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At least 19 recordsLinked to original sources
PubMed1996

Genetic and phylogenetic divergence of feline immunodeficiency virus in the puma (Puma concolor).

Feline immunodeficiency virus (FIV) is a lentivirus which causes an AIDS-like disease in domestic cats (Felis catus). A number of other felid species, including the puma (Puma concolor), carry a virus closely related to domestic cat FIV. Serological testing revealed the presence of antibodies to FIV in 22% of 434 samples from throughout the geographic range of the puma. FIV-Pco pol gene sequences isolated from pumas revealed extensive sequence diversity, greater than has been documented in the domestic cat. The puma sequences formed two highly divergent groups, analogous to the clades which have been defined for domestic cat and lion (Panthera leo) FIV. The puma clade A was made up of samples from Florida and California, whereas clade B consisted of samples from other parts of North America, Central America, and Brazil. The difference between these two groups was as great as that reported among three lion FIV clades. Within puma clades, sequence variation is large, comparable to between-clade differences seen for domestic cat clades, allowing recognition of 15 phylogenetic lineages (subclades) among puma FIV-Pco. Large sequence divergence among isolates, nearly complete species monophyly, and widespread geographic distribution suggest that FIV-Pco has evolved within the puma species for a long period. The sequence data provided evidence for vertical transmission of FIV-Pco from mothers to their kittens, for coinfection of individuals by two different viral strains, and for cross-species transmission of FIV from a domestic cat to a puma. These factors may all be important for understanding the epidemiology and natural history of FIV in the puma.

Amino Acid Sequence↗
PubMedDate not supplied

Genomic ancestry of the American puma (Puma concolor).

Puma concolor, a large American cat species, occupies the most extensive range of any New World terrestrial mammal, spanning 110 degrees of latitude from the Canadian Yukon to the Straits of Magellan. Until the recent Holocene, pumas coexisted with a diverse array of carnivores including the American lion (Panthera atrox), the North American cheetah (Miracynonyx trumani), and the saber toothed tiger (Smilodon fatalis). Genomic DNA specimens from 315 pumas of specified geographic origin (261 contemporary and 54 museum specimens) were collected for molecular genetic and phylogenetic analyses of three mitochondrial gene sequences (16S rRNA, ATPase-8, and NADH-5) plus composite microsatellite genotypes (10 feline loci). Six phylogeographic groupings or subspecies were resolved, and the entire North American population (186 individuals from 15 previously named subspecies) was genetically homogeneous in overall variation relative to central and South American populations. The marked uniformity of mtDNA and a reduction in microsatellite allele size expansion indicates that North American pumas derive from a recent (late Pleistocene circa 10,000 years ago) replacement and recolonization by a small number of founders who themselves originated from a centrum of puma genetic diversity in eastern South America 200,000-300,000 years ago. The recolonization of North American pumas was coincident with a massive late Pleistocene extinction event that eliminated 80% of large vertebrates in North America and may have extirpated pumas from that continent as well.

Americas↗
PubMed2005

Cycle and duration of the seminiferous epithelium in puma (Puma concolor).

Puma or sussuarana (Puma concolor) is the second largest feline in the American continent and has an ample latitudinal distribution in very diverse habitats. In relation to its conservation status, the puma is considered an extinction-threatened species. The study of the testis morphology and the spermatogenic process in a species is fundamental for establishing the physiologic patterns that will make possible the selection of the protocols for assisted reproduction. A number of peculiarities associated with the reproductive biology of specific species such as the duration of spermatogenic process can be used to determine the frequency of sperm collection. Nine adult male pumas maintained in captivity were used to determine the relative frequency of stages in the seminiferous epithelium cycle. Three of them received intra-testicular injections of 0.1ml tritiated thymidine to determine the duration of the seminiferous epithelium cycle, and were subjected to biopsy 7 days later. The cycle of the seminiferous epithelium in puma was didactically described into eight stages by the tubular morphology method. The total duration of one seminiferous epithelium cycle in puma was calculated to be 9.89 days, and approximately 44.5 days are required for development of spermatozoon from spermatogonia. The duration of spermiogenesis, prophase and other events of meiosis were 14.08, 15.20 and 1.79 days, respectively. The relative frequency of the pre-meiotic, meiotic and post-meiotic phases were 3.98, 1.79 and 4.12 days, respectively.

