Role of Rho GTPases in stem cell regulation

Nanomaterials for delivery of drugs and genes to disrupt notch signaling pathway in breast cancer

Breast cancer, marked by considerable heterogeneity and intricate molecular subgroups, poses substantial obstacles to therapy. Epithelial-mesenchymal transition (EMT) and the existence of tumor-initiating cells (TICs) facilitate treatment resistance, metastasis, and worse prognosis. The Notch signaling system has garnered significant interest for its involvement in promoting epithelial-mesenchymal transition (EMT), maintaining tumor-initiating cells (TIC), and facilitating cancer progression, especially in truculent subtypes such as triple-negative breast cancer (TNBC). Targeting the Notch system represents a promising therapeutic strategy; nevertheless, traditional inhibitors frequently encounter obstacles, including inadequate selectivity and bioavailability. Nanocarrier-based drug delivery systems provide novel therapeutic strategies to these difficulties by augmenting the targeted delivery of Notch inhibitors and enhancing therapeutic efficacy. Solid lipid nanoparticles (SLNs), polymeric nanoparticles, lipid-based nanocarriers, and micelles exhibit promise in delivering Notch inhibitors to neoplastic cells, altering the Notch signaling pathway, and surmounting drug resistance. This review examines recent breakthroughs in nanocarrier systems aimed at the Notch signaling pathway in breast cancer, highlighting the therapeutic potential of integrating nanomedicine with Notch inhibition to disrupt epithelial-mesenchymal transition (EMT), tumor-initiating cells (TICs), and metastasis, thereby enhancing clinical outcomes.

Antitumor Activities by a Humanized Cancer-Specific Anti-Podoplanin Monoclonal Antibody humPMab-117 Against Human Tumors

Podoplanin (PDPN), also referred to as T1α/Aggrus, is a type I transmembrane sialoglycoprotein that plays a crucial role in invasiveness, stemness, and epithelial-to-mesenchymal transition, all of which contribute to the malignant progression of tumors. Therefore, a monoclonal antibody (mAb) against PDPN has been evaluated in preclinical models as a promising tumor therapy strategy. However, PDPN plays an essential role in normal development, such as in the development of the lungs. On-target toxicity by anti-PDPN mAbs to normal cells should be avoided to minimize adverse effects. A cancer-specific mAb against PDPN, PMab-117 (rat IgM, kappa), was previously established. This study engineered the humanized IgG1 version (humPMab-117) to investigate antitumor activity. Flow cytometry analysis confirmed that humPMab-117 recognized PDPN-overexpressed glioma LN229 (LN229/PDPN) cells as well as PDPN-positive PC-10 (human lung squamous cell carcinoma) and LN319 (human glioblastoma) cells. In contrast, humPMab-117 did not react with normal epithelial cells from the lung bronchus, gingiva, mammary gland, corneal, and normal kidney podocytes, suggesting that humPMab-117 retains cancer-specific reactivity. Furthermore, humPMab-117 effectively induced antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against LN229/PDPN, PC-10, and LN319 cells. In the xenograft tumor models, humPMab-117 demonstrated strong antitumor efficacy. These results suggest the potential of humPMab-117 as a therapeutic antibody for treating PDPN-positive malignant tumors.

Phosphoproteomics Reveals L1CAM-Associated Signaling Networks in High-Grade Serous Ovarian Carcinoma: Implications for Radioresistance and Tumorigenesis

Quantitative phosphoproteomics enables the comprehensive analysis of signaling pathways driven by overexpressed cancer receptors, revealing the molecular mechanisms that underpin tumor progression and therapy resistance. The glycoprotein L1 cell adhesion molecule (L1CAM) is overexpressed in high-grade serous ovarian carcinoma (HGSOC) and plays a crucial role in carcinogenesis by regulating cancer stem cell properties. Here, CRISPR-Cas9-mediated knockout of L1CAM in ovarian cancer OVCAR8 and OVCAR4 cells significantly impaired anchor-independent growth in soft agar assays and reduced clonogenic survival following external beam irradiation. In vivo, L1CAM knockout decreased cancer stem cell frequency and significantly decreased tumorigenicity. To uncover L1CAM-regulated signaling networks, we employed quantitative phosphoproteomics and proteomics. Bioinformatics analyses and validation studies revealed L1CAM-associated pathways that contribute to radioresistance through DNA repair processes and mammalian target or rapamycin complex 1 (mTORC1)-mediated signaling. In conclusion, our study established a link between L1CAM-dependent tumorigenesis and radioresistance, both hallmarks of cancer stemness, with phosphorylation of key proteins involved in DNA damage response. This study further emphasizes the value of quantitative phosphoproteomics in cancer research, showcasing its ability to enhance understanding of cancer progression and therapy resistance.

