PIM2 kinase is induced by cisplatin in ovarian cancer cells and limits drug efficacy

Identifying hub genes for chemo-radiotherapy sensitivity in cervical cancer: a bi-dataset in silico analysis

PURPOSE

To identify the hub genes that associated with chemo-radiotherapy sensitivity for cervical cancer and to explore the relationship between hub genes and various cellular processes and potential mechanism of cervical cancer.

METHODS

The gene expression data of 21 patients with CESC and the mRNA expression profiles of 296 patients with CESC were obtained from the Gene Expression Omnibus(GEO) and The Cancer Genome Atlas (TCGA) databases, respectively. The potential functions and regulatory mechanisms of differentially expressed genes (DEGs) were identified using GO and KEGG enrichment analyses. Hub genes were identified using random survival forest analysis. The relationship between hub genes and various cellular processes was comprehensively analyzed. The expression of hub genes was assessed using clinical data extracted from the Human Protein Atlas (HPA) database.

RESULTS

A total of 139 and 13 DEGs were found to be upregulated and downregulated, respectively, in CESC. The six hub genes, namely, SELP, PIM2, CCL19, SDS, NRP1, and SF3A2, were significantly correlated with immune cell infiltration, chemotherapy sensitivity, disease-related genes, and enriched signaling pathways (all p-value < 0.05). A nomogram and calibration curve were generated using the six hub genes to predict prognosis with high accuracy. A regulatory network comprising TFs (ZBTB3) and mRNAs (NRP1/PIM2/SELP) and several competitive endogenous RNA (ceRNA) networks comprising mRNAs, miRNAs, and lncRNAs were constructed. Data from HPA indicated that the protein expression of the six hub genes differed significantly between patients with CESC and healthy individuals.

CONCLUSION

Upregulation of SELP, PIM2, CCL19, SDS, NRP1, and SF3A2 is associated with radiotherapy sensitivity and is involved in various cellular processes in CESC. These six genes may serve as biomarkers for predicting the radiotherapy response and prognosis in patients with CESC.

A review on structure-function mechanism and signaling pathway of serine/threonine protein PIM kinases as a therapeutic target

The proviral integration for the Moloney murine leukemia virus (PIM) kinases, belonging to serine/threonine kinase family, have been found to be overexpressed in various types of cancers, such as prostate, breast, colon, endometrial, gastric, and pancreatic cancer. The three isoforms PIM kinases i.e., PIM1, PIM2, and PIM3 share a high degree of sequence and structural similarity and phosphorylate substrates controlling tumorigenic phenotypes like proliferation and cell survival. Targeting short-lived PIM kinases presents an intriguing strategy as in vivo knock-down studies result in non-lethal phenotypes, indicating that clinical inhibition of PIM might have fewer adverse effects. The ATP binding site (hinge region) possesses distinctive attributes, which led to the development of novel small molecule scaffolds that target either one or all three PIM isoforms. Machine learning and structure-based approaches have been at the forefront of developing novel and effective chemical therapeutics against PIM in preclinical and clinical settings, and none have yet received approval for cancer treatment. The stability of PIM isoforms is maintained by PIM kinase activity, which leads to resistance against PIM inhibitors and chemotherapy; thus, to overcome such effects, PIM proteolysis targeting chimeras (PROTACs) are now being developed that specifically degrade PIM proteins. In this review, we recapitulate an overview of the oncogenic functions of PIM kinases, their structure, function, and crucial signaling network in different types of cancer, and the potential of pharmacological small-molecule inhibitors. Further, our comprehensive review also provides valuable insights for developing novel antitumor drugs that specifically target PIM kinases in the future. In conclusion, we provide insights into the benefits of degrading PIM kinases as opposed to blocking their catalytic activity to address the oncogenic potential of PIM kinases.

Mass spectrometry-based proteomic analysis to characterize cisplatin induced early signaling events in head and neck squamous cell carcinoma

