Irregular Vascularization Research Articles

In Silico Approach to Model Heat Distribution of Magnetic Hyperthermia in the Tumoral and Healthy Vascular Network Using Tumor-on-a-Chip to Evaluate Effective Therapy.

Glioblastoma multiforme (GBM) is the most severe form of brain cancer in adults, characterized by its complex vascular network that contributes to resistance to conventional therapies. Thermal therapies, such as magnetic hyperthermia (MHT), emerge as promising alternatives, using heat to selectively target tumor cells while minimizing damage to healthy tissues. The organ-on-a-chip can replicate this complex vascular network of GBM, allowing for detailed investigations of heat dissipation in MHT, while computational simulations refine treatment parameters. In this in silico study, tumor-on-a-chip models were used to optimize MHT therapy by comparing heat dissipation in normal and abnormal vascular networks, considering geometries, flow rates, and concentrations of magnetic nanoparticles (MNPs). In the high vascular complexity model, the maximum velocity was 19 times lower than in the normal vasculature model and 4 times lower than in the low-complexity tumor model, highlighting the influence of vascular complexity on velocity and temperature distribution. The MHT simulation showed greater heat intensity in the central region, with a flow rate of 1 µL/min and 0.5 mg/mL of MNPs being the best conditions to achieve the therapeutic temperature. The complex vasculature model had the lowest heat dissipation, reaching 44.15 °C, compared to 42.01 °C in the low-complexity model and 37.80 °C in the normal model. These results show that greater vascular complexity improves heat retention, making it essential to consider this heterogeneity to optimize MHT treatment. Therefore, for an efficient MHT process, it is necessary to simulate ideal blood flow and MNP conditions to ensure heat retention at the tumor site, considering its irregular vascularization and heat dissipation for effective destruction.

Advanced multimodal imaging of solid thyroid lesions with artificial intelligence-optimized B-mode, elastography, and contrast-enhanced ultrasonography parametric and with perfusion imaging: Initial results.

Goal of the study was the assessment of AI-assisted diagnosis of solid thyroid foci with multimodal modern ultrasound imaging. 50 patients (26-81 years, 54.7±13.1 years) were included in the study. Multimodal ultrasound imaging by means of B-mode with linear probe (4-12 MHz) with option of automated documentation of findings by means of AI, with supplementary Ultra MicroAngiography (UMA) was used. Macrovascularisation was assessed by dynamic contrast ultrasonography (CEUS) with parametric evaluation and perfusion analysis, and microvascularization was assessed by combined strain and shear wave elastography on a novel high-performance ultrasound system (Resona R9/Mindray) by an experienced examiner with independent reading. The evaluation was performed according to TI-RADS III-V.The volume of the thyroid lobes on both sides averaged 39 ml±5 ml (27 to 69 ml). The 13 cases of histologically confirmed thyroid carcinomas (8 papillary, 2 medullary, 2 microfollicular, 1 anaplastic CA) with a mean size of 15 mm±6 mm (9-21 mm) were correctly evaluated by TI-RADS V on the basis of irregular shape, induration > 2.5 m/s or > 30kPA and striking wash-out kinetics. Tumor lymph nodes could only be correctly detected preoperatively in one case of medullary carcinoma according to the surgical findings, based on irregular vascularization with UMA in roundish shape with cortex > 4 mm, transverse diameter up to 11 mm. In 25 cases of inhomogeneous nodular goiter an evaluation with TI-RADS III was performed in 31 cases, in 4 cases with incomplete marginal contour, partial marginal vascularization with UMA and partial wash out with indurations up to 2.5 m/s 30 kPA an evaluation with TI-RADS IV and surgical excision for nodular goiter. In 12 cases regressive nodular changes without relevant malignancy criteria resulted in nodular goiter, with focal changes up to 1.5 cm in diameter, classified as requiring control with TI-RADS III. There were no relevant changes in findings in the controls after 6 months. From the AI tool, the 20/25 goiter nodes were assessed as TI-RADS III, 7/12 adenomas, 5 goiter nodes, and 5 adenomas as TI-RADS IV, 5/13 carcinomas as TI-RADS IV, and 8/13 carcinomas as TI-RADS V.Multimodal ultrasound diagnostics supported by AI has a high diagnostic potential for the evaluation of solid thyroid lesions and standardizes the reporting with digital representative image documentation. CEUS perfusion and modern elastography techniques allow targeted follow-up of TI-RADS III findings.

