Age alters the oncogenic trajectory toward luminal mammary tumors that activate unfolded proteins responses

A major limitation in the use of mouse models in breast cancer research is that most mice develop estrogen receptor-alpha (ERα)-negative mammary tumors, while in humans, the majority of breast cancers are ERα-positive. Therefore, developing mouse models that best mimic the disease in humans is of fundamental need. Here, using an inducible MMTV-rtTA/TetO-NeuNT mouse model, we show that despite being driven by the same oncogene, mammary tumors in young mice are ERα-negative, while they are ERα-positive in aged mice. To further elucidate the mechanisms for this observation, we performed RNAseq analysis and identified genes that are uniquely expressed in aged female-derived mammary tumors. We found these genes to be involved in the activation of the ERα axis of the mitochondrial UPR and the ERα-mediated regulation of XBP-1s, a gene involved in the endoplasmic reticulum UPR. Collectively, our results indicate that aging alters the oncogenic trajectory towards the ERα-positive subtype of breast cancers, and that mammary tumors in aged mice are characterized by the upregulation of multiple UPR stress responses regulated by the ERα.

Can THEM6 targeting stop resistance to prostate cancer treatment?

Prostate cancer (PCa) clinical management relies heavily on androgen‐deprivation therapy (ADT). However, despite experiencing initial clinical benefit, patients getting ADT for non‐resectable PCa eventually relapse and develop fatal castration‐resistant PCa (CRPC). Multiple mechanisms of acquired resistance to treatment have been reported, including metabolic adaptation (Marine et al, 2020). Notably, activation of the endoplasmic reticulum (ER) unfolded protein response (UPR) has been associated with oncogenic transformation (Hart et al, 2012), tumor progression, metastasis dissemination, and resistance to therapy (Chen & Cubillos‐Ruiz, 2021). Targeting different branches of ER UPR has been found to be an effective tool against aggressive PCa (Nguyen et al, 2018; Sheng et al, 2019). Therefore, a better understanding of these pathways may lead to the identification of novel drug targets.

Folding Mitochondrial-Mediated Cytosolic Proteostasis Into the Mitochondrial Unfolded Protein Response

Several studies reported that mitochondrial stress induces cytosolic proteostasis. How mitochondrial stress activates proteostasis in the cytosol remains unclear. However, the cross-talk between the mitochondria and cytosolic proteostasis has far reaching implications for treatment of proteopathies including neurodegenerative diseases. This possibility appears within reach since selected drugs have begun to emerge as being able to stimulate mitochondrial-mediated cytosolic proteostasis. In this review, we focus on studies describing how mitochondrial stress activates proteostasis in the cytosol across multiple model organisms. A model is proposed linking mitochondrial-mediated regulation of cytosolic translation, folding capacity, ubiquitination, and proteasome degradation and autophagy as a multi layered control of cytosolic proteostasis that overlaps with the integrated stress response (ISR) and the mitochondrial unfolded protein response (UPR^mt). By analogy to the conductor in an orchestra managing multiple instrumental sections into a dynamically integrated musical piece, the cross-talk between these signaling cascades places the mitochondria as a major conductor of cellular integrity.

Are the estrogen receptor and SIRT3 axes of the mitochondrial UPR key regulators of breast cancer sub-type determination according to age?

Aging is a major risk factor of developing breast cancer. Despite the fact that post-menopausal women have lower levels of estrogen, older women have a higher rate of estrogen receptor alpha (ERα) positive breast cancer. Conversely, young women who have elevated levels of estrogen tend to develop ERα negative disease that is associated with higher rate of metastasis. This perspective proposes a unifying model centered around the importance of mitochondrial biology in cancer and aging to explain these observations. Mitochondria are essential for the survival of cancer cells and therefore pathways that maintain the functionality of the mitochondrial network in cancer cells fulfill a critical role in the survival of cancer cells. The ERα and the mitochondrial sirtuin-3 (SIRT3) have been reported to be key players of the mitochondrial unfolded protein response (UPR^mt) ^1-5. The UPR^mt is a complex retrograde signaling cascade that regulates the communication between the mitochondria and the nucleus to restore mitochondrial fitness in response to oxidative stress ^5-7. SIRT3 is a major regulator of aging ⁸. Its level decreases with age and single nucleotide polymorphisms (SNPs) that preserve its expression at higher levels are observed in centenarians ^9,10. We propose a model whereby the ERα axis of the UPR^mt acts to compensate for the loss of SIRT3 observed with age, and becomes the dominant axis of the UPR^mt to maintain the integrity of the mitochondria during transformation, thus explaining the selective advantage of ERα positive luminal cells in breast cancer arising from older women.

