Lack of microvessels in well-differentiated regions of human head and neck squamous cell carcinoma A253 associated with functional magnetic resonance imaging detectable hypoxia, limited drug delivery, and resistance to irinotecan therapy

The clinical implication and translational research of OSCC differentiation

BACKGROUND

The clinical value and molecular characteristics of tumor differentiation in oral squamous cell carcinoma (OSCC) remain unclear. There is a lack of a related molecular classification prediction system based on pathological images for precision medicine.

METHODS

Integration of epidemiology, genomics, experiments, and deep learning to clarify the clinical value and molecular characteristics, and develop a novel OSCC molecular classification prediction system.

RESULTS

Large-scale epidemiology data (n = 118,817) demonstrated OSCC differentiation was a significant prognosis indicator (p < 0.001), and well-differentiated OSCC was more chemo-resistant than poorly differentiated OSCC. These results were confirmed in the TCGA database and in vitro. Furthermore, we found chemo-resistant related pathways and cell cycle-related pathways were up-regulated in well- and poorly differentiated OSCC, respectively. Based on the characteristics of OSCC differentiation, a molecular grade of OSCC was obtained and combined with pathological images to establish a novel prediction system through deep learning, named ShuffleNetV2-based Molecular Grade of OSCC (SMGO). Importantly, our independent multi-center cohort of OSCC (n = 340) confirmed the high accuracy of SMGO.

CONCLUSIONS

OSCC differentiation was a significant indicator of prognosis and chemotherapy selection. Importantly, SMGO could be an indispensable reference for OSCC differentiation and assist the decision-making of chemotherapy.

EphA4 signaling is involved in the phenotype of well-differentiated oral squamous cell arcinoma with decreased tumor immunity

Metronomic chemotherapy is defined as a high-frequency low-dose schedule of chemotherapy drug administration. Although metronomic chemotherapy is widely used, the mechanisms underlying resistance to metronomic chemotherapy remain unclear. Therefore, we herein conducted a single institutional phase I/II trial to assess the efficacy and safety of metronomic chemotherapy with bleomycin plus S-1, an oral 5-FU prodrug, in the neoadjuvant setting for patients with oral squamous cell carcinoma (OSCC). The response rate of well-differentiated OSCC to metronomic chemotherapy was significantly lower. We investigated differences in molecular profiles between poorly or moderately differentiated head and neck squamous cell carcinoma (HNSCC) and well-differentiated HNSCC from patients with HNSCC TCGA data. EphA4 expression positively correlated with histological differentiation. An upstream regulator analysis correlated with EphA4 expression identified pathways associated with decreased mTORC1 signaling and T cell activation, including TCR, CD3, CD28, and CD40LG. An EphA4 blocking peptide (KYL) induced mTOR activation in well-differentiated OSCC cell lines. Plasmacytoid dendritic cell and CD8⁺ T cell numbers were higher in the microenvironment of poorly or moderately differentiated HNSCC than in that of well-differentiated HNSCC. Well-differentiated HNSCC had the characteristics of "cold tumors" (immune-excluded tumors). Moreover, KYL used with chemotherapeutic drugs synergistically increased cancer cell death. Well-differentiated OSCC is depleted of immune cells, which may be partly explained by the receptor tyrosine kinase EphA4.

Rapid and Quantitative Intraoperative Pathology-Assisted Surgery by Paired-Agent Imaging-Derived Confidence Map

PURPOSE

In nonmetastatic head and neck cancer treatment, surgical margin status is the most important prognosticator of recurrence and patient survival. Fresh frozen sectioning (FFS) of tissue margins is the standard of care for intraoperative margin assessment. However, FFS is time intensive, and its accuracy is not consistent among institutes. Mapping the epidermal growth factor receptor (EGFR) using paired-agent imaging (PAI) has the potential to provide more consistent intraoperative margin assessment in a fraction of the time as FFS.

PROCEDURES

PAI was carried out through IV injection of an anti-epidermal growth factor receptor (EGFR) affibody molecule (ABY-029, eIND 122,681) and an untargeted IRDye680LT carboxylate. Imaging was performed on 4 µm frozen sections from three oral squamous cell carcinoma xenograft mouse models (n = 24, 8 samples per cell line). The diagnostic ability and tumor contrast were compared between binding potential, targeted, and untargeted images. Confidence maps were constructed based on group histogram-derived tumor probability curves. Tumor differentiability and contrast by confidence maps were evaluated.