Triple negative breast cancer originating from a cystic lesion

According to the World Health Organization, 2.3 million women worldwide were diagnosed with breast cancer in the year 20201 . Triple negative breast cancer, which lacks the expression of hormone receptors and HER-2, accounted for 12% of breast tumors diagnosed in the United States of America between 2012 and 20162 . In addition to the known risk factors for the development of breast cancer, specifically in this type of neoplasm, there are other risk factors, such as age below 40 years, mutation in BRCA1/2 genes and African American ethnicity2,3. The diagnosis of invasive breast carcinoma is made through associated clinical and radiological characteristics and confirmation by cytopathological or histopathological biopsy⁴. Considering the classification of the American College of Radiology (BI-RADS®), simple cysts are classified, in general, as a benign finding, that is BI-RADS 2. However, they can be evaluated as suspicious or highly suspicious (BI-RADS 4 or 5) when presenting hemorrhagic content, signs of wall thickening, irregular septa, associated solid lesion, irregular vascularization, among other radiological findings related to malignancy4-6. Semiology is important to identify a change in the biological behavior of a simple cyst. Cystic lesions characterized as benign, but showing alterations, such as increased size and suspicious radiological characteristics, should be investigated5,6. The objective of this work was to document the case of a young pregnant patient with triple negative breast cancer, diagnosed in the wall of a lesion, previously characterized as a simple cyst.

Gallic acid and myricetin-rich Labisia pumila extract mitigated multiple diabetic eye disorders in rats.

Diabetes affected about a quarter of a billion people globally, and one out of four diabetics has eye or vision problems. This study investigated whether gallic acid and myricetin-rich Labisia pumila extract (LP) consumption would help prevent diabetic eye disorders and some probable biochemistry involved relating to inflammation, vascular leakage, and oxidative tension. Male rats were divided into four groups (n=6), namely healthy control, diabetic non-treated control, and hyperglycemic rats treated with 150 or 300mg/kg LP. Intraperitoneal injection of 60mg/kg streptozotocin was used to induce diabetes. Rats were fed in the morning and evening. Diabetic retinopathy was graded in rats using a dilated retinal digital ophthalmoscopy. Rats were sacrificed at 12weeks and the retina, optic nerve, cornea, lens, sclera, ciliary bodies, iris, and conjunctiva were examined histologically. The diabetic rats consuming LP for 10weeks showed dose-dependent, histopathologically-reduced eye abnormalities (keratopathy, cataract, sclera, conjunctiva, ciliary bodies, iris, limbus, corneal edema, epithelial barrier inefficiency, shallow punctate keratitis, lower basal layer cell density, retinopathy, glaucoma, and corneal changes). The LP significantly suppressed inflammation [increased serum tumor necrosis factor-α (TNF-α), prostaglandin-E2 (PGE2)], vascular leakage [claudin-1], abnormal vascularization [vascular endothelial growth factor (VEGF)], oxidative tension [malondialdehyde/reduced glutathione ratio], and hyperglycemia [fasting blood glucose] of the diabetic rats. The LP consumption was significantly protective against diabetic eye disorders and optic nerve dysfunction which were related to inflammation, vascular leakage, abnormal vascularization, and oxidative tension, which most likely influenced eye hemorrhage and collagen cross-linkage. PRACTICAL APPLICATIONS: The study shows that gallic acid and myricetin-rich Labisia pumila (LP) leaf consumption may be used as a complementary therapy for managing diabetes (fasting blood glucose) and preventing diabetic eye disorders (keratopathy, cataract, sclera, conjunctiva, ciliary bodies, iris, limbus, corneal edema, epithelial barrier inefficiency, shallow punctate keratitis, lower basal layer cell density, retinopathy, glaucoma, and corneal abnormalities). The LP consumptions reduced the serum biomarkers for inflammation (serum tumor necrosis factor-α TNF-α; prostaglandin-E2), vascular leakage/abnormalities (claudin-1 and vascular endothelial growth factor VEGF), and oxidative tension (malondialdehyde/reduced glutathione MDA/GSH ratio). The LP was eye-protective probably by normalizing fasting blood glucose, reducing inflammation, oxidative tension, vascular leakage, and irregular vascularization.

