Smad4 deficiency inhibits lung metastases through enhancing phagocytosis of lung interstitial macrophages.

Smad4, a critical mediator of TGF-ß signaling, plays a pivotal role in regulating various cellular functions, including immune responses. In this study, we investigated the impact of Smad4 knockout specifically in macrophages on anti-tumor immunity, focusing on lung metastasis of B16 melanoma cells. Using a mouse model with Smad4 knockout in macrophages established via Lyz2-cre mice and Smad4 flox/flox mice, we demonstrated a significant inhibition of B16 metastasis in the lungs. Interestingly, the inhibition of tumor growth was found to be independent of adaptive immunity, as no significant changes were observed in the numbers or activities of T cells, B cells, or NK cells. Instead, Smad4 knockout led to the emergence of an MCHIIlow CD206high subset of lung interstitial macrophages, characterized by enhanced phagocytosis function. Our findings highlight the crucial role of Smad4 in modulating the innate immune response against tumors and provide insights into potential therapeutic strategies targeting lung interstitial macrophages to enhance anti-tumor immunity.

Preclinical development of a novel CCR8/CTLA-4 bispecific antibody for cancer treatment by disrupting CTLA-4 signaling on CD8 T cells and specifically depleting tumor-resident Tregs.

Anti-CTLA-4 antibodies faced challenges due to frequent adverse events and limited efficacy, which spurred the exploration of next-generation CTLA-4 therapeutics to balance regulatory T cells (Tregs) depletion and CD8 T cells activation. CCR8, identified primarily on tumor-infiltrating Tregs, has become a target of interest due to the anti-tumor effects demonstrated by CCR8 antibody-mediated Tregs depletion. Single-cell RNA sequencing analysis reveals that CCR8-positive Tregs constitute a small subset, with concurrent expression of CCR8 and CTLA-4. Consequently, we proposed a novel bispecific antibody targeting CCR8 and CTLA-4 that had the potential to enhance T cell activation while selectively depleting intratumor Tregs. The candidate molecule 2MW4691 was developed in a tetravalent symmetric format, maintaining a strong binding affinity for CCR8 while exhibiting relatively weaker CTLA-4 binding. This selective binding ability allowed 2MW4691 to target and deplete tumor-infiltrating Tregs with higher specificity. In vitro assays verified the antibody's capacity for antibody-dependent cellular cytotoxicity (ADCC) to Tregs with high level of CTLA-4 expression, but not CD8 T cells with relatively low level of CTLA-4 on cell surface. Also, 2MW4691 inhibited the CTLA-4 pathway and enhanced T cell activation. The in vivo therapeutic efficacy of 2MW4691 was further demonstrated using hCCR8 or hCTLA-4 humanized mouse models and hCCR8/hCTLA-4 double knock-in mouse models. In cynomolgus monkeys, 2MW4691 was well-tolerated, exhibited the anticipated pharmacokinetic profile, and had a minimal impact on the peripheral T cell population. The promising preclinical results supported the further evaluation of 2MW4691 as a next-generation Treg-based therapeutics in clinical trials.

ROS-Responsive and Self-Tumor Curing Methionine Polymer Library Based Nanoparticles with Self-Accelerated Drug Release and Hydrophobicity/Hydrophilicity Switching Capability for Enhanced Cancer Therapy.

The applications of amino acid-based polymers are impeded by their limited structure and functions. Herein, a small library of methionine-based polymers (Met-P) with programmed structure and reactive oxygen species (ROS)-responsive properties is developed for tumor therapy. The Met-P can self-assemble into sub-100 nm nanoparticles (NPs) and effectively load anticancer drugs (such as paclitaxel (PTX) (P@Met-P NPs)) via the nanoprecipitation method. The screened NPs with superior stability and high drug loading are further evaluated in vitro and in vivo. When encountering with ROS, the Met-P polymers will be oxidized and then switch from a hydrophobic to a hydrophilic state, triggering the rapid and self-accelerated release of PTX. The in vivo results indicated that the screened P@2Met10 NPs possessed significant anticancer performance and effectively alleviated the side effects of PTX. More interestingly, the blank 2Met10 NPs displayed an obvious self-tumor inhibiting efficacy. Furthermore, the other Met-P NPs (such as 2Met8, 4Met8, and 4Met10) are also found to exhibit varied self-anti-cancer capabilities. Overall, this ROS-responsive Met-P library is a rare anticancer platform with hydrophobic/hydrophilic switching, controlled drug release, and self-anticancer therapy capability.

