Protein and Peptide Letters - Current Issue

Endogenous microRNAs (miRNAs) are critical regulators of tumor progression, making their role in breast cancer an important area of investigation.

This study examined the regulation of MSMO1 by miR-584-5p in breast cancer cells. Using bioinformatics and Western blotting, we confirmed MSMO1 expression in breast cancer cells and evaluated its effects on cell migration, invasion, and the AKT signaling pathway. In vivo experiments further supported these findings. The interaction between miR-584-5p and MSMO1 was validated through luciferase reporter assays, while functional studies highlighted the impact of miR-584-5p on cancer progression.

Our findings revealed that MSMO1 is upregulated in breast cancer, enhancing cell migration and invasion. Silencing MSMO1 diminished AKT pathway activity, and luciferase assays confirmed MSMO1 as a direct target of miR-584-5p.

Overexpression of miR-584-5p suppressed migration and invasion of breast cancer cells. In summary, miR-584-5p is likely to modulate MSMO1 and subsequently regulate the AKT/PI3K pathway, presenting a promising therapeutic target for breast cancer treatment.

Natural killer (NK) cells, as part of the group I innate lymphocytes (ILCs) are essential for tumor immune surveillance. NK cells can recognize and eliminate target cells without the need for prior sensitization or restriction of major histocompatibility complexes (MHCs) and antigens. However, the limited infiltration of metastatic NK cells poses significant challenges for advancing adoptive cell immunotherapy for solid tumors.

This study aimed to explore the potential of using tumor penetrating peptide (TPP) iRGD to promote the delivery of activated NK cells to deeper layers of tumor tissue.

Flow cytometry was performed to evaluate the activation, inhibition, and expression of other receptors involved in cytotoxicity. High-pressure liquid chromatography (HPLC) and mass spectrometry were used to detect the purity of iRGD. 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol)-iRGD (DSPE-PEG-iRGD) was synthesized. Surface modification of cells was performed using DSPE-PEG-iRGD. Multicellular tumor spheroids (MCTSs) were established to evaluate permeability. In addition, in order to better simulate the physiological characteristics of solid tumors in vivo, we generated 3D spheroids from HGC27 gastric cancer cell line and BXPC-3 pancreatic cancer cell line to study the anti-tumor effect of NK cells with combination iRGD in vitro. The mouse models of gastric cancer and pancreatic cancer were used. In addition, the synergistic anti-tumor effects were evaluated in vivo based on the tumor volume and body weight of mice.

Initially, we treated NK cells with interleukin-2 (IL-2), resulting in significant activation as indicated by upregulation of CD56. On the 15th day, the proliferation of CD3-/56+cell population in NK cell culture containing IL-2 significantly increased, and the NK cell amplification factor was greater than 300. In addition, NK cells exhibited increased cytotoxicity towards cancer cell lines. When the ratio of effect to target was 10:1, the killing rate of NK cells against BXPC-3 was 83.1%. iRGD modification enabled NK cells to penetrate MCTSs, resulting in cytotoxicity against target HGC27 and BXPC-3 cells. In addition, NK cells modified with iRGD significantly reduced tumor growth in the xenotransplantation model of gastric cancer and pancreatic cancer mice model.

In summary, our results indicated that NK cells exhibited higher efficacy and lifespan against cancer cell lines in vitro. Furthermore, the integration of iRGD into NK cells led to improved infiltration and targeted elimination of MCTSs. Moreover, the application of iRGD-modified NK cells has shown significant anti-tumor efficacy against solid tumors in vivo. This joint strategy may significantly improve the efficacy of NK cell immunotherapy in treating various solid tumors.

Gastric cancer has emerged as one of the major diseases threatening human health. Our previous studies indicated that the anti-cancer bioactive peptide (ACBP) inhibits the initiation and progression of gastric cancer through apoptosis and cell cycle arrest, yet the mechanisms remain unclear. To elucidate the relationships between the effects of ACBP and the levels of cell differentiation, as well as the functional mechanisms of ACBP, we conducted a study using three human gastric cancer cell lines: NCI-N87, MGC-803, and another unspecified line.

We investigated the impact of ACBP on the survival and morphology of these cancer cell lines, examined apoptosis and cell cycle progression, and detected the expression of TP53, TP63, and TP73 in cancer cells, as well as the expression of Bax, PUMA, and Mcl-1 in a xenograft mouse model. ACBP inhibited the proliferation of all three cancer cell lines in a dose-dependent manner, similar to the positive control and 5-fluorouracil (5-FU). The effect of ACBP correlated with the degree of differentiation of the cancer cells; the lower the differentiation degree, the stronger the inhibitory effect.