Electrically Active Biomaterials for Stimulation and Regeneration in Tissue Engineering

In the human body, bioelectric cues are crucial for tissue stimulation and regeneration. Electrical stimulation (ES) significantly enhances the regeneration of nerves, bones, cardiovascular tissues, and wounds. However, the use of conventional devices with stimulating metal electrodes is invasive and requires external batteries. Consequently, electrically active materials with excellent biocompatibility have attracted attention for their applications in stimulation and regeneration in tissue engineering. To fully exploit the potential of these materials, biocompatibility, operating mechanisms, electrical properties, and even biodegradability should be carefully considered. In this review, we categorize various electrically active biomaterials based on their mechanisms for generating electrical cues, such as piezoelectric effect, triboelectric effect, and others. We also summarize the key material properties, including electrical characteristics and biodegradability, and describe their applications in tissue stimulation and regeneration for nerves, musculoskeletal tissues, and cardiovascular tissues. The electrically active biomaterials hold great potential for advancing the field of tissue engineering and their demonstrated success underscores the importance of continued research in this field.

RHO subfamily of small GTPases in the development and function of hematopoietic cells

RHOA, RHOB, and RHOC comprise a subfamily of RHO GTPase proteins famed for controlling cytoskeletal dynamics. RHO proteins operate downstream of multiple signals emerging from the microenvironment, leading to diverse cell responses, such as proliferation, adhesion, and migration. Therefore, RHO signaling has been centrally placed in the regulation of blood cells. Despite their high homology, unique roles of RHOA, RHOB, and RHOC have been described in hematopoietic cells. In this article, we overview the contribution of RHO proteins in the development and function of each blood cell lineage. Additionally, we highlight the aberrations of the RHO signaling pathways found in hematological malignancies, providing clues for the identification of new therapeutic targets.

Canid alphaherpesvirus 1 infection alters the gene expression and secretome profile of canine adipose-derived mesenchymal stem cells in vitro

BACKGROUND

Canine adipose-derived mesenchymal stem cells (cAD-MSCs) demonstrate promising tissue repair and regeneration capabilities. However, the procurement and preservation of these cells or their secreted factors for therapeutic applications pose a risk of viral contamination, and the consequences for cAD-MSCs remain unexplored. Consequently, this research sought to assess the impact of canid alphaherpesvirus 1 (CHV) on the functional attributes of cAD-MSCs, including gene expression profiles and secretome composition.

METHODS

To this end, abdominal adipose tissue from 12 healthy dogs was harvested to isolate cAD-MSCs. These samples were tested for CHV contamination before introducing a wild-type CHV strain via serial passages. Following CHV infection, real-time reverse transcription-polymerase chain reaction array and liquid chromatography with tandem mass spectrometry assessments enabled analyses of gene expression and secretome's proteomic profile, respectively.

RESULTS

This study showed that the initial cAD-MSC populations were devoid of CHV. cAD-MSCs showed susceptibility to infection with wild-type CHV, leading to notable modifications in gene expression and secretome profile. The observed genomic variations in gene expression indicate potential impacts on the stemness, migration, and other functional properties of cAD-MSCs, highlighting the need for further studies to evaluate their functional capacity post-infection. Moreover, gene expression and secretome analyses suggest a shift in stem cell differentiation toward an adipogenic phenotype.

CONCLUSION

To the best of our knowledge, this is the first study of the effects of virus infection on gene expression and secretome composition in cAD-MSCs. The outcomes of our study underscore the imperative of routine viral screening prior to the therapeutic use of cAD-MSCs. Moreover, these findings provide novel insights into the pathogenic mechanisms of CHV and pave the way for future canine stem cell and virus research.

