Ultrasound Modulates Fluorescence Strength and ABCG2 mRNA Response to Aminolevulinic Acid in Glioma Cells.

BACKGROUND: 5-Aminolevulinic Acid (5-ALA) photodiagnosis (PD) is an effective method to detect residual tumors during glioma surgery. However, fluorescence strength differs in malignant gliomas, and false-negative fluorescence may result in tumor residue. We investigated the effect of ultrasound on the intracellular level of protoporphyrin IX (PpIX) and expression level of ATP-binding cassette transporter 2 (ABCG2), which is thought to act as a membrane efflux pump of PpIX from cytosol. METHODS: The malignant glioma cell lines SNB19, U87MG, and T98G were used for in vitro experiments. Cultured cells underwent ultrasound irradiation (1 MHz, 3 W/cm2, duty cycle 10%) after administration of 5-ALA, and morphological changes in tumor cells were observed. PpIX levels and ABCG2 expression were evaluated. RESULTS: The glioma tumor cells showed transient morphological changes and detachment from the culture dish; however, most cells survived and reverted to their original morphology within 6 hours. PpIX expression levels increased in glioma cells after ultrasound irradiation, and the increase was earlier and greater than that for 5-ALA alone. ABCG2 expressions increased after 5-ALA administration but were lower in ultrasound-irradiated glioma cells. CONCLUSIONS: Ultrasound irradiation of malignant gliomas contributes to stronger 5-ALA-induced fluorescence by elevating intracellular PpIX levels. Suppression of ABCG2 expression by ultrasound may contribute to PpIX accumulation in glioma cells.

Gremlin, a bone morphogenetic protein antagonist, is a crucial angiogenic factor in pituitary adenoma.

Gremlin is an antagonist of bone morphogenetic protein (BMP) and a major driving force in skeletal modeling in the fetal stage. Several recent reports have shown that Gremlin is also involved in angiogenesis of lung cancer and diabetic retinopathy. The purpose of this study was to investigate the role of Gremlin in tumor angiogenesis in pituitary adenoma. Double fluorescence immunohistochemistry of Gremlin and CD34 was performed in pituitary adenoma tissues obtained during transsphenoidal surgery in 45 cases (7 PRLoma, 17 GHoma, 2 ACTHoma, and 2 TSHoma). Gremlin and microvascular density (MVD) were detected by double-immunofluorescence microscopy in CD34-positive vessels from tissue microarray analysis of 60 cases of pituitary adenomas (6 PRLoma, 23 GHoma, 22 NFoma, 5 ACTHoma, and 4 TSHoma). In tissue microarray analysis, MVD was significantly correlated with an increased Gremlin level (linear regression: P < 0.005, r (2) = 0.4958). In contrast, Gremlin expression showed no correlation with tumor subtype or Knosp score. The high level of expression of Gremlin in pituitary adenoma tissue with many CD34-positive vessels and the strong coherence of these regions indicate that Gremlin is associated with angiogenesis in pituitary adenoma cells.

Endocan, a new invasion and angiogenesis marker of pituitary adenomas.

Angiogenesis plays a crucial role in tumor growth. Recently, endocan has emerged as a new marker of vascular endothelial cells from cancers in other organs. In this study, we elucidated the relationship between endocan expression and tumor invasion of pituitary adenoma. Tumor tissues were obtained from 70 patients with pituitary adenoma and were examined using fluorescence immunohistochemistry. Tissue samples included 4 adrenocorticotrophic hormone producing adenomas, 10 growth hormone-producing adenomas, 49 clinically nonfunctioning adenomas, 6 prolactin producing adenomas, and 1 thyroid-stimulating hormone producing adenoma. Endocan was exclusively expressed in CD34-positive vascular endothelial cells, with over 90 % colocalization. The CD34 expression was significantly elevated with endocan expression (linear regression slope, 1.200; r(2) = 0.268, F = 23.08, p < 0.0001). As a percentage of CD34 expression, endocan expression was elevated in a Knosp grading dependent manner (Spearman's r-value, 0.651; p < 0.0001), and was also significantly elevated in macroadenomas compared with microadenomas (p = 0.0133). However, no differences in endocan expression were observed between hormonal subtypes (p = 0.066; Kruskal-Wallis test), age (Spearman's rank correlation test, p = 0.4909), or sex (Mann-Whitney test, p = 0.1701). These data show that endocan is closely related to tumor angiogenesis, and may predict tumor invasion into neighboring cavernous sinuses in pituitary adenomas.