A Simplified Ultrasonographic Score for the Prediction ofCytologically Suspicious Thyroid Nodules.

The major aim of ultrasound (US)-based risk stratification systems is to reduce unnecessary thyroid biopsies without losing the ability to recognize nodules with clinically significant malignancy. Each of the classic suspicious features of a thyroid nodule detected on US scan (hypoechoic pattern, microcalcifications, irregular margin, taller than wide shape, irregular vascularization) is significantly independently associated with the probability of malignancy, but none of them has good diagnostic accuracy. Thus, we evaluated the predictive value of a binary score simply based on the combination of these US features, regardless of the specific predictive value of each US feature, against the outcome of suspected malignancy at cytological diagnosis (TIR3 to TIR5 categories by SIAPEC-IAP [TIR+]). 1009 thyroid nodules from 1081patients were considered. The US features of suspicion of all nodules were categorized in 5 binary scores (U1 to U5), each including from 1 to 5 of those features. U2 (at least 2 US suspicious features) was the most balanced predictor of TIR+ (PPV 0.48, NPV 0.93, LR+ 3.05 and LR- 0.24). Weighting the predictivity of the single features did not improve the estimate. Using U2 as the criterion to send nodules to FNAC would have reduced the number of biopsies by 60 % (604 patients) and the false negatives would have only accounted for 41 cases out of 237 TIR+ (17 %) with 39 cases of TIR3 and 2 cases of TIR4, including only 6 malignant nodules on histological examination. U2 performed much better than the ATA recommendations for detecting those nodules, resulting in TIR+ at cytology. This simple and reproducible sonographic score based on 2 US features of suspicion of malignancy has quite a good performance with respect to identifying thyroid lesions categorized by cytology as medium-high risk of malignancy and could allow us to reduce cytology costs for low-risk nodules.

The effect of PHD inhibitor on tumor microenvironment and tumor immune response

Tumor tissue environment is generally exposed to low oxygen, nutrition depletion and high interstitial pressure condition. These circumstances are caused by vascular hyper-permeability, irregular vascularization and immature vessels. The blood vessel is important tissue structures to deliver oxygen, nutrition and so on. An abnormal blood vessel formation is a common feature of tumor tissue that were characterized by hyper-permeability, irregular vascularization, immature vessels and intravasation. Therefore, tumor tissue is exposed to low oxygen nutrition depletion and low pH due to hypoperfusion and elevated interstitial pressure. These environments are one of the reasons for chemo- and radio-resistance. Previously, we reported that prolyl hydroxylase (PHD) inhibitor induced tumor blood vessel normalization and improved tumor microenvironment in tumor mouse model. However, effects of PHD inhibitor on tumor progression is controversial. Enhanced hypoxia inducible factors (HIFs) signaling in cancer cells act to promote cancer proliferation and metastases. On the other hand, increasing of HIFs signaling in immune cells may lead to activate inflammation and elicit anti-tumor effect. We describe our study how PHD inhibitor improved tumor microenvironment and focused on tumor infiltrate immune cells were phenotypic alteration after PHD inhibitor treatment in mouse model. Our results implied that PHD inhibitor was possibly beneficial for anti-cancer therapy.

Electric field distribution study in inhomogeneous biological tissues

AbstractMost solid tumors are inhomogeneous, because of the different types of cells present, different tissues and fat, etc, along with irregular vascularization, pH variation, and heterogeneous oxygen concentration. It is of interest to study the electric field distribution when electrochemotherapy is administered. The variations in the physical and hence the electrical properties, such as the resistance (or conductance), will vary, and parts of the tumor might not get the same electric field and hence will not have the required or the desired efficacy. In this study, the effect of tissue inhomogeneity is explored using potato and apple tissue samples. For this purpose, agar gel and other tissue mimic materials are used to create the inhomogeneity and pulsed to study the effect of electrical pulses. In addition, the electric field distribution is studied using a numerical model to evaluate the effect of tissue inhomogeneity in terms of electric field distribution when electroporation is applied to permeabilize cells, for enhanced drug uptake. The electric field is evaluated by means of finite element analysis and is compared with the distribution found in a phantom model. Good correlation is obtained between the experimental and simulation results. This research has the potential to study the real tumor inhomogeneity conditions.

