PRL3 enhances T-cell acute lymphoblastic leukemia growth through suppressing T-cell signaling pathways and apoptosis

Targeting PRL phosphatases in hematological malignancies

INTRODUCTION

Phosphatase of regenerating liver (PRL) family proteins, also known as protein tyrosine phosphatase 4A (PTP4A), have been implicated in many types of cancers. The PRL family of phosphatases consists of three members, PRL1, PRL2, and PRL3. PRLs have been shown to harbor oncogenic potentials and are highly expressed in a variety of cancers. Given their roles in cancer progression and metastasis, PRLs are potential targets for anticancer therapies. However, additional studies are needed to be performed to fully understand the roles of PRLs in blood cancers.

AREAS COVERED

In this review, we will summarize recent studies of PRLs in normal and malignant hematopoiesis, the role of PRLs in regulating various signaling pathways, and the therapeutic potentials of targeting PRLs in hematological malignancies. We will also discuss how to improve current PRL inhibitors for cancer treatment.

EXPERT OPINION

Although PRL inhibitors show promising therapeutic effects in preclinical studies of different types of cancers, moving PRL inhibitors from bench to bedside is still challenging. More potent and selective PRL inhibitors are needed to target PRLs in hematological malignancies and improve treatment outcomes.

Zebrafish-A Suitable Model for Rapid Translation of Effective Therapies for Pediatric Cancers

Pediatric cancers are the leading cause of disease-related deaths in children and adolescents. Most of these tumors are difficult to treat and have poor overall survival. Concerns have also been raised about drug toxicity and long-term detrimental side effects of therapies. In this review, we discuss the advantages and unique attributes of zebrafish as pediatric cancer models and their importance in targeted drug discovery and toxicity assays. We have also placed a special focus on zebrafish models of pediatric brain cancers-the most common and difficult solid tumor to treat.

Protein Tyrosine Phosphatase PRL-3: A Key Player in Cancer Signaling

Protein phosphatases are primarily responsible for dephosphorylation modification within signal transduction pathways. Phosphatase of regenerating liver-3 (PRL-3) is a dual-specific phosphatase implicated in cancer pathogenesis. Understanding PRL-3's intricate functions and developing targeted therapies is crucial for advancing cancer treatment. This review highlights its regulatory mechanisms, expression patterns, and multifaceted roles in cancer progression. PRL-3's involvement in proliferation, migration, invasion, metastasis, angiogenesis, and drug resistance is discussed. Regulatory mechanisms encompass transcriptional control, alternative splicing, and post-translational modifications. PRL-3 exhibits selective expressions in specific cancer types, making it a potential target for therapy. Despite advances in small molecule inhibitors, further research is needed for clinical application. PRL-3-zumab, a humanized antibody, shows promise in preclinical studies and clinical trials. Our review summarizes the current understanding of the cancer-related cellular function of PRL-3, its prognostic value, and the research progress of therapeutic inhibitors.

Anti-PRL-3 Monoclonal Antibody inhibits the Growth and Metastasis of colorectal adenocarcinoma

Background: Colon cancer is the one of leading causes of cancer-related death. Chemotherapy, radiotherapy and immunotherapy will be the mainstream in inoperable advanced cancer in clinics. Precision treatment is still lack in colon cancer. Materials and Methods: We developed a series of mAbs targeting PRL-3 through different types of immunogens. The binding domains of mAbs were identified through the ELISA and Western blotting experiments. The antitumor activity of mAbs was verified by cell proliferation, migration and invasion experiments. Xenograft subcutaneous and metastatic models and patient derived Xenograft (PDX) model were established. Results: mAb 12G12 targeting 77-120AA exhibited inhibition in migration and invasion experiments. 12G12 inhibited the migration of multiple types of cancer cells, including colon cancer, gastric cancer, esophagus cancer, liver cancer, lung cancer and pancreatic cancer cells. 12G12 decreased the tumor growth and metastasis in Xenograft subcutaneous and metastatic tumor model, respectively. The antitumor activity of mAb 12G12 was also confirmed in PDX model of gastric cancer. PRL-3 interacted with Golgi protein TMED10. Knockdown of TMED10 expression attenuated the cell migration triggered by purified GST-PRL-3 protein. Conclusion: Our results confirmed the antitumor activity of mAb 12G12 in colorectal adenocarcinoma and provided a new potential targeted therapy of colon cancer.

Super-enhancer-driven TOX2 mediates oncogenesis in Natural Killer/T Cell Lymphoma

BACKGROUND

Extranodal natural killer/T-cell lymphoma (NKTL) is an aggressive type of non-Hodgkin lymphoma with dismal outcome. A better understanding of disease biology and key oncogenic process is necessary for the development of targeted therapy. Super-enhancers (SEs) have been shown to drive pivotal oncogenes in various malignancies. However, the landscape of SEs and SE-associated oncogenes remain elusive in NKTL.

