Non-immunosuppressive triazole-based small molecule induces anticancer activity against human hormone-refractory prostate cancers: the role in inhibition of PI3K/AKT/mTOR and c-Myc signaling pathways

Synthesis and biological evaluation of a new class of azole urea compounds as Akt inhibitors with promising anticancer activity in pancreatic cancer models

The PI3K/Akt pathway is crucial in numerous cellular functions such as cell growth, survival proliferation and movement in both normal and cancer cells. It plays also a key role in epithelial-mesenchymal transitions and angiogenesis during the tumorigenesis processes. Since many transformative events in cancer are driven by increased PI3K/Akt pathway signaling, Akt is considered a valuable target for developing new therapies against various tumor types, including pancreatic cancer. This is because the PI3K/AKT/mTOR pathway is a key downstream effector of RAS, and RAS activation is the most prominent genetic alteration in pancreatic cancer. Herein we report the synthesis and the biological evaluation of a new series of azole urea compounds that exhibited promising antiproliferative and antimigratory activities against pancreatic cancer cells through an Akt inhibition mechanism. These effects were demonstrated using a variety of assays, including Sulforhodamine B, cell-cycle, wound-healing, and kinase activity, apotposis and ELISA assays. Additionally, the anticancer properties of the most active compound in the series were confirmed in the 3D spheroid model of PATU-T cells.

Implications of c-Myc in the pathogenesis and treatment efficacy of urological cancers

Urological cancers, including prostate, bladder, and renal cancers, are significant causes of death and negatively impact the quality of life for patients. The development and progression of these cancers are linked to the dysregulation of molecular pathways. c-Myc, recognized as an oncogene, exhibits abnormal levels in various types of tumors, and current evidence supports the therapeutic targeting of c-Myc in cancer treatment. This review aims to elucidate the role of c-Myc in driving the progression of urological cancers. c-Myc functions to enhance tumorigenesis and has been documented to increase growth and metastasis in prostate, bladder, and renal cancers. Furthermore, the dysregulation of c-Myc can result in a diminished response to therapy in these cancers. Non-coding RNAs, β-catenin, and XIAP are among the regulators of c-Myc in urological cancers. Targeting and suppressing c-Myc therapeutically for the treatment of these cancers has been explored. Additionally, the expression level of c-Myc may serve as a prognostic factor in clinical settings.

Targeting Sphingosine 1-Phosphate Metabolism as a Therapeutic Avenue for Prostate Cancer

Prostate cancer (PC) is the second most common cancer in men worldwide. More than 65% of men diagnosed with PC are above 65. Patients with localized PC show high long-term survival, however with the disease progression into a metastatic form, it becomes incurable, even after strong radio- and/or chemotherapy. Sphingosine 1-phosphate (S1P) is a bioactive lipid that participates in all the steps of oncogenesis including tumor cell proliferation, survival, migration, invasion, and metastatic spread. The S1P-producing enzymes sphingosine kinases 1 and 2 (SK1 and SK2), and the S1P degrading enzyme S1P lyase (SPL), have been shown to be highly implicated in the onset, development, and therapy resistance of PC during the last 20 years. In this review, the most important studies demonstrating the role of S1P and S1P metabolic partners in PC are discussed. The different in vitro, ex vivo, and in vivo models of PC that were used to demonstrate the implication of S1P metabolism are especially highlighted. Furthermore, the most efficient molecules targeting S1P metabolism that are under preclinical and clinical development for curing PC are summarized. Finally, the possibility of targeting S1P metabolism alone or combined with other therapies in the foreseeable future as an alternative option for PC patients is discussed. Research Strategy: PubMed from INSB was used for article research. First, key words "prostate & sphingosine" were used and 144 articles were found. We also realized other combinations of key words as "prostate cancer bone metastasis" and "prostate cancer treatment". We used the most recent reviews to illustrate prostate cancer topic and sphingolipid metabolism overview topic.

