Dbl family RhoGEFs in cancer: different roles and targeting strategies.

Small Ras homologous guanosine triphosphatase (Rho GTPase) family proteins are highly associated with tumorigenesis and development. As intrinsic exchange activity regulators of Rho GTPases, Rho guanine nucleotide exchange factors (RhoGEFs) have been demonstrated to be closely involved in tumor development and received increasing attention. They mainly contain two families: the diffuse B-cell lymphoma (Dbl) family and the dedicator of cytokinesis (Dock) family. More and more emphasis has been paid to the Dbl family members for their abnormally high expression in various cancers and their correlation to poor prognosis. In this review, the common and distinctive structures of Dbl family members are discussed, and their roles in cancer are summarized with a focus on Ect2, Tiam1/2, P-Rex1/2, Vav1/2/3, Trio, KALRN, and LARG. Significantly, the strategies targeting Dbl family RhoGEFs are highlighted as novel therapeutic opportunities for cancer.

Neutrophils as potential therapeutic targets for breast cancer.

Breast cancer (BC) remains the foremost cause of cancer mortality globally, with neutrophils playing a critical role in its pathogenesis. As an essential tumor microenvironment (TME) component, neutrophils are emerging as pivotal factors in BC progression. Growing evidence has proved that neutrophils play a Janus- role in BC by polarizing into the anti-tumor (N1) or pro-tumor (N2) phenotype. Clinical trials are evaluating neutrophil-targeted therapies, including Reparixin (NCT02370238) and Tigatuzumab (NCT01307891); however, their clinical efficacy remains suboptimal. This review summarizes the evidence regarding the close relationship between neutrophils and BC, emphasizing the critical roles of neutrophils in regulating metabolic and immune pathways. Additionally, we summarize the existing therapeutic approaches that target neutrophils, highlighting the challenges, and affirming the rationale for continuing to explore neutrophils as a viable therapeutic target in BC management.

FXR agonist GW4064 enhances anti-PD-L1 immunotherapy in colorectal cancer.

Colorectal cancer (CRC) is one of the top three malignant tumors in terms of morbidity, and the limited efficacy of existing therapies urges the discovery of potential treatment strategies. Immunotherapy gradually becomes a promising cancer treatment method in recent decades; however, less than 10% of CRC patients could really benefit from immunotherapy. It is pressing to explore the potential combination therapy to improve the immunotherapy efficacy in CRC patients. It is reported that Farnesoid X receptor (FXR) is deficiency in CRC and associated with immunity. Herein, we found that GW4064, a FXR agonist, could induce apoptosis, block cell cycle, and mediate immunogenic cell death (ICD) of CRC cells in vitro. Disappointingly, GW4064 could not suppress the growth of CRC tumors in vivo. Further studies revealed that GW4064 upregulated PD-L1 expression in CRC cells via activating FXR and MAPK signaling pathways. Gratifyingly, the combination of PD-L1 antibody with GW4064 exhibited excellent anti-tumor effects in CT26 xenograft models and increased CD8+ T cells infiltration, with 33% tumor bearing mice cured. This paper illustrates the potential mechanisms of GW4064 to upregulate PD-L1 expression in CRC cells and provides important data to support the combination therapy of PD-L1 immune checkpoint blockade with FXR agonist for CRC patients.

Crizotinib-based proteolysis targeting chimera suppresses gastric cancer by promoting MET degradation.

As one of the common malignant cancer types, gastric cancer (GC) is known for late-stage diagnosis and poor prognosis. Overexpression of the receptor tyrosine kinase MET is associated with poor prognosis among patients with advanced stage GC. However, no MET inhibitor has been used for GC treatment. Like other tyrosine kinase inhibitors that fit the "occupancy-driven" model, current MET inhibitors are prone to acquired resistance. The emerging proteolysis targeting chimera (PROTAC) strategy could overcome such limitations through direct degradation of the target proteins. In this study, we successfully transformed the MET-targeted inhibitor crizotinib into a series of PROTACs, recruiting cereblon/cullin 4A E3 ubiquitin ligase to degrade the MET proteins. The optimized lead PROTAC (PRO-6 E) effectively eliminated MET proteins in vitro and in vivo, inhibiting proliferation and motility of MET-positive GC cells. In the MKN-45 xenograft model, PRO-6 E showed pronounced antitumor efficacy with a well-tolerated dosage regimen. These results validated PRO-6 E as the first oral PROTAC for MET-dependent GC.

Targeted Protein Degradation Technology and Nanomedicine: Powerful Allies against Cancer.

Targeted protein degradation (TPD) is an emerging therapeutic strategy with the potential of targeting undruggable pathogenic proteins. After the first proof-of-concept proteolysis-targeting chimeric (PROTAC) molecule was reported, the TPD field has entered a new era. In addition to PROTAC, numerous novel TPD strategies have emerged to expand the degradation landscape. However, their physicochemical properties and uncontrolled off-target side effects have limited their therapeutic efficacy, raising concerns regarding TPD delivery system. The combination of TPD and nanotechnology offers great promise in improving safety and therapeutic efficacy. This review provides an overview of novel TPD technologies, discusses their clinical applications, and highlights the trends and perspectives in TPD nanomedicine.

