PlGF Knockdown Decreases Tumorigenicity and Stemness Properties of Spheroid Body Cells Derived from Gastric Cancer Cells

Effect of Mir-4270 Inhibitor and Mimic on Viability and Stemness in Gastric Cancer Stem-Like Cells Derived from MKN-45 Cell Line

Background

MicroRNAs (miRNAs) are significant regulatory factors in stem cell proliferation, and change in miRNA expression influences the cancer stem cell viability and gene expression. Herein, we evaluated the effect of the hsa-miR-4270 inhibitor and its mimic on the expression of stem cell markers in gastric cancer (GC) stem-like cells.

Methods

GC stem-like cells were isolated from the MKN-45 cell line by a non-adherent surface system. The cells were confirmed by differentiation assays using dexamethasone and insulin as adipogenesis-inducing agents and also Staurosporine as a neural-inducing agent. Isolated GC stem-like cells were treated with different concentrations (0, 15, 20, 25, 30, 40, 50, and 60 nM) of hsa-miR-4270 inhibitor and its mimic. The quantity of cell viability was determined by trypan blue method. Transcription of the stem cell marker genes, including CD44, OCT3/4, SOX2, Nanog, and KLF4, was evaluated by real-time RT-PCR.

Results

The results showed that GC stem-like cells were differentiated into both adipose cells using dexamethasone and insulin and neural cells by Staurosporine. Treatment of GC stem-like cells with hsa-miR-4270 inhibitor decreased cell viability and downregulated OCT3/4, CD44, and Nanog to 86%, 79%, and 91% respectively. Also, SOX2 and KLF4 were overexpressed to 8.1- and 1.94-folds, respectively. However, hsa-miR-4270 mimic had opposite effects on the cell viability and gene expression of the stem cell markers.

Conclusion

The effect of hsa-miR-4270 inhibitor and its mimic on the expression of the stem cell markers in GCSCs indicated that hsa-miR-4270 stimulates the stemness property of GCSCs, likely through stimulating the development of gastric stem cells.

Genetic Mutations Associated with Hormone-Positive Breast Cancer in a Small Cohort of Ethiopian Women

In Ethiopia, a breast cancer diagnosis is associated with a prognosis significantly worse than that of Europe and the US. Further, patients presenting with breast cancer in Ethiopia are far younger, on average, and patients are typically diagnosed at very late stages, relative to breast cancer patients of European descent. Emerging data suggest that a large proportion of Ethiopian patients have hormone-positive (ER⁺) breast cancer. This is surprising given (1) that patients have late-stage breast cancer at the time of diagnosis, (2) that African Americans with breast cancer frequently have triple negative breast cancer (TNBC), and (3) these patients typically receive chemotherapy, not hormone-targeting drugs. To further examine the similarity of Ethiopian breast tumors to those of African Americans or of those of European descent, we sequenced matched tumor and normal adjacent tissue from Ethiopian patients from a small pilot collection. We identified mutations in 615 genes across all three patients, unique to the tumor tissue. Across this analysis, we found far more mutations shared between Ethiopian patient tissue and that from white patients (103) than we did comparing to African Americans (3). Several mutations were found in extracellular matrix encoding genes with known roles in tumor cell growth and metastasis. We suggest future mechanistic studies on this disease focus on these genes first, toward finding new treatment strategies for breast cancer patients in Ethiopia.

Treatment Strategies of Gastric Cancer-Molecular Targets for Anti-angiogenic Therapy: a State-of-the-art Review

Purpose

Recent studies have suggested that molecular targets for the anti-angiogenic therapy might constitute a basis for additional therapy in gastric cancer treatment. A vast number of molecules, receptors, pathways, specific interactions, and thus strategies that target gastric cancer angiogenesis specifically have been reported in numerous research articles and clinical trials.

Methods

We conducted a systematic literature review of molecularly targeted treatment strategies in gastric cancer on the following databases—PubMed, Google Scholar, and Scopus—on September 20, 2020. Multiple articles and evaluations were searched for studies reporting newly found and promising molecular anti-angiogenic therapy pathways. Eventually, 39 articles regarding the anti-angiogenic therapy in gastric cancer were included in the final analysis.

