Assignment of the human homologue of Pim-1, a mouse gene implicated in leukemogenesis, to the pter-q12 region of chromosome 6

Role of PIM Kinase Inhibitor in the Treatment of Alzheimer's Disease

Alzheimer's disease (AD), a neurodegenerative disorder, is the most prevalent form of senile dementia, causing progressive deterioration of cognition, behavior, and rational skills. Neuropathologically, AD is characterized by two hallmark proteinaceous aggregates: amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs) formed of hyperphosphorylated tau. A significant study has been done to understand how Aβ and/or tau accumulation can alter signaling pathways that affect neuronal function. A conserved protein kinase known as the mammalian target of rapamycin (mTOR) is essential for maintaining the proper balance between protein synthesis and degradation. Overwhelming evidence shows mTOR signaling's primary role in age-dependent cognitive decline and the pathogenesis of AD. Postmortem human AD brains consistently show an upregulation of mTOR signaling. Confocal microscopy findings demonstrated a direct connection between mTOR and intraneuronal Aβ42 through molecular processes of PRAS40 phosphorylation. By attaching to the mTORC1 complex, PRAS40 inhibits the activity of mTOR. Furthermore, inhibiting PRAS40 phosphorylation can stop the Aβ-mediated increase in mTOR activity, indicating that the accumulation of Aβ may aid in PRAS40 phosphorylation. Physiologically, PRAS40 is phosphorylated by PIM1 which is a serine/threonine kinase of proto-oncogene PIM kinase family. Pharmacological inhibition of PIM1 activity prevents the Aβ-induced mTOR hyperactivity in vivo by blocking PRAS40 phosphorylation and restores cognitive impairments by enhancing proteasome function. Recently identified small-molecule PIM1 inhibitors have been developed as potential therapeutic to reduce AD-neuropathology. This comprehensive study aims to address the activity of PIM1 inhibitor that has been tested for the treatment of AD, in addition to the pharmacological and structural aspects of PIM1.

Therapeutic targeting of PIM KINASE signaling in cancer therapy: Structural and clinical prospects

BACKGROUND

PIM kinases are well-studied drug targets for cancer, belonging to Serine/Threonine kinases family. They are the downstream target of various signaling pathways, and their up/down-regulation affects various physiological processes. PIM family comprises three isoforms, namely, PIM-1, PIM-2, and PIM-3, on alternative initiation of translation and they have different levels of expression in different types of cancers. Its structure shows a unique ATP-binding site in the hinge region which makes it unique among other kinases.

SCOPE OF REVIEW

PIM kinases are widely reported in hematological malignancies along with prostate and breast cancers. Currently, many drugs are used as inhibitors of PIM kinases. In this review, we highlighted the physiological significance of PIM kinases in the context of disease progression and therapeutic targeting. We comprehensively reviewed the PIM kinases in terms of their expression and regulation of different physiological roles. We further predicted functional partners of PIM kinases to elucidate their role in the cellular physiology of different cancer and mapped their interaction network.

MAJOR CONCLUSIONS

A deeper mechanistic insight into the PIM signaling involved in regulating different cellular processes, including transcription, apoptosis, cell cycle regulation, cell proliferation, cell migration and senescence, is provided. Furthermore, structural features of PIM have been dissected to understand the mechanism of inhibition and subsequent implication of designed inhibitors towards therapeutic management of prostate, breast and other cancers.

GENERAL SIGNIFICANCE

Being a potential drug target for cancer therapy, available drugs and PIM inhibitors at different stages of clinical trials are discussed in detail.

Synthesis of new substituted pyridine derivatives as potent anti-liver cancer agents through apoptosis induction: In vitro, in vivo, and in silico integrated approaches