Prospective assessment of concomitant lumbar and chronic subdural hematoma: is migration from the intracranial space involved in their manifestation?

OBJECT: Spinal subdural hematomas (SDHs) are rare and some are concomitant with intracranial SDH. Their pathogenesis and etiology remain to be elucidated although their migration from the intracranial space has been suggested. The authors postulated that if migration plays a major role, patients with intracranial SDH may harbor asymptomatic lumbar SDH. The authors performed a prospective study on the incidence of spinal SDH in patients with intracranial SDH to determine whether migration is a key factor in their concomitance. METHODS: The authors evaluated lumbar MR images obtained in 168 patients (125 males, 43 females, mean age 75.6 years) with intracranial chronic SDH to identify cases of concomitant lumbar SDH. In all cases, the lumbar MRI studies were performed within the 1st week after surgical irrigation of the intracranial SDH. RESULTS: Of the 168 patients, 2 (1.2%) harbored a concomitant lumbar SDH; both had a history of trauma to both the head and the hip and/or lumbar area. One was an 83-year-old man with prostate cancer and myelodysplastic syndrome who suffered trauma to his head and lumbar area in a fall from his bed. The other was a 70-year-old man who had hit his head and lumbar area in a fall. Neither patient manifested neurological deficits and their hematomas disappeared under observation. None of the patients with concomitant lumbar SDH had sustained head trauma only, indicating that trauma to the hip or lumbar region is significantly related to the concomitance of SDH (p < 0.05). CONCLUSIONS: As the incidence of concomitant lumbar and intracranial chronic SDH is rare and both patients in this study had sustained a direct impact to the head and hips, the authors suggest that the major mechanism underlying their concomitant SDH was double trauma. Another possible explanation is hemorrhagic diathesis and low CSF syndrome.

A transfection method for short interfering RNA with the lipid-like self-assembling nanotube, A6K.

The aim of the present study was to develop a novel transfection method for short interfering RNA (siRNA). A nanotube with surfactant activity, A6K, consisting of six alanine residues and a hydrophilic head, lysine, was compared to the conventional cationic transfectant reagents siFECTOR and Lipofectamine 2000. Cytotoxicity for the human glioblastoma cell lines U87MG, A172, and T98G was examined with the MTS assay. Transfection efficiency was analyzed with FITC-labeled siRNA targeting matrix metalloproteinase (MMP)-2 mRNA by fluorescent activity on microscopy. The ultrastructure of A6K was evaluated by electron microscopy. The level of cytotoxicity associated with A6K in the U87MG cells was significantly lower than with siFECTOR and Lipofectamine 2000. Transfection efficiency for siRNA was increased in a dose- and time-dependent fashion. The relative expression of MMP-2 mRNA to ß-actin was reduced in a dose-dependent manner by real-time RT-PCR analysis. The ultrastructure of the A6K was transformed to micelle formation when mixed with the siRNA. The lipid-like self-assembling peptide, A6K, has genes in the micelle associated with the hydrophilic tail. This transfection method is a novel and stable technique with lower cytotoxicity than the current standard methods.

Incidental detection of thyroid nodules at magnetic resonance imaging of the cervical spine.

The incidental detection of thyroid lesions in patients undergoing magnetic resonance (MR) imaging of the cervical spine was prospectively evaluated on 389 MR images. Sagittal images extended from the cranio-cervical junction to the upper thoracic level, and axial images from C3-4 to C7-T1 intervertebral levels. Twenty patients (5.1%) had a total of 26 thyroid nodules. Eighteen patients presented with a single dominant nodule, of whom 2 had a multinodular gland with a single dominant nodule (one had 3 and the other had 5 nodules). Two patients had diffusely enlarged gland without a dominant nodule. The mean size of the nodules was 11.6 mm. One thyroid nodule was detected at the C5-6 intervertebral level, 14 at the C6-7, and 11 at the C7-T1. T(2)-weighted imaging was more useful than T(1)-weighted imaging for the detection of thyroid nodules because of the hyperintense versus isointense appearance of the lesions. Thyroid carcinoma was identified at surgery in one patient. The detection rate was low compared with computed tomography with contrast medium and ultrasonography. Our results suggest that MR imaging has limited value for the detection of thyroid lesions and that the presence of such lesions cannot be denied based only on MR imaging of the cervical spine. However, asymptomatic thyroid lesions, including thyroid cancer, can be identified on MR images of the cervical spine, so we recommend that evaluation of these images should consider such lesions.