Results

As a consequence of the release of the pro-angiogenic molecules from the tumour cells, gastric cancer presents high angiogenic capability. Therefore, potential schemes for future treatment strategies include the decrease of the process ligands as well as the expression of their receptors. Moreover, the increase in the angiogenic inhibitor levels and direct aim for the inner walls of the endothelial cells appear as a promising therapeutic strategy. Beyond that, angiogenesis process inhibition seems to indirectly exaggerate the effects of chemotherapy in the considered patients.

Conclusions

The anti-angiogenic treatment in gastric cancer patients evaluates its significance especially in the early stages of the malignancy. The studies conducted so far show that most of the meaningful angiogenic factors and receptors with the potential molecular pathways should be further evaluated since they could potentially play a substantial role in future therapies.

The Effect of hsa-miR-451b Knockdown on Biological Functions of Gastric Cancer Stem-Like Cells

Numerous researches have extensively studied factors such as microRNAs that lead to cancer. Thus, the current study's purpose is to investigate the biological consequences of hsa-miR-451b inhibition on the properties and functions of gastric cancer stem-like cells. First, gastric cancer stem-like cells were transfected by hsa-miR-451b inhibitor then we used real-time RT-PCR to evaluate its effect on the expression of hsa-miR-451b and two of its direct target genes, Stemness markers such as KLF4, SOX2, CD44, OCT3/4 and NANOG genes and finally Akt, PI3K, Bcl-2, Bax, CASP3 and PCNA genes involved in apoptosis. Here, we conducted a DNA Laddering assay to investigate apoptosis. The level of the MMP-2 and -9 Activities and Migration were examined by Zymography and Transwell invasion assay. HUVEC cells were used to investigate angiogenesis. The outcomes revealed that the level of the MMP-2 and -9 Activities, migration and angiogenesis decreased, but apoptosis was induced by inhibiting hsa-miR-451b. Evaluating KREMEN1 and CASK expression showed that the former increased, and the latter dropped under hsa-miR-451b inhibition. Also, upregulation of the KLF4 and SOX2 and downregulation of the CD44, OCT3/4, and NANOG decreased Self-renewal ability of gastric cancer stem cells under hsa-miR-451b inhibition. Even, under hsa-miR-451b inhibition, downregulation of Akt, PI3K, Bcl-2 and PCNA as well as upregulation of Bax and CASP3 revealed a movement towards apoptosis in MKN-45 stem-like cells. In summary, hsa-miR-451b is an oncomir in the carcinogenesis of gastric cancer stem-like cells and may be suggested as an appropriate therapeutic target for future gastric cancer treatment.

Genetic polymorphisms of PGF and TNFAIP2 genes related to cervical cancer risk among Uygur females from China

BACKGROUND

PGF and TNFAIP2 are important angiogenic factors, which were abnormal expression in cervical cancer (CC). However, there is currently no report investigating the relationship of PGF and TNFAIP2 gene polymorphisms to CC risk.

METHODS

We conducted a case-control study of 342 CC patients and 498 cancer-free controls in a Chinese Uygur female population. Three SNPs (PGF rs8019391, PGF rs2268615, and TNFAIP2 rs710100) were selected and genotyped to assess the possible association of PGF and TNFAIP2 polymorphisms with CC susceptibility. Logistic regression analysis adjusted by age was used.

RESULTS

PGF rs2268615 (OR = 1.39, 95% CI = 1.04-1.86, p = 0.024) and TNFAIP2 rs710100 (OR = 1.44, 95% CI =1.07-1.95, p = 0.018) polymorphisms were associated with the increased risk of CC. Moreover, T allele of PGF rs8019391 was highly represented in patients with stage III-IV compared with stage I-II (OR = 2.17, p = 4.58 × 10- 4). MDR analysis revealed a positive interaction between the SNPs.

CONCLUSION

Our data indicated that PGF rs2268615, and TNFAIP2 rs710100 polymorphisms might be risk factors for CC susceptibility, which contributed to the increased risk of CC.

TRIAL REGISTRATION

Not applicable.

Role of Matrix Metalloproteinases in Angiogenesis and Cancer

During angiogenesis, new vessels emerge from existing endothelial lined vessels to promote the degradation of the vascular basement membrane and remodel the extracellular matrix (ECM), followed by endothelial cell migration, and proliferation and the new generation of matrix components. Matrix metalloproteinases (MMPs) participate in the disruption, tumor neovascularization, and subsequent metastasis while tissue inhibitors of metalloproteinases (TIMPs) downregulate the activity of these MMPs. Then, the angiogenic response can be directly or indirectly mediated by MMPs through the modulation of the balance between pro- and anti-angiogenic factors. This review analyzes recent knowledge on MMPs and their participation in angiogenesis.

