The indolinone MAZ51 induces cell rounding and G2/M cell cycle arrest in glioma cells without the inhibition of VEGFR-3 phosphorylation: involvement of the RhoA and Akt/GSK3β signaling pathways

Decoding the synergistic potential of MAZ-51 and zingerone as therapy for melanoma treatment in alignment with sustainable development goals

Melanoma, an invasive class of skin cancer, originates from mutations in melanocytes, the pigment-producing cells. Globally, approximately 132,000 new cases are reported each year, and in South Africa, the incidence stands at 2.7 per 100,000 people, signifying a worrisome surge in melanoma rates. Therefore, there is a need to explore treatment modalities that will target melanoma's signalling pathways. Melanoma metastasis is aided by ligand activity of transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor-C (VEGF-C) and C-X-C chemokine ligand 12 (CXCL12) which bind to their receptors and promote tumour cell survival, lymphangiogenesis and chemotaxis. (3-(4-dimethylaminonaphthelen-1-ylmethylene)-1,3-dihydroindol-2-one) MAZ-51 is an indolinone-based molecule that inhibits VEGF-C induced phosphorylation of vascular endothelial growth factor receptor 3 (VEGFR-3). Despite the successful use of conventional cancer therapies, patients endure adverse side effects and cancer drug resistance. Moreover, conventional therapies are toxic to the environment and caregivers. The use of medicinal plants and their phytochemical constituents in cancer treatment strategies has become more widespread because of the rise in drug resistance and the development of unfavourable side effects. Zingerone, a phytochemical derived from ginger exhibits various pharmacological properties positioning it as a promising candidate for cancer treatment. This review provides an overview of melanoma biology and the intracellular signalling pathways promoting cell survival, proliferation and adhesion. There is a need to align health and environmental objectives within sustainable development goals 3 (good health and well-being), 13 (climate action) and 15 (life on land) to promote early detection of skin cancer, enhance sun-safe practices, mitigation of environmental factors and advancing the preservation of biodiversity, including medicinal plants. Thus, this review discusses the impact of cytostatic cancer drugs on patients and the environment and examines the potential use of phytochemicals as adjuvant therapy.

Design, synthesis, and antitumor screening of new thiazole, thiazolopyrimidine, and thiazolotriazine derivatives as potent inhibitors of VEGFR-2

New thiazole, thiazolopyrimidine, and thiazolotriazine derivatives 3-12 and 14a-f were synthesized. The newly synthesized analogs were tested for in vitro antitumor activity against HepG2, HCT-116, MCF-7, HeP-2, and Hela cancer cells. Results indicated that compound 5 displayed the highest potency toward the tested cancer cells. Compound 11b possessed enhanced effectiveness over MCF-7, HepG2, HCT-116, and Hela cancer cells. In addition, compounds 4 and 6 showed promising activity toward HCT-116, MCF-7, and Hela cancer cells and eminent activity against HepG2 and HeP-2 cells. Moreover, compounds 3-6 and 11b were tested for their capability to inhibit vascular endothelial growth factor receptor-2 (VEGFR-2) activity. The obtained results showed that compound 5 displayed significant inhibitory activity against VEGFR-2 (half-maximal inhibitory concentration [IC50 ] = 0.044 μM) comparable to sunitinib (IC50  = 0.100 μM). Also, the synthesized compounds 3-6 and 11b were subjected to in vitro cytotoxicity tests over WI38 and WISH normal cells. It was found that the five tested compounds displayed significantly lower cytotoxicity than doxorubicin toward normal cell lines. Cell cycle analysis proved that compound 5 induces cell cycle arrest in the S phase for HCT-116 and Hela cancer cell lines and in the G2/M phase for the MCF-7 cancer cell line. Moreover, compound 5 induced cancer cell death through apoptosis accompanied by a high ratio of BAX/BCL-2 in the screened cancer cells. Furthermore, docking results revealed that compound 5 showed the essential interaction bonds with VEGFR-2, which agreed with in vitro enzyme assay results. In silico studies showed that most of the analyzed compounds complied with the requirements of good oral bioavailability with minimal toxicity threats in humans.