Simple solution for preventing cerebrospinal fluid loss and brain shift during multitrack deep brain stimulation surgery in the semisupine position: polyethylene glycol hydrogel dural sealant capping: rapid communication.

This study evaluated preliminary findings on the efficacy of polyethylene glycol (PEG) hydrogel dural sealant capping for the prevention of cerebrospinal fluid (CSF) leakage and pneumocephalus during deep brain stimulation (DBS) surgery in the semisupine position. Group A consisted of 5 patients who underwent bilateral subthalamic nucleus (STN)-DBS surgery without PEG hydrogel dural sealant capping. Group B consisted of 5 patients who underwent bilateral STN-DBS surgery with PEG hydrogel dural sealant capping. The immediate postoperative intracranial air volume was measured in all patients and compared between the 2 groups using the Welch test. Adverse effects were also examined in both groups. The intracranial air volume in Group A was 32.3 ± 12.3 ml (range 19.1-42.5 ml), whereas that in Group B was 1.3 ± 1.5 ml (range 0.0-3.5 ml), showing a significant difference (p < 0.005). No hemorrhage or venous air embolisms were observed in either group. The effect of brain shift was discriminated by STN recordings in Group B. These preliminary findings indicate that PEG hydrogel dural sealant capping may reduce adverse effects related to CSF leakage and brain shift during DBS surgery.

Early computed tomography signs as early predictors of hemorrhagic transformation under heparinization in patients with cardiogenic embolism.

AIM: Early computed tomography (CT) signs are crucial to predict the onset of hemorrhagic transformation (HT) and are preventive to avoid a fatal hematoma after thrombolysis. In the present study, we retrospectively reviewed the clinical records of patients receiving heparinization to investigate the correlation between early CT signs and the frequency of HT. METHODS: We reviewed 96 patients with cardiogenic cerebral embolism. These patients were admitted within 24 h of the onset and were subsequently given 5000-15,000 units of heparin per day for 3 days. Owing to CT on admission, early CT changes were evaluated. Patient characteristics were also estimated, including evidence of hypertension, diabetes mellitus, hyperlipidemia, coronary heart disease and history of smoking. The probability of hemorrhagic transformation, or good outcome and independence was assessed by backward stepwise logistic regression analysis based on the maximum likelihood ratio. RESULTS: Higher baseline National Institutes of Health Stroke Scale (NIHSS) score, early CT signs and absence of hyperlipidemia diversely correlated with the occurrence of HT. Also, the presence or absence of early CT signs was significantly related to HT classification (χ(2)-test; P < 0.05). It was statistically significant that a higher baseline NIHSS score (OR 8.51; 95% CI 3.11-27.75) affected the outcome without showing a significant relationship to early CT signs. CONCLUSIONS: Presence of early CT signs correlated more strongly with HT than with the interval from symptom onset to hospital arrival. We might extend the therapeutic time for thrombolytic therapy, only if the early CT sign does not appear.

Clinical clerkship course for medical students on lumbar puncture using simulators.

Lumbar puncture is a medical technique that physicians must learn and is, therefore, considered a basic medical procedure. The lumbar puncture simulators Lumbar-Kun (Lumbar Puncture Simulator) and Lumbar-Kun II (Lumbar Puncture Simulator II) (Kyoto Kagaku, Kyoto, Japan) are teaching aids designed for practicing spinal insertions. We describe and results of a lumbar puncture clerkship course, provided to 5th-year medical students during clinical clerkship activity. The aim of this study was to evaluate the effectiveness of the lumbar puncture clerkship course in the medical education program. Comprehension, technical achievement, and satisfaction were scored by students and instructors using a 6-point Likert scale. Scores for both comprehension and technical achievement were high, but technical achievement scores tended to be higher than comprehension scores. In addition, the scores students gave themselves were higher than the scores they were given by instructors. Student satisfaction was high. The lumbar puncture simulators, Lumbar-Kun and Lumbar-Kun II, achieved excellent overall impressions and represent useful tools for training in lumbar puncture procedures. In addition to the simulators, an appropriate preparatory text and a short lecture before training seemed to increase the educational effect of this lumbar puncture clerkship course for medical students.

Transcranial Doppler ultrasonography for diagnosis of cerebral vasospasm after aneurysmal subarachnoid hemorrhage: mean blood flow velocity ratio of the ipsilateral and contralateral middle cerebral arteries.