Cisplatin is the commonly used chemotherapeutic drug in treatment of various cancers. However, development of resistance towards cisplatin results in tumor recurrence. Here, we aim to understand the mechanisms of action of cisplatin and emergence of resistance to cisplatin using mass spectrometry-based proteomic approach. A panel of head and neck squamous cell carcinoma (HNSCC) cell lines were treated with cisplatin at respective IC50 for 24 h and label-free mass spectrometry analysis was carried out. Proteomic analysis of A253, FaDu, Det562 and CAL27 cell lines upon cisplatin treatment resulted in the identification of 5,060, 4,816, 4,537 and 4,142 proteins, respectively. Bioinformatics analysis of differentially regulated proteins revealed proteins implicated in DNA damage bypass pathway, translation and mRNA splicing to be enriched. Further, proteins associated with cisplatin resistance exhibited alterations following short-term cisplatin exposure. Among these, class III tubullin protein (TUBB3) was found to be upregulated in cisplatin-treated cells compared to untreated cells. Western blot analysis confirmed the elevated expression of TUBB3 in cells treated with cisplatin for 24 h, and also in cisplatin resistant HNSCC cell lines. This study delineates the early signaling events that enable HNSCC cells to counteract the cytotoxic effects of cisplatin and facilitate the development of resistance.

Phase 1/2 Study of the Pan-PIM Kinase Inhibitor INCB053914 Alone or in Combination With Standard-of-Care Agents in Patients With Advanced Hematologic Malignancies

BACKGROUND

The Proviral Integration site of Moloney murine leukemia virus (PIM) kinases are implicated in tumorigenesis; the pan-PIM kinase inhibitor, INCB053914, demonstrated antitumor activity in hematologic malignancy preclinical models.

PATIENTS AND METHODS

This phase 1/2 study evaluated oral INCB053914 alone or combined with standard-of-care agents for advanced hematologic malignancies (NCT02587598). In Parts 1/2 (monotherapy), patients (≥18 years) had acute leukemia, high-risk myelodysplastic syndrome (MDS), MDS/myeloproliferative neoplasm, myelofibrosis (MF), multiple myeloma, or lymphoproliferative neoplasms. In Parts 3/4 (combination therapy), patients had relapsed/refractory or newly diagnosed (≥65 years, unfit for intensive chemotherapy) acute myeloid leukemia (AML) or MF with suboptimal ruxolitinib response.

RESULTS

Parts 1/2 (n = 58): 6 patients experienced dose-limiting toxicities (DLTs), most commonly aspartate aminotransferase/alanine aminotransferase-elevated (AST/ALT; each n = 4). Fifty-seven patients (98.3%) had treatment-emergent adverse events (TEAEs), most commonly ALT-elevated and fatigue (36.2% each); 48 (82.8%) had grade ≥3 TEAEs, most commonly anemia (31.0%); 8 (13.8%) had grade ≥3 ALT/AST-elevated TEAEs. Parts 3/4 (n = 39): for INCB053914 + cytarabine (AML; n = 6), 2 patients experienced DLTs (grade 3 maculopapular rash, n = 1; grade 3 ALT-elevated and grade 4 hypophosphatemia, n = 1); for INCB053914 + azacitidine (AML; n = 16), 1 patient experienced a DLT (grade 3 maculopapular rash). Two complete responses were observed (1 with incomplete count recovery). For INCB053914 + ruxolitinib (MF; n = 17), no DLTs occurred; 3 patients achieved best reduction of >25% spleen volume at week 12 or 24.

CONCLUSION

INCB053914 was generally well tolerated as monotherapy and in combinations; TEAEs were most commonly ALT/AST-elevated. Limited responses were observed with combinations. Future studies are needed to identify rational, effective combination strategies.

Phosphorylation of PFKFB4 by PIM2 promotes anaerobic glycolysis and cell proliferation in endometriosis

Endometriosis (EM) is one of the vanquished wonted causes of chronic pelvic sting in women and is closely associated with infertility. The long-term, complex, systemic, and post-treatment recurrence of EM wreaks havoc on women's quality of life. Extensive metabolic reprogramming (aerobic glycolysis, glucose overweening intake, and high lactate production) and cancer-like changes have been found in EM, which bears striking similarities to tumorigenesis. The key glycolysis regulator PFKFB4 is overexpressed in EM. However, the mechanism of PFKFB4 in EM remains unknown. We found that PFKFB4 was upregulated and was closely related to the progression of EM. We identified focus PIM2 as a new pioneering adjoin protein of PFKFB4. Vigorous biochemical methods were used to confirm that PIM2 phosphorylated site Thr140 of PFKFB4. PIM2 also could enhance PFKFB4 protein expression through the ubiquitin-proteasome pathway. Moreover, PIM2 expression was really corresponding prevalent with PFKFB4 in endometriosis in vivo. Importantly, phosphorylation of PFKFB4 on Thr140 by PIM2 promoted EM glycolysis and cell growth. Our study demonstrates that PIM2 mediates PFKFB4 Thr140 phosphorylation thus regulating glycolysis and EM progression. We illustrated a new mechanism that PIM2 simulated a central upstream partnership in the regulation of PFKFB4, and reveal a novel means of PIM2-PFKFB4 setting EM growth. Our research provided new theoretical support for further clarifying the reprogramming of EM glucose metabolism, and provided new clues for exploring non-contraceptive treatments for EM.