Animals↗
PubMed2006

Feline immunodeficiency virus and puma lentivirus in Florida panthers (Puma concolor coryi): epidemiology and diagnostic issues.

This study documents the seroprevalence of feline immunodeficiency virus (FIV) and puma lentivirus (PLV) in free-ranging and captive Florida panthers (Puma concolor coryi) (n = 51) and translocated Texas cougars (P. concolor stanleyana) (n = 10) from 1985 to 1998. The sera were tested for anti-FIV antibodies by enzyme-linked immunosorbent assay (ELISA) and Western blot tests. The ELISAs were read kinetically (KELA) and the sera were retrospectively examined by PLV peptide ELISA. Eleven panthers and one cougar were positive by KELA; 4 panthers and 4 cougars were equivocal; 35 panthers and 5 cougars were negative; and 1 panther had no data. Seven of the 11 KELA-positive panthers were also positive by Western blot tests and all but one were positive by PLV peptide ELISA. Ten KELA-negative and Western blot-negative cats, were positive by PLV peptide ELISA. KELA results varied within cats from one sample period to the next, but PLV peptide ELISA results were consistent. Territorial sympatry and mating behaviour, noted from radiotelemetry location data on the cats, may have contributed to viral transmission between seropositive animals. These findings suggest that Florida panthers and the introduced Texas cougars have been exposed to FIV and/or PLV.

Animals↗
PubMed2006

p53 independent induction of PUMA mediates intestinal apoptosis in response to ischaemia-reperfusion.

BACKGROUND: The small intestine is highly sensitive to ischaemia-reperfusion (I/R) induced injury which is associated with high morbidity and mortality. Apoptosis, or programmed cell death, is a major mode of cell death occurring during I/R induced injury. However, the mechanisms by which I/R cause apoptosis in the small intestine are poorly understood. p53 upregulated modulator of apoptosis (PUMA) is a p53 downstream target and a member of the BH3-only group of Bcl-2 family proteins. It has been shown that PUMA plays an essential role in apoptosis induced by a variety of stimuli in different tissues through a mitochondrial pathway. AIMS: The role of PUMA in I/R induced injury and apoptosis in the small intestine was investigated. The mechanisms by which PUMA is regulated in I/R induced intestinal apoptosis were also studied. METHODS: Ischaemia was induced by superior mesenteric artery occlusion in the mouse small intestine. Induction of PUMA in response to ischaemia alone, or ischaemia followed by reperfusion (I/R), was examined. I/R induced intestinal apoptosis and injury were compared between PUMA knockout and wild-type mice. The mechanisms of I/R induced and PUMA mediated apoptosis were investigated through analysis of caspase activation, cytosolic release of mitochondrial cytochrome c and alterations of the proapoptotic Bcl-2 family proteins Bax and Bak. To determine whether PUMA is induced by reactive oxygen species and/or reactive nitrogen species generated by I/R, superoxide dismutase (SOD) and N-nitro-l-arginine methyl ester (L-NAME) were used to treat animals before I/R. To determine whether p53 is involved in regulating PUMA during I/R induced apoptosis, PUMA induction and apoptosis in response to I/R were examined in p53 knockout mice. RESULTS: PUMA was markedly induced following I/R in the mucosa of the mouse small intestine. I/R induced intestinal apoptosis was significantly attenuated in PUMA knockout mice compared with that in wild-type mice. I/R induced caspase 3 activation, cytochrome c release, Bax mitochondrial translocation and Bak multimerisation were also inhibited in PUMA knockout mice. SOD or L-NAME significantly blunted I/R induced PUMA expression and apoptosis. Furthermore, I/R induced PUMA expression and apoptosis in the small intestine were not affected in the p53 knockout mice. CONCLUSIONS: Our data demonstrated that PUMA is activated by oxidative stress in response to I/R to promote p53 independent apoptosis in the small intestine through the mitochondrial pathway. Inhibition of PUMA is potentially useful for protecting against I/R induced intestinal injury and apoptosis.