BACKGROUND: Transcranial Doppler (TCD) is widely accepted to monitor cerebral vasospasm after subarachnoid hemorrhage (SAH); however, its predictive value remains controversial. OBJECTIVE: To investigate the predictive reliability of an increase in the mean blood flow velocity (mBFV) ratio of the ipsilateral to contralateral middle cerebral arteries (I/C mBFV) compared with the conventional absolute flow velocity. METHODS: We retrospectively investigated the clinical and radiologic data of consecutive patients with SAH admitted from July 2003 to August 2009 who underwent TCD ultrasonography. The highest mBFV value in bilateral middle cerebral arteries was recorded, while delayed cerebral ischemia (DCI) was defined as neurological deficits or computed tomographic evidence of cerebral infarction caused by vasospasm. The ipsilateral side was defined as the side with higher mBFV value when evaluating the I/C mBFV. We thus elucidated the reliability of this rate in comparison with the conventional method for predicting DCI with receiver operating characteristic (ROC) analysis. RESULTS: One hundred and forty-two patients were retrospectively analyzed with specific data from 1262 TCD studies. The ROC curve showed that the overall predictive value for DCI had an area under the curve of 0.86 (95% confidence interval: 0.76-0.96) when the I/C mBFV was used vs 0.80 (0.71-0.88) when the absolute flow velocity was used. The threshold value that best discriminated between patients with and without DCI was I/C mBFV of 1.5. CONCLUSION: In patients with SAH, the I/C mBFV demonstrated a more significant correlation to vasospasm than the absolute mean flow velocity.

Selective posterior decompression of the cervical spine.

Posterior decompression of the cervical spine is an accepted treatment for patients with cervical canal disease, but some patients experience postoperative axial pain and C5 or C6 palsy that affect their quality of life. Here we describe selective posterior decompression using a spinous process-splitting approach to prevent these complications performed in 17 patients with myelopathy treated at median 2.4 levels by selective posterior decompression via the transspinous approach. Clinical symptoms, axial pain, and C5 or C6 palsy were compared before and after treatment. The range of motion of the cervical spine and shift of the cervical cord were studied at the C5 level. All patients experienced symptom improvement and none suffered deterioration or required reoperation. The Japanese Orthopaedic Association score improved from 10.9 to 14.4 points and none of the patients reported C5 or C6 palsy or axial pain at the last follow-up visit. There was no statistically significant change in pre- and postoperative cervical alignment and range of motion. The posterior shift of the spinal cord at the C5 level was 1.7 mm. None of our 17 patients experienced significant postoperative axial pain after selective posterior decompression via the transspinous approach. Minimal spinal cord shift at the C5 level may have contributed to the reduced incidence of postoperative C5 or C6 palsy in our series. Selective posterior decompression is less invasive and effective in some patients with cervical canal disease.

Concomitant cranial and lumbar subdural hematomas -case report-.

A 24-year-old woman presented with concomitant spinal and bilateral intracranial subdural hematomas (SDHs) after hitting her head and lower back in a fall while snowboarding. She developed lower back pain and posture headache. Magnetic resonance imaging revealed bilateral intracranial SDHs and spinal SDH. Her symptoms improved and all hematomas resolved gradually without treatment, and completely disappeared by 5 months after the accident. Simultaneous intracranial SDH and spinal SDH have been reported in only 18 patients, including ours, of whom 6 had suffered trauma. The mechanism of concomitant SDHs has not been clarified, but migration of the hematoma from the intracranial to spinal sites may be an important mechanism. In our patient, low cerebrospinal fluid pressure syndrome and double trauma may also have been involved.

Stromal cell-derived factor-1 expression in pituitary adenoma tissues and upregulation in hypoxia.

The chemokine stromal cell-derived factor-1 (SDF-1/CXCL12) is known to have a homing effect, recruiting endothelial progenitor cells (EPCs) from the bone marrow to ischemic foci. In this study, we investigated whether SDF-1 is triggered by hypoxia and might be a major driving force for tumor angiogenesis in pituitary adenomas. SDF-1 and microvascular density (MVD) were detected by double-immunofluorescence microscopy in CD34-positive vessels from 59 cases with pituitary adenomas. In vitro secretion of SDF-1 by the AtT20 mouse pituitary adenoma cell line under hypoxic conditions was quantitatively analyzed by ELISA, and SDF-1 mRNA levels were determined by real-time RT-PCR. Double-fluorescence immunohistochemistry showed that increases in MVD were significantly correlated with increased SDF-1 grade (P < 0.0001), and, concomitantly, the expression of SDF-1 was significantly greater in macroadenomas (P = 0.0203). SDF-1 secretion was inversely related to oxygen levels, with more severe degrees of hypoxia inducing greater levels of SDF-1 secretion. Real-time RT-PCR demonstrated that the SDF-1 mRNA level in AtT20 cells was significantly increased at 1% oxygen (logarithmic mean value = 1.55 +/- 0.56) compared with that at 21% oxygen. The current study strongly suggests that SDF-1 is a crucial angiogenic factor in pituitary adenomas, where it acts as a homing agent to mediate the mobilization of CD34-positive endothelial progenitor cells to the tumor parenchyma under hypoxic conditions.