A Cancer-Specific Anti-Podoplanin Monoclonal Antibody, PMab-117-mG2a Exerts Antitumor Activities in Human Tumor Xenograft Models

Podoplanin (PDPN) overexpression is associated with poor clinical outcomes in various tumors. PDPN is involved in malignant tumor progression by promoting invasiveness and metastasis. Therefore, PDPN is considered a promising target of monoclonal antibody (mAb)-based therapy. Because PDPN also plays an essential role in normal cells such as kidney podocytes, cancer specificity is required to reduce adverse effects on normal cells. We developed a cancer-specific mAb (CasMab) against PDPN, PMab-117 (rat IgM, kappa), by immunizing rats with PDPN-overexpressed glioblastoma cells. The recombinant mouse IgG2a-type PMab-117 (PMab-117-mG2a) reacted with the PDPN-positive tumor PC-10 and LN319 cells but not with PDPN-knockout LN319 cells in flow cytometry. PMab-117-mG2a did not react with normal kidney podocytes and normal epithelial cells from the lung bronchus, mammary gland, and corneal. In contrast, one of the non-CasMabs against PDPN, NZ-1, showed high reactivity to PDPN in both tumor and normal cells. Moreover, PMab-117-mG2a exerted antibody-dependent cellular cytotoxicity in the presence of effector splenocytes. In the human tumor xenograft models, PMab-117-mG2a exhibited potent antitumor effects. These results indicated that PMab-117-mG2a could be applied to antibody-based therapy against PDPN-expressing human tumors while reducing the adverse effects.

Lectin Receptors in Primary and Metastatic Cancer Cells

PURPOSE

The purpose of this study was to detect the distribution of different lectin receptors in primary cancer cells as well as in the case of metastasis, as these biomolecules can potentially predict cancer development in certain tissues and systems.

METHODS

To detect lectin receptors in tumors, the authors used conjugates of lectins purified by affinity chromatography with peroxidase, and studied their localization in paraffin sections of 12 cases of primary cancer and 33 of its metastases.

RESULT

In primary cancers and their metastases, there is a distinct mosaicity in the histotopography of individual lectins, especially peanut and soybean lectin. Mosaicity increases in metastases, which corresponds to the increase in malignancy of tumour cells. Detected cases of metastases with a decrease in mosaicity may be a sign of their monoclonality or a decrease in their malignancy. The study of lectins in the cells of cancer metastases and their comparison with the primary tumour and with each other suggests that in metastases, as a rule, not only signs of malignancy increase, but also the ability of cells to adhere and migrate. Thus, in the process of tumour growth and metastasis, there is a selection of clones of cells that are more prone to the development of new metastases.

CONCLUSIONS

It has been revealed that the growth of a primary immature tumour from the epithelium and its metastases is accompanied by sialylation of the surface of tumour cells, which leads to the fact that tumour cells are not recognized by the system of mononuclear phagocytes and this, naturally, contributes to the progression of tumour growth.

In vitro aging alters the gene expression and secretome composition of canine adipose-derived mesenchymal stem cells

Introduction

Canine adipose-derived mesenchymal stem cells (cAD-MSCs) hold therapeutic promise due to their regenerative potential, particularly within their secretome. However, concerns arise regarding the impact of in vitro cultivation necessitated for storing therapeutic doses, prompting this study to comprehensively explore the impact of in vitro aging on gene expression and secretome composition.

Methods

The study involved collecting abdominal adipose tissue samples from nine healthy female dogs, from which cAD-MSCs were extracted and cultured. Stem cells were validated through trilineage differentiation assays and flow cytometry immunophenotyping. Gene expression profiling using RT-qPCR array, and cAD-MSCs secretome LC-MS/MS analysis, were conducted at passages 3 and 6 to reveal gene expression and protein composition alterations during in vitro culture.

Results and Discussion

The results demonstrate that the gene expression and secretome composition of cAD-MSCs were impacted by in vitro aging. Among many alterations in gene expression between two passages, two significant downregulations were noted in the MSC-associated PTPRC and IL10 genes. While the majority of proteins and their functional characteristics were shared between passages, the influence of cell aging on secretome composition is highlighted by 10% of proteins being distinctively expressed in each passage, along with 21 significant up- and downregulations. The functional attributes of proteins detected in passage 3 demonstrated a greater inclination towards supporting the regenerative capacity of cAD-MSCs. Moreover, proteins in passage 6 exhibited a noteworthy correlation with the blood coagulation pathway, suggesting an elevated likelihood of coagulation events. To the best of our knowledge, this study presents the first original perspective on the changes in secretome composition that occur when cAD-MSCs age in vitro. Furthermore, it contributes to broadening the currently restricted knowledge base concerning the secretome of cAD-MSCs. In conclusion, our findings show that the regenerative potential of cAD-MSCs, as well as their secretome, may be compromised by in vitro aging. Therefore, our study suggests a preference for earlier passages when considering these cells for therapeutic applications.