Helichrysetin inhibits gastric cancer growth by targeting c-Myc/PDHK1 axis-mediated energy metabolism reprogramming.

Helichrysetin (HEL), a chalcone isolated from Alpinia katsumadai Hayata, has an antitumor activity in human lung and cervical cancers. However, the inhibitory effect and underlying mechanism of HEL in gastric cancer have not been elucidated. Here, HEL significantly inhibited the growth of gastric cancer MGC803 cells in vitro and in vivo. HEL decreased expression and transcriptional regulatory activity of c-Myc and mRNA expression of c-Myc target genes. HEL enhanced mitochondrial oxidative phosphorylation (OXPHOS) and reduced glycolysis as evidenced by increased mitochondrial adenosine triphosphate (ATP) production and excessive reactive oxygen species (ROS) accumulation, and decreased the pPDHA1/PDHA1 ratio and Glyco-ATP production. Pyruvate enhanced OXPHOS after HEL treatment. c-Myc overexpression abolished HEL-induced inhibition of cell viability, glycolysis, and protein expression of PDHK1 and LDHA. PDHK1 overexpression also counteracted inhibitory effect of HEL on cell viability. Conversely, c-Myc siRNA decreased cell viability, glycolysis, and PDHK1 expression. NAC rescued the decrease in viability of HEL-treated cells. Additionally, HEL inhibited the overactivated mTOR/p70S6K pathway in vitro and in vivo. HEL-induced cell viability inhibition was counteracted by an mTOR agonist. mTOR inhibitor also decreased cell viability. Similar results were obtained in SGC7901 cells. HEL repressed lactate production and efflux in MGC803 cells. These results revealed that HEL inhibits gastric cancer growth by targeting mTOR/p70S6K/c-Myc/PDHK1-mediated energy metabolism reprogramming in cancer cells. Therefore, HEL may be a potential agent for gastric cancer treatment by modulating cancer energy metabolism reprogramming.

The Cyr61 Is a Potential Target for Rotundifuran, a Natural Labdane-Type Diterpene from Vitex trifolia L., to Trigger Apoptosis of Cervical Cancer Cells.

Cervical cancer is a common female malignant tumor that seriously threatens human health. This study explored the anticervical cancer effects and potential mechanisms of Rotundifuran (RTF), a natural product isolated from Vitex trifolia L. In this study, we found that RTF can suppress the proliferation of cervical cancer cell lines, including HeLa and SiHa cells (with the IC50 less than 10 µM), via induction of apoptosis in vitro, and the antitumor effect of RTF is further confirmed on the HeLa cell-inoculated xenograft model. In addition, our results proved that the antitumor effects of RTF might be related with the reactive oxygen species- (ROS-) induced mitochondrial-dependent apoptosis through MAPK and PI3K/Akt signal pathways. Using proteomics analysis and the drug affinity responsive target stability- (DARTS-) combined mass spectrometry (DARTS-MS), Cyr61 was indicated as a potential target for RTF in cervical cancer cells. Our present study would be beneficial for the development of RTF as a candidate for treatment of cervical cancer in the future.

Enhanced anti-tumor efficacy by inhibiting HIF-1α to reprogram TAMs via core-satellite upconverting nanoparticles with curcumin mediated photodynamic therapy.

Tumor hypoxic stress after photodynamic therapy (PDT) will be inevitably exacerbated by the vascular blocking effects and oxygen consumption in the tumor microenvironment (TME) which usually leads to compromised efficacy and clinical performance. Increasing evidence links the hypoxia induced up-regulation of hypoxia inducible factor 1α (HIF-1α) with immunosuppressive TME, including the polarization of M2 phenotype tumor associated macrophages (TAMs), which promote the recurrence and metastasis. Here, we reported NIR-triggered core-satellite upconverting nanoparticles (CSNPs) with curcumin (Cur) embedded as a difunctional photosensitizer, which could realize PDT in deep tumors with long excitation wavelength (980 nm) and reverse the immunosuppressive TME induced by up-regulated HIF-1α at the same time. This Cur-loaded CSNPs (Cur-CSNPs)-mediated PDT could successfully induce the immunogenic cell death (ICD) of triple negative breast cancer (TNBC) cell lines (4T1 and MDA-MB-231) in vitro and repolarize the 4T1 cells co-cultured TAMs from pro-tumor M2 to the anti-tumor M1 phenotype. Furthermore, Cur-CSNPs-mediated PDT could suppress the 4T1 tumor growth in primary and distant sites through the synergistic immunotherapeutic effects in vivo by priming M1 type TAMs and CD4+/CD8+ T cells' infiltration. Our data highlight the novel application of CSNPs-embedded Cur as a difunctional photosensitizer to enhance the anti-tumor efficacy of PDT.

