Endoplasmic reticulum-mediated unfolded protein response and mitochondrial apoptosis in cancer.

Abrogation of endoplasmic reticulum (ER) protein folding triggered by exogenous or endogenous factors, stimulates a cellular stress response, termed ER stress. ER stress re-establishes ER homeostasis through integrated signaling termed the ER-unfolded protein response (UPRER). In the presence of severe toxic or prolonged ER stress, the pro-survival function of UPRER is transformed into a lethal signal transmitted to and executed through mitochondria. Mitochondria are key for both apoptotic and autophagic cell death. Thus ER is vital in sensing and coordinating stress pathways to maintain overall physiological homeostasis. However, this function is deregulated in cancer, resulting in resistance to apoptosis induction in response to various stressors including therapeutic agents. Here we review the connections between ER stress and mitochondrial apoptosis, describing potential cancer therapeutic targets.

Mitochondrial dysfunction-mediated apoptosis resistance associates with defective heat shock protein response in African-American men with prostate cancer.

BACKGROUND: African-American (AA) patients with prostate cancer (PCa) respond poorly to current therapy compared with Caucasian American (CA) PCa patients. Although underlying mechanisms are not defined, mitochondrial dysfunction is a key reason for this disparity. METHODS: Cell death, cell cycle, and mitochondrial function/stress were analysed by flow cytometry or by Seahorse XF24 analyzer. Expression of cellular proteins was determined using immunoblotting and real-time PCR analyses. Cell survival/motility was evaluated by clonogenic, cell migration, and gelatin zymography assays. RESULTS: Glycolytic pathway inhibitor dichloroacetate (DCA) inhibited cell proliferation in both AA PCa cells (AA cells) and CA PCa cells (CA cells). AA cells possess reduced endogenous reactive oxygen species, mitochondrial membrane potential (mtMP), and mitochondrial mass compared with CA cells. DCA upregulated mtMP in both cell types, whereas mitochondrial mass was significantly increased in CA cells. DCA enhanced taxol-induced cell death in CA cells while sensitising AA cells to doxorubicin. Reduced expression of heat shock proteins (HSPs) was observed in AA cells, whereas DCA induced expression of CHOP, C/EBP, HSP60, and HSP90 in CA cells. AA cells are more aggressive and metastatic than CA cells. CONCLUSIONS: Restoration of mitochondrial function may provide new option for reducing PCa health disparity among American men.

Evidence for presence of mismatch repair gene expression positive Lynch syndrome cases in India.

Lynch syndrome (LS), the most common form of familial CRC predisposition that causes tumor onset at a young age, is characterized by the presence of microsatellite instability (MSI) in tumors due to germline inactivation of mismatch repair (MMR) system. Two MMR genes namely MLH1 and MSH2 account for majority of LS cases while MSH6 and PMS2 may account for a minor proportion. In order to identify MMR genes causing LS in India, we analyzed MSI and determined expression status of the four MMR genes in forty eight suspected LS patient colorectal tumor samples. Though a majority exhibited MSI, only 58% exhibited loss of MMR expression, a significantly low proportion compared to reports from other populations. PCR-DNA sequencing and MLPA-based mutation and exonic deletion/duplication screening respectively, revealed genetic lesions in samples with and without MMR gene expression. Interestingly, tumor samples with and without MMR expression exhibited significant differences with respect to histological (mucin content) and molecular (instability exhibited by mononucleotide microsatellites) features. The study has revealed for the first time a significant proportion of LS tumors not exhibiting loss of MMR expression.

Splice, insertion-deletion and nonsense mutations that perturb the phenylalanine hydroxylase transcript cause phenylketonuria in India.

Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by mutational inactivation of the phenylalanine hydroxylase (PAH) gene. Missense mutations are the most common PAH mutation type detected in PKU patients worldwide. We performed PAH mutation analysis in 27 suspected Indian PKU families (including 7 from our previous study) followed by structure and function analysis of specific missense and splice/insertion-deletion/nonsense mutations, respectively. Of the 27 families, disease-causing mutations were detected in 25. A total of 20 different mutations were identified of which 7 "unique" mutations accounted for 13 of 25 mutation positive families. The unique mutations detected exclusively in Indian PKU patients included three recurrent mutations detected in three families each. The 20 mutations included only 5 missense mutations in addition to 5 splice, 4 each nonsense and insertion-deletion mutations, a silent variant in coding region and a 3'UTR mutation. One deletion and two nonsense mutations were characterized to confirm significant reduction in mutant transcript levels possibly through activation of nonsense mediated decay. All missense mutations affected conserved amino acid residues and sequence and structure analysis suggested significant perturbations in the enzyme activity of respective mutant proteins. This is probably the first report of identification of a significantly low proportion of missense PAH mutations from PKU families and together with the presence of a high proportion of splice, insertion-deletion, and nonsense mutations, points to a unique PAH mutation profile in Indian PKU patients.