Abstract 187: Trastuzumab induced myeloid cell alterations identifies mechanistic properties of vascular normalization

Abstract Introduction: The purpose of this study is to quantify longitudinal changes in myeloid cell infiltration after trastuzumab treatment to reveal mechanistic properties of improved tumor vascularization in human epidermal growth factor receptor type 2 positive (HER2+) breast cancer. We have previously presented in vivo data showing that trastuzumab increases vascular maturation leading to better delivery of therapeutics. The balance of myeloid cells in the tumor microenvironment (TME) can impact neovascularization. Specifically, M2 macrophages (MACs) promote angiogenesis causing irregular vascularization and M1 MACs exhibit anti-angiogenic properties counteracting the M2 cells and improving tumor perfusion. We present results revealing macrophage polarization towards an M1 phenotype after trastuzumab therapy in HER2+ tumors. Experimental Design: 107 BT474 breast cancer cells were implanted subcutaneously into athymic nude mice. After tumors reached 250 mm3, mice were treated with trastuzumab (10 mg/kg) or saline over one week and were excised for analysis on days 0, 4 and 7. Half of each tumor was fixed in 10% neutral buffered formalin for immunohistochemical staining (IHC) of the TME and half was digested for analysis of myeloid cell infiltration with flow cytometry. The flow cytometry panel used consists of ten markers, two specifically for the identification of M1 and M2 MACs; CD38, and CD206, respectively. A non-parametric Wilcoxon rank sum test was used to determine statistical differences between control and treated groups. Results and Discussion: Initial studies revealed an increase (P = 0.03) of MACs in day 4 and day 7 treated tumors. Of these MACs, there was an increase (P = 0.03) in co-expression of M2 and M1 phenotype markers CD206 and CD38 in day 4 treated tumors indicating a phenotypic switch occurring. After a third dose of trastuzumab, there was an increase (P = 0.03) in M1 MACs (CD38+/CD206-) in day 7 treated tumors. In day 4 and 7 treated tumors, there was a decrease (P = 0.02) in non-differentiated MACs (CD38-/CD206-) supporting evidence that a phenotypic switch is occurring. Ongoing studies are evaluating spatial variations in MAC infiltration (CD206, F4/80), hypoxia (pimonidazole), and vascular maturation index (ratio of alpha-smooth muscle actin to total vessel counts as stained with CD31) through IHC. Cytokine detection assays are being done to evaluate changes in cytokines contributing to macrophage polarization and angiogenesis. Conclusion: These results offer strong evidence supporting the hypothesis that MACs in the TME are switching to an M1 phenotype after trastuzumab treatment and contributing to trastuzumab induced vascular alterations. Analyses of IHC will validate vascular changes occurring simultaneously with myeloid infiltratration. Citation Format: Meghan J. Bloom, Angela M. Jarrett, Todd A. Triplett, Anum K. Syed, Thomas E. Yankeelov, Anna G. Sorace. Trastuzumab induced myeloid cell alterations identifies mechanistic properties of vascular normalization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 187.

The effect of PHD inhibitor on tumor microenvironment and tumor immune response

Tumor tissue environment is generally exposed to low oxygen, nutrition depletion and high interstitial pressure condition. These circumstances are caused by vascular hyper-permeability, irregular vascularization and immature vessels. The blood vessel is important tissue structures to deliver oxygen, nutrition and so on. An abnormal blood vessel formation is a common feature of tumor tissue that were characterized by hyper-permeability, irregular vascularization, immature vessels and intravasation. Therefore, tumor tissue is exposed to low oxygen nutrition depletion and low pH due to hypoperfusion and elevated interstitial pressure. These environments are one of the reasons for chemo- and radio-resistance. Previously, we reported that prolyl hydroxylase (PHD) inhibitor induced tumor blood vessel normalization and improved tumor microenvironment in tumor mouse model. However, effects of PHD inhibitor on tumor progression is controversial. Enhanced hypoxia inducible factors (HIFs) signaling in cancer cells act to promote cancer proliferation and metastases. On the other hand, increasing of HIFs signaling in immune cells may lead to activate inflammation and elicit anti-tumor effect. We describe our study how PHD inhibitor improved tumor microenvironment and focused on tumor infiltrate immune cells were phenotypic alteration after PHD inhibitor treatment in mouse model. Our results implied that PHD inhibitor was possibly beneficial for anti-cancer therapy.