The Role of PIM Kinases in Pediatric Solid Tumors

PIM kinases have been identified as potential therapeutic targets in several malignancies. Here, we provide an in-depth review of PIM kinases, including their structure, expression, activity, regulation, and role in pediatric carcinogenesis. Also included is a brief summary of the currently available pharmaceutical agents targeting PIM kinases and existing clinical trials.

Co-Targeting PIM Kinase and PI3K/mTOR in NSCLC

Simple Summary

PIM kinases interact with major oncogenic players, including the PI3K/Akt pathway, and provide an escape mechanism leading to drug resistance. This study examined PIM kinase expression in NSCLC and the potential of PIM1 as a prognostic marker. The effect on cell signaling of novel preclinical PI3K/mTOR/PIM kinase inhibitor IBL-301 was compared to PI3K/mTOR inhibition in vitro and ex vivo. PI3K-mTOR inhibitor sensitive (H1975P) and resistant (H1975GR) cells were compared for altered IL6/STAT3 pathway expression and sensitivity to IBL-301. All three PIM kinases are expressed in NSCLC and PIM1 is a marker of poor prognosis. IBL-301 inhibited c-Myc, the PI3K-Akt and JAK/STAT pathways in vitro and in NSCLC tumor tissue explants. IBL-301 also inhibited secreted pro-inflammatory cytokine MCP-1. PIM kinases were activated in H1975GR cells which were more sensitive to IBL-301 than H1975P cells. A miRNA signature of PI3K-mTOR resistance was validated. Co-targeting PIM kinase and PI3K-mTOR warrants further clinical investigation.

Abstract

PIM kinases are constitutively active proto-oncogenic serine/threonine kinases that play a role in cell cycle progression, metabolism, inflammation and drug resistance. PIM kinases interact with and stabilize p53, c-Myc and parallel signaling pathway PI3K/Akt. This study evaluated PIM kinase expression in NSCLC and in response to PI3K/mTOR inhibition. It investigated a novel preclinical PI3K/mTOR/PIM inhibitor (IBL-301) in vitro and in patient-derived NSCLC tumor tissues. Western blot analysis confirmed PIM1, PIM2 and PIM3 are expressed in NSCLC cell lines and PIM1 is a marker of poor prognosis in patients with NSCLC. IBL-301 decreased PIM1, c-Myc, pBAD and p4EBP1 (Thr37/46) and peIF4B (S406) protein levels in-vitro and MAP kinase, PI3K-Akt and JAK/STAT pathways in tumor tissue explants. IBL-301 significantly decreased secreted pro-inflammatory cytokine MCP-1. Altered mRNA expression, including activated PIM kinase and c-Myc, was identified in Apitolisib resistant cells (H1975GR) by an IL-6/STAT3 pathway array and validated by Western blot. H1975GR cells were more sensitive to IBL-301 than parent cells. A miRNA array identified a dysregulated miRNA signature of PI3K/mTOR drug resistance consisting of regulators of PIM kinase and c-Myc (miR17-5p, miR19b-3p, miR20a-5p, miR15b-5p, miR203a, miR-206). Our data provides a rationale for co-targeting PIM kinase and PI3K-mTOR to improve therapeutic response in NSCLC.

Protein kinase PIM2: A simple PIM family kinase with complex functions in cancer metabolism and therapeutics

PIM2 (proviral integration site for Moloney murine leukemia virus 2) kinase plays an important role as an oncogene in multiple cancers, such as leukemia, liver, lung, myeloma, prostate and breast cancers. PIM2 is largely expressed in both leukemia and solid tumors, and it promotes the transcriptional activation of genes involved in cell survival, cell proliferation, and cell-cycle progression. Many tumorigenic signaling molecules have been identified as substrates for PIM2 kinase, and a variety of inhibitors have been developed for its kinase activity, including SMI-4a, SMI-16a, SGI-1776, JP11646 and DHPCC-9. Here, we summarize the signaling pathways involved in PIM2 kinase regulation and PIM2 mechanisms in various neoplastic diseases. We also discuss the current status and future perspectives for the development of PIM2 kinase inhibitors to combat human cancer, and PIM2 will become a therapeutic target in cancers in the future.