Liver cancer is the most common type of cancer in many countries. New studies and statistics show rising liver cancer worldwide, so it is essential to seek new agents for this type of cancer. PIM1 has an attractive target in the discovery of cancer medications as it is very much expressed in a variety of malignancies and influences such as tumorigenesis, cell cycle progression, cellular proliferation, apoptosis, and cell migration. Accordingly, a series of pyridones and pyridine-amides were synthesized and tested for anti-liver cancer activity. In the synthetic strategy 4,6-diaryl-3-cyano-2-pyridones 3a-n were synthesized using one-pot four component synthetic method. Structural modifications were done on 4,6-diphenyl-3-cayno-2-pyridone 3a to enhance the activity. Alkylation in the presence of K₂CO₃ afforded the O-alkylated products 4-6. The acetoxy hydrazide 7 was synthesized and cyclized into 1,3,4-oxadiazolethione 8 which alkylated on sulfur to give 10. Azide-coupling method was used to couple the 2-(pyridin-2-yloxy)acetohydrazide 7 to different amines and amino acid esters to furnish the products 12a-e and 13a-b. The synthesized derivatives were subjected to cytotoxic screening against HepG2 and THLE-2 cells, Compounds 10, 12e and 13a have a remarkable cytotoxic activity with IC₅₀ values (10.7-13.9 µM). Compound 7 was found to be more cytotoxic by showing the lowest IC₅₀ value of 7.26 compared to 5-FU (IC₅₀ = 6.98 µM). It inhibited cell growth by 76.76%. Additionally, it significantly stimulated apoptotic liver cancer cell death with 49.78-fold (22.90% compared to 0.46% for the control) arresting cell cycle Pre-G1 with 35.16% of a cell population, compared to 1.57% for the control. Moreover, it validated the intrinsic apoptosis through upregulation of P53, and other related genes, with inhibition of anti-apoptotic genes through PIM-1 inhibition.

Biochemical changes of salivary gland adenoid cystic carcinoma cells induced by SGI-1776

Provirus integration site for Moloney murine leukemia virus 1 (Pim-1) has proved to be an oncogene and it is known that to depress Pim-1 activity may be a novel oncological treatment strategy. SGI-1776, a small molecule, is the first clinically tested inhibitor of the Pim kinase family. Here, we aimed to explore the effect of SGI-1776 on salivary adenoid cystic carcinoma (SACC). Expression of Pim-1 was confirmed in SACC and control tissues by qRT-PCR. After SGI-1776 treatment, the Pim-1 expressions and Pim-1 kinase activity in both SACC-83 and SACC-LM cell lines were measured. Cell proliferation, cell invasion, cell cycle, apoptosis and mitochondrial membrane potential were analyzed. Also, the expression of FOXO3a, p-FOXO3a, RUNX3, Bcl-2, BAD, p-BAD, Bim and p-Bim were detected by Western blot. The results showed that Pim-1 was significantly overexpressed in SACC tissues. SGI-1776 down-regulated the Pim-1 expression, inhibited Pim-1 kinase activity, reduced cell proliferation, decreased invasive ability, increased caspase-3 activity and induced apoptosis, cell cycle arrest and mitochondrial depolarization. Reduced expression was also seen in p-FOXO3a, RUNX3, Bcl-2, p-BAD and p-Bim, whereas no significant changes were observed from FOXO3a, BAD and Bim. These results confirm the pivotal role of Pim-1 in SACC and suggest that targeting Pim-1 kinase signal pathway by SGI-1776 might be a promising therapeutic modality for SACC.

PIM kinase (and Akt) biology and signaling in tumors

The initiation and progression of human cancer is frequently linked to the uncontrolled activation of survival kinases. Two such pro-survival kinases that are commonly amplified in cancer are PIM and Akt. These oncogenic proteins are serine/threonine kinases that regulate tumorigenesis by phosphorylating substrates that control the cell cycle, cellular metabolism, proliferation, and survival. Growing evidence suggests that cross-talk exists between the PIM and Akt kinases, indicating that they control partially overlapping survival signaling pathways that are critical to the initiation, progression, and metastatic spread of many types of cancer. The PI3K/Akt signaling pathway is activated in many human tumors, and it is well established as a promising anticancer target. Likewise, based on the role of PIM kinases in normal and tumor tissues, it is clear that this family of kinases represents an interesting target for anticancer therapy. Pharmacological inhibition of PIM has the potential to significantly influence the efficacy of standard and targeted therapies. This review focuses on the regulation of PIM kinases, their role in tumorigenesis, and the biological impact of their interaction with the Akt signaling pathway on the efficacy of cancer therapy.

Pim kinases in hematological malignancies: where are we now and where are we going?

