Inhibition of mitochondria ATP synthase suppresses prostate cancer growth through reduced insulin-like growth factor-1 secretion by prostate stromal cells

Chimeric SFT2D2-TBX19 Promotes Prostate Cancer Progression by Encoding TBX19-202 Protein and Stabilizing Mitochondrial ATP Synthase through ATP5F1A Phosphorylation

Specific chimeric RNAs and their products are consistently regarded as ideal tumor diagnostic markers and therapeutic targets. Chimeric RNAs can mediate tumor cell plasticity, neuroendocrine processes, polarization of tumor-associated macrophages, and resistance to chemotherapy and immunotherapy. However, the discovery of chimeric RNAs in prostate cancer is still in its early stages. This study identifies the chimeric SFT2D2-TBX19 as a novel transcript encoding the TBX19-202 protein. Both TBX19-202 and its parental TBX19, which share homologous amino acid sequences, enhance prostate cancer cell proliferation, migration, and invasion. Additionally, SFT2D2-TBX19 also functions as a lncRNA, interacting with the ATP synthase F1 subunit ATP5F1A, thereby increasing ATP5F1A phosphorylation mediated by TNK2/ACK1, which stabilizes the interaction between ATP5F1A and ATP5F1B. The region spanning 1801-2400 bp of SFT2D2-TBX19 and the intermediate structural domain of ATP5F1A are crucial functional areas. This stabilization of ATP5F1A and ATP5F1B enhances mitochondrial ATP synthase activity and ATP production. Even under conditions of mitochondrial vulnerability, SFT2D2-TBX19 protects mitochondrial structural stability to maintain prostate cancer cell proliferation. This research provides comprehensive evidence that chimeric SFT2D2-TBX19 promotes prostate cancer progression by encoding the TBX19-202 protein and stabilizing mitochondrial ATP synthase via ATP5F1A phosphorylation. These findings highlight SFT2D2-TBX19 as a potential therapeutic target for prostate cancer.

Stromal-derived MAOB promotes prostate cancer growth and progression

Prostate cancer (PC) develops in a microenvironment where the stromal cells modulate adjacent tumor growth and progression. Here, we demonstrated elevated levels of monoamine oxidase B (MAOB), a mitochondrial enzyme that degrades biogenic and dietary monoamines, in human PC stroma, which was associated with poor clinical outcomes of PC patients. Knockdown or overexpression of MAOB in human prostate stromal fibroblasts indicated that MAOB promotes cocultured PC cell proliferation, migration, and invasion and co-inoculated prostate tumor growth in mice. Mechanistically, MAOB induces a reactive stroma with activated marker expression, increased extracellular matrix remodeling, and acquisition of a protumorigenic phenotype through enhanced production of reactive oxygen species. Moreover, MAOB transcriptionally activates CXCL12 through Twist1 synergizing with TGFβ1-dependent Smads in prostate stroma, which stimulates tumor-expressed CXCR4-Src/JNK signaling in a paracrine manner. Pharmacological inhibition of stromal MAOB restricted PC xenograft growth in mice. Collectively, these findings characterize the contribution of MAOB to PC and suggest MAOB as a potential stroma-based therapeutic target.

Purinergic signalling in cancer therapeutic resistance: From mechanisms to targeting strategies

Purinergic signalling, consisting of extracellular purines and purinergic receptors, modulates cell proliferation, invasion and immunological reaction during cancer progression. Here, we focus on current evidence that suggests the crucial role of purinergic signalling in mediating cancer therapeutic resistance, the major obstacle in cancer treatment. Mechanistically, purinergic signalling can modulate the tumor microenvironment (TME), epithelial-mesenchymal transition (EMT) and anti-tumor immunity, thus affecting drug sensitivity of tumor cells. Currently, some agents attempting to target purinergic signalling either in tumor cells or in tumor-associated immune cells are under preclinical or clinical investigation. Moreover, nano-based delivery technologies significantly improve the efficacy of agents targeting purinergic signalling. In this review article, we summarize the mechanisms of purinergic signalling in promoting cancer therapeutic resistance and discuss the potentials and challenges of targeting purinergic signalling in future cancer treatment.

A new tumorgraft panel to accelerate precision medicine in prostate cancer

Background

Despite the significant advances in the management of advanced prostate cancer (PCa), metastatic PCa is currently considered incurable. For further investigations in precision treatment, the development of preclinical models representing the complex prostate tumor heterogeneity are mandatory. Accordingly, we aimed to establish a resource of patient-derived xenograft (PDX) models that exemplify each phase of this multistage disease for accurate and rapid evaluation of candidate therapies.