METHODS

We used Nano-ChIP-seq of the active enhancer marker histone H3 lysine 27 acetylation (H3K27ac) to profile unique SEs NKTL primary tumor samples. Integrative analysis of RNA-seq and survival data further pinned down high value, novel SE oncogenes. We utilized shRNA knockdown, CRISPR-dCas9, luciferase reporter assay, ChIP-PCR to investigate the regulation of transcription factor (TF) on SE oncogenes. Multi-color immunofluorescence (mIF) staining was performed on an independent cohort of clinical samples. Various function experiments were performed to evaluate the effects of TOX2 on the malignancy of NKTL in vitro and in vivo.

RESULTS

SE landscape was substantially different in NKTL samples in comparison with normal tonsils. Several SEs at key transcriptional factor (TF) genes, including TOX2, TBX21(T-bet), EOMES, RUNX2, and ID2, were identified. We confirmed that TOX2 was aberrantly overexpressed in NKTL relative to normal NK cells and high expression of TOX2 was associated with worse survival. Modulation of TOX2 expression by shRNA, CRISPR-dCas9 interference of SE function impacted on cell proliferation, survival and colony formation ability of NKTL cells. Mechanistically, we found that RUNX3 regulates TOX2 transcription by binding to the active elements of its SE. Silencing TOX2 also impaired tumor formation of NKTL cells in vivo. Metastasis-associated phosphatase PRL-3 has been identified and validated as a key downstream effector of TOX2-mediated oncogenesis.

CONCLUSIONS

Our integrative SE profiling strategy revealed the landscape of SEs, novel targets and insights into molecular pathogenesis of NKTL. The RUNX3-TOX2-SE-TOX2-PRL-3 regulatory pathway may represent a hallmark of NKTL biology. Targeting TOX2 could be a valuable therapeutic intervene for NKTL patients and warrants further study in clinic.

The FACT-targeted drug CBL0137 enhances the effects of rituximab to inhibit B-cell non-Hodgkin's lymphoma tumor growth by promoting apoptosis and autophagy

BACKGROUND

Aggressive B-cell non-Hodgkin's lymphoma (B-NHL) patients often develop drug resistance and tumor recurrence after conventional immunochemotherapy, for which new treatments are needed.

METHODS

We investigated the antitumor effects of CBL0137. In vitro, cell proliferation was assessed by CCK-8 and colony formation assay. Flow cytometry was performed to analyze cell cycle progression, apoptosis, mitochondrial depolarization, and reactive oxygen species (ROS) production. Autophagy was detected by transmission electron microscopy and mGFP-RFP-LC3 assay, while western blotting was employed to detect proteins involved in apoptosis and autophagy. RNA-sequencing was conducted to analyze the transcription perturbation after CBL0137 treatment in B-NHL cell lines. Finally, the efficacy and safety of CBL0137, rituximab, and their combination were tested in vivo.

RESULTS

CBL0137, a small molecule anticancer agent that has significant antitumor effects in B-NHL. CBL0137 sequesters the FACT (facilitates chromatin transcription) complex from chromatin to produce cytotoxic effects in B-NHL cells. In addition, we discovered novel anticancer mechanisms of CBL0137. CBL0137 inhibited human B-NHL cell proliferation by inducing cell cycle arrest in S phase via the c-MYC/p53/p21 pathway. Furthermore, CBL0137 triggers ROS generation and induces apoptosis and autophagy in B-NHL cells through the ROS-mediated PI3K/Akt/mTOR and MAPK signaling pathways. Notably, a combination of CBL0137 and rituximab significantly suppressed B-NHL tumor growth in subcutaneous models, consistent with results at the cellular level in vitro.

CONCLUSIONS

CBL0137 has potential as a novel approach for aggressive B-NHL, and its combination with rituximab can provide new therapeutic options for patients with aggressive B-NHL. Video Abstract.

PRL3 as a therapeutic target for novel cancer immunotherapy in multiple cancer types

Phosphatase of Regenerating Liver-3 (PRL3) was discovered in 1998 and was subsequently found to be correlated with cancer progression and metastasis in 2001. Extensive research in the past two decades has produced significant findings on PRL3-mediated cancer signaling and functions, as well as its clinical relevance in diverse types of cancer. PRL3 has been established to play a role in many cancer-related functions, including but not limited to metastasis, proliferation, and angiogenesis. Importantly, the tumor-specific expression of PRL3 protein in multiple cancer types has made it an attractive therapeutic target. Much effort has been made in developing PRL3-targeted therapy with small chemical inhibitors against intracellular PRL3, and notably, the development of PRL3-zumab as a novel cancer immunotherapy against PRL3. In this review, we summarize the current understanding of the role of PRL3 in cancer-related cellular functions, its prognostic value, as well as perspectives on PRL3 as a target for unconventional immunotherapy in the clinic with PRL3-zumab.