Intracerebral hemorrhage caused by a neoplastic aneurysm from pleomorphic lung carcinoma.

A 61-year-old man presented with an extremely rare neoplastic cerebral aneurysm caused by brain metastasis from pleomorphic lung carcinoma manifesting as intracerebral hematoma and sudden onset of semicoma. Computed tomography demonstrated huge intracerebral hemorrhage in the left cerebral hemisphere, which had collapsed into the lateral ventricle. Cerebral angiography disclosed a fusiform aneurysm in the periphery of the left middle cerebral artery (approximately 2 mm diameter). Resection of the aneurysm and removal of the hematoma were performed. Histological examination revealed that the aneurysm walls were invaded by pleomorphic carcinoma. The present case indicates that neoplastic cerebral aneurysm may be the cause of intracerebral hemorrhage in patients with pleomorphic lung carcinoma.

Elevation of growth hormone-releasing hormone receptor messenger ribonucleic acid expression in growth hormone-secreting pituitary adenoma with Gsalpha protein mutation.

Growth hormone-releasing hormone (GHRH) stimulates not only the synthesis and secretion of GH but also the proliferation of normal somatotrophs. The expression of GHRH receptor (GHRHR) is regulated by GHRH, both of which are known to be expressed in human GH-secreting pituitary adenoma cells. Somatic mutations in the subunit of Gsalpha protein (gsp), lead to the constitutive activation of adenylyl cyclase in pituitary adenomas that secrete GH. It has not been examined how gsp mutations influence GHRHR expression in GH-secreting adenomas. We therefore analyzed the expression levels of GHRHR messenger ribonucleic acid (mRNA) in GH-secreting pituitary adenomas focusing on a gsp mutation. Furthermore, we investigated the effect of GHRH on the expression of GHRHR mRNA in primary cultures of GH-secreting pituitary adenoma cells. GHRHR mRNA expression levels were significantly elevated in gsp mutation-positive GH-secreting adenomas compared with those in gsp mutation-negative ones. In primary-cultured GH-secreting adenoma cells, the increase of GH secretion in response to GHRH was shown in both gsp mutation-positive and -negative adenoma cells with a significantly higher response in the latter adenoma cells. GHRH increased GHRHR mRNA expression level in gsp mutation-negative adenoma cells while it was not influenced by GHRH in gsp mutation-positive adenoma cells. These results suggest that gsp mutations up-regulate GHRHR mRNA expression in GH-secreting pituitary adenoma cells, and that gsp mutations desensitize the adenoma cells to GHRH in terms of their GHRHR mRNA expression probably because of their saturation of GHRH signaling.

Regulation of cell invasion and signalling pathways in the pituitary adenoma cell line, HP-75, by reversion-inducing cysteine-rich protein with kazal motifs (RECK).

Degradation and remodelling of the extracellular matrix has been investigated, with the main focus on the balance between matrix metalloproteinases (MMP) and tissue inhibitor of metalloproteinases (TIMP). Recent reports disclose the presence of a novel MMP-inhibiting cell membrane-anchored glycoprotein designated 'reversion-inducing cysteine-rich protein with Kazal motifs' (RECK). Our main aim in this study was to elucidate the role of RECK in cell invasion of pituitary adenomas and its contribution to signal transduction. The function of RECK in cell invasion was investigated by comparing data obtained from full-length RECK clone transfection and gene silencing with RECK mRNA-targeting siRNA. RECK expression was confirmed using real-time RT-PCR and Western blotting. Levels of matrix metalloproteinases (MMP-2 and -9) and TIMP-1 were measured by zymography and reverse zymography, respectively. Cell invasion was examined with a 3-D invasion assay. The signal cascade was investigated by cDNA microarray analysis. As expected, expression of RECK was elevated upon cDNA transfection, and diminished using siRNA. We observed elevation of MMP-2 and -9 expression and consequent 3-D cell invasion in cells under-expressing RECK. However, TIMP expression was not affected by RECK. Analysis with cDNA microarray revealed that RECK additionally upregulates growth hormone-releasing hormone receptor (GHRHR) and latrophilin 2 at the transcriptional level. Our findings collectively suggest that RECK regulates the cell signalling pathway, playing a critical neuroendocrinological role in the pituitary adenoma cell line.