Animals↗
PubMed2006

PUMA sensitizes lung cancer cells to chemotherapeutic agents and irradiation.

PURPOSE: Lung cancer, the leading cause of cancer mortality worldwide, is often diagnosed at late stages and responds poorly to conventional therapies, including chemotherapy and irradiation. A great majority of lung tumors are defective in the p53 pathway, which plays an important role in regulating apoptotic response to anticancer agents. PUMA was recently identified as an essential mediator of DNA damage-induced and p53-dependent apoptosis. In this study, we investigated whether the regulation of PUMA by anticancer agents is abrogated in lung cancer cells and whether PUMA expression suppresses growth of lung cancer cells and/or sensitizes lung cancer cells to chemotherapeutic agents and irradiation through induction of apoptosis. EXPERIMENTAL DESIGNS: The expression of PUMA was examined in lung cancer cells with different p53 status treated with chemotherapeutic agents. An adenovirus expressing PUMA (Ad-PUMA), alone or in combination with chemotherapeutic agents or gamma-irradiation, was used to treat lung cancer cells. The growth inhibitory and apoptotic effects of PUMA in vitro and in vivo were examined. The mechanisms of PUMA-mediated growth suppression and apoptosis were investigated through analysis of caspase activation and release of mitochondrial apoptogenic proteins. The cytotoxicities of PUMA on cancer and normal/nontransformed cells were compared. The efficacy of PUMA and p53 in suppressing the growth of lung cancer cells was also compared. RESULTS: We showed that the induction of PUMA by chemotherapeutic agents is abolished in p53-deficient lung cancer cells. PUMA expression resulted in potent growth suppression of lung cancer cells and suppressed xenograft tumor growth in vivo through induction of apoptosis. Low dose of Ad-PUMA significantly sensitized lung cancer cells to chemotherapeutic agents and gamma-irradiation through induction of apoptosis. The effects of PUMA are mediated by enhanced caspase activation and release of cytochrome c and apoptosis-inducing factor into the cytosol. Furthermore, PUMA seems to be selectively toxic to cancer cells and more efficient than p53 in suppressing lung cancer cell growth. CONCLUSIONS: Our findings indicate that PUMA is an important modulator of therapeutic responses of lung cancer cells and is potentially useful as a sensitizer in lung cancer therapy.

Animals↗
PubMed2005

Puma(*)Mcl-1 interaction is not sufficient to prevent rapid degradation of Mcl-1.

Although Puma (p53 upregulated modulator of apoptosis) was known as a principal mediator of cell death in response to diverse apoptotic signals, the molecular mechanism underlying its proapoptotic regulation remains largely uncharacterized. Here we reported that myeloid cell leukemia-1 (Mcl-1), an anti-apoptotic member of the Bcl-2 family with a rapid turnover rate, interacts with Puma. The Puma/Mcl-1 interaction was verified by both yeast two-hybrid assay and co-immuno-precipation studies. Their binding sites were mapped to BH3 (Bcl-2 homology) domain of Puma and BH1 domain of Mcl-1, respectively. Mcl-1 and Puma was shown to colocalize at the mitochondria by immunostaining. The level of Mcl-1 was increased when coexpressed with Puma, indicating Puma is able to stabilize Mcl-1. Puma binding to Mcl-1 via its BH3 domain is the prerequisite for this effect, which is further supported by the finding that Puma mutant lacking BH3 domain no longer promotes Mcl-1 protein stability. This Puma-enhanced Mcl-1 stabilization was validated in vivo under non-overexpression conditions. We also showed that BH1 domain is essential for Mcl-1 to inhibit Puma-induced apoptosis, since Mcl-1 mutant lacking BH1 domain completely abrogates its protective function. In addition, we concluded that binding of Puma to BH1 domain of Mcl-1 is necessary, but not sufficient to prevent rapid degradation of Mcl-1. In addition to PEST (proline, glutamic acid, serine, and threonine) and BH1 domain, some additional degradation signal is expected to reside in the C-terminal region of Mcl-1. In conclusion, our results provide the first evidence that the interaction between Mcl-1 and Puma may represent a novel mechanism by which Mcl-1 prevents apoptosis by increasing its stability through binding to Puma.