(Invited) High Efficient Tumor Therapeutic Technique Based on Water Soluble Metallofullerene Derivatives

For a long time, researchers have been puzzled of the therapy of malignant tumors and the current therapeutic strategies are always accompanied by toxicity or side effects. Making use of the irregular vascularization with abnormal leakiness of the tumor vessels, gadofullerene nanoparticles functionalized with amino acid (specially β-alanine, abbreviated as GF-Ala), circulate in the blood and then accumulate at the tumor site through the enhanced permeation and retention (EPR) effect. Due to the involvement of β-alanine onto the fullerene cage improving the uniformity of size distribution, magnetic properties and the affinity with proteins, GF-Ala nanoparticles assisted by radiofrequency have exhibited a higher antitumor activity than multihydroxylated gadolinium endohedral metallofullerenes (GF-OH) nanoparticlesour recently reported. We speculate the superior properties of GF-Ala nanoparticles result in a stronger interaction with radiofrequency and long blood circulation time, which would influence the nanoparticles to destruction of tumor vasculature. Long-term toxicity evaluation show GF-Ala nanoparticles could be eliminated from the mice after several days and no obvious toxicity was found to the main organs. All these results suggest GF-Ala is valuable to develop into a potential anticancer drug with high-efficacy and low-toxicity Reference s Zhou Y.; Deng, R.J.; Zhen, M.M.; Li, J.; Guan, M.R.; Jia, W.; Li, X.; Zhang, Y.; Yu, T., Zou, T.J.; Lu, Z.G.; Guo, J.; Sun, L.; Shu, C.Y.; Wang, C.R. Biomaterials, 2017, 133, 107Zhen, M.M.; Shu, C.Y.; Li, J.; Zhang, G.Q.; Wang, T.S.; Luo, Y.; Zou, T.J.; Deng, R.J.; Fang, F.; Lei, H.; Wang, C.R.; Bai, C.L.. Science China-Materials, 2015, 58, 799

The visualization of gastro-esophageal junction vascular supply during a laparoscopic sleeve gastrectomy. Role of a new device.

Leaks arising at the level of gastro-esophageal junction remain a major complication in patients who undergo a laparoscopic sleeve gastrectomy. Besides technical pitfalls, these fistulas are mainly attributable to tissue ischemia following the preparation of the gastric sleeve, explained by the irregular vascularization often present in the area of the gastro-esophageal junction. This video presentation shows how, the utilization of a new model of bougie can be of help in preventing a leak, allowing a better visualization of the particular vascular anatomy present at the level of the gastro-esophageal junction area. Currently, 25/334 (18 F-7 M) (7.4%) patients, who underwent a laparoscopic sleeve gastrectomy at our institution, were operated on using this new model of bougie. No leaks have been so far reported.

HER2 isoforms co-expression differently tunes mammary tumor phenotypes affecting onset, vasculature and therapeutic response.

Full-length HER2 oncoprotein and splice variant Delta16 are co-expressed in human breast cancer. We studied their interaction in hybrid transgenic mice bearing human full-length HER2 and Delta16 (F1 HER2/Delta16) in comparison to parental HER2 and Delta16 transgenic mice. Mammary carcinomas onset was faster in F1 HER2/Delta16 and Delta16 than in HER2 mice, however tumor growth was slower, and metastatic spread was comparable in all transgenic mice. Full-length HER2 tumors contained few large vessels or vascular lacunae, whereas Delta16 tumors presented a more regular vascularization with numerous endothelium-lined small vessels. Delta16-expressing tumors showed a higher accumulation of i.v. injected doxorubicin than tumors expressing full-length HER2. F1 HER2/Delta16 tumors with high full-length HER2 expression made few large vessels, whereas tumors with low full-length HER2 and high Delta16 contained numerous small vessels and expressed higher levels of VEGF and VEGFR2. Trastuzumab strongly inhibited tumor onset in F1 HER2/Delta16 and Delta16 mice, but not in full-length HER2 mice. Addiction of F1 tumors to Delta16 was also shown by long-term stability of Delta16 levels during serial transplants, in contrast full-length HER2 levels underwent wide fluctuations. In conclusion, full-length HER2 leads to a faster tumor growth and to an irregular vascularization, whereas Delta16 leads to a faster tumor onset, with more regular vessels, which in turn could better transport cytotoxic drugs within the tumor, and to a higher sensitivity to targeted therapeutic agents. F1 HER2/Delta16 mice are a new immunocompetent mouse model, complementary to patient-derived xenografts, for studies of mammary carcinoma onset, prevention and therapy.