Mitochondrially targeted cytochrome P450 2D6 is involved in monomethylamine-induced neuronal damage in mouse models

Parkinson's disease (PD) is a major human disease associated with degeneration of the central nervous system. Evidence suggests that several endogenously formed 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-mimicking chemicals that are metabolic conversion products, especially β-carbolines and isoquinolines, act as neurotoxins that induce PD or enhance progression of the disease. We have demonstrated previously that mitochondrially targeted human cytochrome P450 2D6 (CYP2D6), supported by mitochondrial adrenodoxin and adrenodoxin reductase, can efficiently catalyze the conversion of MPTP to the toxic 1-methyl-4-phenylpyridinium ion. In this study, we show that the mitochondrially targeted CYP2D6 can efficiently catalyze MPTP-mimicking compounds, i.e. 2-methyl-1,2,3,4-tetrahydroisoquinoline, 2-methyl-1,2,3,4-tetrahydro-β-carboline, and 9-methyl-norharmon, suspected to induce PD in humans. Our results reveal that activity and respiration in mouse brain mitochondrial complex I are significantly affected by these toxins in WT mice but remain unchanged in Cyp2d6 locus knockout mice, indicating a possible role of CYP2D6 in the metabolism of these compounds both in vivo and in vitro These metabolic effects were minimized in the presence of two CYP2D6 inhibitors, quinidine and ajmalicine. Neuro-2a cells stably expressing predominantly mitochondrially targeted CYP2D6 were more sensitive to toxin-mediated respiratory dysfunction and complex I inhibition than cells expressing predominantly endoplasmic reticulum-targeted CYP2D6. Exposure to these toxins also induced the autophagic marker Parkin and the mitochondrial fission marker Dynamin-related protein 1 (Drp1) in differentiated neurons expressing mitochondrial CYP2D6. Our results show that monomethylamines are converted to their toxic cationic form by mitochondrially directed CYP2D6 and result in neuronal degradation in mice.

Cigarette Smoke Toxins-Induced Mitochondrial Dysfunction and Pancreatitis Involves Aryl Hydrocarbon Receptor Mediated Cyp1 Gene Expression: Protective Effects of Resveratrol

We previously reported that mitochondrial CYP1 enzymes participate in the metabolism of polycyclic aromatic hydrocarbons and other carcinogens leading to mitochondrial dysfunction. In this study, using Cyp1b1-/-, Cyp1a1/1a2-/-, and Cyp1a1/1a2/1b1-/- mice, we observed that cigarette and environmental toxins, namely benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), induce pancreatic mitochondrial respiratory dysfunction and pancreatitis. Our results suggest that aryl hydrocarbon receptor (AhR) activation and resultant mitochondrial dysfunction are associated with pancreatic pathology. BaP treatment markedly inhibits pancreatic mitochondrial oxygen consumption rate (OCR), ADP-dependent OCR, and also maximal respiration, in wild-type mice but not in Cyp1a1/1a2-/- and Cyp1a1/1a2/1b1-/- mice. In addition, both BaP and TCDD treatment markedly affected mitochondrial complex IV activity, in addition to causing marked reduction in mitochondrial DNA content. Interestingly, the AhR antagonist resveratrol, attenuated BaP-induced mitochondrial respiratory defects in the pancreas, and reversed pancreatitis, both histologically and biochemically in wild-type mice. These results reveal a novel role for AhR- and AhR-regulated CYP1 enzymes in eliciting mitochondrial dysfunction and cigarette toxin-mediated pancreatic pathology. We propose that increased mitochondrial respiratory dysfunction and oxidative stress are involved in polycyclic aromatic hydrocarbon associated pancreatitis. Resveratrol, a chemo preventive agent and AhR antagonist, and CH-223191, a potent and specific AhR inhibitor, confer protection against BaP-induced mitochondrial dysfunction and pancreatic pathology.