Amino Acid Motifs↗
PubMed2006

PUMA Dissociates Bax and Bcl-X(L) to induce apoptosis in colon cancer cells.

PUMA is a BH3-only Bcl-2 family protein that plays an essential role in DNA damage-induced apoptosis. PUMA interacts with anti-apoptotic Bcl-2 and Bcl-X(L) and is dependent on Bax to induce apoptosis. In this study, we investigated how the interactions of PUMA with the antiapoptotic proteins coordinate with Bax to initiate apoptosis in HCT116 colon cancer cells. We found that Bcl-X(L) was most effective among several antiapoptotic proteins in suppressing PUMA-induced apoptosis and PUMA-dependent apoptosis induced by the DNA-damaging agent adriamycin. Mutant Bcl-X(L) that cannot interact with Bax was unable to protect cells from PUMA-mediated apoptosis. Knockdown of Bcl-X(L) by RNA interference significantly enhanced PUMA-mediated apoptosis in HCT116 cells but not in PUMA-knockout cells. Furthermore, Bax was found to be dissociated preferentially from Bcl-X(L) in HCT116 cells but not in the PUMA-knockout cells, in response to PUMA induction and adriamycin treatment. PUMA inhibited the association of Bax and Bcl-X(L) in vitro by directly binding to Bcl-X(L) through its BH3 domain. Finally, we found that wild-type Bax, but not mutant Bax deficient in either multimerization or mitochondrial localization, was able to restore PUMA-induced apoptosis in the BAX-knockout cells. Together, these results indicate that PUMA initiates apoptosis in part by dissociating Bax and Bcl-X(L), thereby promoting Bax multimerization and mitochondrial translocation.

Amino Acid Sequence↗
PubMed2006

PUMA regulation and proapoptotic effects in fibroblast-like synoviocytes.

OBJECTIVE: Although p53 is overexpressed in rheumatoid arthritis (RA) synovial tissue (ST), few synoviocytes undergo apoptosis. This could be partly due to low expression of proapoptotic genes. Deficient p53 up-regulated modulator of apoptosis (PUMA), which is a major effector of p53-mediated cell death, could contribute to this phenomenon. To evaluate a method to induce apoptosis, the expression and function of PUMA was investigated in ST and cultured fibroblast-like synoviocytes (FLS). METHODS: PUMA expression in ST was measured by immunohistochemistry, Western blot analysis, and quantitative polymerase chain reaction analysis. Ad-p53 and plasmids encoding hemagglutinin-tagged, full-length PUMA expression vector (HA-PUMA), PUMA lacking the Bcl-2 homology 3 domain, or pCEP4 were used to transfect FLS. Apoptosis was quantified by trypan blue exclusion, DNA fragmentation, and caspase 3 activation. RESULTS: PUMA protein was detected in RA ST, although most of the immunoreactive protein was localized to sublining cells rather than the intimal lining synoviocytes. Western blot analysis showed no difference between RA ST and osteoarthritis (OA) ST. PUMA messenger RNA was detected in RA and OA ST, although the amounts were markedly lower than in the spleen and FLS. To determine if PUMA was inducible, FLS were transduced with Ad-p53. Even though p53 protein was produced and p21 expression was increased, PUMA expression was not enhanced. Consistent with this observation, Ad-p53 did not induce apoptosis in FLS. However, HA-PUMA transfection into FLS resulted in rapid apoptosis with the activation of caspase 3. CONCLUSION: PUMA can induce apoptosis by FLS and represents a potential target in RA.