Abstract IA20: Hypoxic influences on the tumor microenvironment

Abstract Solid tumors typically develop hostile microenvironments characterized by irregular vascularization and poor oxygen (O2) and nutrient supply. Whereas normal cells modulate anabolic and catabolic pathways in response to changes in nutrient availability, cancer cells exhibit unregulated growth even under nutrient scarcity. Recent studies have demonstrated that constitutive activation of growth-promoting pathways results in dependence on unsaturated fatty acids for survival under O2 deprivation. In cancer cells, this dependence represents a critical metabolic vulnerability that could be exploited therapeutically. Here I will review how this dependence on unsaturated lipids is affected by the microenvironmental conditions faced by cancer cells, particularly in the setting of sarcomas. Citation Format: M. Celeste Simon. Hypoxic influences on the tumor microenvironment. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr IA20.

Abstract IA08: Hypoxia, metabolism, and tumor progression

Abstract Solid tumors typically develop hostile microenvironments characterized by irregular vascularization and poor oxygen (O2) and nutrient supply. Whereas normal cells modulate anabolic and catabolic pathways in response to changes in nutrient availability, cancer cells exhibit unregulated growth even under nutrient scarcity. Recent studies have demonstrated that constitutive activation of growth-promoting pathways results in dependence on unsaturated fatty acids for survival under O2 deprivation. In cancer cells, this dependence represents a critical metabolic vulnerability that could be exploited therapeutically. I will review how this dependence on unsaturated lipids is affected by the microenvironmental conditions faced by cancer cells. Citation Format: M Celeste Simon. Hypoxia, metabolism, and tumor progression. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr IA08.

Which lesions should be biopsied during high-resolution anoscopy? Prospective descriptive study of simple morphological criteria.

High-resolution anoscopy (HRA) is a useful screening tool for anal intraepithelial neoplasia (AIN), although reputedly challenging for interpretation of suspected lesions. All consecutive patients who underwent biopsies for at least 1 lesion suspicious for AIN during HRA from November 2010 to March 2012 were prospectively included. The characteristics (borders, staining with acetic acid and Lugol iodine solution, and patterns of epithelium and vascularization) of the lesions detected during HRA were compared with histology. A total of 168 suspicious anal lesions were biopsied and analyzed in 103 patients (68% men, mean age ± standard deviation = 49.8 ± 9 y, 57% positive status on human immunodeficiency virus infection). According to histology, 41.7% of the lesions were high grade, 34.5% were low grade, and 23.8% were nondysplastic. Lesions with irregular epithelial pattern (or irregular vascularization) were twice as likely to be high grade compared with lesions with regular epithelial pattern (or regular vascularization). The incidences of acetic acid-induced whitening were 91.4%, 94.8%, and 70% among the high-grade AIN, low-grade AIN, and nondysplastic samples, respectively. Among the high-grade AIN, 62.9% were not stained by Lugol solution (vs 31% of the low-grade AIN). The positive predictive value of a combination of these simple morphological criteria was 68.6%. Several simple morphological criteria are significantly associated with high-grade AIN and are found less often in low-grade AIN. A combination of these morphological criteria provides sufficient positive predictive value to guide biopsy placement during HRA.

