One-year trajectories of nutritional status in perimenopausal women: a community-based multi-centered prospective study.

BACKGROUND: Nutritional status is a modifiable factor associated with perimenopausal women's health and quality of life. Assessing body composition indicators helps to comprehensively understand nutritional status compared with using body mass index (BMI) only. However, few published studies measured the trends in body composition among perimenopausal women. OBJECTIVES: To assess the one-year trajectory of the nutritional status of perimenopausal women and to explore its influential factors. METHODS: A community-based observational study with 3-wave repeated measurements at 6-month intervals was carried out. The nutritional status indicators include weight, body mass index (BMI), and body composition variables. Bioelectrical impedance analysis was used to assess body composition. Repeated measures ANOVA and Chi-square test were used to calculate the changes in nutritional status and generalized estimating equations were performed to explore their influential factors. RESULTS: 2760 participants completed the study. Increasing trajectories in weight (from 56.05 ± 7.55 to 57.02 ± 7.60), fat mass (from 17.99 ± 4.80 to 20.49 ± 4.90), and waist-hip ratio (from 0.86 ± 0.04 to 0.91 ± 0.15) were found (P < 0.001). Decreasing trajectories in skeletal muscle (from 20.30 ± 2.38 to 19.19 ± 2.46), protein level (from 7.39 ± 0.79 to 7.06 ± 0.81), and total body water (from 27.87 ± 2.92 to 27.00 ± 3.01) were found (P < 0.001). Being married/unmarried with a partner and without negative life events were associated with higher total body water, skeletal muscle, and protein level, while negatively associated with fat mass and waist-hip ratio. Age was positively associated with fat mass (P < 0.001). Participants with junior high school education were prone to increased fat mass (P = 0.018) compared with those holding primary school education and below. A per capita monthly income of 1500 to 3000 Yuan was associated with higher total body water, skeletal muscle, and protein level (P < 0.001) compared with a per capita monthly income of less than 1500 Yuan. CONCLUSION: Worsening nutritional status exists in perimenopausal women, which is characterized by increased weight, fat mass, and waist-hip ratio, and decreased skeletal muscle, total body water, and protein level. For greater efficiency, precision nutritional interventions are needed, and recipients should be classified into different risk levels based on their sociodemographic background.

Depressive symptoms and physical activity among community-dwelling perimenopausal women: a prospective longitudinal study.

BACKGROUND: Women in perimenopause are vulnerable to depressive symptoms, and physical activity was reported to be a potential protective factor. The trajectories of physical activity and depressive symptoms over time and their longitudinal relationships in Chinese perimenopausal women have not been explored yet, leaving a research gap hindering us from better understanding and managing perimenopause depressive symptoms. METHODS: A multi-center prospective longitudinal study was conducted in four cities in Sichuan Province, China. Depressive symptoms and physical activity in perimenopausal women were collected in March 2019, June 2019, September 2019, and December 2019, respectively. Multivariable linear regression by generalized estimation equation was used to identify the relevant factors associated with depressive symptoms and physical activity. A four-wave autoregressive and cross-lagged panel model was performed to explore their longitudinal relationships. RESULTS: A total of 1875 women who completed the four-wave data collection were included in the data analysis. Depressive symptoms exacerbated over time and were associated with women's age, monthly income, marital status, chronic disease, and negative life events. Physical activity decreased over time and was associated with educational background and monthly income. According to the cross-lagged panel model, perimenopausal women with more severe depressive symptoms tended to be less physically active, and similarly, perimenopausal women with less physical activity were more prone to report more severe depressive symptoms. CONCLUSION: The cross-lagged panel model disclosed longitudinal bidirectional relationships between depressive symptoms and physical activity in perimenopausal women. Appropriate physical activity should be recommended for perimenopausal women to improve their mental well-being. Tailored physical activity duration and maintenance measures should be proposed based on different sociodemographic statuses.