Design, Synthesis, and Evaluation of Novel 3-Carboranyl-1,8-Naphthalimide Derivatives as Potential Anticancer Agents

We synthesized a series of novel 3-carboranyl-1,8-naphthalimide derivatives, mitonafide and pinafide analogs, using click chemistry, reductive amination and amidation reactions and investigated their in vitro effects on cytotoxicity, cell death, cell cycle, and the production of reactive oxygen species in a HepG2 cancer cell line. The analyses showed that modified naphthalic anhydrides and naphthalimides bearing ortho- or meta-carboranes exhibited diversified activity. Naphthalimides were more cytotoxic than naphthalic anhydrides, with the highest IC₅₀ value determined for compound 9 (3.10 µM). These compounds were capable of inducing cell cycle arrest at G0/G1 or G2M phase and promoting apoptosis, autophagy or ferroptosis. The most promising conjugate 35 caused strong apoptosis and induced ROS production, which was proven by the increased level of 2′-deoxy-8-oxoguanosine in DNA. The tested conjugates were found to be weak topoisomerase II inhibitors and classical DNA intercalators. Compounds 33, 34, and 36 fluorescently stained lysosomes in HepG2 cells. Additionally, we performed a similarity-based assessment of the property profile of the conjugates using the principal component analysis. The creation of an inhibitory profile and descriptor-based plane allowed forming a structure–activity landscape. Finally, a ligand-based comparative molecular field analysis was carried out to specify the (un)favorable structural modifications (pharmacophoric pattern) that are potentially important for the quantitative structure–activity relationship modeling of the carborane–naphthalimide conjugates.

Long non-coding RNA RNCR3 promotes glioma progression involving the Akt/GSK-3β pathway

Increasing evidence has confirmed that long non-coding RNAs (lncRNAs) serve critical roles in the development of a large number of human malignancies, including glioma. Several previously published studies have reported that the lncRNA retinal non-coding RNA3 (RNCR3; also termed LINC00599) exerts important roles in certain human malignancies; however, the precise biological role and underlying molecular mechanisms of RNCR3 in the development of glioma are yet to be fully elucidated. In the present study, it was revealed that the expression of RNCR3 was increased in glioma tissues compared with in corresponding adjacent normal tissues. Furthermore, increased levels of RNCR3 expression were associated with tumor progression and poor survival rates of patients with glioma. In addition, the U87 and U251 cell lines were selected to investigate the biological function and potential mechanisms of RNCR3 in glioma, and it was observed that RNCR3 knockdown led to an impairment of the proliferative and invasive abilities of cells; furthermore, G1 phase arrest was induced in glioma cells in vitro. Finally, the results of western blot analyses revealed that knockdown of RNCR3 led to a decrease in the expression levels of phosphorylated Akt and glycogen synthase kinase-3β (GSK-3β), without any clear effect on the expression levels of total Akt and GSK-3β. Collectively, these results suggested that RNCR3 is able to regulate cell proliferation, the cell cycle and cell invasion in glioma, potentially via the Akt/GSK-3β signaling pathway.

Dual-mechanistic antibody-drug conjugate via site-specific selenocysteine/cysteine conjugation

Background

While all clinically translated antibody-drug conjugates (ADCs) contain a single-drug payload, most systemic cancer chemotherapies involve use of a combination of drugs. These regimens improve treatment outcomes and slow development of drug resistance. We here report the generation of an ADC with a dual-drug payload that combines two distinct mechanisms of action.

Methods

Virtual DNA crosslinking agent PNU-159682 and tubulin polymerization inhibitor monomethyl auristatin F (MMAF) were conjugated to a HER2-targeting antibody via site-specific conjugation at engineered selenocysteine and cysteine residues (thio-selenomab).

Results

The dual-drug ADC showed selective and potent cytotoxicity against HER2-expressing cell lines and exhibited dual mechanisms of action consistent with the attached drugs. While PNU-159682 caused S-phase cell cycle arrest due to its DNA-damaging activity, MMAF simultaneously inhibited tubulin polymerization and caused G2/M-phase cell cycle arrest.

Conclusion

The thio-selenomab platform enables the assembly of dual-drug ADCs with two distinct mechanisms of action.

Impact of Hybrid-polar Histone Deacetylase Inhibitor m-Carboxycinnamic Acid bis-Hydroxyamide on Human Pancreatic Adenocarcinoma Cells

Background:

Histone deacetylase inhibitors (HDACIs) have got immense importance as promising drugs for cancer treatment as these inhibitors regulate cellular differentiation, gene expression, cell cycle arrest and apoptosis. The current study investigates the effect of the hybrid-polar HDACI m-carboxycinnamic acid bishydroxyamide (CBHA) on the growth of human pancreatic adenocarcinoma cells, using the cell line MIA PaCa- 2 as an in vitro model.