Black phosphorus-incorporated novel Ti-12Mo-10Zr implant for multimodal treatment of osteosarcoma.

The repair and reconstruction of large bone defects after bone tumor resection is still a great clinical challenge. At present, orthopedic implant reconstruction is the mainstream treatment for repairing bone defects. However, according to clinical feedback, local tumor recurrence and nonunion of bone graft are common reasons leading to the failure of bone defect repair and reconstruction after bone tumor resection, which seriously threaten the physical and mental health of patients. On this basis, here the self-developed low modulus Ti-12Mo-10Zr alloy (TMZ) was chosen as substrate material. To improve its biological activity and osteointegration, calcium, oxygen, and phosphorus co-doped microporous coating was prepared on TMZ alloy by microarc oxidation (MAO). Then, black phosphorus (BP) nanosheets were incorporated onto MAO treated TMZ alloy to obtain multifunctional composites. The obtained BP-MAO-TMZ implant exhibited excellent photothermal effects and effective ablation of osteosarcoma cancer cells under the irradiation of 808 nm near infrared laser, while no photothermal or therapeutic effects were observed for TMZ alloy. Meanwhile, the structure/component bionic coating obtained after MAO treatment as well as the P-driven in situ biomineralization performance after incorporation of BP nanosheets endowed BP-MAO-TMZ implant with synergistic promoting effect on MC3T3-E1 osteoblasts' activity, proliferation and differentiation ability. This study is expected to provide effective clinical solutions for problems of difficult bone regeneration and tumor recurrence after tumor resection in patients with bone tumors and to solve a series of medical problems such as poor prognosis and poor postoperative quality of patients life with malignant bone tumors.

Multifunctional elastin-like polypeptide nanocarriers for efficient miRNA delivery in cancer therapy.

BACKGROUND: The exogenous delivery of miRNA to mimic and restore miRNA-34a activity in various cancer models holds significant promise in cancer treatment. Nevertheless, its effectiveness is often impeded by challenges, including a short half-life, propensity for off-target accumulation, susceptibility to inactivation by blood-based enzymes, concerns regarding patient safety, and the substantial cost associated with scaling up. As a means of overcoming these barriers, we propose the development of miRNA-loaded Tat-A86 nanoparticles by virtue of Tat-A86's ability to shield the loaded agent from external environmental factors, reducing degradation and inactivation, while enhancing circulation time and targeted accumulation. RESULTS: Genetically engineered Tat-A86, featuring 16 copies of the interleukin-4 receptor (IL-4R)-binding peptide (AP1), Tat for tumor penetration, and an elastin-like polypeptide (ELP) for presenting target ligands and ensuring stability, served as the basis for this delivery system. Comparative groups, including Tat-E60 and A86, were employed to discern differences in binding and penetration. The designed ELP-based nanoparticle Tat-A86 effectively condensed miRNA, forming stable nanocomplexes under physiological conditions. The miRNA/Tat-A86 formulation bound specifically to tumor cells and facilitated stable miRNA delivery into them, effectively inhibiting tumor growth. The efficacy of miRNA/Tat-A86 was further evaluated using three-dimensional spheroids of lewis lung carcinoma (LLC) as in vitro model and LLC tumor-bearing mice as an in vivo model. It was found that miRNA/Tat-A86 facilitates effective cell killing by markedly improving miRNA penetration, leading to a substantial reduction in the size of LLC spheroids. Compared to other controls, Tat-A86 demonstrated superior efficacy in suppressing the growth of 3D cellular aggregates. Moreover, at equivalent doses, miRNA-34a delivered by Tat-A86 inhibited the growth of LLC cells in allograft mice. CONCLUSIONS: Overall, these studies demonstrate that Tat-A86 nanoparticles can deliver miRNA systemically, overcoming the basic hurdles impeding miRNA delivery by facilitating both miRNA uptake and stability, ultimately leading to improved therapeutic effects.