Dose rate and dose robustness for proton transmission FLASH-RT treatment in lung cancer.

Purposes: To evaluate the plan quality and robustness of both dose and dose rate of proton pencil beam scanning (PBS) transmission FLASH delivery in lung cancer treatment. Methods and materials: An in-house FLASH planning platform was used to optimize 10 lung cancer patients previously consecutively treated with proton stereotactic body radiation therapy (SBRT) to receive 3 and 5 transmission beams (Trx-3fds and Trx-5fds, respectively) to 34 Gy in a single fraction. Perturbation scenarios (n=12) for setup and range uncertainties (5 mm and 3.5%) were introduced, and dose-volume histogram and dose-rate-volume histogram bands were generated. Conventional proton SBRT clinical plans were used as a reference. RTOG 0915 dose metrics and 40 Gy/s dose rate coverage (V40Gy/s) were used to assess the dose and dose rate robustness. Results: Trx-5fds yields a comparable iCTV D2% of 105.3%, whereas Trx-3fds resulted in inferior D2% of 111.9% to the clinical SBRT plans with D2% of 105.6% (p<0.05). Both Trx-5fds and Trx-3fds plans had slightly worse dose metrics to organs at risk than SBRT plans. Trx-5fds achieved superior dosimetry robustness for iCTV, esophagus, and spinal cord doses than both Trx-3fds and conventional SBRT plans. There was no significant difference in dose rate robustness for V40Gy/s coverage between Trx-3fds and Trx-5fds. Dose rate distribution has similar distributions to the dose when perturbation exists. Conclusion: Transmission plans yield overall modestly inferior plan quality compared to the conventional proton SBRT plans but provide improved robustness and the potential for a toxicity-sparing FLASH effect. By using more beams (5- versus 3-field), both dose and dose rate robustness for transmission plans can be achieved.

Use of single-energy proton pencil beam scanning Bragg peak for intensity-modulated proton therapy FLASH treatment planning in liver-hypofractionated radiation therapy.

PURPOSE: The transmission proton FLASH technique delivers high doses to the normal tissue distal to the target, which is less conformal compared to the Bragg peak technique. To investigate FLASH radiotherapy (RT) planning using single-energy Bragg peak beams with a similar beam arrangement as clinical intensity-modulated proton therapy (IMPT) in a liver stereotactic body radiation therapy (SBRT) and to characterize the plan quality, dose sparing of organs-at-risk (OARs), and FLASH dose rate percentage. MATERIALS AND METHODS: An in-house platform was developed to enable inverse IMPT-FLASH planning using single-energy Bragg peaks. A universal range shifter and range compensators were utilized to effectively align the Bragg peak to the distal edge of the target. Two different minimum MU settings of 400 and 800 MU/spot (Bragg-400 MU and Bragg-800 MU) plans were investigated on 10 consecutive hepatocellular carcinoma patients previously treated by IMPT-SBRT to evaluate the FLASH dose and dose rate coverage for OARs. The IMPT-FLASH using single-energy Bragg peaks delivered 50 Gy in five fractions with similar or identical beam arrangement to the clinical IMPT-SBRT plans. NRG GI003 dose constraint metrics were used. Three dose rate calculation methods, including average dose rate (ADR), dose threshold dose rate (DTDR), and dose-ADR (DADR), were all studied. RESULTS: The novel spot map optimization can fulfill the inverse planning using single-energy Bragg peaks. All the Bragg peak FLASH plans achieved similar results for the liver-gross tumor volume (GTV) Dmean and heart D 0.5 c m 3 ${D_{0.5\,{\rm{c}}{{\rm{m}}^3}}}$ , compared to SBRT-IMPT. The Bragg-800 MU plans resulted in 18.3% higher clinical target volume (CTV) D 2 c m 3 ${D_{2\,{\rm{c}}{{\rm{m}}^{\rm{3}}}}}$ compared with SBRT (p < 0.05), and no significant difference was found between Bragg-400 MU and SBRT plans. For the CTV Dmax , SBRT plans resulted in 10.3% (p < 0.01) less than Bragg-400 MU plans and 16.6% (p < 0.01) less than Bragg-800 MU plans. The Bragg-800 MU plans generally achieved higher ADR, DADR, and DTDR dose rates than Bragg-400 MU plans, and DADR mostly led to the highest V40 Gy/s compared to other dose rate calculation methods, whereas ADR led to the lowest. The lower dose rate portions in certain OARs are related to the lower dose deposited due to the farther distances from targets, especially in the penumbra of the beams. CONCLUSION: Single-energy Bragg peak IMPT-FLASH plans eliminate the exit dose in normal tissues, maintaining comparable dose metrics to the conventional IMPT-SBRT plans, while achieving a sufficient FLASH dose rate for liver cancers. This study demonstrates the feasibility of and sufficiently high dose rate when applying the Bragg peak FLASH treatment for a liver cancer hypofractionated FLASH therapy. The advancement of this novel method has the potential to optimize treatment for liver cancer patients.