Pyrroline-5-Carboxylate Reductase 1: a novel target for sensitizing multiple myeloma cells to bortezomib by inhibition of PRAS40-mediated protein synthesis

Background

Multiple myeloma (MM) remains an incurable cancer despite advances in therapy. Therefore, the search for new targets is still essential to uncover potential treatment strategies. Metabolic changes, induced by the hypoxic bone marrow, contribute to both MM cell survival and drug resistance. Pyrroline-5-carboxylate reductase 1 and 2 (PYCR1 and PYCR2) are two mitochondrial enzymes that facilitate the last step in the glutamine-to-proline conversion. Overexpression of PYCR1 is involved in progression of several cancers, however, its’ role in hematological cancers is unknown. In this study, we investigated whether PYCR affects MM viability, proliferation and response to bortezomib.

Methods

Correlation of PYCR1/2 with overall survival was investigated in the MMRF CoMMpass trial (653 patients). OPM-2 and RPMI-8226 MM cell lines were used to perform in vitro experiments. RPMI-8226 cells were supplemented with ¹³C-glutamine for 48 h in both normoxia and hypoxia (< 1% O₂, by chamber) to perform a tracer study. PYCR1 was inhibited by siRNA or the small molecule inhibitor pargyline. Apoptosis was measured using Annexin V and 7-AAD staining, viability by CellTiterGlo assay and proliferation by BrdU incorporation. Differential protein expression was evaluated using Western Blot. The SUnSET method was used to measure protein synthesis. All in vitro experiments were performed in hypoxic conditions.

Results

We found that PYCR1 and PYCR2 mRNA expression correlated with an inferior overall survival. MM cells from relapsed/refractory patients express significantly higher levels of PYCR1 mRNA. In line with the strong expression of PYCR1, we performed a tracer study in RPMI-8226 cells, which revealed an increased conversion of ¹³C-glutamine to proline in hypoxia. PYCR1 inhibition reduced MM viability and proliferation and increased apoptosis. Mechanistically, we found that PYCR1 silencing reduced protein levels of p-PRAS40, p-mTOR, p-p70, p-S6, p-4EBP1 and p-eIF4E levels, suggesting a decrease in protein synthesis, which we also confirmed in vitro. Pargyline and siPYCR1 increased bortezomib-mediated apoptosis. Finally, combination therapy of pargyline with bortezomib reduced viability in CD138⁺ MM cells and reduced tumor burden in the murine 5TGM1 model compared to single agents.

Conclusions

This study identifies PYCR1 as a novel target in bortezomib-based combination therapies for MM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02250-3.

Inhibitors of the PI3K/Akt/mTOR Pathway in Prostate Cancer Chemoprevention and Intervention

The phosphatidylinositol 3-kinase (PI3K)/serine-threonine kinase (Akt)/mammalian target of the rapamycin (mTOR)-signaling pathway has been suggested to have connections with the malignant transformation, growth, proliferation, and metastasis of various cancers and solid tumors. Relevant connections between the PI3K/Akt/mTOR pathway, cell survival, and prostate cancer (PC) provide a great therapeutic target for PC prevention or treatment. Recent studies have focused on small-molecule mTOR inhibitors or their usage in coordination with other therapeutics for PC treatment that are currently undergoing clinical testing. In this study, the function of the PI3K/Akt/mTOR pathway, the consequence of its dysregulation, and the development of mTOR inhibitors, either as an individual substance or in combination with other agents, and their clinical implications are discussed. The rationale for targeting the PI3K/Akt/mTOR pathway, and specifically the application and potential utility of natural agents involved in PC treatment is described. In addition to the small-molecule mTOR inhibitors, there are evidence that several natural agents are able to target the PI3K/Akt/mTOR pathway in prostatic neoplasms. These natural mTOR inhibitors can interfere with the PI3K/Akt/mTOR pathway through multiple mechanisms; however, inhibition of Akt and suppression of mTOR 1 activity are two major therapeutic approaches. Combination therapy improves the efficacy of these inhibitors to either suppress the PC progression or circumvent the resistance by cancer cells.