A Small Insulinomimetic Molecule Also Improves Insulin Sensitivity in Diabetic Mice

Dramatic increase of diabetes over the globe is in tandem with the increase in insulin requirement. This is because destruction and dysfunction of pancreatic β-cells are of common occurrence in both Type1 diabetes and Type2 diabetes, and insulin injection becomes a compulsion. Because of several problems associated with insulin injection, orally active insulin mimetic compounds would be ideal substitute. Here we report a small molecule, a peroxyvanadate compound i.e. DmpzH[VO(O2)2(dmpz)], henceforth referred as dmp, which specifically binds to insulin receptor with considerable affinity (KD-1.17μM) thus activating insulin receptor tyrosine kinase and its downstream signaling molecules resulting increased uptake of [14C] 2 Deoxy-glucose. Oral administration of dmp to streptozotocin treated BALB/c mice lowers blood glucose level and markedly stimulates glucose and fatty acid uptake by skeletal muscle and adipose tissue respectively. In db/db mice, it greatly improves insulin sensitivity through excess expression of PPARγ and its target genes i.e. adiponectin, CD36 and aP2. Study on the underlying mechanism demonstrated that excess expression of Wnt3a decreased PPARγ whereas dmp suppression of Wnt3a gene increased PPARγ expression which subsequently augmented adiponectin. Increased production of adiponectin in db/db mice due to dmp effected lowering of circulatory TG and FFA levels, activates AMPK in skeletal muscle and this stimulates mitochondrial biogenesis and bioenergetics. Decrease of lipid load along with increased mitochondrial activity greatly improves energy homeostasis which has been found to be correlated with the increased insulin sensitivity. The results obtained with dmp, therefore, strongly indicate that dmp could be a potential candidate for insulin replacement therapy.

Genistein, the Isoflavone in Soybean, Causes Amyloid Beta Peptide Accumulation in Human Neuroblastoma Cell Line: Implications in Alzheimer's Disease

The isoflavone, genistein, present in soybean is being actively investigated for its potential beneficial effect against Alzheimer's disease. Our data, however, show that in SHSY5Y cells genistein causes increased expression (mRNA and protein) of amyloid precursor protein (APP), increased mRNA expression and activity of β-secretase and diminished level of insulin degrading enzyme (IDE) which also degrades amyloid beta peptide. These effects of genistein lead to enhanced accumulation of amyloid beta peptide (Aβ42) in SHSY5Y cells. The results do not support the view that genistein could be a putative drug against AD and instead strengthen the epidemiological study which implies that genistein content of soybean food product (Tofu) leads to cognitive impairment.

Oxidative stress and amyloid beta toxicity in Alzheimer's disease: intervention in a complex relationship by antioxidants

The elucidation of the intriguing relationship between oxidative stress and Alzheimer's disease is crucial to understand the pathogenesis of the disease as also to design a suitable drug trial with antioxidants against this condition. We begin by reviewing the basic facts about Alzheimer's disease and the chemistry and biology of oxygen free radicals with particular reference to the cellular adaptive response through redox-signalling pathways. The post-mortem evidence of oxidative damage in the brain of Alzheimer's disease patients is overwhelming which is also supported by the similar changes in transgenic mice models of this disease. However, the causal relationship of oxidative stress with amyloid beta pathology or the genesis of Alzheimer's disease is not clear. Considering the available evidence the review suggests that the oxidative stress could be an early event in the disease process and may trigger various adaptive responses such as the alterations of amyloid beta metabolism and the activation of stress responsive kinases which can subsequently lead to neuronal degeneration and AD pathology. Further, we have presented a large body of evidence from various studies to highlight the beneficial effects of antioxidants against amyloid beta toxicity or AD pathology in animal or cell based models of AD. The failure of clinical trials with antioxidants against AD has been mentioned and the possible causes of such failures have been analysed.

Mitochondrial bioenergetics is not impaired in nonobese subjects with type 2 diabetes mellitus

Although mitochondrial dysfunction has been well documented in obese people with type 2 diabetes mellitus, its presence or absence in nonobese subjects with type 2 diabetes mellitus has not been well studied so far. The aim of the present study was to assess the status of mitochondrial oxidative phosphorylation in subcutaneous adipose tissue of nonobese type 2 diabetes mellitus subjects in comparison to control, obese nondiabetic, and obese type 2 diabetes mellitus subjects. Mitochondria were isolated from subcutaneous white adipose tissue obtained from the abdominal region of control, obese nondiabetic, nonobese type 2 diabetes mellitus, and obese type 2 diabetes mellitus subjects. The activities of complex I, I to III, II to III, and IV; transmembrane potential; and inorganic phosphate utilization of mitochondria from different groups were measured. Mitochondrial transmembrane potential, inorganic phosphate utilization, and the activities of respiratory chain complexes were significantly reduced in obese nondiabetic and obese type 2 diabetes mellitus patients compared with those in control subjects. No detectable change in mitochondrial functional parameters was observed in case of nonobese type 2 diabetes mellitus subjects compared with control subjects. Furthermore, a significant difference was noticed in mitochondrial phosphate utilization and activities of respiratory complexes, for example, I, I to III, and II to III, between obese type 2 diabetes mellitus subjects and obese nondiabetic subjects. Obesity modulates mitochondrial dysfunction associated with type 2 diabetes mellitus.