Comprehensive Evaluation of Carbon-Fiber-Reinforced Polyetheretherketone (CFR-PEEK) Spinal Hardware for Proton and Photon Planning.

Purpose: To evaluate a novel spine implant, carbon-fiber-reinforced polyetheretherketone (CFR-PEEK), for proton and photon treatment planning. Materials and Methods: We compared target coverage and sparing of organs-at-risk (OARs) for a spinal phantom with 4 different spine configurations: (a) normal (no implant); (b) Titanium; (c) CFR-PEEK; and (d) hybrid (CFR-PEEK with Titanium tulip head). The spinal phantom was imaged via computed tomography (CT) scan, and the iterative Metal Artifact Reduction (iMAR) CT set was used for planning. A representative spinal chordoma target and associated OARs were contoured. The prescription dose was 50 Gy to the initial target volume, followed by a 24 Gy boost, for which multi-field optimization (MFO) proton plans were developed with a 3 mm setup and 3.5% range uncertainties. For photon planning, volumetric modulated arc therapy (VMAT) plans were developed for the initial and boost plans. OAR dose constraints were set according to our institutional guidelines. Results: For the 4 spine configurations, the proton plans achieved similar nominal target coverage and OARs sparing. While evaluating coverage and OAR dose under uncertainty scenario analysis for initial clinical target volume (CTV) 50 Gy 95% and 90% coverage, higher means and the narrower band of doses variations were achieved for the normal and CFR-PEEK plans. Similarly, uncertainty analysis of spinal cord Dmax showed tighter distribution for normal and CFR-PEEK plans. Overall plan quality showed no significant difference for photon planning when compared to normal spine versus other inserts. However, for proton planning, there is a larger difference for the normal spine insert scenario versus the Titanium insert scenario. For each insert scenario comparison between photon and proton plans, there was a larger difference for OARs: heart and spinal cord. Conclusion: The CFR-PEEK implant has similar clinical properties to a normal spine for proton planning, allowing us to pass protons through the material and achieve superior target coverage and OAR sparing under nominal and uncertainty conditions.

Using patient-specific bolus for pencil beam scanning proton treatment of periorbital disease.