The proviral insertion in murine (PIM) lymphoma proteins are a serine/threonine kinase family composed of three isoformes: Pim-1, Pim-2 and Pim-3. They play a critical role in the control of cell proliferation, survival, homing and migration. Recently, overexpression of Pim kinases has been reported in human tumors, mainly in hematologic malignancies. In vitro and in vivo studies have confirmed their oncogenic potential. Indeed, PIM kinases have shown to be involved in tumorgenesis, to enhance tumor growth and to induce chemo-resistance, which is why they have become an attractive therapeutic target for cancer therapy. Novel molecules inhibiting Pim kinases have been evaluated in preclinical studies, demonstrating to be effective and with a favorable toxicity profile. Given the promising results, some of these compounds are currently under investigation in clinical trials. Herein, we provide an overview of the biological activity of PIM-kinases, their role in hematologic malignancies and future therapeutic opportunities.

The PIM family of serine/threonine kinases in cancer

The proviral insertion site in Moloney murine leukemia virus, or PIM proteins, are a family of serine/threonine kinases composed of three different isoforms (PIM1, PIM2, and PIM3) that are highly evolutionarily conserved. These proteins are regulated primarily by transcription and stability through pathways that are controlled by Janus kinase/Signal transducer and activator of transcription, JAK/STAT, transcription factors. The PIM family proteins have been found to be overexpressed in hematological malignancies and solid tumors, and their roles in these tumors were confirmed in mouse tumor models. Furthermore, the PIM family proteins have been implicated in the regulation of apoptosis, metabolism, cell cycle, and homing and migration, which has led to the postulation of these proteins as interesting targets for anticancer drug discovery. In the present work, we review the importance of PIM kinases in tumor growth and as drug targets.

Conditional transgenic expression of PIM1 kinase in prostate induces inflammation-dependent neoplasia

The Pim proteins are a family of highly homologous protein serine/threonine kinases that have been found to be overexpressed in cancer. Elevated levels of Pim1 kinase were first discovered in human leukemia and lymphomas. However, more recently Pim1 was found to be increased in solid tumors, including pancreatic and prostate cancers, and has been proposed as a prognostic marker. Although the Pim kinases have been identified as oncogenes in transgenic models, they have weak transforming abilities on their own. However, they have been shown to greatly enhance the ability of other genes or chemical carcinogens to induce tumors. To explore the role of Pim1 in prostate cancer, we generated conditional Pim1 transgenic mice, expressed Pim1 in prostate epithelium, and analyzed the contribution of PIM1 to neoplastic initiation and progression. Accordingly, we explored the effect of PIM1 overexpression in 3 different settings: upon hormone treatment, during aging, and in combination with the absence of one Pten allele. We have found that Pim1 overexpression increased the severity of mouse prostate intraepithelial neoplasias (mPIN) moderately in all three settings. Furthermore, Pim1 overexpression, in combination with the hormone treatment, increased inflammation surrounding target tissues leading to pyelonephritis in transgenic animals. Analysis of senescence induced in these prostatic lesions showed that the lesions induced in the presence of inflammation exhibited different behavior than those induced in the absence of inflammation. While high grade prostate preneoplastic lesions, mPIN grades III and IV, in the presence of inflammation did not show any senescence markers and demonstrated high levels of Ki67 staining, untreated animals without inflammation showed senescence markers and had low levels of Ki67 staining in similar high grade lesions. Our data suggest that Pim1 might contribute to progression rather than initiation in prostate neoplasia.

Pim kinases in cancer: diagnostic, prognostic and treatment opportunities

PIM proteins belong to a family of ser/thr kinases composed of 3 members, PIM1, PIM2 and PIM3, with greatly overlapping functions. PIM kinases are mainly responsible for cell cycle regulation, antiapoptotic activity and the homing and migration of receptor tyrosine kinases mediated via the JAK/STAT pathway. PIM kinases have been found to be upregulated in many hematological malignancies and solid tumors. Although these kinases have been described as weak oncogenes, they are heavily targeted for anticancer drug discovery. The present review summarizes the discoveries made to date regarding PIM kinases as driving oncogenes in the process of tumorigenesis and their validation as drug targets.