Abstract 4583: In situ photocontrolled intratumoral depot for combined photodynamic therapy and brachytherapy for solid tumor

Abstract Intratumoral (i.t.) drug delivery can circumvent the transport barriers_high intratumoral fluid pressure and irregular vascularization_of solid tumors that limit the effectiveness of systemically delivered therapeutics. Unfortunately, long tumor retention and tumor coverage are difficult to concurrently optimize in most i.t. delivery methodologies. One method to overcome this limitation is to design an i.t. delivery system where the initial dissemination of the delivery system_as a liquid_can be independently controlled from its liquid-solid transition by an external stimulus. Herein, we propose such a system in which a liquid can be converted to a solid by photo-oxidation within the tumor. This approach builds upon our previous work, wherein we successfully cross-linked elastin-like polypeptides (ELPs) within a tumor by mixing a cysteine containing ELP (cELP) with a low concentration of H2O2, a strong oxidant for the formation of disulfides. I.t. injection of the mixture led to quick (< 2min) crosslinking of the cELP that resulted in prolonged tumor retention of the cELP. However, we could not control the timing of the ELP crosslinking in this methodology. We hypothesized that the strong oxidative agent, singlet oxygen (O3), produced in photodynamic therapy (PDT) may provide the potential to trigger the in situ crosslinking of a cELP in solid tumor injected with a photosensitizer-loaded cELP and exposed to light to produce O3 within the tumor.We hypothesized that upon the i.t. injection, a soluble, photosensitizer (PS)-conjugated cELP (cELP-PS) will freely distribute within the tumor interstitium due to initial_injection driven_convection and subsequently by convection because of the intratumoral fluid pressure, and by diffusion driven by the concentration gradient. After dissemination within the tumor, its retention is ensured by photoirradiation (PR) of the tumor with light of a specific wavelength tuned to the absorbance maximum of the PS to generate O3 that triggers the cross-linking of cysteines in the cELP-PS. In this scenario, the cELP-PS is thus immobilized in the tumor after achieving sufficient tumor coverage without transport outside the tumor. Our results show that a conjugate of cELP with a PS, chlorine E6 (Ce6), exhibited in vitro cELP gelation after exposure to light at 660 nm (the peak absorbance wavelength). Exposure to the light also successfully triggered in situ hydrogel formation after i.t. infusion of the conjugate, resulting in significantly higher tumor retention than either cELP+Ce6 w/o PR or cELP with PR. The antitumor efficacy of this PS-cELP-PDT system for local radiotherapy is ongoing. The results suggest that in situ crosslinking of a cELP-Ce6 conjugate by PR of the tumor may provide a solution to maximizing tumor coverage and tumor retention. Furthermore, this system could provide a multi-functional platform for controlled release of additional antitumor agents within a solid tumor. Citation Format: Wenge Liu, Ratul Mukerji, Xinghai Li, Jeff Schaal, Jayanta Bhattacharyya, Michael Zalutsky, Ashutosh Chilkoti. In situ photocontrolled intratumoral depot for combined photodynamic therapy and brachytherapy for solid tumor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4583. doi:10.1158/1538-7445.AM2014-4583

Hypoxia, lipids, and cancer: surviving the harsh tumor microenvironment.

Solid tumors typically develop hostile microenvironments characterized by irregular vascularization and poor oxygen (O2) and nutrient supply. Whereas normal cells modulate anabolic and catabolic pathways in response to changes in nutrient availability, cancer cells exhibit unregulated growth even under nutrient scarcity. Recent studies have demonstrated that constitutive activation of growth-promoting pathways results in dependence on unsaturated fatty acids for survival under O2 deprivation. In cancer cells, this dependence represents a critical metabolic vulnerability that could be exploited therapeutically. Here we review how this dependence on unsaturated lipids is affected by the microenvironmental conditions faced by cancer cells.

Thyroid nodules: pathophysiological insight on oncogenesis and novel diagnostic techniques.

Thyroid nodules are a very frequent pathology among common population. Despite the vast majority of them are of benign origin, the incidence of thyroid cancer is currently rather rising. Although there are several risk factors of thyroid cancer and several clinical, ultrasound, biochemical and molecular diagnostic markers, the exact mechanisms of thyroid oncogenesis and the linkage between thyroid nodule ultrasound appearance and its biological character remain unclear. While ionizing radiation is the only one well-known risk factor for thyroid cancer, the significance of some others remains unclear. The aim of our review was to discuss some not completely known pathophysiological mechanisms involved in thyroid oncogenesis as hypothyroidism, mutations of genes regulating cell proliferation, thyroid autoimmunity and pregnancy and to describe pathophysiological background of some ultrasound markers of thyroid cancer (size, echogenicity, vascularization, calcifications and stiffness). Better knowledge in this field is crucial for development of novel diagnostic techniques and therapeutic approaches. For example, the analysis of BRAF, RAS and other mutations in cytological samples may help to distinction between follicular thyroid carcinoma and follicular thyroid adenoma and may significantly decrease the number of unnecessary surgery among patients with thyroid nodules. Alternatively, the different malign cells growth, angiogenesis, destructions of thyroid follicles, reparative changes, growth retardation, fibrosis and increased interstitial fluid pressure implicate the typical ultrasound appearance of papillary thyroid cancer (hypoechogenicity, irregular vascularization, microcalcifications, stiffness) which is essential to catch the suspicious nodules on the basis of their ultrasound appearance among large amount of benign nodules.