Inhibitors of cullin-RING E3 ubiquitin ligase 4 with antitumor potential.

Cullin-RING (really intersting new gene) E3 ubiquitin ligases (CRLs) are the largest E3 family and direct numerous protein substrates for proteasomal degradation, thereby impacting a myriad of physiological and pathological processes including cancer. To date, there are no reported small-molecule inhibitors of the catalytic activity of CRLs. Here, we describe high-throughput screening and medicinal chemistry optimization efforts that led to the identification of two compounds, 33-11 and KH-4-43, which inhibit E3 CRL4 and exhibit antitumor potential. These compounds bind to CRL4's core catalytic complex, inhibit CRL4-mediated ubiquitination, and cause stabilization of CRL4's substrate CDT1 in cells. Treatment with 33-11 or KH-4-43 in a panel of 36 tumor cell lines revealed cytotoxicity. The antitumor activity was validated by the ability of the compounds to suppress the growth of human tumor xenografts in mice. Mechanistically, the compounds' cytotoxicity was linked to aberrant accumulation of CDT1 that is known to trigger apoptosis. Moreover, a subset of tumor cells was found to express cullin4 proteins at levels as much as 70-fold lower than those in other tumor lines. The low-cullin4-expressing tumor cells appeared to exhibit increased sensitivity to 33-11/KH-4-43, raising a provocative hypothesis for the role of low E3 abundance as a cancer vulnerability.

Poly(lactic acid hydroxyacetic acid)-poly(ethylene glycol)-modified ginsenoside Rg3 nanomedicine enhances anti-tumor effect in hepatocellular carcinoma.

OBJECTIVE: This research aims to improve the bioavailability and anti-hepatocellular carcinoma (HCC) efficacy of Ginsenoside Rg3 by modification with poly (lactic acid hydroxyacetic acid)-poly(ethylene glycol) (PLGA-PEG). METHODS: PLGA-PEG-Rg3 was obtained by emulsification and evaluated it physiochemical characterization by FTIR, SEM, laser particle-size analyzer and HPLC. The effect of the PLGA-PEG-Rg3 and Rg3 on HepG2 cells was compared in vitro studies, including cell proliferation, transwell and a series of apoptosis detection, and in-situ HCC model. RESULTS: The PLGA-PEG-Rg3 were 122 nm in size and 0.112 in polydispersity index with sustained release profile in vitro. Compared to Rg3, PLGA-PEG-Rg3 was more effective in suppressing HepG2 growth and inducing apoptosis by the mitochondrial apoptosis pathway in vitro. And PLGA-PEG modification enhanced the liver-targeting ability and drug circulation time of Rg3 in vivo, resulting in PLGA-PEG-Rg3 possessing superior performance in inhibiting tumor growth and prolonging the survival time of tumor-bearing mice than Rg3. CONCLUSIONS: Overall, these results showed PLGA-PEG-Rg3 enhanced the anti-tumor effect of Rg3 in HCC.

Structural basis of the oncogenic KRAS mutant and GJ101 complex.

KRAS mutations occur in a quarter of all human cancers. When activated in its GTP-bound form, RAS stimulates diverse cellular systems, such as cell division, differentiation, growth, and apoptosis through the activations of various signaling pathways, which include mitogen-activated protein kinase (MAPK), phosphoinositide 3 kinases (PI3K), and RAL-GEFs pathways. We found that GJ101 (65LYDVA69) binds directly to the KRAS mutant (G12V) and showed tumor-suppressive activity. In addition, the GJ101 peptide inhibited KRAS mutant as determined by a [α-32P] guanosine triphosphate (GTP) binding assay and suppressed pancreatic cell line in a cell proliferation assay. Herein, the complex structure of KRAS and GJ101 was clarified by X-ray crystallography. Isothermal titration calorimetry showed that GJ101 binds highly with KRAS mutant and the complex structure of KRAS G12V.GJ101 complex presented that the residue of Q61 directly interacted with L65 of GJ101. Overall, the results suggest GJ101 be considered a developmental starting point for KRAS G12V inhibitor.