Hypoxia-mediated up-regulation of Pim-1 contributes to solid tumor formation

Tumor hypoxia directly promotes genomic instability and facilitates cell survival, resulting in tumors with a more aggressive phenotype. The proto-oncogene pim-1 regulates apoptosis and the cell cycle by phosphorylating target proteins. Overexpression of Pim-1 can cause genomic instability and contribute to lymphomagenesis. It is not clear whether Pim-1 is involved in hypoxia-mediated tumor survival in solid tumors. Here, we show that hypoxia can stabilize Pim-1 by preventing its ubiquitin-mediated proteasomal degradation and can cause Pim-1 translocation from the cytoplasm to the nucleus. Importantly, overexpression of Pim-1 increases NIH3T3 cell transformation exclusively under hypoxic conditions, suggesting that Pim-1 expression under hypoxia may be implicated in the transformation process of solid tumors. Also, blocking Pim-1 function by introduction of dominant negative Pim-1 resensitizes pancreatic cancer cells to apoptosis induced by glucose-deprivation under hypoxia. Introduction of short interfering RNAs for Pim-1 also resensitizes cancer cells to glucose deprivation under hypoxic conditions, while forced overexpression of Pim-1 causes solid tumor cells to become resistant to glucose deprivation. Moreover, dominant negative Pim-1 reduces tumorigenicity in pancreatic cancer cells and HeLa xenograft mouse models. Together, our studies indicate that Pim-1 plays a distinct role in solid tumor formation in vivo, implying that Pim-1 may be a novel target for cancer therapy.

Pim kinases phosphorylate multiple sites on Bad and promote 14-3-3 binding and dissociation from Bcl-XL

Background

Pim-1, 2 and 3 are a group of enzymes related to the calcium calmodulin family of protein kinases. Over-expression of Pim-1 and Pim-2 in mice promotes the development of lymphomas, and up-regulation of Pim expression has been observed in several human cancers.

Results

Here we show that the pim kinases are constitutively active when expressed in HEK-293 cells and are able to phosphorylate the Bcl-2 family member Bad on three residues, Ser112, Ser136 and Ser155 in vitro and in cells. In vitro mapping showed that Pim-2 predominantly phosphorylated Ser112, while Pim-1 phosphorylated Ser112, but also Ser136 and Ser155 at a reduced rate compared to Ser112. Pim-3 was found to be the least specific for Ser112, and the most effective at phosphorylating Ser136 and Ser155. Pim-3 was also able to phosphorylate other sites in Bad in vitro, including Ser170, another potential in vivo site. Mutation of Ser136 to alanine prevented the phosphorylation of Ser112 and Ser155 by Pim kinases in HEK-293 cells, suggesting that this site must be phosphorylated first in order to make the other sites accessible. Pim phosphorylation of Bad was also found to promote the 14-3-3 binding of Bad and block its association with Bcl-X_L.

Conclusion

All three Pim kinase family members predominantly phosphorylate Bad on Ser112 and in addition are capable of phosphorylating Bad on multiple sites associated with the inhibition of the pro-apoptotic function of Bad in HEK-293 cells. This would be consistent with the proposed function of Pim kinases in promoting cell proliferation and preventing cell death.

Construction of a high-resolution 2.5-Mb transcript map of the human 6p21.2-6p21.3 region immediately centromeric of the major histocompatibility complex

We have constructed a 2.5-Mb physical and transcription map that spans the human 6p21.2-6p21.3 region and includes the centromeric end of the MHC, using a combination of techniques. In total 88 transcription units including exons, cDNAs, and cDNA contigs were characterized and 60 were confidently positioned on the physical map. These include a number of genes encoding nuclear and splicing factors (Ndr kinase, HSU09564, HSRP20); cell cycle, DNA packaging, and apoptosis related [p21, HMGI(Y), BAK]; immune response (CSBP, SAPK4); transcription activators and zinc finger-containing genes (TEF-5, ZNF76); embryogenesis related (Csa-19); cell signaling (DIPP); structural (HSET), and other genes (TULP1, HSPRARD, DEF-6, EO6811, cyclophilin), as well as a number of RP genes and pseudogenes (RPS10, RPS12-like, RPL12-like, RPL35-like). Furthermore, several novel genes (a Br140-like, a G2S-like, a FBN2-like, a ZNF-like, and B1/KIAA0229) have been identified, as well as cDNAs and cDNA contigs. The detailed map of the gene content of this chromosomal segment provides a number of candidate genes, which may be involved in several biological processes that have been associated with this region, such as spermatogenesis, development, embryogenesis, and neoplasia. The data provide useful tools for synteny studies between mice and humans, for genome structure analysis, gene density comparisons, and studies of nucleotide composition, of different isochores and Giemsa light and Giemsa dark bands.

