data, and then designed a stable and cancer-targeted selenium nanosystem (RGD@SeNPs) by using RGD polypeptide as the targeting modifier. In vitro experiments showed that RGD@SeNPs could specifically recognized tumor cells, especially in co-culture cells model. The RGD@SeNPs can be used for clinical samples staining without the use of primary and secondary antibody. Fluorescence difference of the tissue specimens staining with RGD@SeNPs could be used to distinguish normal tissues and tumor tissues or estimate different pathological grades of cancer at tissue level. 132 clinical tumor specimens with three types of tumor and 76 non-tumor specimens were examined which verified that the nanoparticles could specific and sensitive distinguish tumor tissue from normal tissue with a specificity of 92% and sensitivity of 96%. These results demonstrate the potential of cancer-targeted RGD@SeNPs as translational nanodiagnostics for rapid visualizing and pathological grading of bladder tumor tissues in clinical specimens.

c-Met-targeted near-infrared fluorescent probe for real-time depiction and dissection of perineural invasion and lymph node metastasis lesions in pancreatic ductal adenocarcinoma xenograft models.

Pancreatic ductal adenocarcinoma (PDAC), a fatal malignant tumour, has a high postoperative recurrence rate, mainly due to the difficulty of discerning occult lesions, including those related to perineural invasion (PNI) and lymph node metastasis (LNM). Cellular mesenchymal-epithelial transition factor (c-Met), an excellent imaging marker, is aberrantly expressed in the majority of PDACs. Thus, we plan to utilize a c-Met-targeted near-infrared fluorescent (NIRF) probe for real-time visualization and dissection of PDAC, and corresponding PNI and LNM lesions. Immunohistochemistry showed c-Met expression in PDAC, PNI and LNM reached 94.3% (100/106), 88.3% (53/60), and 71.4% (25/35), respectively, and its expression in PNI and LNM was significantly correlated with that in primary PDAC (r = 0.66, p < 0.0001 and r = 0.44, p < 0.01, respectively). SHRmAb-IR800 was successfully synthesized using an anti-c-Met antibody and a NIRF dye. The in vitro targeting ability of SHRmAb-IR800 was higher in CFPAC1 cells (c-Met positive) than in Miapaca-2 cells (c-Met negative) (p < 0.05). In vivo NIRF imaging of CFPAC1 subcutaneous tumours demonstrated higher accumulation of SHRmAb-IR800 than the control probe (p < 0.05). The signal-to-background ratio (TBR) of an orthotopic PDAC tumour was 3.38 ± 0.46, and imaging with SHRmAb-IR800 facilitated the resection of metastatic lesions with sensitivity and specificity values of 93.3% (56/60) and 87.1% (27/31), respectively. Furthermore, tiny PNI and LNM lesions in xenograft models were detected by NIRF imaging, with TBRs measuring 2.59 ± 0.19 and 2.88 ± 0.72, respectively. Therefore, the clinical translation of this probe might shed new light on NIRF-guided pancreatectomy and improve the surgical prognosis of PDAC patients.

Near-infrared fluorescence-guided resection of micrometastases derived from esophageal squamous cell carcinoma using a c-Met-targeted probe in a preclinical xenograft model.

The postoperative survival of esophageal squamous cell carcinoma (eSCC) is notably hindered by cancer recurrence due to difficulty in identifying occult metastases. Cellular mesenchymal-epithelial transition factor (c-Met), which is highly expressed in different cancers, including eSCC, has become a target for the development of imaging probes and therapeutic antibodies. In this study, we synthesized an optical probe (SHRmAb-IR800) containing a near-infrared fluorescence (NIRF) dye and c-Met antibody, which may help in NIRF-guided resection of micrometastases derived from eSCC. Cellular uptake of SHRmAb-IR800 was assessed by flow cytometry and confocal microscopy. In vivo accumulation of SHRmAb-IR800 and the potential application of NIRF-guided surgery were evaluated in eSCC xenograft tumor models. c-Met expression in human eSCC samples and lymph node metastases (LNMs) was analyzed via immunohistochemistry (IHC). Cellular accumulation of SHRmAb-IR800 was higher in c-Met-positive EC109 eSCC cells than in c-Met-negative A2780 cells. Infusion of SHRmAb-IR800 produced higher fluorescence intensity and a higher tumor-to-background ratio (TBR) than the control probe in EC109 subcutaneous tumors (P < 0.05). The TBRs of orthotopic EC109 tumors and LNMs were 3.01 ± 0.17 and 2.77 ± 0.56, respectively. The sensitivity and specificity of NIRF-guided resection of metastases derived from orthotopic cancers were 92.00% and 89.74%, respectively. IHC results demonstrated positive staining in 97.64% (124/127) of eSCC samples and 91.67% (55/60) of LNMs. Notably, increased c-Met expression was observed in LNMs compared to normal lymph nodes (P < 0.0001). Taken together, the results of this study indicated that SHRmAb-IR800 facilitated the resection of micrometastases of eSCC in the xenograft tumor model. This c-Met-targeted probe possesses translational potential in NIRF-guided surgery due to the high positive rate of c-Met protein in human eSCCs.