RESULTS

PAI outperformed ABY-029 and IRDye 680LT alone, demonstrating the highest individual receiver operating characteristic (ROC) curve area under the curve (PAI AUC: 0.91, 0.90, and 0.79) and contrast-to-noise ratio (PAI CNR: 1, 1.1, and 0.6) for FaDu, Det 562, and A253. PAI confidence maps (PAI CM) maintain high tumor diagnostic ability (PAI CMAUC: 0.91, 0.90, and 0.79) while significantly enhancing tumor contrast (PAI CMCNR: 1.5, 1.3, and 0.8) in FaDu, Det 562, and A253. Additionally, the PAI confidence map allows avascular A253 to be differentiated from a healthy tissue with significantly higher contrast than PAI. Notably, PAI does not require additional staining and therefore significantly reduces the tumor delineation time in a 5 [Formula: see text] 5 mm slice from ~ 35 min to under a minute.

CONCLUSION

This study demonstrated that PAI improved tumor detection in frozen sections with high diagnostic accuracy and rapid analysis times. The novel PAI confidence map improved the contrast in vascular tumors and differentiability in avascular tumors. With a larger database, the PAI confidence map promises to standardize fluorescence imaging in intraoperative pathology-assisted surgery (IPAS).

Anti-tumor effects of P-LPK-CPT, a peptide-camptothecin conjugate, in colorectal cancer

To explore highly selective targeting molecules of colorectal cancer (CRC) is a challenge. We previously identified a twelve-amino acid peptide (LPKTVSSDMSLN, namely P-LPK) by phage display technique which may specifically binds to CRC cells. Here we show that P-LPK selectively bind to a panel of human CRC cell lines and CRC tissues. In vivo, Gallium-68 (⁶⁸Ga) labeled P-LPK exhibits selective accumulation at tumor sites. Then, we designed a peptide-conjugated drug comprising P-LPK and camptothecin (CPT) (namely P-LPK-CPT), and found P-LPK-CPT significantly inhibits tumor growth with fewer side effects in vitro and in vivo. Furthermore, through co-immunoprecipitation and molecular docking experiment, the glutamine transporter solute carrier 1 family member 5 (SLC1A5) was identified as the possible target of P-LPK. The binding ability of P-LPK and SLC1A5 is verified by surface plasmon resonance and immunofluorescence. Taken together, P-LPK-CPT is highly effective for CRC and deserves further development as a promising anti-tumor therapeutic for CRC, especially SLC1A5-high expression type.

A peptide that specifically targets amino acid transporter SLC1A5 in colorectal cancer cells is identified and conjugated with camptothecin to show selective cytotoxicity to colorectal cancer cells in preclinical models.

Escape From Cisplatin-Induced Senescence of Hypoxic Lung Cancer Cells Can Be Overcome by Hydroxychloroquine

Chemotherapy is the commonly used treatment for advanced lung cancer. However, it produces side effects such as the development of chemoresistance. A possible responsible mechanism may be therapy-induced senescence (TIS). TIS cells display increased senescence-associated β-galactosidase (SA-β-gal) activity and irreversible growth arrest. However, recent data suggest that TIS cells can reactivate their proliferative potential and lead to cancer recurrence. Our previous study indicated that reactivation of proliferation by TIS cells might be related with autophagy modulation. However, exact relationship between both processes required further studies. Therefore, the aim of our study was to investigate the role of autophagy in the senescence-related chemoresistance of lung cancer cells. For this purpose, human and murine lung cancer cells were treated with two commonly used chemotherapeutics: cisplatin (CIS), which forms DNA adducts or docetaxel (DOC), a microtubule poison. Hypoxia, often overlooked in experimental settings, has been implicated as a mechanism responsible for a significant change in the response to treatment. Thus, cells were cultured under normoxic (~19% O₂) or hypoxic (1% O₂) conditions. Herein, we show that hypoxia increases resistance to CIS. Lung cancer cells cultured under hypoxic conditions escaped from CIS-induced senescence, displayed reduced SA-β-gal activity and a decreased percentage of cells in the G2/M phase of the cell cycle. In turn, hypoxia increased the proliferation of lung cancer cells and the proportion of cells proceeding to the G0/G1 phase. Further molecular analyses demonstrated that hypoxia inhibited the prosenescent p53/p21 signaling pathway and induced epithelial to mesenchymal transition in CIS-treated cancer cells. In cells treated with DOC, such effects were not observed. Of importance, pharmacological autophagy inhibitor, hydroxychloroquine (HCQ) was capable of overcoming short-term CIS-induced resistance of lung cancer cells in hypoxic conditions. Altogether, our data demonstrated that hypoxia favors cancer cell escape from CIS-induced senescence, what could be overcome by inhibition of autophagy with HCQ. Therefore, we propose that HCQ might be used to interfere with the ability of senescent cancer cells to repopulate following exposure to DNA-damaging agents. This effect, however, needs to be tested in a long-term perspective for preclinical and clinical applications.