Ultrasonic Nanotherapy of Pancreatic Cancer: Lessons from Ultrasound Imaging

Pancreatic ductal adenocarcinoma (PDA) is the fourth most common cause of cancer death in the United States, with a median survival time of only 3-6 months for forty percent of patients. Current treatments are ineffective, and new PDA therapies are urgently needed. In this context, ultrasound-mediated chemotherapy by polymeric micelles and/or nanoemulsion/microbubble encapsulated drugs may offer an innovative approach to PDA treatment. PDA xenografts were orthotopically grown in the pancreas tails of nu/nu mice by surgical insertion of red fluorescence protein (RFP)-transfected MiaPaCa-2 cells. Tumor growth was controlled by fluorescence imaging. Occasional sonographic measurements correlated well with the formal tumor tracking by red fluorescence. Tumor accumulation of paclitaxel-loaded nanoemulsion droplets and droplet-to-bubble transition under therapeutic ultrasound was monitored by diagnostic ultrasound imaging. MiaPaCa-2 tumors manifested resistance to treatment by gemcitabine (GEM). This drug is the gold standard for PDA therapy. The GEM-resistant tumors proved sensitive to paclitaxel. Among six experimental groups studied, the strongest therapeutic effect was exerted by the following drug formulation: GEM + nanodroplet-encapsulated paclitaxel (nbGEN) combined with tumor-directed 1-MHz ultrasound that was applied for 30 s four to five hours after the systemic drug injection. Ultrasound-mediated PDA therapy by either micellar or nanoemulsion encapsulated paclitaxel resulted in substantial suppression of metastases and ascites, suggesting ultrasound-enhanced killing of invasive cancerous cells. However, tumors relapsed after the completion of therapy, indicating survival of some tumor cells. The recurrent tumors manifested development of paclitaxel resistance. Ultrasound imaging suggested nonuniform distribution of nanodroplets in the tumor volume due to irregular vascularization, which may result in the development of zones with subtherapeutic drug concentration. This is implicated as a possible cause of the resistance development, which may be pertinent to various modes of tumor nanotherapy.

The effects of alcohol on rat placenta

In this study, daily food and water consumption and body weights, histopathology of placenta, tenascin (TN), type IV collagen and EGF and its receptor immunolocalization in the placenta of albino rats treated with two doses of alcohol (1 and 5 g kg(-1) day(-1)) were determined. Alcohol was administered in three different periods i.e. the whole 4 weeks before the pregnancy, during the pregnancy, and during the 4 weeks before the pregnancy plus pregnancy itself. The samples of placenta obtained from control and treated rats on days 10, 12, 14, 16, 18, 20 and 21 of gestation were evaluated morphologically and fixed for histology and immunohistochemistry. Some differences in food and water consumption between the groups were determined. The placental weight, especially in the groups receiving 1 and 5 g kg(-1) day(-1) alcohol during the pregnancy, showed increases. The changes in placental histology such as increases in the number and the size of trophoblastic giant cells, cytoplasmic dissolution and nuclear polymorphism, degenerations in spongiotrophoblasts, hyperemia at the basal zone and labyrinth, hyperplasia at the labyrinth and irregular vascularization were seen particularly in the groups receiving alcohol during the pregnancy, and during the 4 weeks before the pregnancy plus pregnancy itself. Increases in the immunolocalization of TN and type IV collagen and decreases in the immunolocalization of EGF and EGFR in the placentas of alcohol-receiving rats were found. In conclusion, ethanol treatment during pregnancy in rats affected placentation and the immunolocalization of TN, type IV collagen, EGF and EGFR in the placentas.