PURPOSE: A unique mantle cell lymphoma case with bilateral periorbital disease unresponsive to chemotherapy and with dosimetry not conducive to electron therapy was treated with pencil beam scanning (PBS) proton therapy. This patient presented treatment planning challenges due to the thin target, immediately adjacent organs at risk (OAR), and nonconformal orbital surface anatomy. Therefore, we developed a patient-specific bolus and hypothesized that it would provide superior setup robustness, dose uniformity and dose conformity. MATERIALS/METHODS: A blue-wax patient-specific bolus was generated from the patient's face contour to conform to his face and eliminate air gaps. A relative stopping power ratio (RSP) of 0.972 was measured for the blue-wax, and the HUs were overridden accordingly in the treatment planning system (TPS). Orthogonal kV images were used for bony alignment and then to ensure positioning of the bolus through fiducial markers attached to the bolus and their contours in TPS. Daily CBCT was used to confirm the position of the bolus in relation to the patient's surface. Dosimetric characteristics were compared between (a) nonbolus, (b) conventional gel bolus and (c) patient-specific bolus plans. An in-house developed workflow for assessment of daily treatment dose based on CBCT images was used to evaluate inter-fraction dose accumulation. RESULTS: The patient was treated to 24 cobalt gray equivalent (CGE) in 2 CGE daily fractions to the bilateral periorbital skin, constraining at least 50% of each lacrimal gland to under 20 Gy. The bolus increased proton beam range by adding 2-3 energy layers of different fields to help achieve better dose uniformity and adequate dose coverage. In contrast to the plan with conventional gel bolus, dose uniformity was significantly improved with patient-specific bolus. The global maximum dose was reduced by 7% (from 116% to 109%). The max and mean doses were reduced by 6.0% and 7.7%, respectively, for bilateral retinas, and 3.0% and 13.9% for bilateral lacrimal glands. The max dose of the lens was reduced by 2.1%. The rigid shape, along with lightweight, and smooth fit to the patient face was well tolerated and reported as "very comfortable" by the patient. The daily position accuracy of the bolus was within 1 mm based on IGRT marker alignment. The daily dose accumulation indicates that the target coverage and OAR doses were highly consistent with the planning intention. CONCLUSION: Our patient-specific blue-wax bolus significantly increased dose uniformity, reduced OAR doses, and maintained consistent setup accuracy compared to conventional bolus. Quality PBS proton treatment for periorbital tumors and similar challenging thin and shallow targets can be achieved using such patient-specific bolus with robustness on both setup and dosimetry.

Intrafraction tumor motion during deep inspiration breath hold pancreatic cancer treatment.

PURPOSE: Beam gating with deep inspiration breath hold (DIBH) has been widely used for motion management in radiotherapy. Normally it relies on some external surrogate for estimating the internal target motion, while the exact internal motion is unknown. In this study, we used the intrafraction motion review (IMR) application to directly track an internal target and characterized the residual motion during DIBH treatment for pancreatic cancer patients through their full treatment courses. METHODS AND MATERIALS: Eight patients with pancreatic cancer treated with DIBH volumetric modulated arc therapy in 2017 and 2018 were selected for this study, each with some radiopaque markers (fiducial or surgical clips) implanted near or inside the target. The Varian Real-time Position Management (RPM) system was used to monitor the breath hold, represented by the anterior-posterior displacement of an external surrogate, namely reflective markers mounted on a plastic block placed on the patient's abdomen. Before each treatment, a cone beam computed tomography (CBCT) scan under DIBH was acquired for patient setup. For scan and treatment, the breath hold reported by RPM had to lie within a 3 mm window. IMR kV images were taken every 20° or 40° gantry rotation during dose delivery, resulting in over 5000 images for the cohort. The internal markers were manually identified in the IMR images. The residual motion amplitudes of the markers as well as the displacement from their initial positions located in the setup CBCT images were analyzed. RESULTS: Even though the external markers indicated that the respiratory motion was within 3 mm in DIBH treatment, significant residual internal target motion was observed for some patients. The range of average motion was from 3.4 to 7.9 mm, with standard deviation ranging from 1.2 to 3.5 mm. For all patients, the target residual motions seemed to be random with mean positions around their initial setup positions. Therefore, the absolute target displacement relative to the initial position was small during DIBH treatment, with the mean and the standard deviation 0.6 and 2.9 mm, respectively. CONCLUSIONS: Internal target motion may differ from external surrogate motion in DIBH treatment. Radiographic verification of target position at the beginning and during each fraction is necessary for precise RT delivery. IMR can serve as a useful tool to directly monitor the internal target motion.