Modified microvessel density based on perfusion distance: a preferable NSCLC prognostic factor

Background

Despite the vital role of blood perfusion in tumor progression, the prognostic value of typical blood perfusion markers, such as microvessel density (MVD) or microvessel area (MVA), in patients with non-small cell lung cancer (NSCLC) is still unclear. This study established a modified MVD (mMVD) measurement based on perfusion distance and determined its prognostic value in patients with NSCLC.

Methods

A total of 100 patients with NSCLC were enrolled in this retrospective study. The intratumor microvessels of NSCLC patients were visualized using immunohistochemical staining for CD31. The blood perfusion distance was evaluated as the distance from each vessel to its nearest cancer cell (D_mvcc), and the cutoff value for prognosis was determined. Apart from the total MVD (tMVD), microvessels near cancer cells within the cutoff-D_mvcc were counted as mMVD. Predictive values for mortality and recurrence were evaluated and compared.

Results

The D_mvcc ranged from 1.6 to 269.8 µm (median, 13.1 µm). The mMVD (range: 2-70; median 23) was counted from tMVD according to the cutoff-D_mvcc (~20 µm). Compared with tMVD, a larger fraction of mMVD (80% vs. 2.9%) played a significant role in overall survival, with an improved area under the receiver operating characteristic (ROC) curve (AUC) (0.74 vs. 0.56). A high mMVD was an independent positive indicator of overall survival (OS) and progression-free survival (PFS). In contrast, tMVD was only related to PFS at the optimal cutoff.

Conclusions

Perfusion-distance-based mMVD is a promising prognostic factor for NSCLC patients with superior sensitivity, specificity, and clinical applicability compared to tMVD. This study provides novel insights into the prognostic role of tumor vessel perfusion in patients with NSCLC.

A molecular signature of well-differentiated oral squamous cell carcinoma reveals a resistance mechanism to metronomic chemotherapy and novel therapeutic candidates

Well-differentiated head and neck squamous cell carcinoma (HNSCC), accounts for approximately 10% of all HNSCCs and, while these cases are associated with good prognosis after surgery, these are resistant to chemotherapy. Here we designed a retrospective study to evaluate the effects of histological differentiation on tongue squamous cell carcinoma (TSCC) patients undergoing surgery or metronomic neoadjuvant chemotherapy. The metronomic neoadjuvant chemotherapy significantly improved overall survival of patients with poorly or moderately differentiated tumour, but not those with well-differentiated tumour. Analysis of the Cancer Genome Atlas (TCGA) showed that FAT1 mutations were significantly enriched in more differentiated HNSCC while ASPM mutations were significantly enriched among the poorly differentiated HNSCC. Interestingly, Wnt/β-catenin pathway was activated in well-differentiated HNSCC. Active β-catenin is translocated to the nucleus in the well-differentiated oral squamous cell carcinoma cell lines. Wnt inhibitor, Wnt974, were synergistic with methotrexate in killing well-differentiated oral squamous cell carcinoma (OSCC) cell lines. TCGA data analyses reveal a signature in patients with well-differentiated HNSCC who have no benefits from metronomic neoadjuvant chemotherapy, suggesting that there might be novel nosology and therapeutic candidates for improving HNSCC patient survival. Well-differentiated OSCC is synergistically killed by combination chemotherapy with Wnt inhibitor, making it promising therapeutic candidates.

The transcription factor FOXM1 regulates the balance between proliferation and aberrant differentiation in head and neck squamous cell carcinoma

Sustained expression of FOXM1 is a hallmark of nearly all human cancers including squamous cell carcinomas of the head and neck (HNSCC). HNSCCs partially preserve the epithelial differentiation program, which recapitulates fetal and adult traits of the tissue of tumor origin but is deregulated by genetic alterations and tumor-supporting pathways. Using shRNA-mediated knockdown, we demonstrate a minimal impact of FOXM1 on proliferation and migration of HNSCC cell lines under standard cell culture conditions. However, FOXM1 knockdown in three-dimensional (3D) culture and xenograft tumor models resulted in reduced proliferation, decreased invasion, and a more differentiated-like phenotype, indicating a context-dependent modulation of FOXM1 activity in HNSCC cells. By ectopic overexpression of FOXM1 in HNSCC cell lines, we demonstrate a reduced expression of cutaneous-type keratin K1 and involucrin as a marker of squamous differentiation, supporting the role of FOXM1 in modulation of aberrant differentiation in HNSCC. Thus, our data provide a strong rationale for targeting FOXM1 in HNSCC. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Biocompatibility and therapeutic evaluation of magnetic liposomes designed for self-controlled cancer hyperthermia and chemotherapy