Modeling leukemia with zebrafish (Danio rerio): Towards precision medicine

Leukemia is a type of blood cancer characterized by high genetic heterogeneity and fatality. While chemotherapy remains the primary form of treatment for leukemia, its effectiveness was profoundly diminished by the genetic heterogeneity and cytogenetic abnormalities of leukemic cells. Therefore, there is an unmet need to develop precision medicine for leukemia with distinct genetic backgrounds. Zebrafish (Danio rerio), a freshwater fish with exceptional feasibility in genome editing, is a powerful tool for rapid human cancer modeling. In the past decades, zebrafish have been adopted in modeling human leukemia, exploring the molecular mechanisms of underlying genetic abnormalities, and discovering novel therapeutic agents. Although many recurrent mutations of leukemia have been modeled in zebrafish for pathological study and drug discovery, its great potential in leukemia modeling was not yet fully exploited, particularly in precision medicine. In this review, we evaluated the current zebrafish models of leukemia/pre-leukemia and genetic techniques and discussed the potential of zebrafish models with novel techniques, which may contribute to the development of zebrafish as a disease model for precision medicine in treating leukemia.

Therapeutic targeting of LCK tyrosine kinase and mTOR signaling in T-cell acute lymphoblastic leukemia

Relapse and refractory T-cell acute lymphoblastic leukemia (T-ALL) has a poor prognosis, and new combination therapies are sorely needed. Here, we used an ex vivo high-throughput screening platform to identify drug combinations that kill zebrafish T-ALL and then validated top drug combinations for preclinical efficacy in human disease. This work uncovered potent drug synergies between AKT/mTORC1 (mammalian target of rapamycin complex 1) inhibitors and the general tyrosine kinase inhibitor dasatinib. Importantly, these same drug combinations effectively killed a subset of relapse and dexamethasone-resistant zebrafish T-ALL. Clinical trials are currently underway using the combination of mTORC1 inhibitor temsirolimus and dasatinib in other pediatric cancer indications, leading us to prioritize this therapy for preclinical testing. This combination effectively curbed T-ALL growth in human cell lines and primary human T-ALL and was well tolerated and effective in suppressing leukemia growth in patient-derived xenografts (PDX) grown in mice. Mechanistically, dasatinib inhibited phosphorylation and activation of the lymphocyte-specific protein tyrosine kinase (LCK) to blunt the T-cell receptor (TCR) signaling pathway, and when complexed with mTORC1 inhibition, induced potent T-ALL cell killing through reducing MCL-1 protein expression. In total, our work uncovered unexpected roles for the LCK kinase and its regulation of downstream TCR signaling in suppressing apoptosis and driving continued leukemia growth. Analysis of a wide array of primary human T-ALLs and PDXs grown in mice suggest that combination of temsirolimus and dasatinib treatment will be efficacious for a large fraction of human T-ALLs.

Proteomic profiling of plasma exosomes from patients with B-cell acute lymphoblastic leukemia

We aimed to comprehensively investigate the proteomic profile and underlying biological function of exosomal proteins associated with B-cell acute lymphoblastic leukemia. Exosomes were isolated from plasma samples collected from five patients with B-ALL and five healthy individuals, and their protein content was quantitatively analyzed by liquid chromatography with tandem mass spectrometry. A total of 342 differentially expressed proteins were identified in patients with B-ALL. The DEPs were mainly associated with protein metabolic processes and protein activity regulation and were significantly enriched in the Notch and autophagy pathways. Furthermore, we found that ADAM17 and ATG3 were upregulated in patients with B-ALL and enriched in the Notch and autophagy pathways, respectively. Further western blot analysis of exosomes collected from additional 18 patients with B-ALL and 10 healthy controls confirmed that both ADAM17 and ATG3 were overexpressed in exosomes derived from patients with B-ALL (p < 0.001). The areas under the curves of ADAM17 and ATG3 were 0.989 and 0.956, respectively, demonstrating their diagnostic potential. In conclusion, ADAM17 and ATG3 in plasma-derived exosomes may contribute to the progression of B-ALL by regulating the Notch and autophagy pathways. Hence, these proteins may represent valuable diagnostic biomarkers and therapeutic targets for B-ALL.