Phosphoproteomic strategies in cancer research: a minireview

Understanding the cellular processes is central to comprehend disease conditions and is also true for cancer research. Proteomic studies provide significant insight into cancer mechanisms and aid in the diagnosis and prognosis of the disease. Phosphoproteome is one of the most studied complements of the whole proteome given its importance in the understanding of cellular processes such as signaling and regulations. Over the last decade, several new methods have been developed for phosphoproteome analysis. A significant amount of these efforts pertains to cancer research. The current use of powerful analytical instruments in phosphoproteomic approaches has paved the way for deeper and sensitive investigations. However, these methods and techniques need further improvements to deal with challenges posed by the complexity of samples and scarcity of phosphoproteins in the whole proteome, throughput and reproducibility. This review aims to provide a comprehensive summary of the variety of steps used in phosphoproteomic methods applied in cancer research including the enrichment and fractionation strategies. This will allow researchers to evaluate and choose a better combination of steps for their phosphoproteome studies.

Fructose-1, 6-bisphosphatase 1 interacts with NF-κB p65 to regulate breast tumorigenesis via PIM2 induced phosphorylation

Rationale: Fructose-1, 6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis, was recently shown to be a tumor suppressor and could mediate the activities of multiple transcriptional factors via its non-canonical functions. However, the underlying mechanism of posttranscriptional modification on the non-canonical functions of FBP1 remains elusive.

Methods: We employed immunoaffinity purification to identify binding partner(s) and used co-immunoprecipitation to verify their interactions. Kinase reaction was used to confirm PIM2 could phosphorylate FBP1. Overexpression or knockdown proteins were used to assess the role in modulating p65 protein stability. Mechanistic analysis was involved in protein degradation and polyubiquitination assays. Nude mice and PIM2-knockout mice was used to study protein functions in vitro and in vivo.

Results: Here, we identified Proviral Insertion in Murine Lymphomas 2 (PIM2) as a new binding partner of FBP1, which could phosphorylate FBP1 on Ser144. Surprisingly, phosphorylated FBP1 Ser144 abrogated its interaction with NF-κB p65, promoting its protein stability through the CHIP-mediated proteasome pathway. Furthermore, phosphorylation of FBP1 on Ser144 increased p65 regulated PD-L1 expression. As a result, phosphorylation of FBP1 on Ser144 promoted breast tumor growth in vitro and in vivo. Moreover, the levels of PIM2 and pSer144-FBP1 proteins were positively correlated with each other in human breast cancer and PIM2 knockout mice.

Conclusions: Our findings revealed that phosphorylation noncanonical FBP1 by PIM2 was a novel regulator of NF-κB pathway, and highlights PIM2 inhibitors as breast cancer therapeutics.

PIM2 promotes hepatocellular carcinoma tumorigenesis and progression through activating NF-κB signaling pathway

Inflammatory factors and activation of oncogenes both played critical roles in the development and progression of human hepatocellular carcinoma (HCC). However, the interplay between these two has not been well studied. In this study, we found that regulated by TNFα, Pim-2 proto-oncogene, serine/threonine kinase (PIM2) was highly expressed in HCC and correlated with poor prognosis (P = 0.007) as well as tumor recurrence (P = 0.014). Functional studies showed that PIM2 could enhance abilities of cell proliferation, cell motility, angiogenesis, chemo-resistance, and in vivo tumorigenicity and HCC metastasis. Mechanistic studies revealed that PIM2 could activate NF-κB signaling pathway through upregulating phosphorylation level of RIPK2. Interestingly, TNFα treatment could induce the expression of PIM2, and overexpression of PIM2 could in turn upregulate the expression of TNFα in HCC cells. More importantly, we found the expression level of PIM2 increased with the progression of liver cirrhosis, and PIM kinase inhibitor AZD1208 treatment could effectively attenuate HCC cells’ tumorigenic ability both in vitro and in vivo. Collectively, our study revealed the interaction between an inflammatory factor and a proto-oncogene that contributed to tumorigenesis and progression of HCC, and PIM kinase inhibition may serve as a therapeutic target in the treatment of HCC.