Effects of irregular respiratory motion on the positioning accuracy of moving target with free breathing cone-beam computerized tomography.

For positioning a moving target, a maximum intensity projection (MIP) or average intensity projection (AIP) image derived from 4DCT is often used as the reference image which is matched to free breathing cone-beam CT (FBCBCT) before treatment. This method can be highly accurate if the respiratory motion of the patient is stable. However, a patient's breathing pattern is often irregular. The purpose of this study is to investigate the effects of irregular respiration on positioning accuracy for a moving target aligned with FBCBCT. Nine patients' respiratory motion curves were selected to drive a Quasar motion phantom with one embedded cubic and two spherical targets. A 4DCT of the phantom was acquired on a CT scanner (Philips Brilliance 16) equipped with a Varian RPM system. The phase binned 4DCT images and the corresponding MIP and AIP images were transferred into Eclipse for analysis. FBCBCTs of the phantom driven by the same respiratory curves were also acquired on a Varian TrueBeam and fused such that both CBCT and MIP/AIP images share the same target zero positions. The sphere and cube volumes and centroid differences (alignment error) determined by MIP, AIP and FBCBCT images were calculated, respectively. Compared to the volume determined by MIP, the volumes of the cube, large sphere, and small sphere in AIP and FBCBCT images were smaller. The alignment errors for the cube, large sphere and small sphere with center to center matches between MIP and FBCBCT were 2.5 ± 1.8mm, 2.4±2.1 mm, and 3.8±2.8 mm, and the alignment errors between AIP and FBCBCT were 0.5±1.1mm, 0.3±0.8mm, and 1.8±2.0 mm, respectively. AIP images appear to be superior reference images to MIP images. However, irregular respiratory pattern could compromise the positioning accuracy, especially for smaller targets.

Rotation effects on the target-volume margin determination.

Rotational setup errors are usually neglected in most clinical centers. An analytical formula is developed to determine the extra margin between clinical target volume (CTV) and planning target volume (PTV) to account for setup errors. The proposed formula corrects for both translational and rotational setup errors and then incorporated into margin determination for PTV.

Nitric oxide signaling and neural stem cell differentiation in peripheral nerve regeneration.

OBJECTIVE: The objective was to examine whether nitric oxide signaling plays a role in human embryonic stem cell differentiation into neural cells. This article reviews current literature on nitric oxide signaling and neural stem cell differentiation for potential therapeutic application to peripheral nerve regeneration. METHODS: Human embryonic H9-stem cells were grown, maintained on mitomycin C-treated mouse embryonic fibroblast feeder layer, cultured on Matrigel to be feeder-free, and used for all the experiments. Fluorescent dual-immunolabeling and confocal image analysis were used to detect the presence of the neural precursor cell markers nestin and nitric oxide synthase-1. Fluorescence-activated cell sorting analysis was used to determine the percentage of expression. RESULTS: We have shown the confocal image of stage 1 human embryonic stem cells coexpressing nestin and nitric oxide synthase-1. Fluorescence-activated cell sorting analysis indicated 24.3% positive labeling of nitric oxide synthase-1. Adding retinoic acid (10(-6) M) to the culture medium increased the percent of nitric oxide synthase-1 positive cells to 33.9%. Combining retinoic acid (10(-6) M) with 8-brom cyclic guanosine monophosphate (10(-5) M), the fluorescence-activated cell sorting analysis demonstrated a further increase of nitric oxide synthase-1 positive cells to 45.4%. Our current results demonstrate a prodifferentiation potency of nitric oxide synthase-1, stimulated by retinoic acid with and without cyclic guanosine monophosphate. CONCLUSION: We demonstrated for the first time how nitric oxide/cyclic guanosine monophosphate signaling contributes to the development of neural precursors derived from human embryonic stem cells and enhances the differentiation of precursors toward functional neurons for peripheral nerve regeneration.