Methods

Fresh tumor samples along with normal corresponding tissues were obtained directly from patients at surgery. To ensure that the established models reproduce the main features of patient's tumor, both PDX tumors at multiple passages and patient's primary tumors, were processed for histological characteristics. STR profile analyses were also performed to confirm patient identity. Finally, the responses of the PDX models to androgen deprivation, PARP inhibitors and chemotherapy were also evaluated.

Results

In this study, we described the development and characterization of 5 new PDX models of PCa. Within this collection, hormone-naïve, androgen-sensitive and castration-resistant (CRPC) primary tumors as well as prostate carcinoma with neuroendocrine differentiation (CRPC-NE) were represented. Interestingly, the comprehensive genomic characterization of the models identified recurrent cancer driver alterations in androgen signaling, DNA repair and PI3K, among others. Results were supported by expression patterns highlighting new potential targets among gene drivers and the metabolic pathway. In addition, in vivo results showed heterogeneity of response to androgen deprivation and chemotherapy, like the responses of patients to these treatments. Importantly, the neuroendocrine model has been shown to be responsive to PARP inhibitor.

Conclusion

We have developed a biobank of 5 PDX models from hormone-naïve, androgen-sensitive to CRPC primary tumors and CRPC-NE. Increased copy-number alterations and accumulation of mutations within cancer driver genes as well as the metabolism shift are consistent with the increased resistance mechanisms to treatment. The pharmacological characterization suggested that the CRPC-NE could benefit from the PARP inhibitor treatment. Given the difficulties in developing such models, this relevant panel of PDX models of PCa will provide the scientific community with an additional resource for the further development of PDAC research.

Hsa_circ_0079480 enhances cell proliferation, migration, and invasion in colorectal cancer through miR-498/ATP5E axis

Circular RNAs play critical roles in tumorigenesis. hsa_circ_0079480 was reported to be upregulated in colorectal cancer (CRC). However, its specific molecule in CRC is poorly understood. Hsa_circ_0079480, miR-498, and ATP5E expressions in CRC tissues and CRC cells were determined using quantitative real-time polymerase chain reaction assay. ATP5E protein level was assessed using Western blot. Cell proliferation, migration, and invasion were examined by 3-(4, 5-Dimethylthiazolyl2)-2, 5-diphenyltetrazolium bromide assay and Transwell assays, respectively. Dual-luciferase reporter gene assay was performed to analyze the interactions between hsa_circ_0079480, miR-498, and ATP5E. This study results showed that hsa_circ_0079480 and ATP5E expressions were significantly increased in CRC tissues and CRC cells, while miR-498 was downregulated. Hsa_circ_0079480 knockdown dramatically suppressed CRC cell proliferation, migration, and invasion. Meanwhile, it turned out that hsa_circ_0079480 knockdown inhibited CRC tumor growth in vivo. Hsa_circ_0079480 could negatively regulate miR-498 expression by directly targeting miR-498. MiR-498 overexpression dramatically inhibited CRC cell malignant behaviors. miR-498 negatively regulated ATP5E expression by directly binding to ATP5E. ATP5E knockdown suppressed CRC cell malignant behaviors. ATP5E overexpression mitigated the inhibitory effect of hsa_circ_0079480 on CRC cell malignant behaviors. Since hsa_circ_0079480 knockdown inhibited CRC cells malignant behaviors through regulation of the miR-498/ATP5E axis, it can be concluded that hsa_circ_0079480 might have great potential as therapeutic target for CRC.

Niclosamide in prostate cancer: An inhibitor of AR-V7, a mitochondrial uncoupler, or more?