Magnetic liposome-mediated combined chemotherapy and hyperthermia is gaining importance as an effective therapeutic modality for cancer. However, control and maintenance of optimum hyperthermia are major challenges in clinical settings due to the overheating of tissues. To overcome this problem, we developed a novel magnetic liposomes formulation co-entrapping a dextran coated biphasic suspension of La_0.75Sr_0.25MnO₃ (LSMO) and iron oxide (Fe₃O₄) nanoparticles for self-controlled hyperthermia and chemotherapy. However, the general apprehension about biocompatibility and safety of the newly developed formulation needs to be addressed. In this work, in vitro and in vivo biocompatibility and therapeutic evaluation studies of the novel magnetic liposomes are reported. Biocompatibility study of the magnetic liposomes formulation was carried out to evaluate the signs of preliminary systemic toxicity, if any, following intravenous administration of the magnetic liposomes in Swiss mice. Therapeutic efficacy of the magnetic liposomes formulation was evaluated in the fibrosarcoma tumour bearing mouse model. Fibrosarcoma tumour-bearing mice were subjected to hyperthermia following intratumoral injection of single or double doses of the magnetic liposomes with or without chemotherapeutic drug paclitaxel. Hyperthermia (three spurts, each at 3 days interval) with drug loaded magnetic liposomes following single dose administration reduced the growth of tumours by 2.5 fold (mean tumour volume 2356 ± 550 mm³) whereas the double dose treatment reduced the tumour growth by 3.6 fold (mean tumour volume 1045 ± 440 mm³) compared to their corresponding control (mean tumour volume 3782 ± 515 mm³). At the end of the tumour efficacy studies, the presence of MNPs was studied in the remnant tumour tissues and vital organs of the mice. No significant leaching or drainage of the magnetic liposomes during the study was observed from the tumour site to the other vital organs of the body, suggesting again the potential of the novel magnetic liposomes formulation for possibility of developing as an effective modality for treatment of drug resistant or physiologically vulnerable cancer.

Predictive factors for 6 vs 12 cycles of Folfiri-Bevacizumab in metastatic colorectal cancer

Early switching to de-intensified maintenance regimen is still a matter of debate in metastatic colorectal cancer (mCRC).

The MARTHA trial, a S.I.C.O.G. phase III randomized trial, compared FOLOFIRI+bevacizumab (B) for 12 cycles (6 months) followed by B for up to 12 months (FOLFIRI +B*12 arm) vs FOLFIRI+B for 6 cycles (3 months) followed by capecitabine+B for 4 cycles followed by B for up to 12 months (FOLFIRI+B*6 arm). Chemotherapy-naïve mCRC patients were randomized, primary endpoint was progression free survival (PFS), with overall survival (OS) as a secondary endpoint. A novel analysis, the Death Pace Analysis (DPA), was performed to identify patients who benefited from a specific treatment.

No PFS difference was seen in 198 enrolled patients (101 in FOLFIRI+B*12, 97 in FOLFIRI+B*6). A non-significant superior OS was observed for FOLFIRI+B*6 (HR 0.74, p 0.098). The DPA demonstrated that 14% of patients were identifiable as FOLFIRI+B*6-benefiting patients. According to a logistic regression analysis including 23 clinicopathological variables, baseline Hb was the only independent predictor of DPA-defined FOLFIRI+B*6-benefit status. Among patients with Hb ≤ 11.1 gr/dL a statistically significant prolonged OS was observed for FOLFIRI+B*6 over FOLFIRI+B*12 (median OS: 20.7 vs 12.6 months, respectively, HR 0.54, p 0.048). No survival difference was observed between arms in patients with Hb > 11.1.

mCRC patients with low baseline Hb levels are better treated with FOLFIRI+B*6 first-line strategy. Possible biological explanations for this finding are being investigated.

Mdm2 and aurora kinase a inhibitors synergize to block melanoma growth by driving apoptosis and immune clearance of tumor cells

Therapeutics that induce cancer cell senescence can block cell proliferation and promote immune rejection. However, the risk of tumor relapse due to senescence escape may remain high due to the long lifespan of senescent cells that are not cleared. Here, we show how combining a senescence-inducing inhibitor of the mitotic kinase Aurora A (AURKA) with an MDM2 antagonist activates p53 in senescent tumors harboring wild-type 53. In the model studied, this effect is accompanied by proliferation arrest, mitochondrial depolarization, apoptosis, and immune clearance of cancer cells by antitumor leukocytes in a manner reliant upon Ccl5, Ccl1, and Cxcl9. The AURKA/MDM2 combination therapy shows adequate bioavailability and low toxicity to the host. Moreover, the prominent response of patient-derived melanoma tumors to coadministered MDM2 and AURKA inhibitors offers a sound rationale for clinical evaluation. Taken together, our work provides a preclinical proof of concept for a combination treatment that leverages both senescence and immune surveillance to therapeutic ends.