Three-photon-induced four-photon absorption and nonlinear refraction in ZnO quantum dots

Three-photon-induced four-photon absorption via excited-state absorption and self-defocusing nonlinear refraction are reported for the first time, to our knowledge, in ZnO quantum dots with average sizes of 2.0+/-0.1 nm with 1064 nm radiation from a Q-switched Nd:YAG laser at a peak intensity of 2.5 GW/cm(2). By employing the three-level two-step model, the experimental results can be explained quite satisfactorily.

Prolonged preservation of nerve function in diabetic neuropathy in mice by herpes simplex virus-mediated gene transfer

AIMS/HYPOTHESIS

The aim of this study was to determine whether prolonged expression of neurotrophin-3 (NT-3) in mice, achieved by herpes simplex virus (HSV)-mediated gene transfer with gene expression under the control of an HSV latency promoter, can provide protection against the progression of diabetic neuropathy over a 6 month period.

MATERIALS AND METHODS

Mice with diabetes induced by streptozotocin were inoculated s.c. into both hind feet with a non-replicating HSV vector containing the coding sequence for NT-3 under the control of the HSV latency-associated promoter 2 (LAP2) elements or with a control vector. Nerve function was evaluated by electrophysiological and behavioural measures over the course of 6 months after the onset of diabetes.

RESULTS

Animals inoculated with the NT-3-expressing vector, but not animals inoculated with control vector, showed preservation of sensory and motor nerve amplitude and conduction velocity measured electrophysiologically, small fibre sensory function assessed by withdrawal from heat, autonomic function measured by pilocarpine-induced sweating, skin innervation assessed by protein gene product 9.5 staining of axons, and density of calcitonin gene-related peptide terminals in the spinal cord measured by immunohistochemistry 5.5 months after vector inoculation.

CONCLUSIONS/INTERPRETATION

These results indicate that the continuous production of NT-3 by LAP2-driven expression of the transgene from an HSV vector over a 6 month period protects against progression of diabetic neuropathy in mice, and provide a proof-of-principle demonstration for the development of a novel therapy for preventing the progression of diabetic neuropathy.

Nanoengineered analytical immobilized metal affinity chromatography stationary phase by atom transfer radical polymerization: separation of synthetic prion peptides

Atom transfer radical polymerization (ATRP) was employed to create isolated, metal-containing nanoparticles on the surface of nonporous polymeric beads with the goal of developing a new immobilized metal affinity chromatography (IMAC) stationary phase for separating prion peptides and proteins. Transmission electron microscopy was used to visualize nanoparticles on the substrate surface. Individual ferritin molecules were also visualized as ferritin-nanoparticle complexes. The column's resolving power was tested by synthesizing peptide analogs to the copper binding region of prion protein and injecting mixtures of these analogs onto the column. As expected, the column was capable of separating prion-related peptides differing in number of octapeptide repeat units (PHGGGWGQ), (PHGGGWGQ)(2), and (PHGGGWGQ)(4). Unexpectedly, the column could also resolve peptides containing the same number of repeats but differing only in the presence of a hydrophilic tail, Q-->A substitution, or amide nitrogen methylation.

HSV-mediated gene transfer of vascular endothelial growth factor to dorsal root ganglia prevents diabetic neuropathy

We examined the utility of herpes simplex virus (HSV) vector-mediated gene transfer of vascular endothelial growth factor (VEGF) in a mouse model of diabetic neuropathy. A replication-incompetent HSV vector with VEGF under the control of the HSV ICP0 promoter (vector T0VEGF) was constructed. T0VEGF expressed and released VEGF from primary dorsal root ganglion (DRG) neurons in vitro, and following subcutaneous inoculation in the foot, expressed VEGF in DRG and nerve in vivo. At 2 weeks after induction of diabetes, subcutaneous inoculation of T0VEGF prevented the reduction in sensory nerve amplitude characteristic of diabetic neuropathy measured 4 weeks later, preserved autonomic function measured by pilocarpine-induced sweating, and prevented the loss of nerve fibers in the skin and reduction of neuropeptide calcitonin gene-related peptide and substance P in DRG neurons of the diabetic mice. HSV-mediated transfer of VEGF to DRG may prove useful in treatment of diabetic neuropathy.