Targeting TAF1 with BAY-299 induces antitumor immunity in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a heterogeneous breast cancer subtype with poor prognoses and limited therapeutic options. The TATA-box binding protein associated factor 1 (TAF1) is an essential protein involved in the transcriptional regulation of cancer development and progress. However, the therapeutic potential and underlying mechanism of targeting TAF1 in TNBC remain unknown. Here, using chemical probe BAY-299, we identify that TAF1 inhibition leads to the induction of endogenous retrovirus (ERVs) expression and double-stranded RNA (dsRNA) formation, resulting in the activation of interferon responses and cell growth suppression in a subset of TNBC, resembling anti-viral mimicry effect. This correlation between TAF1 and interferon signature was validated in three independent breast cancer patient datasets. Furthermore, we observe heterogeneous responses to TAF1 inhibition across a set of TNBC cell lines. By integrating transcriptome and proteome data, we demonstrate that high levels of proliferating cell nuclear antigen (PCNA) protein serve as a predictive biomarker associated with suppressive tumor immune responses in various cancers, which may limit the efficiency of TAF1 inhibition.

Effect of chronic stress on tumorigenesis and development.

Chronic stress activates the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis to aggravates tumorigenesis and development. Although the importance of SNS and HPA in maintaining homeostasis has already attracted much attention, there is still a lot remained unknown about the molecular mechanisms by which chronic stress influence the occurrence and development of tumor. While some researches have already concluded the mechanisms underlying the effect of chronic stress on tumor, complicated processes of tumor progression resulted in effects of chronic stress on various stages of tumor remains elusive. In this reviews we concluded recent research progresses of chronic stress and its effects on premalignancy, tumorigenesis and tumor development, we comprehensively summarized the molecular mechanisms in between. And we highlight the available treatments and potential therapies for stressed patients with tumor.

Long-circulating doxorubicin and Schizandrin A liposome with drug-resistant liver cancer activity: in vitro and in vivo evaluation.

Co-loading doxorubicin (DOX) and Schizandrin A (SchA) long-circulating liposome (SchA-DOX-Lip) have been confirmed to have good antitumor activity in vitro. However, in vivo pharmacodynamics, targeting, safety, and mechanism of action of SchA-DOX-Lip still need to be further verified. We investigated the tumor inhibition effect, targeting, safety evaluation, and regulation of tumor apoptosis-related proteins of the SchA-DOX-Lip. MTT assay was used to investigate the inhibitory effect of SchA-DOX-Lip on CBRH7919 cells. The drug uptake of CBRH7919 cells was observed by inverted fluorescence microscope. The tumor-bearing nude mice models of CBRH7919 were established, and the anti-tumor effect of SchA-DOX-Lip in vivo was evaluated by tumor biological observation, H&E staining, and TUNEL staining. The distribution and targeting of SchA-DOX-Lip in nude mice models were investigated by small animal imaging and tissue distribution experiment of CBRH7919. The biosafety of SchA-DOX-Lip was evaluated by blood routine parameters, biochemical indexes, and H&E staining. The expression of tumor-associated apoptotic proteins (Bcl-2, Bax, and Caspase-3) was detected by immunohistochemistry anvd western blotting. The results showed that SchA-DOX-Lip had cytotoxicity to CBRH7919 cells which effectively inhibited the proliferation of CBRH7919 cells, improved the uptake of drugs by CBRH7919 cells and the targeting effect of drugs on tumor site. H&E staining and biochemical detection results showed that SchA-DOX-Lip had high biosafety and did not cause serious damage to normal tissues. Western-blotting and TUNEL staining results showed that SchA-DOX-Lip could improve the regulatory effect of drugs on tumor apoptosis proteins. It was demonstrated that SchA-DOX-Lip had high safety and strong tumor inhibition effects, providing a new method for the clinical treatment of hepatocellular carcinoma (HCC).