Apoptosis↗
PubMed2006

Targeted deletion of Puma attenuates cardiomyocyte death and improves cardiac function during ischemia-reperfusion.

The p53-upregulated modulator of apoptosis (Puma), a BH3-only member of the Bcl-2 protein family, is required for p53-dependent and -independent forms of apoptosis and has been implicated in the pathomechanism of several diseases, including cancer, acquired immunodeficiency syndrome, and ischemic brain disease. The role of Puma in cardiomyocyte death, however, has not been analyzed. On the basis of the ability of Puma to integrate diverse cell death stimuli, we hypothesized that Puma might be critical for cardiomyocyte death upon ischemia-reperfusion (I/R) of the heart. Here we show that hypoxia-reoxygenation of isolated cardiomyocytes led to an increase in Puma mRNA and protein levels. Moreover, if Puma was delivered by an adenoviral construct, cardiomyocytes died by apoptosis. Under ATP-depleted conditions, however, Puma overexpression primarily induced necrosis, suggesting that Puma is involved in the development of both types of cell death. Consistent with these findings, targeted deletion of Puma in a mouse model attenuated both apoptosis and necrosis. When the Langendorff ex vivo I/R model was used, infarcts were approximately 50% smaller in Puma(-/-) than in wild-type mice. As a result, after I/R, cardiac function was significantly better preserved in Puma(-/-) mice than in their wild-type littermates. Our study thus establishes Puma as an essential mediator of cardiomyocyte death upon I/R injury and offers a novel therapeutic target to limit cell loss in ischemic heart disease.

Animals↗
PubMed2001

PUMA-G, an IFN-gamma-inducible gene in macrophages is a novel member of the seven transmembrane spanning receptor superfamily.

IFN-gamma is a key immunoregulatory cytokine that plays a predominant role in innate immunity. By employing PCR-Select to search for genes differentially expressed in IFN-gamma/TNF-alpha stimulated macrophages, we identified a novel IFN-gamma-induced transcript designated PUMA-G (protein up-regulated in macrophages by IFN-gamma). PUMA-G codes for a protein with seven transmembrane helices, a feature commonly shared with the G protein-coupled receptor superfamily (GPCR). The PUMA-G protein is most similar to the human orphan GPCR HM74 (73 % identity) and GPR31 (30 % identity). PUMA-G mRNA was readily induced in macrophages after stimulation with IFN-gamma, LPS, polyIC and CpG oligonucleotides. In vivo PUMA-G was up-regulated in mice suffering from microbial sepsis or from Listeria monocytogenes infection. Characterization of the genomic locus revealed an intronless PUMA-G open reading frame. Genomic Southern blot analysis indicates that PUMA-G is a single-copy gene. PUMA-G maps to mouse chromosome 5F. Confocal microscopy of transiently transfected 264.7 RAW macrophages and 293T cells with a PUMA-G-EGFP fusion construct showed predominant fluorescence at the cell surface, suggesting a localization at the cell membrane. Taken together, our data indicate that PUMA-G is a new inducible representative of GPCR, with potential importance in macrophage functions.

Amino Acid Sequence↗
PubMed2006

PUMA is critical for neonatal cardiomyocyte apoptosis induced by endoplasmic reticulum stress.