Treatment of Sjögren's syndrome: current therapy and future directions

SS is usually described as having severe fatigue, dryness, diffuse pain, glandular swelling, and various extraglandular (systemic) manifestations. Clinical trials have generally failed because the vast majority of enrolled patients had no extraglandular manifestations at the time of enrolment but suffered from fatigue, dryness and pain that did not significantly respond to the study medication. A number of hypotheses on the pathogenesis of pSS have been put forward, including disturbances of innate and adaptive immunity as well as abnormalities of the interface between immune disorders and the neuro-endocrine system related to lacrimal and secretory gland dysfunction. Thus, future therapies must be designed for improvement of the symptoms of dry eyes and dry mouth, extraglandular disease, and fatigue and cognitive deficits. Given the inadequacies and limitations of current treatment options, we suggest that innovative directions involving interactions with neuroscientists and neuropsychiatrists together or combined with new immune targeting may be hold promise for better treating pSS.

Mission Possible: Advances in MYC Therapeutic Targeting in Cancer

MYC is a master transcriptional regulator that controls almost all cellular processes. Over the last several decades, researchers have strived to define the context-dependent transcriptional gene programs that are controlled by MYC, as well as the mechanisms that regulate MYC function, in an effort to better understand the contribution of this oncoprotein to cancer progression. There are a wealth of data indicating that deregulation of MYC activity occurs in a large number of cancers and significantly contributes to disease progression, metastatic potential, and therapeutic resistance. Although the therapeutic targeting of MYC in cancer is highly desirable, there remain substantial structural and functional challenges that have impeded direct MYC-targeted drug development and efficacy. While efforts to drug the ‘undruggable’ may seem futile given these challenges and considering the broad reach of MYC, significant strides have been made to identify points of regulation that can be exploited for therapeutic purposes. These include targeting the deregulation of MYC transcription in cancer through small-molecule inhibitors that induce epigenetic silencing or that regulate the G-quadruplex structures within the MYC promoter. Alternatively, compounds that disrupt the DNA-binding activities of MYC have been the long-standing focus of many research groups, since this method would prevent downstream MYC oncogenic activities regardless of upstream alterations. Finally, proteins involved in the post-translational regulation of MYC have been identified as important surrogate targets to reduce MYC activity downstream of aberrant cell stimulatory signals. Given the complex regulation of the MYC signaling pathway, a combination of these approaches may provide the most durable response, but this has yet to be shown. Here, we provide a comprehensive overview of the different therapeutic strategies being employed to target oncogenic MYC function, with a focus on post-translational mechanisms.

Rapamycin and FTY720 Alleviate Atherosclerosis by Cross Talk of Macrophage Polarization and Autophagy

Foam cell formation and macrophage polarization are involved in the pathologic development of atherosclerosis, one of the most important human diseases affecting large and medium artery walls. This study was designed to assess the effects of rapamycin and FTY720 (fingolimod) on macrophages and foam cells. Mouse peritoneal macrophages were collected and treated with rapamycin and FTY720 to study autophagy, polarization, and lipid accumulation. Next, foam cells were formed by oxidizing low-density lipoprotein to observe changes in lipid accumulation, autophagy, and polarization in rapamycin-treated or FTY720-treated foam cells. Lastly, foam cells that had been treated with rapamycin and FTY720 were evaluated for sphingosine 1-phosphate receptor (S1prs) expression. Autophagy microtubule-associated protein 1 light chain 3- (LC3-) II was increased, and classically activated macrophage phenotype markers interleukin- (IL-) 6, cyclooxygenase-2 (COX2), and inducible nitric oxide synthase (iNOS) were increased, whereas alternatively activated macrophage phenotype markers transforming growth factor- (TGF-) β, arginase 1 (Arg1), and mannose receptor C-type 1 (Mrc1) were decreased by rapamycin in peritoneal macrophages. LC3-II was also obviously enhanced, though polarization markers were unchanged in rapamycin-treated foam cells. Moreover, lipid accumulation was inhibited in rapamycin-treated macrophage cells but was unchanged in rapamycin-treated foam cells. For FTY720, LC3-II did not change, whereas TGF-β, Arg1 and Mrc1 were augmented, and IL-6 was suppressed in macrophages. However, LC3-II was increased, and TGF-β, ARG1 and MRC1 were strikingly augmented, whereas IL-6, COX2 and iNOS could be suppressed in foam cells. Furthermore, lipid accumulation was alleviated in FTY720-treated foam cells. Additionally, S1pr1 was markedly decreased in foam cells (P < .05); S1pr2, S1pr3, S1pr4 and S1pr5 were unchanged in rapamycin-treated foam cells. In FTY720-treated foam cells, S1pr3 and S1pr4 were decreased, and S1pr1, S1pr2 and S1pr5 were unchanged. Therefore, we deduced that rapamycin stimulated classically activated macrophages and supressed early atherosclerosis. Rapamycin may also stabilize artery plaques by preventing apoptosis and S1PR1 in advanced atherosclerosis. FTY720 allowed transformation of foam cells into alternatively activated macrophages through the autophagy pathway to alleviate advanced atherosclerosis.