Tumor progression-dependent angiogenesis in gastric cancer and its potential application

Despite improvements in the early diagnosis, prognosis and therapeutic strategies for gastric cancer (GC), human GC remains one of the most frequently diagnosed malignant tumors in the world, and the survival rate of GC patients remains very poor. Thus, a suitable therapeutic strategy for GC is important for prolonging survival. Both tumor cells themselves and the tumor microenvironment play an important role in tumorigenesis, including angiogenesis, inflammation, immunosuppression and metastasis. Importantly, these cells contribute to gastric carcinogenesis by altering the angiogenic phenotype switch. The development, relapse and spreading of tumors depend on new vessels that provide the nutrition, growth factors and oxygen required for continuous tumor growth. Therefore, a state of tumor dormancy could be induced by blocking tumor-associated angiogenesis. Recently, several antiangiogenic agents have been identified, and their potential for the clinical management of GC has been tested. Here, we provide an up-to-date summary of angiogenesis and the angiogenic factors associated with tumor progression in GC. We also review antiangiogenic agents with a focus on the anti-vascular endothelial growth factor receptor (VEGFR)-mediated pathway for endothelial cell growth and their angiogenesis ability in GC. However, most antiangiogenic agents have reported no benefit to overall survival (OS) compared to chemotherapy alone in local or advanced GC. In phase III clinical trials, only ramucirumab (anti-VEGFR blocker) and apatinib (VEGFR-TKI blocker) have reported an improved median overall response rate and prolonged OS and progression-free survival outcomes as a 2nd-line agent combined with chemotherapy treatment in advanced GC. By providing insights into the molecular mechanisms of angiogenesis associated with tumor progression in GC, this review will hopefully aid the optimization of antiangiogenesis strategies for GC therapy in combination with chemotherapy and adjuvant treatment.

Multifaceted Role of the Placental Growth Factor (PlGF) in the Antitumor Immune Response and Cancer Progression

The sharing of molecules function that affects both tumor growth and neoangiogenesis with cells of the immune system creates a mutual interplay that impairs the host’s immune response against tumor progression. Increasing evidence shows that tumors are able to create an immunosuppressive microenvironment by recruiting specific immune cells. Moreover, molecules produced by tumor and inflammatory cells in the tumor microenvironment create an immunosuppressive milieu able to inhibit the development of an efficient immune response against cancer cells and thus fostering tumor growth and progression. In addition, the immunoediting could select cancer cells that are less immunogenic or more resistant to lysis. In this review, we summarize recent findings regarding the immunomodulatory effects and cancer progression of the angiogenic growth factor namely placental growth factor (PlGF) and address the biological complex effects of this cytokine. Different pathways of the innate and adaptive immune response in which, directly or indirectly, PlGF is involved in promoting tumor immune escape and metastasis will be described. PlGF is important for building up vascular structures and functions. Although PlGF effects on vascular and tumor growth have been widely summarized, its functions in modulating the immune intra-tumoral microenvironment have been less highlighted. In agreement with PlGF functions, different antitumor strategies can be envisioned.

PlGF knockdown induced apoptosis through Wnt signaling pathway in gastric cancer stem cells

Despite the fact that much research has focused on gastric cancer, it is still a worldwide concern, because of the difficulties with factors such as signaling pathway crosstalk and gastric cancer stem cell (GCSC). Placental growth factor (PlGF) is one of these factors, and its tumorigenicity potential still remains a question. As a result, we have investigated the effect of PlGF knockdown on apoptosis and genes involved in the Wnt signaling pathway, and apoptosis in cancer stem cells derived from AGS an MKN-45 gastric cancer cell lines. We isolated GCSCs from MKN-45 and AGS cell lines on a nonadherent surface. Then the cell viability, the real-time reverse transcription-polymerase chain reaction data of the genes involved in the Wnt signaling pathway, and apoptosis were evaluated. Furthermore, DNA laddering was used to show the apoptotic effect and DNA fragmentation caused by the PlGF knockdown. Our investigation revealed that the PlGF knockdown with PlGF-specific small interfering RNA at 40 pmol for GCSCs derived from MKN-45 and AGS at 24 hours can significantly affect the cell viability, the Wnt signaling pathway, and the apoptosis-related genes expression. In conclusion, we showed the PlGF knockdown may induce apoptosis via the Wnt signaling pathway in GCSCs.