OBJECTIVE: Puma (p53-upregulated modulator of apoptosis), a proapoptotic BH3-only member of the Bcl-2 protein family, has been implicated in the pathomechanism of several diseases, including cancer, AIDS, and ischemic brain disease. We have recently shown that Puma is required for cardiac cell death upon ischemia/reperfusion of mouse hearts. Since ischemia/reperfusion is also associated with endoplasmic reticulum (ER) stress, in the present study we investigated whether Puma contributes to the ER stress-dependent component of cardiomyocyte apoptosis. METHODS: Primary cultures of rat and mouse neonatal cardiomyocytes were treated with 3 muM thapsigargin or 100 ng mL(-1) tunicamycin. Puma levels were suppressed by adenoviral delivery of shRNA or targeted deletion of the puma gene. Puma expression was detected by RT-PCR and Western blotting. Apoptosis was assessed by TUNEL assay, caspase-3 cleavage, and cytochrome c release. RESULTS: We have shown that in rat neonatal cardiac myocytes, thapsigargin or tunicamycin treatment led to ER-stress, transcriptional upregulation of Puma, and apoptosis. Most importantly, cardiac myocytes acquired resistance to ER stress-induced apoptosis if Puma expression was downregulated by adenoviral delivery of shRNA or eliminated by targeted deletion in knockout mice. CONCLUSION: Taken together, our data indicate that Puma is a critical component of ER stress-induced apoptosis in cardiac myocytes, and inhibition of Puma activity may be used to treat cardiac infarcts or prevent heart failure by blocking ER stress-induced apoptosis.

Animals↗
PubMed2005

Transcriptional upregulation of PUMA modulates endoplasmic reticulum calcium pool depletion-induced apoptosis via Bax activation.

PUMA, a key mediator of p53-induced apoptosis, is a BH3-only domain proapoptotic protein that localizes to mitochondria and interacts with antiapoptotic Bcl-2 and Bcl-X(L). Recent evidence implicates Bax to be an important mediator of PUMA-activated apoptotic signals. We have previously demonstrated that Bax deficiency significantly affects thapsigargin (TG)-mediated endoplasmic reticulum calcium pool depletion-induced apoptosis. We now present evidence that TG upregulates PUMA expression and that although Bax-deficient cells exhibit resistance to TG, Bax deficiency does not attenuate TG upregulation of PUMA expression. Furthermore, TG transcriptionally upregulates PUMA expression in a p53-independent manner and that PUMA-deficient cells are more resistant to undergo TG-induced apoptosis than the PUMA-proficient counterparts. Thus, our results demonstrate that TG engages PUMA and Bax for full transduction of apoptotic signals and both PUMA and Bax appear to exist in the same TG-activated apoptotic pathway in which PUMA may reside upstream of Bax.

Apoptosis↗
PubMed2006

BH3-only proapoptotic Bcl-2 family members Noxa and Puma mediate neural precursor cell death.

Neural precursor cells (NPCs) are highly sensitive to genotoxic injury, which triggers activation of the intrinsic mitochondria-dependent apoptotic pathway. This pathway is typically initiated by members of the BH3 (Bcl-2 homology 3)-only subgroup of the Bcl-2 (B-cell CLL/lymphoma 2) protein family, which are positioned upstream in the apoptotic pathway to respond to specific death stimuli. We have shown previously that NPCs deficient in the tumor suppressor protein p53 show significantly less death after exposure to genotoxic injury or to staurosporine (STS), a broad kinase inhibitor and potent apoptosis inducer. p53 has been shown to regulate the expression of both Noxa and Puma, two BH3-only proteins, although their involvement in p53-dependent cell death appears to be cell-type and stimulus specific. A systematic comparison of the relative contributions of Noxa and Puma to NPC apoptosis has not yet been performed. We hypothesized that p53-dependent transcription of Noxa and Puma leads to death in telencephalic NPCs exposed to genotoxic stress. We found that genotoxic injury induces a rapid p53-dependent increase in expression of Noxa and Puma mRNA in telencephalic NPCs. Furthermore, deficiency of either Noxa or Puma inhibited DNA damage-induced caspase-3 activation and cell death in telencephalic NPCs in vitro. However, only Puma deficiency protected telencephalic ventricular zone NPCs from death in vivo. In contrast to genotoxic injury, STS produced a p53-independent increase in Noxa and Puma expression, but neither Noxa nor Puma was required for STS-induced NPC death. Together, these experiments identify Noxa and Puma as important regulators of genotoxin-induced telencephalic NPC death.