Comparison between LMA ProSeal and I-gel airway in anesthetized patients on spontaneous ventilation during daycare procedures: A prospective randomized study.

Background: General anesthesia remains the most popular technique for ambulatory surgeries with patients, surgeons, and anesthesia providers. The supraglottic airway (SGA) devices result in fewer incidences of sore throat, laryngospasm, coughing, and hoarseness as compared to inserting a tracheal tube. This study was conducted to compare two second-generation SGA devices, LMA ProSeal and I-gel airway, in anesthetized patients on spontaneous ventilation during daycare procedures to establish the superior SGA device. Methodology: This prospective randomized study was done on 90 patients of either sex aged 15-60 years, ASA grade I-II, Mallampatti grade I and II, and BMI between 20 and 30 kg/m2 scheduled for elective surgeries of duration less than 90 min. Patients were randomly allocated into two groups-group A (I-gel) and group B (LMA ProSeal). Insertion parameters, hemodynamic responses, oxygenation, ventilation, peak airway pressure (PAP), and postoperative complications were recorded. Statistical analysis was done using SPSS version 21.0 statistical analysis software. Results: Mean insertion time of LMA ProSeal was found to be significantly higher as compared to I-gel (33.27 ± 3.88 vs 18.49 ± 3.18 s; P < 0.001). No significant difference was found between the groups in the number of attempts and of operators attempted for insertion, as well as in hemodynamic response, oxygenation, and ventilation. Postoperative complications were lesser in group A. Conclusion: I-gel is an easy-to-insert cuffless SGA device requiring lesser time for insertion, provides adequate ventilation with lesser postoperative complications and thus appears to be better than LMA ProSeal.

Molecular genetic analysis of MSUD from India reveals mutations causing altered protein truncation affecting the C-termini of E1α and E1ß.

Maple Syrup Urine Disease is a rare metabolic disorder caused by reduced/absent activity of the branched chain α-Ketoacid dehydrogenase enzyme complex. Mutations in BCKDHA, BCKDHB, and DBT, that encode important subunits of the enzyme complex namely E1α, E1ß, and E2, are the primary cause for the disease. We have performed the first molecular genetic analysis of MSUD from India on nine patients exhibiting classical MSUD symptoms. BCKDHA and BCKDHB mutations were identified in four and five patients, respectively including seven novel mutations namely the BCKDHA c.1249delC, c.1312T>C, and c.1561T>A and the BCKDHB c.401T>A, c.548G>A, c.964A>G, and c.1065delT. The BCKDHB c.970C>T (p.R324X) mutation was shown to trigger nonsense mediated decay-based degradation of the transcript. Seven of the total 11 mutations resulted in perturbations in the E1α or E1ß C-termini either through altered termination or through an amino acid change; these are expected to result in disruption of E1 enzyme complex assembly. Our study has therefore revealed that BCKDHA and BCKDHB mutations might be primarily responsible for MSUD in the Indian population.

A low prevalence of MYH7/MYBPC3 mutations among familial hypertrophic cardiomyopathy patients in India.

Familial Hypertrophic Cardiomyopathy (FHC) is an autosomal dominant disorder affecting the cardiac muscle and exhibits varied clinical symptoms because of genetic heterogeneity. Several disease causing genes have been identified and most code for sarcomere proteins. In the current study, we have carried out clinical and molecular analysis of FHC patients from India. FHC was detected using echocardiography and by analysis of clinical symptoms and family history. Disease causing mutations in the ß-cardiac myosin heavy chain (MYH7) and Myosin binding protein C3 (MYBPC3) genes were identified using Polymerase Chain Reaction-Deoxyribose Nucleic Acid (PCR-DNA) sequencing. Of the 55 patient samples screened, mutations were detected in only nineteen in the two genes; MYBPC3 mutations were identified in 12 patients while MYH7 mutations were identified in five, two patients exhibited double heterozygosity. All four MYH7 mutations were missense mutations, whereas only 3/9 MYPBC3 mutations were missense mutations. Four novel mutations in MYBPC3 viz. c.456delC, c.2128G>A (p.E710K), c.3641G>A (p.W1214X), and c.3656T>C (p.L1219P) and one in MYH7 viz. c.965C>T (p.S322F) were identified. A majority of missense mutations affected conserved amino acid residues and were predicted to alter the structure of the corresponding mutant proteins. The study has revealed a greater frequency of occurrence of MYBPC3 mutations when compared to MYH7 mutations.