Satellite-tagged transcribing sequences in Bubalus bubalis genome undergo programmed modulation in meiocytes: possible implications for transcriptional inactivation

We cloned and sequenced a 1378 bp BamHI satellite DNA fraction from the water buffalo Bubalus bubalis and have studied its expression in different tissues. The GC-rich sequences of the resultant contig pDS5 crosshybridize only with bovid DNA and are not conserved evolutionarily. Typing of buffalo genomic DNA using pDS5 with several restriction enzymes revealed multilocus monomorphic bands. Similar typing of cattle, buffalo, goat, sheep, and gaur genomic DNA revealed variations in copy number and allele length giving rise to species-specific band patterns. Expression study of pDS5 in bubaline samples by RNA slot-blot, Northern blot, and RT-PCR showed various levels of signal in all the somatic tissues and germline cells except heart. A GenBank database search revealed homology of pDS5 sequences in the 5' region from nt 1-1261 with collagen gene. An AluI typing analysis of DNA from bubaline semen samples showed consistent loss of two bands. The presence of corresponding bands in somatic tissues suggests a sequence modulation within the pDS5 array in meiocytes during spermatogenesis, which is restored in the somatic cells after fertilization. Modulation of the satellite-tagged transcribing sequence in the meiocytes may be a mechanism of its inactivation.

Flunarizine enhances functional recovery following sciatic nerve crush lesion in rats

We have used the rat sciatic nerve crush (SNC) injury model to assess the neuroprotective effects of flunarizine (FNZ), a calcium channel antagonist and a vasodilator. The animals were treated with FNZ for various durations following SNC (0.33 mg/kg per day, i.p). Employing the physical disector method, we quantitated the rates of neuron loss in the dorsal root ganglion and spinal cord and protective effects of FNZ. FNZ treatment following SNC reduced neuron loss up to 86.6 and 82.5% in DRG sensory and spinal cord motor neurons, respectively. Functional recovery following SNC with or without FNZ treatment was assessed using the measurements of the total, 1-5 and 2-4-toe spread to quantitate percentage relative toe spread in relation to the respective controls. FNZ provided a superior return of function, i.e. near absolute recovery of both sensory and motor functions in 4 weeks, which is consistent with its neuroprotective effects.

Biosocial factors influencing women to become prostitutes in India

Based on materials collected during a study of risk factors associated with cervix cancer among prostitutes in Domjur, Howrah, West Bengal, this report explores various biosocial factors which may lead women to prostitution. When family and marital ties fail or disintegrate for various reasons, the life situations which a woman encounters may themselves generate a "process" of anchorlessness. The failure of family support along with the lack of ability to provide for themselves due to poverty and illiteracy were key factors why the women in this study had adopted prostitution.

Renal handling of amino acid 99mtechnetium chelates

Four amino acids--alanine, 2,3-diaminopropionic acid, cystine, and cystein--and also one diamine, ethylenediamine, were chelated with 99m-technetium (99mTc), and their renal excretion patterns were studied in rabbits in the presence and absence of two renal tubular transport inhibitors, probenecid and 2,4-dinitrophenol. From the depression of renal excretion for the first three amino acid chelates, in the presence of the inhibitors, a renal tubular excretory pathway of elimination was suggested for these compounds. The renal excretions of 99mTc-cystein and 99mTc-ethylenediamine however, remained undepressed under similar experimental conditions. An explanation of these observations was forwarded from the possible chemical structures of these chelates.

99mTc-2,3-diaminopropionic acid complex as renal function agent: comparison of biological properties with 99mTc-DTPA and 131I-OIH

The preparation, purification, biodistribution, blood disappearance kinetics and imaging characteristics of 99mTc-2,3-diamino propionic acid (99m-Tc-DAPA) is studied. The latter three studies were conducted on rabbits as the experimental animal and the data thus obtained were compared with 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) and 131I-orthoiodohippurate (131I-OIH) with a view to find a possible replacement of the latter radiopharmaceutical with a more convenient 99mTc based compound. Preliminary data indicates favourable results for 99mTc-2,3-diamino propionic acid which warrants further investigation.