ZnAs@SiO2 nanoparticles as a potential anti-tumor drug for targeting stemness and epithelial-mesenchymal transition in hepatocellular carcinoma via SHP-1/JAK2/STAT3 signaling.

Rationale: Current therapies for hepatocellular carcinoma (HCC) are hampered by treatment failure and recurrence due to the remaining treatment-resistant liver cancer stem cells (CSCs). Stemness and epithelial-mesenchymal transition (EMT) are regarded as two fundamental characteristics of liver CSCs necessary for cancer progression; thus, drugs that simultaneously target both characteristics should prove effective in eliminating HCC and impeding recurrence. In this study, we developed new arsenic trioxide (ATO)-based nanoparticles (NPs), which are expected to be more effective than the current HCC therapy, and explored their potential mechanism. Methods: A "one-pot" reverse emulsification approach was employed to prepare the ZnAs@SiO2 NPs. HCC cell lines, MHCC97L and Hep3b, were used to analyze the antitumor activity of ZnAs@SiO2 NPs in vitro and in vivo by quantifying cell growth and metastasis as well as to study the effect on stemness and EMT. SHP-1 siRNA was used to validate the role of the SHP-1/JAK2/STAT3 signaling pathway in mediating inhibition of stemness and EMT by ZnAs@SiO2. Results: Compared with the current ATO treatment, ZnAs@SiO2 NPs promoted apoptosis and significantly inhibited proliferation, migration, and invasion of both MHCC97L and Hep3b cells. In the in vivo assay, ZnAs@SiO2 NPs inhibited tumor growth by 2.2-fold and metastasis by 3.5-fold as compared to ATO. The ZnAs@SiO2 NPs also inhibited tumor spheroid formation in vitro and tumor initiation in vivo and induced significant changes in the expression of stemness markers (CD133, Sox-2, and Oct-4) and EMT markers (E-cadherin, Vimentin, and Slug) both in vitro and in vivo. These effects of ZnAs@SiO2 that correlated with prognosis of HCC were mediated by the SHP-1/JAK2/STAT3 signaling. Conclusions: ZnAs@SiO2 NPs can effectively suppress tumor initiation, growth, metastasis, and inhibit stemness and EMT through regulation of SHP-1/JAK2/STAT3 signaling pathway in liver cancer cells in vitro and in vivo. Thus, ZnAs@SiO2 NPs have immense potential for HCC treatment in the future.

Therapeutic nanosystems co-deliver anticancer drugs and oncogene SiRNA to achieve synergetic precise cancer chemo-gene therapy.

Co-delivering a chemotherapeutic agent and cancer-specific small interfering RNA (siRNA) as a new therapeutic modality provides a promising strategy for cancer treatment. In this study, we designed and described a cancer-target and pH-sensitivity nanosystem (RGD-SeNPs/siRNA) which has a DOX-loaded SeNPs core and c-myc siRNA-delivered PAMAM-RGD decoration for combination therapy against glioblastoma. The nanosystem exhibited high stability in water and FBS solutions for a long time. PAMAM-RGD surface decoration significantly enhanced the cellular uptake of RGD-SeNPs/siRNA and increased the selectivity between normal and cancer cells. More importantly, the nanosystem expanded to petaloid particles under pH 5.3 circumstance, which prolonged the duration of drugs after ingestion and reduced undesirable side effects. In addition, a blood-brain barrier (BBB) model we established in vitro revealed the nanosystem effectively penetrated BBB and enhanced antitumor activity. Moreover, the nanosystem also exhibited excellent advantages in penetrating ability and inhibitory effects on U251 tumor spheroids, demonstrating its in vivo anticancer potential. Therefore, this study provides a strategy for the design of cancer-targeted nanoplatforms as carriers of oncogene siRNA and chemotherapeutics to achieve synergistic cancer therapy.

Cancer-targeted design of bioresponsive prodrug with enhanced cellular uptake to achieve precise cancer therapy.

Chemical drug design based on the biochemical characteristics of cancer cells has become an important strategy for discovery of novel anticancer drugs to enhance the cancer targeting effects and biocompatibility, and decrease toxic side effects. Camptothecin (CPT) demonstrated strong anticancer activity in clinical trials but also notorious adverse effects. In this study, we presented a smart targeted delivery system (Biotin-ss-CPT) that consists of cancer-targeted moiety (biotin), a cleavable disulfide linker (S-S bond) and the active drug CPT. Biotin-ss-CPT was found to exhibit potent effects on the migration of cancer cells and induced apoptosis by induction of ROS-mediated mitochondrial dysfunction and perturbation of GSH/GPXs system, as well as activation of caspases. In vivo tumor suppression investigation including toxicity evaluation and pathology analysis, accompanied by MR images showed that Biotin-ss-CPT can be recognized specifically and selectively and taken up preferentially by cancers cells, followed by localization and accumulation effectively in tumor site, then released CPT by biological response to achieve high therapeutic effect and remarkably reduced the side effects that free CPT caused, such as liver damage, renal injury, and weight loss to realize precise cancer therapy. Taken together, our results suggest that biotinylation and bioresponsive functionalization of anticancer drugs could be a good way for the discovery of next-generation cancer therapeutics.