A recent phase Ib study investigating the use of reformulated niclosamide in combination with abiraterone and prednisone in patients with castration-resistant prostate cancer (CRPC) demonstrated encouraging preliminary efficacy with low toxicity. Preclinical studies have reported that niclosamide at clinically relevant concentrations inhibits androgen receptor splice variant 7 (AR-V7), a known tumor driver in CRPC. However, the magnitude of anti-tumor effects of niclosamide either used alone or in combination with abiraterone in these experimental models, far exceeded what could have been explained as a simple AR-V7 inhibition. Niclosamide at clinically relevant concentrations also acts as an oxidative phosphorylation (OxPhos) uncoupler in mitochondria. This raises the question whether the observed effects of niclosamide were partly mediated by OxPhos inhibition. Most OxPhos inhibitors did not demonstrate selectivity towards cancer cells and failed to enter clinical practice due to unacceptable toxicity. However, some mitochondrial uncouplers have greater cytotoxicity against cancerous cells compared to non-cancerous. Hyperpolarization of cancer cell mitochondria, or the more alkaline mitochondrial matrix of cancer cells could be potential reasons for this. Niclosamide can also alter Wnt/β-catenin, mTOR, Notch, NF-kB and STAT3 signaling pathways. Hence, the mechanism of action of reformulated niclosamide in CRPC patients requires further investigation. This will potentially lead to new opportunities to develop and investigate even more selective and effective treatments against prostate cancer.

A Mini-Review of Flavone Isomers Apigenin and Genistein in Prostate Cancer Treatment

The initial responses to standard chemotherapies among prostate cancer (PCa) patients are usually significant, while most of them will finally develop drug resistance, rendering them with limited therapies. To discover new regimens for the treatment of PCa including resistant PCa, natural products, the richest source of bioactive compounds, can serve as a library for screening and identifying promising candidates, and flavones such as apigenin and genistein have been used in lab and clinical trials for treating PCa over decades. In this mini-review, we take a look into the progress of apigenin and genistein, which are isomers, in treating PCa in the past decade. While possessing very similar structure, these two isomers can both target the same signaling pathways; they also are found to work differently in PCa cells. Given that more combinations are being developed and tested, genistein appears to be the more promising option to be approved. The anticancer efficacies of these two flavones can be confirmed by in-vitro and in-vivo studies, and their applications remain to be validated in clinical trials. Information gained in this work may provide important information for new drug development and the potential application of apigenin and genistein in treating PCa.

Targeting the IGF-1R in prostate and colorectal cancer: reasons behind trial failure and future directions

IGF-1Rs enact a significant part in cancer growth and its progress. IGF-1R inhibitors were encouraged in the early trials, but the patients did not benefit due to the unavailability of predictive biomarkers and IGF-1R system complexity. However, the linkage between IGF-1R and cancer was reported three decades ago. This review will shed light on the IGF-1R system, targeting IGF-1R through monoclonal antibodies, reasons behind IGF-1R trial failure and future directions. This study presented that targeting IGF-1R through monoclonal antibodies is still effective in cancer treatment, and there is a need to look for future directions. Cancer patients may benefit from using mAbs that target existing and new cancer targets, evidenced by promising results. It is also essential that the academician, trial experts and pharmaceutical companies play their role in finding a treatment for this deadly disease.

Targeting Mitochondrial OXPHOS and Their Regulatory Signals in Prostate Cancers

Increasing evidence suggests that tumor development requires not only oncogene/tumor suppressor mutations to drive the growth, survival, and metastasis but also metabolic adaptations to meet the increasing energy demand for rapid cellular expansion and to cope with the often nutritional and oxygen-deprived microenvironment. One well-recognized strategy is to shift the metabolic flow from oxidative phosphorylation (OXPHOS) or respiration in mitochondria to glycolysis or fermentation in cytosol, known as Warburg effects. However, not all cancer cells follow this paradigm. In the development of prostate cancer, OXPHOS actually increases as compared to normal prostate tissue. This is because normal prostate epithelial cells divert citrate in mitochondria for the TCA cycle to the cytosol for secretion into seminal fluid. The sustained level of OXPHOS in primary tumors persists in progression to an advanced stage. As such, targeting OXPHOS and mitochondrial activities in general present therapeutic opportunities. In this review, we summarize the recent findings of the key regulators of the OXPHOS pathway in prostate cancer, ranging from transcriptional regulation, metabolic regulation to genetic regulation. Moreover, we provided a comprehensive update of the current status of OXPHOS inhibitors for prostate cancer therapy. A challenge of developing OXPHOS inhibitors is to selectively target cancer mitochondria and spare normal counterparts, which is also discussed.