Generation of a Novel SORT1×HER2 Bispecific Antibody-Drug Conjugate Targeting HER2-Low-Expression Tumor.

Human epidermal growth factor receptor 2 (HER2) is considered an ideal antibody-drug conjugate (ADC) target because the gene is overexpressed in many tumors compared to normal tissues. Multiple anti-HER2 ADCs conjugated with different toxic payloads bring benefits to patients with high HER2 expression. However, HER2-targeted ADC technology needs further optimization to improve its effect for the treatment of patients with low HER2 expression. We hypothesized that bispecific antibody-drug conjugate (bsADC) targeting HER2 and Sortilin-1 (SORT1) would overcome this limitation. SORT1 is a suitable target for pairing with HER2 to generate a bispecific antibody (BsAb) since the gene is co-expressed with HER2 in tumors and possesses rapid internalization. We developed a BsAb (bsSORT1×HER2) that exhibited strong binding and internalization activity on HER2-low-expression tumor cells and facilitated higher HER2 degradation. The bsSORT1×HER2 was further conjugated with DXd to generate a bsADC (bsSORT1×HER2-DXd) that showed strong cytotoxicity on HER2-low-expression tumor cells and antitumor efficacy in an MDA-MB-231 xenograft mice model. These results demonstrated that employment of a SORT1×HER2-targeted bsADC may be promising to improve the antitumor efficacy of HER2-targeted ADC for the treatment of tumors with low HER2 expression.

Combined strategies for effective cancer immunotherapy with a novel anti-CD47 monoclonal antibody.

CD47 is a widely expressed cell-surface protein that regulates phagocytosis mediated by cells of the innate immune system, such as macrophages and dendritic cells. CD47 serves as the ligand for a receptor on these innate immune cells, signal regulatory protein (SIRP)-α, which in turn inhibits phagocytosis. Several targeted CD47 therapeutic antibodies have been investigated clinically; however, how to improve its therapeutic efficacy remains unclear. Herein, we developed a CD47 blocking antibody, named IBI188, that could specifically block the CD47-SIRP-α axis, which transduces the "don't eat me" signal to macrophages. In vitro phagocytosis assays demonstrated the pro-phagocytosis ability of IBI188. Furthermore, several in vivo models were chosen to evaluate the anti-tumor efficacy of IBI188. IBI188 treatment upregulated cell movement- and inflammation-related genes in macrophages. Synergism was observed when combined with an anti-CD20 therapeutic antibody, whose function depends on antibody-dependent cellular cytotoxicity/phagocytosis (ADCC/ADCP). CD47 expression was evaluated following azacytidine (AZA) treatment, a standard-of-care for patients with multiple myeloma; enhanced anti-tumor efficacy was observed in the combination group in AML xenograft models. Notably, IBI188 treatment increased vascular endothelial growth factor-A (VEGF-A) levels in a solid tumor model, and combined treatment with an anti-VEGF-A antibody and IBI188 resulted in an enhanced anti-tumor effect. These data indicate that IBI188 is a therapeutic anti-CD47 antibody with anti-tumor potency, which can be enhanced when used in combination with standard-of-care drugs for cancer treatment.

Diversity of actinomycete and their metabolites isolated from Howz Soltan Lake, Iran.

Saline environments are largely unexplored sources of actinomycetes with the potential to produce biologically active secondary metabolites. A total of 34 actinomycete isolates from water, sediments and mostly rhizosphere (82%) were collected from different sites at Howz Soltan Lake in Iran. Based on phylogenetic analysis, the isolates belonged to the genera Streptomyces, Nocardia and Saccharomonospora. Cytotoxic assay revealed extract from isolate act9 as the most potent (19.716±5.72 µg/ml) against the MDA-MB-231 human breast cancer cell. Also, 38% of the isolates showed antimicrobial activity against some of the test microorganisms. The ethyl-acetate extract of isolate act18 showed the strongest antibacterial effect against Staphylococcus aureus and MRSA, and was further analyzed by GC/MS. Ar-tumerone (26.41%) and butyl isodecyl phthalate (21.77 %) were the main constituents detected in the extract. This is the first time Ar-tumerone is being detected in a prokaryote. Isolate act18 showed a high 16S rRNA sequence similarity to that of Streptomyces youssoufiensis DSM 41920. In addition, a number of the isolates produced different enzymes including lipase, amylase, protease, gelatinase, urease and lecithinase. Some of the isolates belonging to the genera Streptomyces and Nocardia exhibited plant growth promoting activity such as increased seed germination, stem length and the number of Echium leaves during the 20 days. Findings from this study indicated the diversity and biosynthetic potential of actinomycetes from saline environment.