High-fat diet promotes colorectal carcinogenesis through SERCA2 mediated serine phosphorylation of Annexin A2

Colorectal cancer (CRC) is a highly common malignancy, being the third leading cause of cancer death worldwide. Recent epidemiological studies have indicated that carcinogenic effect of diet was mainly attributed to high-fat diets. To investigate the mechanism of high-fat diet-induced colorectal cancer, we systematically quantified the phosphoproteome in human HT-29 cells treated with sodium palmitate (PA). p-Annexin A2 (S26) was predicted to be specifically up-regulated by PA. We confirmed that PA-induced Annexin A2 phosphorylation at Ser26 in C57BL/6 J-Apc^Min/J mice fed with high-fat diet. Phosphorylation of Annexin A2 at Ser26 promotes PA-induced proliferation of HT-29 cells. Moreover, PA suppressed SERCA activity and SERCA2 expression was compensatorily increased. Mechanistically, SERCA2 can partially reverse Annexin A2 phosphorylation at Ser26 caused by PA through intracellular calcium release. Finally, SERCA2 knockdown inhibited high-fat diet-induced tumor growth and Annexin A2 phosphorylation at Ser26 in SCID mice. In all, our studies demonstrate that high-fat diet promotes colorectal carcinogenesis through SERCA2 mediated serine phosphorylation of Annexin A2.

Anti-leukemic effect and molecular mechanism of 11-methoxytabersonine from Melodinus cochinchinensis via network pharmacology, ROS-mediated mitochondrial dysfunction and PI3K/Akt signaling pathway

Melodinus cochinchinensis (Lour.) Merr. is a Yunnan endemic folk medicine. Our previous study showed that 11-methoxytabersonine (11-MT) isolated from M. cochinchinensis has strong cytotoxicity on human T-ALL cells, but its molecular mechanism has not been studied. In current study, the cytotoxicity and possible mechanism of 11-MT on T-cell acute lymphoblastic leukemia was explored using network pharmacology and molecular biology techniques. 11-MT significantly inhibited the cell proliferations on different four human T-ALL cells (MOLT-4, Jurkat, CCRF-CEM, and CEM/C1 cells). 11-MT triggered ROS accumulation, calcium concentration and cell apoptosis, and decreased the mitochondrial membrane potential (MMP) in human T-ALL cells, especially MOLT-4 cells. Western blot analysis showed that it can induce MOLT-4 cell apoptosis by up-regulating PI3K/Akt signaling pathway. Therefore, 11-MT induces human T-ALL cells apoptosis via up-regulation of ROS-mediated mitochondrial dysfunction and down-regulation of PI3K/Akt/mTOR signaling pathway.

Druggable cancer phosphatases

The phosphorylation status of oncoproteins is regulated by both kinases and phosphatases. Kinase inhibitors are rarely sufficient for successful cancer treatment, and phosphatases have been considered undruggable targets for cancer drug development. However, innovative pharmacological approaches for targeting phosphatases have recently emerged. Here, we review progress in the therapeutic targeting of oncogenic Src homology region 2 domain-containing phosphatase-2 (SHP2) and tumor suppressor protein phosphatase 2A (PP2A) and select other druggable oncogenic and tumor suppressor phosphatases. We describe the modes of action for currently available small molecules that target phosphatases, their use in drug combinations, and advances in clinical development toward future cancer therapies.

The depletion of Circ-PRKDC enhances autophagy and apoptosis in T-cell acute lymphoblastic leukemia via microRNA-653-5p/Reelin mediation of the PI3K/AKT/mTOR signaling pathway

A range of circular (Circ) RNAs have been demonstrated to be of therapeutic significance for the treatment of acute lymphoblastic leukemia (ALL). Here, we investigated the mechanisms underlying the action of Circ-PRKDC and the microRNA-653-5p/Reelin (miR-653-5p/RELN) axis in T-cell ALL (T-ALL).Clinical specimens were obtained from patients with T-ALL (n = 39) and healthy controls (n = 30). In each specimen, we determined the expression levels of Circ-PRKDC, miR-653-5p, and RELN. Human T-ALL cells (Jurkat) were transfected with Circ-PRKDC- or miR-653-5p-related sequences to investigate cell proliferation, apoptosis, and autophagy. We also determined the levels of Circ-PRKDC, miR-653-5p, RELN, and signaling proteins related to phosphoinositide 3-kinase (PI3K), AKT, and mammalian target of rapamycin (mTOR). Finally, we decoded the interactions between Circ-PRKDC, miR-653-5p, and RELN. The expression levels of Circ-PRKDC and RELN were upregulated in T-ALL tissues and cells while the levels of miR-653-5p were downregulated. Thereafter, then silencing of Circ-PRKDC, or the enforced expression of miR-653-5p, repressed the expression of RELN and the activation of the PI3K/AKT/mTOR signaling pathway, thus enhancing cell autophagy and apoptosis, and disrupting cell proliferation. Circ-PRKDC acted a sponge for miR-653-5p while miR-653-5p targeted RELN. The knockdown of miR-653-5p abrogated the silencing of Circ-PRKDC-induced effects in T-ALL cells. The depletion of Circ-PRKDC elevated miR-653-5p to silence RELN-mediated PI3K/AKT/mTOR signaling activation, thereby enhancing autophagy and apoptosis in T-ALL cells.