Preclinical evaluation of a novel triple-acting PIM/PI3K/mTOR inhibitor, IBL-302, in breast cancer

The proviral integration of Moloney virus (PIM) family of protein kinases are overexpressed in many haematological and solid tumours. PIM kinase expression is elevated in PI3K inhibitor-treated breast cancer samples, suggesting a major resistance pathway for PI3K inhibitors in breast cancer, potentially limiting their clinical utility. IBL-302 is a novel molecule that inhibits both PIM and PI3K/AKT/mTOR signalling. We thus evaluated the preclinical activity of IBL-302, in a range of breast cancer models. Our results demonstrate in vitro efficacy of IBL-302 in a range of breast cancer cell lines, including lines with acquired resistance to trastuzumab and lapatinib. IBL-302 demonstrated single-agent, anti-tumour efficacy in suppression of pAKT, pmTOR and pBAD in the SKBR-3, BT-474 and HCC-1954 HER2+/PIK3CA-mutated cell lines. We have also shown the in vivo single-agent efficacy of IBL-302 in the subcutaneous BT-474 and HCC-1954 xenograft model in BALB/c nude mice. The combination of trastuzumab and IBL-302 significantly increased the anti-proliferative effect in HER2+ breast cancer cell line, and matched trastuzumab-resistant line, relative to testing either drug alone. We thus believe that the novel PIM and PI3K/mTOR inhibitor, IBL-302, represents an exciting new potential treatment option for breast cancer, and that it should be considered for clinical investigation.

Current perspectives on targeting PIM kinases to overcome mechanisms of drug resistance and immune evasion in cancer

PIM kinases are a class of serine/threonine kinases that play a role in several of the hallmarks of cancer including cell cycle progression, metabolism, inflammation and immune evasion. Their constitutively active nature and unique catalytic structure has led them to be an attractive anticancer target through the use of small molecule inhibitors. This review highlights the enhanced activity of PIM kinases in cancer that can be driven by hypoxia in the tumour microenvironment and the important role that aberrant PIM kinase activity plays in resistance mechanisms to chemotherapy, radiotherapy, anti-angiogenic therapies and targeted therapies. We highlight an interaction of PIM kinases with numerous major oncogenic players, including but not limited to, stabilisation of p53, synergism with c-Myc, and notable parallel signalling with PI3K/Akt. We provide a comprehensive overview of PIM kinase's role as an escape mechanism to targeted therapies including PI3K/mTOR inhibitors, MET inhibitors, anti-HER2/EGFR treatments and the immunosuppressant rapamycin, providing a rationale for co-targeting treatment strategies for a more durable patient response. The current status of PIM kinase inhibitors and their use as a combination therapy with other targeted agents, in addition to the development of novel multi-molecularly targeted single therapeutic agents containing a PIM kinase targeting moiety are discussed.

Inhibition of PIM2 in liver cancer decreases tumor cell proliferation in vitro and in vivo primarily through the modulation of cell cycle progression

Liver cancer is the fourth leading cause of cancer-related mortality worldwide with limited therapeutic options. Thus, novel treatment strategies are urgently required. While the oncogenic kinase, proviral integration site for Moloney murine leukemia virus 2 (PIM2), has been shown to be overexpressed in liver cancer, little is known about the role of PIM2 in this tumor entity. In this study, we explored the functional relevance and therapeutic potential of PIM2 in liver cancer. Using PIM2-specific siRNAs, we examined the effects of PIM2 knockdown on proliferation (WST-1 assays and spheroid assays), 3D-colony formation and colony spread, apoptosis (flow cytometry and caspase 3/caspase 7 activity), as well as cell cycle progression (flow cytometry, RT-qPCR and western blot analysis) in the two liver cancer cell lines, HepG2 and Huh-7. In subcutaneous liver cancer xenografts, we assessed the effects of PIM2 knockdown on tumor growth via the systemic delivery of polyethylenimine (PEI)-complexed siRNA. The knockdown of PIM2 resulted in potent anti-proliferative effects in cells grown on plastic dishes, as well as in spheroids. This was due to G0/G1 cell cycle blockade and the subsequent downregulation of genes related to the S phase as well as the G2/M phase of the cell cycle, whereas the apoptotic rates remained unaltered. Furthermore, colony formation and colony spread were markedly inhibited by PIM2 knockdown. Notably, we found that HepG2 cells were more sensitive to PIM2 knockdown than the Huh-7 cells. In vivo, the therapeutic nanoparticle-mediated delivery of PIM2 siRNA led to profound anti-tumor effects in a liver cancer xenograft mouse model. On the whole, the findings of this study underscore the oncogenic role of PIM2 and emphasize the potential of targeted therapies based on the specific inhibition of PIM2 in liver cancer.