Animals↗
PubMed2003

Perugia urodynamic method of analysis (PUMA): a new advanced method of urodynamic analysis applied clinically and compared with other advanced methods.

AIMS: The aim of this study is to compare PUMA curves with different pathologic conditions causing bladder dysfunction in 158 men and 83 women. METHODS: PUMA results in terms of bladder outlet obstruction and detrusor contractility were compared in 92 men with benign prostatic hypertrophy (BPH) and p(ves) congruent with p(det) (i.e., p(abd) congruent with 0) with the results of the urodynamics operator's opinion, the provisional International Continence Society method, Abrams and Griffith's diagram, urethral resistence factor (URA), Schäfer's diagram, and Watt factor. PUMA curves correlated reliably with different pathologic conditions such as obstructive BPH, orthotopic bladder, cystocele, the neurological bladder, and bladder diverticulum. Statistical analysis indicated excellent agreement between PUMA and URA; agreement with other methods was good in cases of obstruction and nonobstruction. In doubtful cases, as diagnosed by standard methods, PUMA agreed only with the Abrams and Griffith's diagram. PUMA and Wmax were in good agreement on detrusor con traction force. Agreement between PUMA and Schäfer's diagram was excellent for patients with detrusor hypercontractility and good for patients with detrusor hypocontractility and normocontractility. PUMA is the only method applicable to women. It is easy to perform. When integrated with other diagnostic tests, it provides realistic data for diagnosis, medical or surgical therapy, and outcome.

Adult↗
PubMed2003

Bax conformational change is a crucial step for PUMA-mediated apoptosis in human leukemia.

The BH3-only protein, PUMA, plays an important role in p53-mediated apoptosis. The apoptotic effect of PUMA on the mitochondria was studied using a p53-negative, human leukemia K562 cell line. Overexpression of PUMA was accompanied by an increased Bax expression, Bax conformational change, and translocation to mitochondria. A PUMA-BH3 peptide can induce Bax conformational change, cytochrome c release, and reduction in the mitochondrial membrane potential (DeltaPsi(m)) in isolated K562 mitochondria and can be inhibited by Bcl-XL. The homo-dimer of Bax/Bax was also weakly shown after mitochondria were treated with PUMA-BH3 peptide but may not be lethal for PUMA-induced apoptosis in K562 cells. Our results suggest that PUMA-induced Bax conformational change and Bax translocation to mitochondria can be separate events and the conformational change in Bax is crucial for PUMA-induced mitochondrial dysfunction.

Animals↗
PubMed2006

The BH3-only protein, PUMA, is involved in oxaliplatin-induced apoptosis in colon cancer cells.

Oxaliplatin, the first line chemotherapeutic of colon cancer, induces damage to tumors via induction of apoptosis. PUMA (p53 up-regulate modulator of apoptosis) is an important pro-apoptotic member of Bcl-2 family and regulated mainly by p53. Here we investigated the role of PUMA in oxalipaltin-induced apoptosis and the potential mechanism. We showed that oxaliplatin-induced PUMA expression in a time- and dose-dependent manner and suppression of PUMA expression by stable transfecting anti-sense PUMA plasmid decreased oxaliplatin-induced apoptosis in colon cancer cells. By abrogating the function of p53, we further demonstrated that the induction was p53-independent. We also found that oxaliplatin could inactivate ERK and suppression of ERK activity by its specific inhibitor (PD98059), and dominant negative plasmid (DN-MEK1) enhanced the oxaliplatin-induced PUMA expression and apoptosis in a p53-independent manner. Taken together, our data suggest that PUMA plays an important role in oxaliplatin-induced apoptosis and the induction could be both p53-dependent and p53-independent. Moreover, PUMA expression and apoptosis in oxaliplatin-treated colon cancer cells could be regulated partly by ERK inactivation. Identification of the molecular components involved in regulating the cellular sensitivity to oxaliplatin may provide potential targets for development of novel compounds that may be useful in enhancement of oxaliplatin cytotoxicity in p53 deficient colon cancer.

Antineoplastic Agents↗