Treatment with antisense oligonucleotide reduces the expression of type I collagen in a human-skin organ-wound model: implications for antifibrotic gene therapy.

Increased collagen expression during wound healing causes scar formation, abnormal contracture, low tensile strength, functional impairment, and disfigurement. A novel ex vivo wound-injury model demonstrated that AS60, an antisense oligonucleotide (ASO) to type I collagen, reduced the mRNA and protein expression of type 1 collagen. Following a cutaneous wound injury in a human-skin organ culture, AS60 injection resulted in a 36% (P < 0.001) and 30% decrease (P < 0.001) in type 1 collagen mRNA and protein expression after 7 days. Similarly, transfection of cultured human fibroblasts with ASO resulted in a 36% decrease (P < 0.001) and a 31% decrease (P < 0.001) in type 1 collagen mRNA and protein expression. Immunofluorescence of human skin organ culture treated with ASO showed a specific reduction in collagen expression. Using AS60 to reduce collagen expression in human skin may have implications for its use as a gene therapy agent to reduce the formation of fibrotic scarring.

Rational drug design of G-quartet DNA as anti-cancer agents.

The ability of certain DNA sequences to form G-quartet structures has been exploited recently to develop novel anti-cancer agents including small molecules that promote G-quartet formation within the c-MYC promoter thereby repressing c-MYC transcription and introducing G-quartet-forming oligodeoxynucleotides (GQ-ODN) into cancer cells resulting in p53-dependent cell cycle arrest and inhibition of DNA replication. GQ-ODNs also have been developed as potent inhibitors of signal transducer and activator of transcription (STAT) 3, a critical mediator of oncogenic signaling in many cancers. This review summarizes the rational design of G-quartet forming DNA drugs as Stat3 inhibitors. Topics that are reviewed include the strategy of structure-based drug design, establishment of a structure-activity relationship, development of a novel intracellular delivery system for G-quartet-forming DNA agents and in vivo drug testing to assess the anti-cancer effects of DNA drugs in tumor xenografts. Results to date with GQ-ODN targeting Stat3 are encouraging, and it is hoped that continued pursuit of the methodology outlined here may lead to development of an effective agent for treatment of metastatic cancers, such as prostate and breast, in which Stat3 is constitutively activated.

Dosimetric advantage and clinical implication of a micro-multileaf collimator in the treatment of prostate with intensity-modulated radiotherapy.

This paper investigates the dosimetric benefits of a micro-multileaf (4-mm leaf width) collimator (mMLC) for intensity-modulated radiation therapy (IMRT) treatment planning of the prostate cancer and its potential application for dose escalation and hypofractionation. We compared treatment plans for IMRT delivery using 2 different multileaf collimator (MLC) leaf widths (4 vs. 10 mm) for 10 patients with prostate cancer. Treatment planning was performed on the XknifeRT2 treatment planning system. All beams and optimization parameters were identical for the mMLC and MLC plans. All of the plans were normalized to ensure that 95% of the planning target volume (PTV) received 100% of the prescribed dose (74 Gy). The differences in dose distribution between the 2 groups of plans using the mMLC and the MLC were assessed by dose-volume histogram (DVH) analysis of the target and critical organs. Significant reductions in the volume of rectum receiving medium to higher doses were achieved using the mMLC. The average decrease in the volume of the rectum receiving 40, 50, and 60 Gy using the mMLC plans was 40.2%, 33.4%, and 17.7%, respectively, with p-values less than 0.0001 for V40 and V50 and 0.012 for V60. The mean dose reductions for D17 and D35 for the rectum were 20.0% (p < 0.0001) and 18.3% (p < 0.0002), respectively, when compared to those with the MLC plans. There were consistent reductions in all dose indices studied for the bladder. The target dose inhomogeneity was improved in the mMLC plans by an average of 32%. In the high-dose range, there was no significant difference in the dose deposited in the "hottest" 1 cc of the rectum between the 2 MLC plans for all cases (p > 0.78). Because of the reduction of rectal volume receiving medium to higher doses, dose to the prostate target can be escalated by about 20 Gy to over 74 Gy, while keeping the rectal dose (either denoted by D17 or D35) the same as those with the use of the MLC. The maximum achievable dose, derived when the rectum is allowed to reach the tolerance level, was found to be in the range of 113-172 Gy (using the tolerance value of D17). We conclude that the use of the mMLC for IMRT of the prostate may facilitate dose hypofractionation due to its dosimetric advantage in significantly improving the DVH parameters of the prostate and critical organs. When used for conventional fractionation scheme, mMLC for IMRT of the prostate may reduce the toxicity to the critical organs.