Phosphorylation of HSF1 by PIM2 Induces PD-L1 Expression and Promotes Tumor Growth in Breast Cancer

Heat shock transcription factor 1 (HSF1) is the master regulator of the proteotoxic stress response, which plays a key role in breast cancer tumorigenesis. However, the mechanisms underlying regulation of HSF1 protein stability are still unclear. Here, we show that HSF1 protein stability is regulated by PIM2-mediated phosphorylation of HSF1 at Thr120, which disrupts the binding of HSF1 to the E3 ubiquitin ligase FBXW7. In addition, HSF1 Thr120 phosphorylation promoted proteostasis and carboplatin-induced autophagy. Interestingly, HSF1 Thr120 phosphorylation induced HSF1 binding to the PD-L1 promoter and enhanced PD-L1 expression. Furthermore, HSF1 Thr120 phosphorylation promoted breast cancer tumorigenesis in vitro and in vivo. PIM2, pThr120-HSF1, and PD-L1 expression positively correlated with each other in breast cancer tissues. Collectively, these findings identify PIM2-mediated HSF1 phosphorylation at Thr120 as an essential mechanism that regulates breast tumor growth and potential therapeutic target for breast cancer. SIGNIFICANCE: These findings identify heat shock transcription factor 1 as a new substrate for PIM2 kinase and establish its role in breast tumor progression.

Discovery of a small-molecule inhibitor of specific serine residue BAD phosphorylation

Human BCL-2-associated death promoter (hBAD) is an apoptosis-regulatory protein mediating survival signals to carcinoma cells upon phosphorylation of Ser99, among other residues. Herein, we screened multiple small-molecule databases queried in a Laplacian-modified naive Bayesian-based cheminformatics platform and identified a Petasis reaction product as a site-specific inhibitor for hBAD phosphorylation. Based on apoptotic efficacy against mammary carcinoma cells, N-cyclopentyl-3-((4-(2,3-dichlorophenyl) piperazin-1-yl) (2-hydroxyphenyl) methyl) benzamide (NPB) was identified as a potential lead compound. In vitro biochemical analyses demonstrated that NPB inhibited the phosphorylation of hBAD specifically on Ser99. NPB was observed to exert this effect independently of AKT and other kinase activities despite the demonstration of AKT-mediated BAD-Ser99 phosphorylation. Using a structure-based bioinformatics platform, we observed that NPB exhibited predicted interactions with hBAD in silico and verified the same by direct binding kinetics. NPB reduced phosphorylation of BAD-Ser99 and enhanced caspase 3/7 activity with associated loss of cell viability in various human cancer cell lines derived from mammary, endometrial, ovarian, hepatocellular, colon, prostatic, and pancreatic carcinoma. Furthermore, by use of a xenograft model, it was observed that NPB, as a single agent, markedly diminished BAD phosphorylation in tumor tissue and significantly inhibited tumor growth. Similar doses of NPB utilized in acute toxicity studies in mice did not exhibit significant effects. Hence, we report a site-specific inhibitor of BAD phosphorylation with efficacy in tumor models.

PIM2 survival kinase is upregulated in a p53-dependent manner in cells treated with camptothecin or co-treated with actinomycin D and nutlin-3a

The p53 protein is an inducer of apoptosis, acting as a transcriptional regulator of apoptotic genes. In a previous study, we found that actinomycin D and nutlin-3a (A + N) synergistically activate p53. To better understand the molecular consequences of this synergism, we incubated arrays of antibodies against apoptotic proteins with extracts of A549 cells in which p53 had been activated. We found that strong activation of p53, marked by serine 46 and 392 phosphorylation, was associated with inactivating phosphorylation of proapoptotic BAD protein on serine 136. Investigation of the source of this phosphorylation revealed that activation of p53 was associated with accumulation of PIM2, a survival kinase. The accumulation of PIM2 following treatment with A + N was suppressed in p53-knockdown cells. Others discovered that PIM2 was activated by cooperatively acting p53 molecules. Our results are consistent with this finding. Moreover, we found that in A549 cells, the treatment with A + N stimulated in p53-dependent fashion the expression of other high cooperativity p53 target genes, DRAXIN and H19. Activation of antiapoptotic H19 can mechanistically explain relatively low rate of apoptosis of A549 cells exposed to A + N. We conclude that PIM2, DRAXIN and H19 are efficiently stimulated by strongly activated p53 molecules, probably acting cooperatively.