The IVS-II-837 (T>G) appears to be a relatively common 'rare' ß-globin gene mutation in ß-thalassemia patients in Karnataka State, South India.

ß-Thalassemia (ß-thal) is a common single gene autosomal recessive disorder resulting in severe anemia due to reduced or absent ß-globin polypeptide synthesis. The disease is caused by mutations in the ß-globin gene; eight common mutations are proposed to cause the majority of ß-thal in India. However, the occurrence of a region-specific mutation spectrum in India has also been suggested. We had earlier carried out analyses of the ß-globin gene mutation spectrum from southern Indian states of Andhra Pradesh and Karnataka. In the current study, we have analyzed three of 73 transfusion-dependent patients visiting a referral hospital in Karnataka State, South India, who did not carry any of the 22 common ß-globin gene mutations as determined by reverse dot-blot analysis. The IVS-II-837 (T>G) (ß(+)) (HBB:c.316-14TG) mutation was detected in two of the three patients analyzed suggesting a higher occurrence of the mutation in ß-thal patients in Karnataka when compared to other regions of India. The rare polyadenylation (poly A) site (T>C) (AATAAA>AACAAA; ß(+)) mutation was detected in the third patient. The IVS-II-837 mutation was also identified in asymptomatic carrier parents during routine high performance liquid chromatography (HPLC)-based Hb A(1c) screening in suspected diabetes patients. This is the first report of the identification of ß-thal trait through HPLC-based diabetes screening in India, revealing the importance of linking diabetes screening with screening for thalassemia.

A mitochondrial unfolded protein response inhibitor suppresses prostate cancer growth in mice via HSP60.

Mitochondrial proteostasis, regulated by the mitochondrial unfolded protein response (UPRmt), is crucial for maintenance of cellular functions and survival. Elevated oxidative and proteotoxic stress in mitochondria must be attenuated by the activation of a ubiquitous UPRmt to promote prostate cancer (PCa) growth. Here we show that the 2 key components of the UPRmt, heat shock protein 60 (HSP60, a mitochondrial chaperonin) and caseinolytic protease P (ClpP, a mitochondrial protease), were required for the development of advanced PCa. HSP60 regulated ClpP expression via c-Myc and physically interacted with ClpP to restore mitochondrial functions that promote cancer cell survival. HSP60 maintained the ATP-producing functions of mitochondria, which activated the ß-catenin pathway and led to the upregulation of c-Myc. We identified a UPRmt inhibitor that blocked HSP60's interaction with ClpP and abrogated survival signaling without altering HSP60's chaperonin function. Disruption of HSP60-ClpP interaction with the UPRmt inhibitor triggered metabolic stress and impeded PCa-promoting signaling. Treatment with the UPRmt inhibitor or genetic ablation of Hsp60 inhibited PCa growth and progression. Together, our findings demonstrate that the HSP60-ClpP-mediated UPRmt is essential for prostate tumorigenesis and the HSP60-ClpP interaction represents a therapeutic vulnerability in PCa.

Effect of preoperative multimedia based video information on perioperative anxiety and hemodynamic stability in patients undergoing surgery under spinal anesthesia.

BACKGROUND AND AIMS: Pre-anesthesia checkup (PAC) gives unique opportunity for providing necessary information, patient education and allaying anxiety. Our objective was to measure the effect of preoperative multimedia video information (self made short video of 12 minutes) on patient's anxiety and hemodynamic parameters during surgery under spinal anesthesia. METHODS: This prospective randomized study was conducted in 80 patients of either sex with ASA physical status I and II posted for lower limb surgery under spinal anesthesia. Patents were randomized to control or test group. At the end of preoperative visit, patients in test group watched the film and patient in control group did not watch any video. Verbal briefing by the attending anesthesiologist on the day of surgery was given to all patients of both the groups. Anxiety using Amsterdam Preoperative Anxiety and Information Scale (APAIS) and hemodynamic parameters (SBP, DBP and HR) at various time intervals (A1: Baseline, A2: post intervention, A3: just before surgery, A4: after surgery) were measured. RESULTS: Baseline anxiety (A1) scores were severe in both the groups and showed no statistical significance (P = 0.436). Patients in test group (video) showed better/lower anxiety levels than the control group (non video) at A2 (P = 0.020) and A3 (P = 0.005) respectively, similarly hemodynamic parameters were better controlled and showed lesser deviation from baseline values in test group as compared to control group and showed statistical significant difference (P < 0.001) just before surgery. CONCLUSION: Combination of multimedia based video information at the time of PAC and short verbal briefing on the day of surgery by the attending anesthesiologist provides effective management of perioperative anxiety. It can be cost effective way of enhancing patient care and providing adequate information to people with reading and comprehension difficulties.