After ACBP treatment, the expression of TP53, TP63, and TP73 increased in all cell lines. In the xenograft mouse model, ACBP inhibited the growth of MGC-803 cells in vivo. The apoptotic-related genes Bax and PUMA were upregulated, while Mcl-1 was downregulated. ACBP inhibited tumor cell growth by inducing apoptosis through the TP53 signaling cascade, upregulating TP53, TP63, and TP73 and their downstream apoptosis-promoting genes Bax and PUMA while downregulating the anti-apoptotic gene Mcl-1.

Notably, after ACBP treatment, Mcl-1 expression was significantly reduced in the tumor tissue of the xenograft model, indicating that ACBP induced apoptosis through the TP53 signaling cascade. This project provides a scientific basis for exploring the antitumor mechanism of ACBP in gastric cancer therapy.

The role of ZNF165 in only a few tumors has been reported. ZNF165 plays an important role in liver cancer, gastric cancer, and breast cancer, especially in regulating the immune microenvironment, promoting tumor cell proliferation and migration, and serving as a potential target for immunotherapy.

This study aimed to enhance an understanding of how the ZNF165 gene functions and influences cancer development.

Using a suite of online resources, including TIMER, TCGA, GTEx, GEPIA2, cBioPortal, TIMER2, STRING, DAVID, RNAactDrug, CancerSEA, and UCSC, along with comprehensive statistical analyses, we conducted a thorough investigation of the pan-cancer landscape of ZNF165. This study encompassed an assessment of ZNF165 levels, their associations with patient outcomes, and clinical correlates. We examined the interplay between ZNF165 and key cancer biomarkers, such as Microsatellite Instability (MSI), Tumor Mutational Burden (TMB), immune cell infiltration, and the expression of immune checkpoint genes. We delved into the genetic variations of ZNF165, its biological roles across various cancer types, and its potential links to drug responsiveness. We analyzed single-cell expression patterns of ZNF165 and their implications for the functional dynamics of cancer. We employed quantitative Reverse Transcription PCR (qRT-PCR) to measure ZNF165 levels in Ovarian Cancer (OC) cell lines.

ZNF165 expression displayed aberrations across a diverse range of human cancers and exhibited correlations with clinical stages. High ZNF165 expression in KIRC, KIRP, STAD, and UCEC was significantly associated with poor overall survival. ZNF165 has encouraging diagnostic value in specific tumor types, with gene amplification identified as the predominant genetic alteration. Our analysis further uncovered significant associations between ZNF165 levels and MSI across three distinct cancer types, as well as with TMB in six different malignancies. We detected substantial correlations between ZNF165 levels and immune cell infiltration, as well as the expression of immune checkpoint genes. ZNF165 was found to be involved in several prevalent signaling pathways across various cancer types. ZNF165 may potentially contribute to chemotherapy and chemoresistance, and was observed to be involved in cancer progression. A ceRNA regulatory network involving AFDN-DT, miR-191-5p, and ZNF165 was constructed for OC, revealing significantly elevated ZNF165 levels in OC cell lines. Dysregulated ZNF165 expression across a spectrum of malignancies might play a role in cancer initiation and advancement via multiple biological pathways.

ZNF165 may serve as a promising therapeutic target for the treatment of cancer in human patients.

MARVEL domain-containing 1 (MARVELD1) has been implicated in the progression of several cancers, but its role in pancreatic adenocarcinoma (PAAD) remains poorly understood.

RNA-seq data from the TCGA-PAAD and GTEx-Pancreas cohorts were analyzed to assess MARVELD1 expression. Stable MARVELD1 knockdown and overexpression were conducted in BxPC3 and PANC-1 cells. Cell viability, proliferation, migration, and invasion were evaluated using functional assays, and western blotting was employed to examine EMT-associated protein levels, including Vimentin, MMP2, MMP9, and E-cadherin. Differentially expressed genes (DEGs) between MARVELD1-high and MARVELD1-low groups were identified, and pathway enrichment analyses were performed.

We observed a significant increase of MARVELD1 in PAAD patient samples, with elevated MARVELD1 levels correlating with poor clinical survival. Knockdown of MARVELD1 in PAAD cells remarkably decreased cell proliferation and colony formation, while overexpression of MARVELD1 enhanced these properties. Moreover, simulated cell invasion and migration assay further suggested that MARVELD1 might contribute to PAAD cell aggressiveness. Mechanistically, MARVELD1 promoted tumor cell migration and invasion through the activation of Vimentin, MMP2, and MMP9 protein while suppressing E-cadherin. Bioinformatics analysis revealed that MARVELD1-high samples were enriched in EMT-related pathways, including TGF-β receptor signaling, actin cytoskeleton regulation, and cell adhesion.

Taken together, our study highlights the roles of MARVELD1 in promoting tumor cell proliferation and invasion, suggesting its potential application as a prognostic and diagnostic biomarker for PAAD in the clinical context.