Preclinical characterization of INCB053914, a novel pan-PIM kinase inhibitor, alone and in combination with anticancer agents, in models of hematologic malignancies

The Proviral Integration site of Moloney murine leukemia virus (PIM) serine/threonine protein kinases are overexpressed in many hematologic and solid tumor malignancies and play central roles in intracellular signaling networks important in tumorigenesis, including the Janus kinase-signal transducer and activator of transcription (JAK/STAT) and phosphatidylinositol 3-kinase (PI3K)/AKT pathways. The three PIM kinase isozymes (PIM1, PIM2, and PIM3) share similar downstream substrates with other key oncogenic kinases and have differing but mutually compensatory functions across tumors. This supports the therapeutic potential of pan-PIM kinase inhibitors, especially in combination with other anticancer agents chosen based on their role in overlapping signaling networks. Reported here is a preclinical characterization of INCB053914, a novel, potent, and selective adenosine triphosphate-competitive pan-PIM kinase inhibitor. In vitro, INCB053914 inhibited proliferation and the phosphorylation of downstream substrates in cell lines from multiple hematologic malignancies. Effects were confirmed in primary bone marrow blasts from patients with acute myeloid leukemia treated ex vivo and in blood samples from patients receiving INCB053914 in an ongoing phase 1 dose-escalation study. In vivo, single-agent INCB053914 inhibited Bcl-2-associated death promoter protein phosphorylation and dose-dependently inhibited tumor growth in acute myeloid leukemia and multiple myeloma xenografts. Additive or synergistic inhibition of tumor growth was observed when INCB053914 was combined with selective PI3Kδ inhibition, selective JAK1 or JAK1/2 inhibition, or cytarabine. Based on these data, pan-PIM kinase inhibitors, including INCB053914, may have therapeutic utility in hematologic malignancies when combined with other inhibitors of oncogenic kinases or standard chemotherapeutics.

PIM Kinases and Their Relevance to the PI3K/AKT/mTOR Pathway in the Regulation of Ovarian Cancer

Ovarian cancer is a medical term that includes a number of tumors with different molecular biology, phenotypes, tumor progression, etiology, and even different diagnosis. Some specific treatments are required to address this heterogeneity of ovarian cancer, thus molecular characterization may provide an important tool for this purpose. On a molecular level, proviral-integration site for Moloney-murine leukemia virus (PIM) kinases are over expressed in ovarian cancer and play a vital role in the regulation of different proteins responsible for this tumorigenesis. Likewise, the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is also a central regulator of the ovarian cancer. Interestingly, recent research has linked the PIM kinases to the PI3K/AKT/mTOR pathway in several types of cancers, but their connection in ovarian cancer has not been studied yet. Once the exact relationship of PIM kinases with the PI3K/AKT/mTOR pathway is acquired in ovarian cancer, it will hopefully provide effective treatments on a molecular level. This review mainly focuses on the role of PIM kinases in ovarian cancer and their interactions with proteins involved in its progression. In addition, this review suggests a connection between the PIM kinases and the PI3K/AKT/mTOR pathway and their parallel mechanism in the regulation of ovarian cancer.

PIM activity in tumours: A key node of therapy resistance

The PIM kinases are proto-oncogenes which have been shown to facilitate cell survival and proliferation to drive malignancy and resistance post-therapy. They are able to suppress cell death signals, sustain PI3K/AKT/mTORC1 pathway activity and regulate the MYC oncogenic program. Recent work has revealed PIM kinase essentiality for advanced tumour maintenance and described tumour sensitivity to small molecule inhibitors targeting PIM kinase in multiple malignancies.

Facile total synthesis of lysicamine and the anticancer activities of the RuII, RhIII, MnII and ZnII complexes of lysicamine

Lysicamine is a natural oxoaporphine alkaloid, which isolated from traditional Chinese medicine (TCM) herbs and has been shown to possess cytotoxicity to hepatocarcinoma cell lines. Reports on its antitumor activity are scarce because lysicamine occurs in plants at a low content. In this work, we demonstrate a facile concise total synthesis of lysicamine from simple raw materials under mild reaction conditions, and the preparation of the Ru(II), Rh(III), Mn(II) and Zn(II) complexes 1–4 of lysicamine (LY). All the compounds were fully characterized by elemental analysis, IR, ESI-MS, ¹H and ¹³C NMR, as well as single-crystal X-ray diffraction analysis. Compared with the free ligand LY, complexes 2 and 3 exhibited superior in vitro cytotoxicity against HepG2 and NCI-H460. Mechanistic studies indicated that 2 and 3 blocked the cell cycle in the S phase by decreasing of cyclins A2/B1/D1/E1, CDK 2/6, and PCNA levels and increasing levels of p21, p27, p53 and CDC25A proteins. In addition, 2 and 3 induced cell apoptosis via both the caspase-dependent mitochondrial pathway and the death receptor pathway. in vivo study showed that 2 inhibited HepG2 tumor growth at 1/3 maximum tolerated dose (MTD) and had a better safety profile than cisplatin.