A Comparison Between Dexmedetomidine and Clonidine as Adjuvants to Levobupivacaine in Labour Analgesia.

Background The epidural analgesia technique is effective for labor analgesia and combinations of various local anesthetics with lipophilic opioids like fentanyl are used. However, fentanyl can cause an increased incidence of pruritus, urinary retention, nausea, vomiting, giddiness, shivering, and respiratory depression. Dexmedetomidine and clonidine are selective alpha 2 agonists with analgesic properties and have been used via the neuraxial route with local anesthetics for the same without the side effects of fentanyl. Thus, the primary objective was to assess and compare the analgesic efficacy of the two-drug combinations by the visual analog scale (VAS) score. Methods Fifty-four primigravida women were randomly allocated in two groups of 27 each and were given an initial bolus of 10 mL of 0.125% levobupivacaine with dexmedetomidine 0.5 ug/kg in Group A and with clonidine 1 µg/kg in Group B. Subsequently, each patient received a background infusion rate of 10 mL/h, a bolus dose of 5 ml, and a lock-out interval of 10 min via a patient-controlled-analgesia (PCA) pump. The blood pressure, heart rate, and severity of pain using VAS were assessed. Durations of the stages of labor, rate of instrumental delivery, and cesarean section, side effects, maternal sedation, and neonatal Apgar scores were also recorded. Results VAS scores in both the groups progressively decreased to <3 by 15 min with significant differences at five, 10, 15, and 120 min being lower in group A. Onset of analgesia and time for maximum analgesia was significantly shorter in group A. There was a significant decrease in hemodynamic parameters from baseline in both groups. The fall in heart rate was significantly greater in Group A and at almost all the time intervals after baseline, diastolic blood pressure (DBP) was also lower in group A. Maternal motor blockade scores, the intensity of maternal sedation, the incidence of maternal complications, the duration of the first and second stage of labor, the rate of instrumental delivery and cesarean section, total analgesic dose and PCA bolus requirement, and neonatal Apgar scores did not show a significant difference between the two groups. Conclusion Both dexmedetomidine and clonidine provide hemodynamically stable labor with a fall in heart rate and maternal blood pressure in the initial hours. Dexmedetomidine has the advantage of faster onset of analgesia and time for maximum analgesia.

Phenylalanine hydroxylase gene mutations in phenylketonuria patients from India: identification of novel mutations that affect PAH RNA.

Analysis of seven Indian phenylketonuria families has revealed four novel mutations in the phenylalanine hydroxylase gene; two affected consensus splice sequence and the 3' UTR, respectively, while the other two were single base insertion and deletion mutations, respectively. A novel 3' splice site mutation c.168-2A>G resulted in the activation of a cryptic 3' splice site that generated a premature termination codon leading to very low levels of the mutant transcript, probably due to activation of the nonsense-mediated decay (NMD) pathway. This is probably the first report of PKU caused by the activation of NMD.

Synergistic effect of stromelysin-1 (matrix metalloproteinase-3) promoter (-1171 5A->6A) polymorphism in oral submucous fibrosis and head and neck lesions.