Micropeptide ASAP encoded by LINC00467 promotes colorectal cancer progression by directly modulating ATP synthase activity

Emerging evidence has shown that open reading frames inside long noncoding RNAs (lncRNAs) could encode micropeptides. However, their roles in cellular energy metabolism and tumor progression remain largely unknown. Here, we identified a 94 amino acid-length micropeptide encoded by lncRNA LINC00467 in colorectal cancer. We also characterized its conservation across higher mammals, localization to mitochondria, and the concerted local functions. This peptide enhanced the ATP synthase construction by interacting with the subunits α and γ (ATP5A and ATP5C), increased ATP synthase activity and mitochondrial oxygen consumption rate, and thereby promoted colorectal cancer cell proliferation. Hence, this micropeptide was termed ATP synthase-associated peptide (ASAP). Furthermore, loss of ASAP suppressed patient-derived xenograft growth with attenuated ATP synthase activity and mitochondrial ATP production. Clinically, high expression of ASAP and LINC00467 predicted poor prognosis of colorectal cancer patients. Taken together, our findings revealed a colorectal cancer-associated micropeptide as a vital player in mitochondrial metabolism and provided a therapeutic target for colorectal cancer.

Label-Free Fluorescent Aptasensor for Adenosine Triphosphate Detection Using SYBR Gold as a Probe

In this experimental research, a label-free sensing strategy is developed and employed to detect adenosine triphosphate with utilization of aptamers, including exonuclease I and SYBR Gold. The conformation of aptamers bonding to the specific target molecule (ATP) is transformed into an antiparallel G-quadruplex structure from a random coil. Afterwards, considering the unfolded aptamers are the preferred substrates for exonuclease I, the addition of exonuclease I is used so as to digest unfolded aptamers in the mixture in a selective manner. In the follow-up study, in order to strengthen the fluorescence intensity, SYBR Gold is applied as a fluorescent probe. The aptasensor presents the features of high selectivity against adenosine triphosphate and the low detecting limit of concentrations (39.2 nM). In order to verify the validation of experimental procedures and the practical application of the aptasensor, the detection of adenosine triphosphate for human serum samples is performed with satisfactory success. The recovery result with the range of 93.8%-108.1% is desirable and suggests that the designed approach is applicable. The outcomes of the cellular adenosine triphosphate assay manifest that the level of adenosine triphosphate concentrations in cell extracts can be monitored without the interference of other substances in the cells. Subject to its advantageous benefits (cost-effective, easiness, rapidity, and extraordinary selectivity), the designed approach has a promising implication for adenosine triphosphate detection in the research domain of bioanalytical science and biology.

The therapeutic potential of mitochondrial toxins

When screening active compounds by phenotypic assays, we often encounter mitochondrial toxins, which are compounds that can affect mitochondrial functions. In normal cells, these toxins may have relatively low toxicity but can nonetheless show measurable effects even at low concentrations. On the other hand, in animals, mitochondrial toxins can exert severe toxicity. Mitochondrial toxins that act as inhibitors of respiratory chain complexes in oxidative phosphorylation (OXPHOS) are typically avoided during drug discovery efforts, as such compounds can directly promote lethal inhibition of pulmonary respiration. However, mitochondrial toxins could in fact have beneficial therapeutic effects. Anti-cancer strategies that target mitochondrial functions, particularly OXPHOS, have received increasing attention in recent years. In this review article we examine the significance of OXPHOS inhibitors as anti-cancer drug candidates and discuss compounds having microbial origins.

Current updates on precision therapy for breast cancer associated brain metastasis: Emphasis on combination therapy

Cancer therapies have undergone a tremendous progress over the past decade. Precision medicine provides a more tailored approach, making the combination of existing therapies more precise. Different types of cancers are characterized by unique biomarkers that are targeted using various genomic approaches by clinicians and companies worldwide to achieve efficient treatment with minimal side effects. Precision medicine has two broad approaches namely stratified and personalized medicine. The driver mutations could vary within a subtype while the same driver mutations could be found across different subtypes. Precision medicine has recently gained a lot of importance for breast cancer therapy. Various kinds of mutations like hotspot mutations, gene alterations, gene amplification mutations are targeted to design a more specific therapy. Apart from these known gene mutations there are various unknown mutations. Thus, tumor heterogeneity can pose a challenge to precision medicine. For breast cancer, one of the most successful models developed in case of precision medicine is the anti-HER2 therapies as HER2 was considered to have the worst prognosis being highly malignant. But now due to the advent of HER2 receptor targeted therapies, it has a good prognosis. Moreover, precision medicine helps in identifying if the drug molecules being used for the treatment of one kind of cancer can be beneficial in the treatment of another kind of cancer as well, considering the signaling pathways and machinery is similar in most of the cancers. This reduces the time for new drug development and is economically more feasible. Precision medicine will prove to be very advantageous in case of brain metastasis.