PIM kinases 1, 2 and 3 in intracellular LIF signaling, proliferation and apoptosis in trophoblastic cells

Proviral insertion in murine (PIM) lymphoma proteins are mainly regulated by the Janus Kinase/Signal Transducer Activator of Transcription (JAK/STAT) signaling pathway, which can be activated by members of the Interleukin-6 (IL-6) family, including Leukemia Inhibitory Factor (LIF). Aim of the study was to compare PIM1, PIM2 and PIM3 expression and potential cellular functions in human first and third trimester trophoblast cells, the immortalized first trimester extravillous trophoblast cell line HTR8/SVneo and the choriocarcinoma cell line JEG-3. Expression was analyzed by qPCR and immunochemical staining. Functions were evaluated by PIM inhibition followed by analysis of kinetics of cell viability as assessed by MTS assay, proliferation by BrdU assay, and apoptosis by Western blotting for BAD, BCL-XL, (cleaved) PARP, CASP3 and c-MYC. Apoptosis and necrosis were tested by flow cytometry (annexin V/propidium iodide staining). All analyzed PIM kinases are expressed in primary trophoblast cells and both cell lines and are regulated upon stimulation with LIF. Inhibition of PIM kinases significantly reduces viability and proliferation and induces apoptosis. Simultaneously, phosphorylation of c-MYC was reduced. These results demonstrate the involvement of PIM kinases in LIF-induced regulation in different trophoblastic cell lines which may indicate similar functions in primary cells.

Oridonin effectively reverses cisplatin drug resistance in human ovarian cancer cells via induction of cell apoptosis and inhibition of matrix metalloproteinase expression

Cisplatin is a first generation platinum‑based chemotherapeutic agent, however, the extensive application of cisplatin inevitably results in drug resistance, which is a major obstacle in cancer chemotherapy. The aim of the present study was to investigate the efficiency of reversing cisplatin‑resistance with the use of combination therapy with oridonin and cisplatin in human ovarian cancer cells, and attempt to reduce the side effects of the therapeutic agents when used alone. The half maximal inhibitory concentration (IC50) values of cisplatin were determined in cisplatin‑sensitive and cisplatin‑resistant ovarian cancer cells using an MTT assay. IC50 values of cisplatin in A2780, A2780/DDP, SKOV3 and SKOV3/DDP cells were significantly decreased in a time‑dependent manner. The antitumor effect of oridonin in A2780/DDP cells was also detected by the MTT assay and the inhibitory effects of oridonin increased in a dose‑ and time‑dependent manner. A2780/DDP cells were treated with 20 µM oridonin in combination with increasing concentrations of cisplatin for 48 h, and the result demonstrated that oridonin synergistically increased the antitumor effects of cisplatin in A2780/DDP cells. Notably, the combination treatment of oridonin and cisplatin effectively reversed cisplatin resistance and the IC50 values were significantly decreased from 50.97 µM and 135.20 to 26.12 µM and 73.00 µM in A2780/DDP and SKOV3/DDP cells at 48 h, respectively. Furthermore, oridonin induced cell apoptosis in a dose‑dependent manner and promoted cell‑cycle arrest at the G0/G1 phase in ovarian cancer cells. Oridonin and cisplatin synergistically increased the cell apoptosis rate of A2780/DDP cells, which was detected by fluorescence‑activated cell sorting analysis. Downregulated expression levels of Bcl‑2 and upregulated the expression of Bax protein were demonstrated by western blot analysis, further indicating increased apoptosis. In addition, the expression levels of matrix metalloproteinase (MMP)‑2 and MMP‑9 decreased in a dose‑dependent manner with oridonin treatment. The results from the present study demonstrated that oridonin exerted a synergistic effect with cisplatin to inhibit proliferation and induce cell apoptosis in cisplatin‑resistant ovarian cancer cells. Thus, combination therapy with oridonin and cisplatin effectively reversed cisplatin resistance in human ovarian cancer cells, which may have useful clinical applications.