Silencing geranylgeranyltransferase I inhibits the migration and invasion of salivary adenoid cystic carcinoma through RhoA/ROCK1/MLC signaling and suppresses proliferation through cell cycle regulation

Geranylgeranyltransferase type I (GGTase-I) significantly affects Rho proteins, such that the malignant progression of several cancers may be induced. Nevertheless, the effect and underlying mechanism of GGTase-I in the malignant progression of salivary adenoid cystic carcinoma (SACC) remain unclear. This study primarily aimed to investigate the role and mechanism of GGTase-I in mediating the malignant progression of SACC. The level of GGTase-I gene in cells was stably knocked down by short hairpin RNA-EGFP-lentivirus. The effects of GGTase-I silencing on the migration, invasion, and spread of cells were examined, the messenger RNA levels of GGTase-I and RhoA genes of SACC cells after GGTase-I knockdown were determined, and the protein levels of RhoA and RhoA membrane of SACC cells were analyzed. Moreover, the potential underlying mechanism of silencing GGTase-I on the above-mentioned aspects in SACC cells was assessed by examining the protein expression of ROCK1, MLC, p-MLC, E-cadherin, Vimentin, MMP2, and MMP9. Furthermore, the underlying mechanism of SACC cells proliferation was investigated through the analysis of the expression of cyclinD1, MYC, E2F1, and p21CIP1/WAF1 . Besides, the change of RhoA level in SACC tissues compared with normal paracancer tissues was demonstrated through quantitative reverse-transcription polymerase chain reaction and western blot experiments. Next, the effect after GGTase-I silencing was assessed through the subcutaneous tumorigenicity assay. As indicated by the result of this study, the silencing of GGTase-I significantly reduced the malignant progression of tumors in vivo while decreasing the migration, invasion, and proliferation of SACC cells and RhoA membrane, Vimentin, ROCK1, p-MLC, MMP2, MMP9, MYC, E2F1, and CyclinD1 expression. However, the protein expression of E-cadherin and p21CIP1/WAF1 was notably upregulated. Subsequently, no significant transform of RhoA and MLC proteins was identified. Furthermore, RhoA expression in SACC tissues was significantly higher than that in paracancerous tissues. As revealed by the results of this study, GGTase-I shows a correlation with the proliferation of SACC through the regulation of cell cycle and may take on vital significance in the migration and invasion of SACC by regulating RhoA/ROCK1/MLC signaling pathway. GGTase-I is expected to serve as a novel exploration site of SACC.

Mutant p53, the Mevalonate Pathway and the Tumor Microenvironment Regulate Tumor Response to Statin Therapy

Tumor cells have the ability to co-opt multiple metabolic pathways, enhance glucose uptake and utilize aerobic glycolysis to promote tumorigenesis, which are characteristics constituting an emerging hallmark of cancer. Mutated tumor suppressor and proto-oncogenes are frequently responsible for enhanced metabolic pathway signaling. The link between mutant p53 and the mevalonate (MVA) pathway has been implicated in the advancement of various malignancies, with tumor cells relying heavily on increased MVA signaling to fuel their rapid growth, metastatic spread and development of therapy resistance. Statin drugs inhibit HMG-CoA reductase, the pathway’s rate-limiting enzyme, and as such, have long been studied as a potential anti-cancer therapy. However, whether statins provide additional anti-cancer properties is worthy of debate. Here, we examine retrospective, prospective and pre-clinical studies involving the use of statins in various cancer types, as well as potential issues with statins’ lack of efficacy observed in clinical trials and future considerations for upcoming clinical trials.

Roles of Podoplanin in Malignant Progression of Tumor

Podoplanin (PDPN) is a cell-surface mucin-like glycoprotein that plays a critical role in tumor development and normal development of the lung, kidney, and lymphatic vascular systems. PDPN is overexpressed in several tumors and is involved in their malignancy. PDPN induces platelet aggregation through binding to platelet receptor C-type lectin-like receptor 2. Furthermore, PDPN modulates signal transductions that regulate cell proliferation, differentiation, migration, invasion, epithelial-to-mesenchymal transition, and stemness, all of which are crucial for the malignant progression of tumor. In the tumor microenvironment (TME), PDPN expression is upregulated in the tumor stroma, including cancer-associated fibroblasts (CAFs) and immune cells. CAFs play significant roles in the extracellular matrix remodeling and the development of immunosuppressive TME. Additionally, PDPN functions as a co-inhibitory molecule on T cells, indicating its involvement with immune evasion. In this review, we describe the mechanistic basis and diverse roles of PDPN in the malignant progression of tumors and discuss the possibility of the clinical application of PDPN-targeted cancer therapy, including cancer-specific monoclonal antibodies, and chimeric antigen receptor T technologies.