Assessing Nordihydroguaiaretic Acid Therapeutic Effect for Glioblastoma Multiforme.

In this study, we demonstrate that Raman microscopy combined with computational analysis is a useful approach to discriminating accurately between brain tumor bio-specimens and to identifying structural changes in glioblastoma (GBM) bio-signatures after nordihydroguaiaretic acid (NDGA) administration. NDGA phenolic lignan was selected as a potential therapeutic agent because of its reported beneficial effects in alleviating and inhibiting the formation of multi-organ malignant tumors. The current analysis of NDGA's impact on GBM human cells demonstrates a reduction in the quantity of altered protein content and of reactive oxygen species (ROS)-damaged phenylalanine; results that correlate with the ROS scavenger and anti-oxidant properties of NDGA. A novel outcome presented here is the use of phenylalanine as a biomarker for differentiating between samples and assessing drug efficacy. Treatment with a low NDGA dose shows a decline in abnormal lipid-protein metabolism, which is inferred by the formation of lipid droplets and a decrease in altered protein content. A very high dose results in cell structural and membrane damage that favors transformed protein overexpression. The information gained through this work is of substantial value for understanding NDGA's beneficial as well as detrimental bio-effects as a potential therapeutic drug for brain cancer.

Ferroptosis-Strengthened Metabolic and Inflammatory Regulation of Tumor-Associated Macrophages Provokes Potent Tumoricidal Activities.

Modulation of tumor-associated macrophages (TAMs) holds promise for cancer treatment, mainly relying on M1 signaling activation and pro-inflammatory promotion. Nevertheless, the antitumor activity is often limited by the anti-inflammatory factors in the tumor microenvironment. Moreover, the metabolic function of TAMs is also critical to tumor progression. However, there are a few strategies that can simultaneously regulate both inflammatory and metabolic functions to achieve safe and potent antitumor activation of TAMs. Herein, we demonstrate that an iron-based metal organic framework nanoparticle and a ferroptosis-inducing agent synergistically induce mitochondrial alternation in TAMs, resulting in a radical metabolic switch from mitochondrial oxidative phosphorylation to glycolysis, which is resistant to anti-inflammatory stimuli challenge. The ferroptosis stress strengthened by the nanoformulation also drives multiple pro-inflammatory signaling pathways, enabling macrophage activation with potent tumoricidal activities. The ferroptosis-strengthened macrophage regulation strategy present in this study paves the way for TAM-centered antitumoral treatment to overcome the limitations of conventional methods.

[Self-Aggregating Porphyrin-Based Photosensitizer Nano Micelles for Photodynamic Therapy].

Objective: To prepare supramolecular photosensitizer that can be retained at the site of tumors and that has high light conversion efficiency so as to improve the efficacy of tumor photodynamic therapy (PDT). Methods: A covalent organic framework material based on amino tetraphenyl porphyrin (Tapp), henceforth referred to as Tapp-COF, was synthesized. The spectral characteristics, energy gap characteristics and singlet oxygen generation ability of the material were characterized. Then, Tapp-COF was processed by thin film hydration method to derive T-C@PP, a nano micelle unstable in physiological environment. The same method was used to process Tapp in order to make T@PP micelles, which were used as the controls. The particle size, potential, surface morphology and stability were examined. B16F10 mouse melanoma cells were injected subcutaneously into C57 mice and T-C@PP or T@PP were injected intratumorally, followed by light exposure or no light exposure. We assessed the in vitro photodynamic killing efficiency of the nano micelles and the status of tumor cells co-cultured with the photosensitizer micelles and validated the tumor retention ability and killing efficiency of the micelles . Results: Compared with Tapp, Tapp-COF displayed higher photodynamic conversion efficiency, and could produce more ROS. The T-C@PP micelles were unstable in physiological environment, and adsorptive aggregation would occur after co-culturing with tumor cells for a period of time. T-C@PP showed low cytotoxicity when there was no light exposure, but could kill tumor cells at relatively low concentration under 660 nm laser irradiation. T-C@PP could be retained in tumor tissue, and had better in vivo killing efficiency that that of T@PP. Conclusion: In this study, highly efficient TPP-COF based T-C@PP micelles were prepared. Under physiological conditions, these micelles could achieve tumor retention through self-aggregation. Possessing sound safety, the nano micelles showed promise for potential application in tumor PDT.