Methods:

Following CBHA treatment of the MIA PaCa-2 cells, we characterized the effect of CBHA by in vitro cytotoxicity evaluation, clonogenic assay, cell cycle analysis, immunoblotting for soluble and insoluble fractions of tubulin, immunofluorescence and caspase-3 assay.

Results:

We observed that the histone deacetylase inhibitor CBHA markedly impaired growth of the pancreatic cancer cells by resulting in dose-dependent G2/M arrest, disruption of microtubule organization, induction of caspase-mediated apoptosis and in vitro suppression of HDAC6. Our study also shows that inhibition of HDAC6 by CBHA induced acetylation of α-tubulin.

Conclusion:

Together, our findings show that CBHA can be a potential plausible therapeutic that could be exploited for pancreatic cancer therapy.

Pard3 suppresses glioma invasion by regulating RhoA through atypical protein kinase C/NF-κB signaling

Partitioning defective protein 3 (Pard3) has been reported to inhibit the progression of numerous human cancer cell types. However, the role of Pard3 in glioma progression remains unclear. In this study, the expression of Pard3 was measured in human gliomas of different grades by both quantitative polymerase chain reaction and Western blotting. The effect of Pard3 on glioma progression was tested using cell counting kit‐8 assays, EdU assays, colony formation assays, cell migration, and invasion assays and tumor xenografts. The effect of Pard3 on Ras homolog family member A (RhoA) protein levels, subcellular localization, and transcriptional activity was measured by immunoblotting and immunofluorescence. Our results indicate that Pard3 functions as a tumor suppressor in gliomas and that the loss of Pard3 protein is strongly associated with a higher grade and poorer outcome. Pard3 overexpression inhibits glioma progression by upregulating RhoA protein levels. However, the level of GTP‐RhoA protein remained unchanged. Further evidence demonstrates that Pard3 regulates RhoA protein levels, subcellular localization and transcriptional activity by activating atypical protein kinase C/NF‐κB signaling. Mouse modeling experiments show that Pard3 overexpression inhibits glioma cell growth in vivo. Taken together, these findings identify RhoA as a novel target of Pard3 in gliomas and substantiate a novel regulatory role for Pard3 in glioma progression. This study reveals that Pard3 plays an inhibitory role in gliomas by regulating RhoA, which reveals a potential benefit for Pard3 activators in the prevention and therapy of gliomas.

Design, Synthesis and Evaluation of Naphthalimide Derivatives as Potential Anticancer Agents for Hepatocellular Carcinoma

Two kinds of naphthalimide derivatives were synthesized and evaluated for in vitro their anti-hepatocellular carcinoma properties. Compound 3a with a fused thiazole fragment to naphthalimide skeleton inhibited cell migration of SMMC-7721 and HepG2, and further in vivo trials with two animal models confirmed that compound 3a moderately inhibited primary H22 tumor growth (52.6%) and potently interrupted lung metastasis (75.7%) without obvious systemic toxicity at the therapeutic dose. Mechanistic research revealed that compound 3a inhibited cancerous liver cell growth mostly by inducing G2/M phase arrest. Western blotting experiments corroborated that 3a could up-regulate the cell cycle related protein expression of cyclin B1, CDK1 and p21, and inhibit cell migration by elevating the E-cadherin and attenuating integrin α6 expression. Our study showed that compound 3a is a valuable lead compound worthy of further investigation.

Fuling Granule, a Traditional Chinese Medicine Compound, Suppresses Cell Proliferation and TGFβ-Induced EMT in Ovarian Cancer

The compound fuling granule (CFG) is a traditional Chinese drug which has been used to treat ovarian cancer in China for over twenty years. Nevertheless, the underlying molecular mechanism of its anti-cancer effect remains unclear. In this study, microarray data analysis was performed to search differentially expressed genes in CFG-treated ovarian cancer cells. Several cell cycle and epithelial-mesenchymal transition (EMT) related genes were identified. The microarray analyses also revealed that CFG potentially regulates EMT in ovarian cancer. We also found that, functionally, CFG significantly suppresses ovarian cancer cell proliferation by cell cycle arrest, apoptosis and senescence and the AKT/GSK-3β pathway is possibly involved. Additionally, the invasion and migration ability of ovarian cancer induced by TGFβ is significantly suppressed by CFG. In conclusion, our results demonstrated that CFG suppresses ovarian cancer cell proliferation as well as TGFβ1-induced EMT in vitro. Finally, we discovered that CFG suppresses tumor growth and distant metastasis in vivo. Overall, these findings provide helpful clues to design novel clinical treatments against cancer.