Human-mouse homologies in the region of the polycystic kidney disease gene (PKD1)

Autosomal dominant polycystic kidney disease (PKD1) is linked to the alpha-globin locus near the telomere of chromosome 16p. We established the existence of a conserved linkage group in mouse by mapping conserved sequences and cDNAs from the region surrounding the PKD1 gene in the mouse genome. Results obtained with the BXD recombinant strain system and somatic cell hybrids show the homologous region to be located on mouse chromosome 17 near the globin pseudogene Hba-ps4, an unprocessed alpha-like globin gene. The markers we mapped are widely distributed over the region known to contain the PKD1 gene, and it is therefore likely that the mouse homologue of PKD1 is also located on mouse chromosome 17.

Mapping of the L-methylmalonyl-CoA mutase gene to mouse chromosome 17

In humans, methylmalonyl acidemia is caused by a deficiency of L-methylmalonyl-CoA mutase (MUT) controlled by a gene that has been mapped to chromosome 6. The mouse homolog of this gene has now been mapped to mouse chromosome 17. Recombinant inbred and congenic strains place the mouse Mut locus 1.06 cM distal to H-2, between Pgk-2 and Ce-2. The relative order of syntenic probes flanking H-2 on mouse chromosome 17 and HLA on human chromosome 6 is shown to be different.

Translocation (1;6)(p12;p23) in ANLL

We report here a case of acute nonlymphocytic leukemia evolving from a myelodysplastic syndrome which developed in an elderly man who had received radiation therapy for a prior cancer. Cytogenetic analysis revealed the following karyotype: 47,XY, + 8,t(1;6)(p13;p23). The breakpoints in the translocation are in the regions of the NRAS1 and PIM1 oncogenes on chromosomes 1 and 6, respectively. This translocation has not been previously observed in hematological malignancies.

Synteny mapping of the genes for 21 steroid hydroxylase, alpha A crystallin, and class I bovine leukocyte antigen in cattle

Synteny mapping of the genes for bovine alpha A crystallin (CRYA-1), steroid 21 hydroxylase (21OH), and a class I major histocompatibility locus bovine leukocyte antigen (BoLA) was accomplished by Southern blot analysis of DNA from bovine-hamster hybrid somatic cells. Comparison of the distribution patterns of CRYA-1, 21OH, and BoLA sequences among the hybrid cells revealed that the genes are located on two different chromosomes in the bovine genome. CRYA-1 mapped with superoxide dismutase (SOD1 in syntenic group U10, while 21OH and BoLA were concordant with glyoxylase (GLO1) in syntenic group U21. Therefore, the syntenic array of CRYA-1, 21OH, and BoLA in cattle is different from that observed in rodents, where the genes are closely linked to each other and to GLO1, and consistent with reported linkages in man.

The short arm of chromosome 6 is nonrandomly rearranged in secondary myelodysplastic syndromes

Eight patients with a myelodysplastic syndrome showed a structural rearrangement of the short arm of chromosome #6 involving the distal segment 6p22----6pter. In four cases the myelodysplastic disorder appeared after treatment with chemo- and/or radiotherapy. Cytogenetically, the 6p anomaly was consistently associated with abnormalities of chromosome #5 and/or #7 in seven of eight cases. We believe we identified a new site on 6p that is nonrandomly involved in iatrogenically and possibly also environmentally induced malignant hematologic disorders.

Translocation t(6;9)(p22.3;q34) in myelodysplastic syndrome--refractory anemia with excess blasts

A 69-year-old male patient with refractory anemia with excess blasts (RAEB) was found to have a consistent chromosomal abnormality, t(6;9)(p22.3;q34), in the bone marrow and unstimulated peripheral blood cells. Twenty patients with t(6;9) and leukemia have been reported; some of them had a myelodysplastic syndrome (MDS) before developing overt ANLL. Our patient was still in the MDS stage when the t(6;9) was found. This result suggests that t(6;9) represents one of the pathways from MDS to leukemia in patients with ANLL.

Chromosome maps of man and mouse, III

Data on loci whose positions are known in both man and mouse are presented in the form of chromosomal displays, a table, and autosomal and X-chromosomal grids. At least 40 conserved autosomal segments with two or more loci, as well as 17 homologous X-linked loci, are now known in the two species, in which mitochondrial DNA is also highly conserved. Apart from the Y, the only chromosome now lacking a conserved group is human 13. Human 17 has a single conserved group which includes both short and long arms, and so may have remained largely intact in mammalian evolution. Human and mouse chromosomal maps show the approximate locations of homologous genes while the mouse map also shows the positions of translocations used in gene location.