Suppression of c-Myc enhances p21WAF1/CIP1 -mediated G1 cell cycle arrest through the modulation of ERK phosphorylation by ascochlorin

Numerous anti-cancer agents inhibit cell cycle progression via a p53-dependent mechanism; however, other genes such as the proto-oncogene c-Myc are promising targets for anticancer therapy. In the present study, we provide evidence that ascochlorin, an isoprenoid antibiotic, is a non-toxic anti-cancer agent that induces G1 cell cycle arrest and p21WAF1/CIP1 expression by downregulating of c-Myc protein expression. Ascochlorin promoted the G1 arrest, upregulated p53 and p21WAF1/CIP1 , and downregulated c-Myc in HCT116 cells. In p53-deficient cells, ascochlorin enhanced the expression of G1 arrest-related genes except p53. Small interfering RNA (siRNA) mediated c-Myc silencing indicated that the transcriptional repression of c-Myc was related to ascochlorin-mediated modulation of p21WAF1/CIP1 expression. Ascochlorin suppressed the stabilization of the c-Myc protein by inhibiting ERK and P70S6K/4EBP1 phosphorylation, whereas it had no effect on c-Myc degradation mediated by PI3K/Akt/GSK3β. The ERK inhibitor PD98059 and siRNA-mediated ERK silencing induced G1 arrest and p21WAF1/CIP1 expression by downregulating c-Myc in p53-deficient cells. These results indicated that ascochlorin-induced G1 arrest is associated with the repression of ERK phosphorylation and c-Myc expression. Thus, we reveal a role for ascochlorin in inhibiting tumor growth via G1 arrest, and identify a novel regulatory mechanism for ERK/c-Myc.

MYC and tumor metabolism: chicken and egg

Transcription factors of the MYC family are deregulated in the majority of all human cancers. Oncogenic levels of MYC reprogram cellular metabolism, a hallmark of cancer development, to sustain the high rate of proliferation of cancer cells. Conversely, cells need to modulate MYC function according to the availability of nutrients, in order to avoid a metabolic collapse. Here, we review recent evidence that the multiple interactions of MYC with cell metabolism are mutual and review mechanisms that control MYC levels and function in response to metabolic stress situations. The main hypothesis we put forward is that regulation of MYC levels is an integral part of the adaptation of cells to nutrient deprivation. Since such mechanisms would be particularly relevant in tumor cells, we propose that-in contrast to growth factor-dependent controls-they are not disrupted during tumorigenesis and that maintaining flexibility of expression is integral to MYC's oncogenic function.