Structural basis of the p53 DNA binding domain and PUMA complex.

PUMA (p53-upregulated modulator of apoptosis) is localized in mitochondria and a direct target in p53-mediated apoptosis. p53 elicits mitochondrial apoptosis via transcription-dependent and independent mechanisms. p53 is known to induce apoptosis via the transcriptional induction of PUMA, which encodes proapoptotic BH3-only members of the Bcl-2 protein family. However, the transcription-independent mechanisms of human PUMA remain poorly defined. For example, it is not known whether PUMA interacts directly with the DNA binding domain (DBD: residues 92-293) of p53 in vitro. Here, the structure of the complex between the DBD of p53 and PUMA peptide was elucidated by X-ray crystallography. Isothermal titration calorimetry showed that PUMA peptide binds strongly with p53 DBD, and the crystal structure of p53-PUMA peptide complex revealed it contains four molecules of p53 DBD and one PUMA peptide per asymmetric unit in space group P1. PUMA peptide bound to the N-terminal residues of p53 DBD. A cell proliferation assay demonstrated PUMA peptide inhibited the growth of a lung cancer cell line. These results contribute to understanding of the mechanism responsible for p53-mediated apoptosis.

Catalytic core-shell nanoparticles with self-supplied calcium and H2O2 to enable combinational tumor inhibition.

Nanoparticles, presenting catalytic activity to induce intracellular oxidative species, have been extensively explored for tumor treatment, but suffer daunting challenges in the limited intracellular H2O2 and thus suppressed therapeutic efficacy. Here in this study, a type of composite nanoparticles, consisting CaO2 core and Co-ferrocene shell, is designed and synthesized for combinational tumor treatment. The findings indicate that CaO2 core can be hydrolyzed to produce large amounts of H2O2 and calcium ions at the acidic tumor sites. Meanwhile, Co-ferrocene shell acts as an excellent Fenton catalyst, inducing considerable ROS generation following its reaction with H2O2. Excessive cellular oxidative stress triggers agitated calcium accumulation in addition to the calcium ions released from the particles. The combined effect of intracellular ROS and calcium overload causes significant tumor inhibition both in vitro and in vivo.

[Mesenchymal Stem Cells Cultured in 3D System Inhibit Non-small Cell Lung Cancer Cells Through p38 MAPK and CXCR4/AKT Pathways by IL-24 Regulating].

Non-small cell lung cancer (NSCLC) is prevalent worldwide and has a high mortality rate. Even if mesenchymal stem cells (MSCs) are suggested as cancer treatment, the studies of their effects on NSCLC cells contradict each other, mainly due to utilization of two-dimensional (2D) culture system. Three-dimensional (3D) culture systems resemble tissue organization in vivo. Here we comprehensively explore the inhibitory effects of MSCs on NSCLC cells in a 3D culture system. We confirmed that the inhibitory effects of 3D-cultured MSCs (3D-MSCs) on the proliferation and migration of NSCLC cells are greater than that of the 2D-cultured MSCs. 3D-MSCs overexpress IL-24, which serve as the key factor enhancing antitumor effects of MSCs. In these cells, IL-24 affects p38 MAPK and CXCR4/AKT pathways. Overall, this study provides the support for use of MSCs in tumor.