Expression of Livin and PlGF in human osteosarcoma is associated with tumor progression and clinical outcome

Baculoviral IAP repeat containing 7 (BIRC7/Livin/ML-IAP/KIAP; referred to as Livin throughout the present study) and placental growth factor (PlGF) are not detectable in the majority of normal differentiated tissues, but are present in a number of types of cancer, including hepatocellular carcinoma, ovarian cancer and renal cell carcinoma. The aim of the present study was to assess the expression levels of Livin and PlGF in human osteosarcoma specimens and cell lines, and to analyze the functions of Livin and PIGF in the prognosis of osteosarcoma. The expression levels of Livin and PlGF in 48 osteosarcoma specimens and three osteosarcoma cells were determined using immunohistochemistry and reverse transcription-quantitative polymerase chain reaction. The positivity rates of Livin and PlGF in osteosarcoma specimens were 58.3 and 60.4%, respectively, but were 0% in normal bone tissues. The expression levels of Livin and PlGF were increased in MG-63 cells, compared with those in the other cell lines evaluated in the present study. In addition, the expression levels of Livin and PlGF were significantly associated with tumor diameter and Enneking staging, but were independent of tumor site, age and sex of patients. The expression level of Livin was not associated with PlGF. Furthermore, the 5-year overall survival rate was decreased in the Livin or PlGF expression group, compared with that in the non-expression group (P=0.034 and P=0.012, respectively). The expression levels of Livin and PlGF were independent prognostic factors for patients with osteosarcoma. The results of the present study demonstrated that Livin and PlGF may participate in the pathogenesis of osteosarcoma. Therefore, pharmacological inhibition of Livin or PlGF may provide a novel strategy for osteosarcoma treatment.

Ibuprofen reduces cell proliferation through inhibiting Wnt/β catenin signaling pathway in gastric cancer stem cells

Nowadays, most studies focused on cancer stem cells (CSCs) through their abilities to cause tumorigenicity, drug resistance, and cancer recurrence. On the other side, nonsteroidal anti-inflammatory drugs (NSAIDs) have been taken into consideration because of cheapness and availability. For the reasons mentioned above, we have studied the effect of ibuprofen as an NSAID on CSCs derived from AGS and MKN-45 gastric cancer cell lines to perform effective cancer therapy. We evaluated cell viability, spheroid body formation, monolayer, and soft agar colony formation to express the anti-cancer effect of ibuprofen on CSCs. Also, real-time RT-PCR data of stemness markers and genes affected on, or downstream of Wnt signaling pathway were evaluated. Our findings suggest that ibuprofen at 1,000 μM for 48 h can reduce cell proliferation, stemness features in CSCs by changing the expression level of CD44, OCT3/4, SOX2, Nanog, and KLF4 as stemness markers. Furthermore, ibuprofen can have an inhibitory role in Wnt signaling pathway by changing the expression level of some genes, including CTNNB1, CTNNBIP1, SMARCD1, PYGO2, SUFU, CASK, and KREMEN1. According to our study, ibuprofen has an anti-proliferative effect on CSCs derived from AGS and MKN-45 cells.

Angiogenesis and Anti-Angiogenic Therapy in Gastric Cancer

Gastric cancer is one of the most frequent malignancies worldwide. Despite improvements in diagnosis and therapy, the overall prognosis remains poor. In the last decade, several anti-angiogenic drugs for cancer treatment have been approved and lately also introduced to gastric cancer treatment. While the initial trials focused only on unresectable or metastatic cancer, anti-angiogenic treatment is now also investigated in the perioperative and neoadjuvant setting. In this review, an overview of the role of angiogenesis and angiogenic factors in gastric cancer as well as anti-angiogenic treatment of gastric cancer is provided. Findings from in vitro and animal studies are summarized and put in a context with translational data on angiogenesis in gastric cancer. The most important angiogenic factors and their effect in gastric cancer are highlighted and clinical trials including anti-angiogenic drugs are discussed. Finally, an outlook of biomarkers for predicting response to anti-angiogenic treatment is presented, the ongoing trials on this topic are discussed and current challenges of anti-angiogenic therapy are outlined.