Advances in the Study of Structural Modification and Biological Activities of Anoplin.

Anoplin is an amphipathic, α-helical bioactive peptide from wasp venom. In recent years, pharmaceutical and organic chemists discovered that anoplin and its derivatives showed multiple pharmacological activities in antibacterial, antitumor, antifungal, and antimalarial activities. Owing to the simple and unique structure and diverse biological activities, anoplin has attracted considerable research interests. This review highlights the advances in structural modification, biological activities, and the outlook of anoplin in order to provide a basis for new drug design and delivery.

Brucine: A Review of Phytochemistry, Pharmacology, and Toxicology.

Brucine, a weak alkaline indole alkaloid, is one of the main bioactive and toxic constituents of Nux-vomica. Modern pharmacology studies and clinical practice demonstrate that brucine possesses wide pharmacological activities, such as anti-tumor, anti-inflammatory, analgesic, and the effects on cardiovascular system and nervous system, etc. However, its central nervous system toxicity severely limits its clinical application. Herein, the physicochemical properties, pharmacological activities, and toxicity of brucine were reviewed, and the novel strategies to address the toxicity issues were discussed, aiming to bring new insights into further research and application of this active component.

[Effects of Ginseng panaxadiol saponin on proliferation and differentiation of human bone marrow CD34+ cells].

The study was purposed to investigate the effects of the panaxadiol saponin (PDS) from Ginseng on proliferation and differentiation of human CD34(+) cells from human bone marrow. Highly purified CD34(+) cells were isolated from human bone marrow by using the Dynal CD34 Cell Selection System (Dynal, Norway). The cells were exposed to PDS at various concentrations in both agar semi-solid culture of CFU-Mix and suspension culture of myeloid and erythroid cells in order to observe the effects of PDS on proliferation of CD34(+) cells. The cells were marked with 4 kinds of monoclonal antibody in related with their differentiation toward to myeloid and erythroid lineages, then examined by flow cytometry (FACS) after being incubated with PDS for 14 days. The results showed that the number of CD34(+) cells was 1.0 +/- 0.15% out of marrow nuclear cells after being purified by Dynal beads system. The enrichment of CD34(+) cells reached to 86.8 +/- 2.8%. The best efficiency in promoting proliferation of CD34(+) cells in vitro was obtained when the concentration of PDS was 25 mg/L, the formation of CFU-Mix colonies significantly increased by 56.3 +/- 3.5% over those of no-PDS control (p < 0.01). The results from suspension culture revealed that myeloid cells elevated in a dose-dependent manner with a peak increasing rate of 35.6 +/- 3.2%, and erythroid cells significantly increased by 22.3 +/- 2.1% over those of no-PDS control (all p < 0.01). After incubation with PDS for 14 days, number of CD33(+) cells increased in a dose-dependent manner with a peak increasing rate at 50 mg/L. CD71(+) cells reaching the peak were at 25 mg/L, while G-A(+) cells were increased by 7.2 +/- 1.3% (p < 0.01) at 10 mg/L, but the number of CD15(+) cells was not found to be changed before and after treating with PDS. It is concluded that PDS not only enhance the proliferation of CD34(+) cells, but also induce differentiation of CD34(+) cells toward to myeloid and erythroid lineages. PDS may play the roles as like hematopoietic growth factor, or provide synergistic effects on growth factor in the regulation of hematopoiesis.

[Proliferation and differentiation of human CD34+ hematopoietic stem/progenitor cells induced by Panax notoginosides].

The object of this study was to explore the effects of Panax notoginosides (PNS) on proliferation and differentiation of human CD34(+) stem/progenitor cells. CD34(+) cells were isolated from human bone marrow by using immune beads of Dynal M- 450 system. The cells were exposed to PNS at different concentrations in both liquid and semi-solid culture for 14 days. The cells were marked with monoclonal antibodies and analyzed by flow cytometry after culture. The CFU-Mix colony formation from CD34(+) cells was assayed. The results showed that: (1) The yield of CD34(+) cells after being selected by immune beads were (1.03 +/- 0.74)% out of bone marrow nuclear cells with purity of 86% - 93%. (2) PNS (10 - 25 mg/L) stimulated the proliferation of CD34(+) cells, and raised the colony numbers of CFU-Mix obviously in vitro. PNS 25 mg/L was the optimal concentration to promote proliferation of CD34(+) cells, the increasing rate of CFU-Mix colony was (34.7 +/- 16.0)%. (3) The differentiation of CD34(+) cells was induced by exposure to PNS (25, 50 and 100 mg/L) in liquid culture for 14 days. The percentages of CD33(+) and CD15(+) cells were increased after PNS exposure, which were significantly higher than those of control (P < 0.01), however CD71(+) and G-A(+) cells were no obviously difference after PNS treatment. In conclusion, Panax notoginosides not only promote the proliferation of CD34(+) cells, but also induce the differentiation committed to granulocytes.