Sequentially Triggered Delivery System of Black Phosphorus Quantum Dots with Surface Charge-Switching Ability for Precise Tumor Radiosensitization.

Cancer radiotherapy suffers from drawbacks such as radiation resistance of hypoxic cells, excessive radiation that causes damage of adjacent healthy tissues, and concomitant side effects. Hence, radiotherapy sensitizers with improved radiotherapeutic performance and requiring a relatively small radiation dose are highly desirable. In this study, a nanosystem based on poly(lactic- co-glycolic acid) (PLGA) and ultrasmall black phosphorus quantum dots (BPQDs) is designed and prepared to accomplish precise tumor radiosensitization. The PLGA nanoparticles act as carriers to package the BPQDs to avoid off-target release and rapid degradation during blood circulation. The nanosystem that targets the polypeptide peptide motif Arg-Gly-Asp-Gys actively accumulates in tumor tissues. The 2,3-dimethylmaleic anhydride shell decomposes in an acidic microenvironment, and the nanoparticles become positively charged, thereby favoring cellular uptake. Furthermore, glutathione (GSH) deoxidizes the disulfide bond of cystamine and sequentially triggers release of BPQDs, rendering tumor cells sensitive to radiotherapy. The treatment utilizing the PLGA-SS-D@BPQDs nanosystem and X-ray induces cell apoptosis triggered by overproduction of reactive oxygen species. In the in vivo study, the nanosystem shows excellent radiotherapy sensitization efficiency but negligible histological damage of the major organs. This study provides insights into the design and fabrication of surface-charge-switching and pH-responsive nanosystems as potent radiosensitizers to achieve excellent radiotherapy sensitization efficacy and negligible toxic side effects.

Designing multifunctional cancer-targeted nanosystem for magnetic resonance molecular imaging-guided theranostics of lung cancer.

The integration of diagnosis and therapy is an effective way to improve therapeutic effects for cancer patients, which has acquired widely attentions from researchers. Herein, a multifunctional drug-loaded nanosystem (F/A-PLGA@DOX/SPIO) has been designed and synthesized to reduce the side effects of traditional chemotherapy drugs and realize simultaneous tumor diagnosis and treatment. The surface modification of folic acid (FA) and activatable cell-penetrating peptide (ACPP) endows the nanosystem with excellent cancer targeting capabilities, thus reducing toxicity to normal organs. Besides, the F/A-PLGA@DOX/SPIO nanosystem can serve as an excellent magnetic resonance imaging (MRI) T2-negative contrast agent. More importantly, according to in vitro experiments, the F/A-PLGA@DOX/SPIO nanosystem can promote the overproduction of reactive oxygen species (ROS) within A549 lung cancer cells, inducing cell apoptosis, greatly enhancing the antineoplastic effect. Furthermore, with the help of MRI technology, the targeting imaging of the F/A-PLGA@DOX/SPIO nanosystem within tumors and the dynamic monitoring of medicine efficacy can be realized. Therefore, this study provided a multifunctional drug-loaded F/A-PLGA@DOX/SPIO targeted nanosystem for magnetic resonance molecular imaging-guided theranostics, which has excellent potential for the application in tumor diagnosis and therapy.

Ruthenium complexes with phenylterpyridine derivatives target cell membrane and trigger death receptors-mediated apoptosis in cancer cells.

Elucidation of the communication between metal complexes and cell membrane may provide useful information for rational design of metal-based anticancer drugs. Herein we synthesized a novel class of ruthenium (Ru) complexes containing phtpy derivatives (phtpy = phenylterpyridine), analyzed their structure-activity relationship and revealed their action mechanisms. The result showed that, the increase in the planarity of hydrophobic Ru complexes significantly enhanced their lipophilicity and cellular uptake. Meanwhile, the introduction of nitro group effectively improved their anticancer efficacy. Further mechanism studies revealed that, complex (2c), firstly accumulated on cell membrane and interacted with death receptors to activate extrinsic apoptosis signaling pathway. The complex was then transported into cell cytoplasm through transferrin receptor-mediated endocytosis. Most of the intracellular 2c accumulated in cell plasma, decreasing the level of cellular ROS, inducing the activation of caspase-9 and thus intensifying the apoptosis. At the same time, the residual 2c can translocate into cell nucleus to interact with DNA, induce DNA damage, activate p53 pathway and enhance apoptosis. Comparing with cisplatin, 2c possesses prolonged circulation time in blood, comparable antitumor ability and importantly, much lower toxicity in vivo. Taken together, this study uncovers the role of membrane receptors in the anticancer actions of Ru complexes, and provides fundamental information for rational design of membrane receptor targeting anticancer drugs.