Assessment of tris (1, 3-dichloro-2-propyl) phosphate toxicology in PC12 cells by using digital gene expression profiling

Tris (1,3-dichloro-2-propyl) phosphate (TDCIPP), one of the most universally used organophosphate flame retardants (OPFRs), is an environmental pollutant. However, limited information is available regarding its toxicity and environmental health risk. In the present study, PC12 cells provided a useful model for the evaluation of the toxic effects of TDCIPP. Exposure to 7.5, 15, 30, or 60 μM TDCIPP for 72 h inhibited cell viability, and enhanced cellular apoptosis and oxidative stress. To further explore the underlying mechanisms, digital gene expression (DGE) technology was used to identify early transcriptional changes following TDCIPP exposure. Expression of the transcripts of 161 genes was significantly altered upon treatment with TDCIPP. Functional and pathway analysis of the transcriptional profile demonstrated that genes showing significant TDCIPP-associated changes in expression were involved in the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, extracellular matrix-receptor interactions, protein digestion and absorption, and microRNAs in cancer. Using quantitative real-time PCR, we validated the differential expression of selected genes. These results showed that the expression profiles of cells exposed to 60 μM TDCIPP were consistent with the DGE data. Furthermore, western blotting showed that treatment with TDCIPP reduced the Bcl-2/Bax ratio and attenuated PI3K/Akt/Myc signaling. Taken together, these data suggest that TDCIPP exposure can reduce cell viability and induce apoptosis in PC12 cells by inhibiting activation of the PI3K/Akt/Myc signaling pathway. These observations provide valuable preliminary information regarding the mechanisms of TDCIPP-induced toxicity in PC12 cells and indicate that further study of the toxicity of other environmental OPFRs is warranted.

MCM7 amplification and overexpression promote cell proliferation, colony formation and migration in esophageal squamous cell carcinoma by activating the AKT1/mTOR signaling pathway

The roles and mechanisms of mini-chromosome maintenance complex component 7 (MCM7) amplification and overexpression in esophageal carcinogenesis were investigated. By analyzing the TCGA datasets, we found that MCM7 was amplified in approximately 12% of esophageal squamous cell carcinomas (ESCCs), and in more than 4% of head and neck squamous cell carcinomas and stomach carcinomas. Overexpression of MCM7 was further verified in three independent GEO datasets of esophageal cancer. Knockdown of MCM7 using two siRNAs significantly inhibited cell proliferation, colony formation and migration of KYSE510 and EC9706 cells in vitro. Noteworthy, we further found that silencing of MCM7 suppressed the phosphorylation of AKT1 and mTOR both in KYSE510 and EC9706 cells, and reduced the cell cycle regulatory proteins cyclin D1, cyclin E2 and CDK2. Taken together, our findings suggested that MCM7 promoted tumor cell proliferation, colony formation and migration of ESCC cells via activating AKT1/mTOR signaling pathway.

Targeting MYC Dependence by Metabolic Inhibitors in Cancer

MYC is a critical growth regulatory gene that is commonly overexpressed in a wide range of cancers. Therapeutic targeting of MYC transcriptional activity has long been a goal, but it has been difficult to achieve with drugs that directly block its DNA-binding ability. Additional approaches that exploit oncogene addiction are promising strategies against MYC-driven cancers. Also, drugs that target metabolic regulatory pathways and enzymes have potential for indirectly reducing MYC levels. Glucose metabolism and oxidative phosphorylation, which can be targeted by multiple agents, promote cell growth and MYC expression. Likewise, modulation of the signaling pathways and protein synthesis regulated by adenosine monophosphate-activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) can also be an effective route for suppressing MYC translation. Furthermore, recent data suggest that metabolism of nucleotides, fatty acids and glutamine are exploited to alter MYC levels. Combination therapies offer potential new approaches to overcome metabolic plasticity caused by single agents. Although potential toxicities must be carefully controlled, new inhibitors currently being tested in clinical trials offer significant promise. Therefore, as both a downstream target of metabolism and an upstream regulator, MYC is a prominent central regulator of cancer metabolism. Exploiting metabolic vulnerabilities of MYC-driven cancers is an emerging research area with translational potential.