Transient uptake of thallium-201 into a cerebral infarction: a case report.

We describe a 51-year-old woman with a cerebral infarction that showed transient accumulation of thallium-201. On admission, this lesion was well-enhanced by gadolinium injection and gradually expanded, mimicking a malignant brain tumor. A cerebral angiogram, however, did not indicate the presence of a malignant brain tumor. Ethyl cysteinate dimer single photon computerized tomography showed perfusion defects throughout hospitalization. The final diagnosis of cerebral infarction was established by pathological examination. Six months after onset, the enhancement by gadolinium and the expansion of the lesion disappeared. A cerebral infarction showing transient uptake of thallium-201, and lesion expansion is indicative of a lesion in the liquefaction stage that might mimic a malignant tumor. Although thallium-201 scintigrams are useful for the differential diagnosis of radiation necrosis and recurrent brain tumor, the findings in this patient should alert clinicians to the differential diagnosis of intracerebral expansive lesions.

Enhancement of pituitary adenoma cell invasion and adhesion is mediated by discoidin domain receptor-1.

The discoidin domain receptor-1 (DDR1) tyrosine kinases are a family of cell surface receptors that bind to several types of collagen and facilitate cell adhesion that is known association with several cancers. However, no previous study has examined the expression and function of DDR1 in pituitary adenoma. Tissue microarray analysis of DDR1 expression levels in 52 pituitary adenoma tissues revealed that DDR1 expression was significantly related to hormonal background (Kruskal-Wallis test; P < 0.0001). To further elucidate the function of DDR1 in pituitary adenoma, we developed DDR1 over- and under-expressing cell lines using DDR1 clone transfection and short interfering ribonucleic acids (siRNA)-based DDR1 gene silencing, respectively, in a human pituitary adenoma cell line (HP-75). Real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting confirmed that expression of both DDR1 isoforms (DDR1a and DDR1b) was elevated by clone transfection and diminished by siRNA. Matrigel invasion assays revealed that cell invasion was increased in HP-75 cells over-expressing DDR1 and decreased in cells under-expressing DDR1. Consistent with this, zymography revealed that the activation levels of matrix metalloproteinase (MMP)-2 and -9 were increased and decreased in cells over- and under-expressing DDR1, respectively. Examination of in vitro cell adhesion to collagen types I, II, III, and IV with respect to MMP-2 and -9 expression revealed that DDR1 regulated cell adhesion to collagen type I, which was responsible for accelerating secretion of MMP-2 and -9 in DDR1 over-expressing cells. Taken together, these results strongly suggest that DDR1 mediates cell invasion-related signaling between collagen type I and MMP-2 and -9 in pituitary adenoma cells.

The use of 3-D culture in peptide hydrogel for analysis of discoidin domain receptor 1-collagen interaction.

The aim of this study is to examine a novel drop culture model using a biologically inspired self-assembling peptide: hydrogel (RAD16-I, also called PuraMatrix), which produces a nanoscale environment similar to native extracellular matrix (ECM) for a cell line weakly adherent to a plastic surface during cell culture. Our work investigates quantitatively analyzing discoidin domain receptor (DDR) 1-mediated protein interactions between collagen type I and matrix metalloproteinase (MMP)-2 or -9, as well as cell invasion, using, as a scaffold, PuraMatrix, a novel peptide hydrogel. Results demonstrate that the dynamic cell culture technique produced a highly stable reharvesting of cells throughout the constructs with HP-75, human pituitary adenoma cell line when compared to the traditional seeding methods. Secretion of MMP via collagen type I was observed quantitatively in the supernatant (EC50; MMP-2, 50.4 ng/ml: MMP-9, 57.6 ng/ml). In PuraMatrix gel impregnated with 50 ng/ml of collagen type I, transfection of the vector encoding full-length DDR1 or siRNA targeting DDR1 up- or downregulated respectively secretion of MMP-2 and -9, and cell invasion. Our results show that incorporation of this peptide with each ECM component provides a more permissive environment to elucidate ECM to cell signal interaction.