Blockade of FLT4 suppresses metastasis of melanoma cells by impaired lymphatic vessels

The metastatic spread of tumor cells via lymphatic vessels affects the relapse of tumor patients. New lymphatic vessel formation, including lymphangiogenesis, is promoted in the tumor environment. The lymphangiogenic factor VEGF-C can mediate lymphatic vessel formation and induce tumor metastasis by binding with FLT4. In melanoma, metastasis via lymphatics such as lymph nodes is one of the main predictors of poor outcome. Thus, we investigated whether blockade of FLT4 can reduce metastasis via the suppression of lymphatic capillaries. Proliferative lymphatic capillaries in melanoma were estimated by immunohistochemistry using FLT4 antibody after the injection of the FLT4 antagonist MAZ51. The numbers of tumor modules in metastasised lungs were calculated by gross examination and lymphatic related factors were examined by qRT-PCR. MAZ51 injection resulted in the suppression of tumor size and module number and the inhibition of proliferative lymphatic vessels in the intratumoral region in the lung and proliferating melanoma cells in the lung compared to those of untreated groups. Additionally, high FLT4 and TNF-alpha were detected in melanoma-induced tissue, while lymphatic markers such as VEGF-C, FLT4 and Prox-1 were significantly decreased in MAZ51 treated groups, implying that anti-lymphangiogenesis by MAZ51 may provide a potential strategy to prevent tumor metastasis in melanoma and high number of lymphatic capillaries could be used diagnosis for severe metastasis.

DIM attenuates TGF-β1-induced myofibroblast differentiation in neonatal rat cardiac fibroblasts

3,3'-Diindolylmethane (DIM) is a natural component of cruciferous plants. Previous studies have shown that DIM has multiple physiological effects including anti-angiogenic, anti-inflammatory and anti-cancer effect. However, little is known about the role of DIM on myofibroblast differentiation and extracellular matrix (ECM) production. This study investigated the effect of DIM on myofibroblast differentiation and ECM production in neonatal rat cardiac fibroblasts induced by transforming growth factor β1 (TGF-β1). We found that DIM blunted TGF-β1 induced conversion of cardiac fibroblast into myofibroblast, and reduced the mRNA and protein expressions of α-smooth muscle actin (α-SMA). Furthermore, DIM also significantly decreased the mRNA expression of fibrosis markers (Collagen I, Collagen III, connective tissue growth factor (CTGF) in neonatal rat cardiac fibroblasts induced by TGF-β1. DIM attenuated the phosphorylation AKT and glycogen synthase kinase-3β (GSK-3β) induced by TGF-β1. Our results showed that DIM was a potential drug to attenuate myofibroblast differentiation and excessive ECM production induced by TGF-β1 through down-regulated AKT/GSK-3β signaling pathways.

Expression of vascular endothelial growth factor-C (VEGF-C) and its receptor (VEGFR-3) in the glial reaction elicited by human mesenchymal stem cell engraftment in the normal rat brain

To determine whether vascular endothelial growth factor-C (VEGF-C) and its receptor (VEGFR-3) are involved in the glial reaction elicited by transplanted mesenchymal stem cells (MSCs), we examined the cellular localization of VEGF-C and VEGFR-3 proteins in the striatum of adult normal rats that received bone marrow-derived human MSCs. The MSC grafts were infiltrated with activated microglia/macrophages and astrocytes over a 2-week period post-transplantation, which appeared to parallel the loss of transplanted MSCs. VEGF-C/VEGFR-3 was expressed in activated microglia/macrophages recruited to the graft site, where the induction of VEGF-C protein was rather late compared with that of its receptor. VEGF-C protein was absent or very weak on day 3, whereas VEGFR-3 immunoreactivity was evident within the first three days. Furthermore, within three days, VEGF-C could be detected in the brain macrophages localized immediately adjacent to the needle track. At the same time, almost all the brain macrophages in both regions expressed VEGFR-3. Reactive astrocytes at the graft site expressed VEGFR-3, but not VEGF-C. These data demonstrated the characteristic time- and cell-dependent expression patterns for VEGF-C and VEGFR-3 within the engrafted brain tissue, suggesting that they may contribute to neuroinflammation in MSC transplantation, possibly through the recruitment and/or activation of microglia/macrophages and astrogliosis.