Inhibitors of F1F0-ATP synthase enzymes for the treatment of tuberculosis and cancer

The spectacular success of the mycobacterial F₁F₀-ATP synthase inhibitor bedaquiline for the treatment of drug-resistant tuberculosis has generated wide interest in the development of other inhibitors of this enzyme. Work in this realm has included close analogues of bedaquiline with better safety profiles and 'bedaquiline-like' compounds, some of which show potent antibacterial activity in vitro although none have yet progressed to clinical trials. The search has lately extended to a range of new scaffolds as potential inhibitors, including squaramides, diaminoquinazolines, chloroquinolines, dihydropyrazolo[1,5-a]pyrazin-4-ones, thiazolidinediones, diaminopyrimidines and tetrahydroquinolines. Because of the ubiquitous expression of ATP synthase enzymes, there has also been interest in inhibitors of other bacterial ATP synthases, as well as inhibitors of human mitochondrial ATP synthase for cancer therapy. The latter encompass both complex natural products and simpler small molecules. The review seeks to demonstrate the breadth of the structural types of molecules able to effectively inhibit the function of variants of this intriguing enzyme.

Catalytic Asymmetric Total Synthesis of Leucinostatin A

This review describes our efforts toward achieving catalytic asymmetric total synthesis of leucinostatin A, a compound that interferes with the tumor-stroma interaction. The synthesis utilizes four catalytic asymmetric reactions, including direct-type reactions exemplified by high atom-economy, and three C-C bond forming reactions. Thorough analysis of the NMR data, HPLC profiles, and biologic activity led us to unambiguously revise the absolute configuration regarding the 6-position of the AHMOD residue side chain from S (reported) to R. Other examples of previously reported important studies on the stereoselective synthesis of HyLeu and AHMOD are also described.

Natural products and other inhibitors of F1FO ATP synthase

F₁F_O ATP synthase is responsible for the production of >95% of all ATP synthesis within the cell. Dysregulation of its expression, activity or localization is linked to various human diseases including cancer, diabetes, and Alzheimer's and Parkinson's disease. In addition, ATP synthase is a novel and viable drug target for the development of antimicrobials as evidenced by bedaquiline, which was approved in 2012 for the treatment of tuberculosis. Historically, natural products have been a rich source of ATP synthase inhibitors that help unravel the role of F₁F_O ATP synthase in cellular bioenergetics. During the last decade, new modulators of ATP synthase have been discovered through the isolation of novel natural products as well as through a ligand-based drug design process. In addition, new data has been obtained with regards to the structure and function of ATP synthase under physiological and pathological conditions. Crystal structure studies have provided a significant insight into the rotary function of the enzyme and may provide additional opportunities to design a new generation of inhibitors. This review provides an update on recently discovered ATP synthase modulators as well as an update on existing scaffolds.

Anti-Metastatic Activity of an Anti-EGFR Monoclonal Antibody against Metastatic Colorectal Cancer with KRAS p.G13D Mutation

The now clinically-used anti-epidermal growth factor receptor (EGFR) monoclonal antibodies have demonstrated significant efficacy only in patients with metastatic colorectal cancer (mCRC), with wild-type Kirsten rat sarcoma viral oncogene homolog (KRAS). However, no effective treatments for patients with mCRC with KRAS mutated tumors have been approved yet. Therefore, a new strategy for targeting mCRC with KRAS mutated tumors is desired. In the present study, we examined the anti-tumor activities of a novel anti-EGFR monoclonal antibody, EMab-17 (mouse IgG_2a, kappa), in colorectal cancer (CRC) cells with the KRAS p.G13D mutation. This antibody recognized endogenous EGRF in CRC cells with or without KRAS mutations, and showed a high sensitivity for CRC cells in flow cytometry, indicating that EMab-17 possesses a high binding affinity to the endogenous EGFR. In vitro experiments showed that EMab-17 exhibited antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity activities against CRC cells. In vivo analysis revealed that EMab-17 inhibited the metastases of HCT-15 and HCT-116 cells in the livers of nude mouse metastatic models, unlike the anti-EGFR monoclonal antibody EMab-51 of subtype mouse IgG₁. In conclusion, EMab-17 may be useful in an antibody-based therapy against mCRC with the KRAS p.G13D mutation.