G-quartet oligonucleotides: a new class of signal transducer and activator of transcription 3 inhibitors that suppresses growth of prostate and breast tumors through induction of apoptosis.

Stat3 is a signaling molecular and oncogene activated frequently in many human malignancies including the majority of prostate, breast, and head and neck cancers; yet, no current chemotherapeutic approach has been implemented clinically that specifically targets Stat3. We recently developed G-rich oligodeoxynucleotides, which form intramolecular G-quartet structures (GQ-ODN), as a new class of Stat3 inhibitor. GQ-ODN targeted Stat3 protein directly inhibiting its ability to bind DNA. When delivered into cells using polyethyleneimine as vehicle, GQ-ODN blocked ligand-induced Stat3 activation and Stat3-mediated transcription of antiapoptotic genes. To establish the effectiveness of GQ-ODN as a potential new chemotherapeutic agent, we systemically administered GQ-ODN (T40214 or T40231) plus polyethyleneimine or polyethyleneimine alone (placebo) by tail-vein injection into nude mice with prostate and breast tumor xenografts. Whereas the mean volume of breast tumor xenografts in placebo-treated mice increased >7-fold over 18 days, xenografts in the GQ-ODN-treated mice remained unchanged. Similarly, whereas the mean volume of prostate tumor xenografts in placebo-treated mice increased 9-fold over 10 days, xenografts in GQ-ODN-treated mice increased by only 2-fold. Biochemical examination of tumors from GQ-ODN-treated mice demonstrated a significant reduction in Stat3 activation, levels of the antiapoptotic proteins Bcl-2 and Bcl-xL, and an 8-fold increase in the number of apoptotic cells compared with the tumors of placebo-treated mice. Thus, GQ-ODN targeting Stat3 induces tumor cell apoptosis when delivered into tumor xenografts and represents a novel class of chemotherapeutic agents that holds promise for the systemic treatment of many forms of metastatic cancer.

Potassium-dependent folding: a key to intracellular delivery of G-quartet oligonucleotides as HIV inhibitors.

Several groups have demonstrated that G-rich oligonucleotides forming G-quartet structures display activity as potential drugs, such as potent HIV inhibitors. The delivery of G-quartet oligonucleotides to their intracellular targets is a key obstacle to overcome for their clinical success. Here we have developed a novel system to deliver G-rich oligonucleotides into the cell nucleus, e.g., the site of HIV integration. On the basis of the property of potassium-induced formation of G-quartet structure, we explored the difference of K(+) concentrations inside (140 mM) and outside (4 mM) cells to induce the G-rich oligonucleotides to form different structures inside and outside cells. The key steps of this delivery system include the following: (i) First, the G-quartet structure is denatured to form a lipid-DNA complex, so that the molecules can be well delivered into cells. (ii) Then the delivered molecules are induced to form G-quartet structures by potassium inside cells since the G-quartet structure is the primary requirement for inhibition of HIV-1 HIV integrase (IN) activity. The molecules of a novel G-quartet HIV inhibitor, T40214, with the sequence of (GGGC)(4) were successfully delivered into the nuclei of target cells, which significantly decreased HIV-1 replication and increased the probability to target HIV-1 IN in infected cells.