BACKGROUND: Matrix metalloproteinases (MMPs) are enzymes that degrade all the components of extra cellular matrix and collagen. Various types of MMPs are known to be expressed and activated in patients with oral submucous fibrosis (OSMF) as well as head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to asses the association of the single nucleotide polymorphism (SNP) adenosine insertion/deletion polymorphism (-1171 5A->6A) in the MMP-3 promoter region in these lesions. METHODS: MMP-3 SNP was genotyped by polymerase chain reaction-restriction fragment polymorphism (PCR-RFLP) analysis in a case control study consisting of 362 participants; 101 cases of OSMF, 135 of HNSCC and 126 controls, compared for age, sex and habits. ROC distribution was plotted to assess the contributions of genetic variation in MMP-3 genotypes with relation to age. RESULTS: Analysis of MMP 3 (-1171 5A->6A) polymorphism revealed the frequency of 5A allele in OSMF, HNSCC and controls to be 0.15, 0.13 and 0.07, respectively. A significant difference was found in 5A genotype frequency between OSMF (5A genotype frequency = 0.15, p = 0.01, OR = 2.26, 95% CI = 1.22-4.20) and in controls (5A genotype frequency 0.07) as well as HNSCC (5A genotype frequency 0.13, p = 0.03,95%CI = 1.06-3.51) and controls (5A genotype frequency = 0.07) In this study, 5A genotype had greater than two fold risk for developing OSMF (OR = 2.26) and nearly the same in case of HNSCC (OR = 1.94) as compared to controls. In patients with OSMF as well as HNSCC, the ROC analysis between the MMP-3 genotype and age, 6A/6A allele was found to be significant in patients both over and under 45 years of age; while the 5A/5A carrier alleles showed an association only in patients less than 45 years of age. CONCLUSIONS: This study concluded that the expression of MMP-3 genotype associated with the 5A alleles, it may have an important role in the susceptibility of the patients to develop OSMF and HNSCC.

Role of MMP-2 and its inhibitor TIMP-2 as biomarkers for susceptibility to systemic lupus erythematosus.

Aim: To investigate the possible association between MMP-2 (-1575 G/A, -1306 C/T) and its inhibitor TIMP-2 (-418 G/C) functional polymorphisms with development of severity in systemic lupus erythematosus (SLE) patients. Materials & methods: 150 SLE patients and matched healthy controls were recruited. Polymorphisms were detected by PCR-RFLP and serum levels by ELISA. Results: Mean MMP-2 and TIMP-2 serum level and mRNA expression were significantly increased in SLE cases as compared with controls (p < 0.0001). The concomitant presence of both MMP-2 1575A and its inhibitor TIMP-2 418C alleles synergistically increased the risk of SLE by 3.25-fold (CI: 1.44-7.34, p = 0.003). Conclusion: MMP-2, TIMP-2 and MMP-2/TIMP-2 ratios may act as biomarkers for susceptibility to SLE.

Cytochrome c Deficiency Confers Apoptosome and Mitochondrial Dysfunction in African-American Men with Prostate Cancer.

Although African-American (AA) patients with prostate cancer tend to develop greater therapeutic resistance and faster prostate cancer recurrence compared with Caucasian-American (CA) men, the molecular mechanisms of this racial prostate cancer disparity remain undefined. In this study, we provide the first comprehensive evidence that cytochrome c deficiency in AA primary tumors and cancer cells abrogates apoptosome-mediated caspase activation and contributes to mitochondrial dysfunction, thereby promoting therapeutic resistance and prostate cancer aggressiveness in AA men. In AA prostate cancer cells, decreased nuclear accumulation of nuclear respiration factor 1 (Nrf1) and its subsequent loss of binding to the cytochrome c promoter mediated cytochrome c deficiency. The activation of cellular Myc (c-Myc) and NF-κB or inhibition of AKT prevented nuclear translocation of Nrf1. Genetic and pharmacologic inhibition of c-Myc and NF-κB or activation of AKT promoted Nrf1 binding to cytochrome c promoter, cytochrome c expression, caspase activation, and cell death. The lack of p-Drp1S616 in AA prostate cancer cells contributed to defective cytochrome c release and increased resistance to apoptosis, indicating that restoration of cytochrome c alone may be insufficient to induce effective apoptosis. Cytochrome c deficiency promoted the acquisition of glycolytic phenotypes and mitochondrial dysfunction, whereas cytochrome c restoration via inhibition of c-Myc and NF-κB or activation of AKT attenuated glycolysis in AA prostate cancer cells. Inhibition of c-Myc and NF-κB enhanced the efficacy of docetaxel in tumor xenografts. Therefore, restoring cytochrome c may overcome therapeutic resistance and prostate cancer aggressiveness in AA men. Overall, this study provides the first comprehensive experimental, mechanistic, and clinical evidence for apoptosome and mitochondrial dysfunction in prostate cancer racial disparity. SIGNIFICANCE: Mechanistic insights on prostate cancer health disparity among American men provide novel approaches to restore mitochondrial function, which can address therapeutic resistance and aggressiveness in African-American men with prostate cancer.

Nimbolide reduces CD44 positive cell population and induces mitochondrial apoptosis in pancreatic cancer cells.

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive disease and current treatment regimens fail to effectively cure PDAC. Development of resistance to current therapy is one of the key reasons for this outcome. Nimbolide (NL), a triterpenoid obtained from Azadirachta indica, exhibits anticancer properties in various cancer including PDAC cells. However, the underlying mechanism of this anticancer agent in PDAC cells remains undefined. We show that NL exerts a higher level of apoptotic cell death compared to the first-line agent gemcitabine for PDAC, as well as other anticancer agents including sorafenib and curcumin. The anticancer efficacy of NL was further evidenced by a reduction in the CD44+ as well as cancer stem-like cell (CSC) population, as it causes decreased sphere formation. Mechanistically, the anticancer efficacy of NL associates with reduced mutant p53 as well as increased mitochondrial activity in the form of increased mitochondrial reactive oxygen species and mitochondrial mass. Together, this study highlights the therapeutic potential of NL in mutant p53 expressing pancreatic cancer.

Investigation of Mitochondrial Metabolic Response to Doxorubicin in Prostate Cancer Cells: An NADH, FAD and Tryptophan FLIM Assay.

Prostate cancer (PCa) is one of the leading cancers in men in the USA. Lack of experimental tools that predict therapy response is one of the limitations of current therapeutic regimens. Mitochondrial dysfunctions including defective oxidative phosphorylation (OXPHOS) in cancer inhibit apoptosis by modulating ROS production and cellular signaling. Thus, correction of mitochondrial dysfunction and induction of apoptosis are promising strategies in cancer treatment. We have used Fluorescence Lifetime Imaging Microscopy (FLIM) to quantify mitochondrial metabolic response in PCa cells by tracking auto-fluorescent NAD(P)H, FAD and tryptophan (Trp) lifetimes and their enzyme-bound fractions as markers, before and after treatment with anti-cancer drug doxorubicin. A 3-channel FLIM assay and quantitative analysis of these markers for cellular metabolism show in response to doxorubicin, NAD(P)H mean fluorescence lifetime (τm) and enzyme-bound (a2%) fraction increased, FAD enzyme-bound (a1%) fraction was decreased, NAD(P)H-a2%/FAD-a1% FLIM-based redox ratio and ROS increased, followed by induction of apoptosis. For the first time, a FRET assay in PCa cells shows Trp-quenching due to Trp-NAD(P)H interactions, correlating energy transfer efficiencies (E%) vs NAD(P)H-a2%/FAD-a1% as sensitive parameters in predicting drug response. Applying this FLIM assay as early predictor of drug response would meet one of the important goals in cancer treatment.

Mitochondrial dysfunction and prostate cancer racial disparities among American men.

The gap between prostate cancer disparities among American men is narrowing, which is mostly due to increased screening of African American (AA) men. However, the biological reasons for prostate cancer disparities among American men still remain undefined. Mitochondrion, an organelle within cells, regulates both cell survival and cell death mechanisms. These cellular signaling pathways require various proteins localized to mitochondria, which are encoded by both nuclear DNA (nDNA) and mitochondrial DNA (mtDNA). Interestingly, prostate tissues from AA men harbor reduced mtDNA content compared to Caucasian American (CA) men. Therefore, changes in mitochondrial genes may have detrimental consequences in terms of cellular signaling regulated by mitochondria in AA men. This review describes the plausible underlying mechanism of mtDNA depletion and its impact in driving resistance to therapy leading to faster progression and poor prognosis in African American men with prostate cancer. Since defective cellular signaling is critical for prostate cancer cell survival, restoring mitochondrial function may provide strategies to alleviate prostate cancer disparities among American men.

Pleiotropic Roles of Metalloproteinases in Hematological Malignancies: an Update.

Controlled remodeling of the extracellular matrix (ECM) is essential for cell growth, invasion and metastasis. Matrix metalloproteinases (MMPs) are a family of secreted, zincdependent endopeptidases capable of degradation of ECM components. The expression and activity of MMPs in a variety of human cancers have been intensively studied. They play important roles at different steps of malignant tumor formation and have central significance in embryogenesis, tissue remodeling, inflammation, angiogenesis and metastasis. However, increasing evidence demonstrates that MMPs are involved earlier in tumorigenesis. Recent studies also suggest that MMPs play complex roles in tumor progression. MMPs and membrane type (MT)MMPs are potentially significant therapeutic targets in many cancers, so that designing of specific MMP inhibitors would be helpful for clinical trials. Here, we review the pleiotropic roles of the MMP system in hematological malignancies invitro and invivo models.