Proton channels and exchangers in cancer

Although cancer is characterized by an intratumoral genetic heterogeneity, a totally deranged pH control is a common feature of most cancer histotypes. Major determinants of aberrant pH gradient in cancer are proton exchangers and transporters, including V-ATPase, Na+/H+ exchanger (NHE), monocarboxylate transporters (MCTs) and carbonic anhydrases (CAs). Thanks to the activity of these proton transporters and exchangers, cancer becomes isolated and/or protected not only from the body reaction against the growing tumor, but also from the vast majority of drugs that when protonated into the acidic tumor microenvironment do not enter into cancer cells. Proton transporters and exchangers represent a key feature tumor cells use to survive in the very hostile microenvironmental conditions that they create and maintain. Detoxifying mechanisms may thus represent both a key survival option and a selection outcome for cells that behave as unicellular microorganisms rather than belonging to an organ, compartment or body. It is, in fact, typical of malignant tumors that, after a clinically measurable yet transient initial response to a therapy, resistant tumor clones emerge and proliferate, thus bursting a more malignant behavior and rapid tumor progression. This review critically presents the background of a novel and efficient approach that aims to fight cancer through blocking or inhibiting well characterized proton exchangers and transporters active in human cancer cells. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

H460 non-small cell lung cancer stem-like holoclones yield tumors with increased vascularity

Cancer stem-like cells were isolated from several human tumor cell lines by limiting dilution assays and holoclone morphology, followed by assessment of self-renewal capacity, tumor growth, vascularity, and blood perfusion. H460 holoclone-derived tumors grew slower than parental H460 tumors, but displayed significantly increased microvessel density and tumor blood perfusion. Microarray analysis identified 177 differentially regulated genes in the holoclone-derived tumors, of which 47 were associated with angiogenesis. The dysregulated genes include several small leucine-rich proteoglycans that may modulate angiogenesis and serve as novel therapeutic targets for inhibiting cancer stem cell-driven angiogenesis.

Low microvascular density at the tumor center is related to the expression of metalloproteases and their inhibitors and with the occurrence of distant metastasis in breast carcinomas

BACKGROUND

The aims of this study were to evaluate the microvascular density (MVD) at the center of breast carcinomas, its relationship with the expression of metalloproteases (MMPs) and their inhibitors (TIMPs), and its connection with the distant metastasis rate.

METHODS

An immunohistochemical study of four MMPs and two TIMPs was performed on cancer specimens from 97 women with a histological confirmed diagnosis of early invasive breast cancer.

RESULTS

Expressions of MMP-9 by cancerous cells, or MMP-11 and TIMP-2 by stromal cells, were all negative and significantly associated with MVD, whereas MMP-7 score values were positive and also significantly associated with MVD. However, positive expression of MMP-1 by mononuclear inflammatory cells was significantly associated with MVD. Multivariate analysis demonstrated a significant and inverse relationship between MVD and the occurrence of distant metastasis.

CONCLUSIONS

Our data point out the clinical importance of low MVD at the tumor center as an independent prognostic factor of distant metastasis development in breast cancer.

Augmented therapeutic efficacy of irinotecan is associated with enhanced drug accumulation

The goal of this study is to determine whether treatment with methylselenocysteine (MSC) results in differential uptake of irinotecan and its active metabolite (SN-38) between tumors of head and neck squamous cell carcinomas and normal tissue. The in vivo synergy between MSC and irinotecan is influenced by treatment schedule and associated with enhancement of tumor vessel maturation, intra-tumor concentration of SN-38 and apoptotic death of tumor cells. Normal tissue drug concentrations were not impacted by selenium treatment. The finding is of clinical relevance for enabling the delivery of higher doses of irinotecan to reverse tumor resistance, recurrence and ultimately enhancing cure rates.

Mild elevation of body temperature reduces tumor interstitial fluid pressure and hypoxia and enhances efficacy of radiotherapy in murine tumor models

Human and rodent solid tumors often exhibit elevated interstitial fluid pressure (IFP). This condition is recognized as a prognostic indicator for reduced responses to therapy and decreased disease-free survival rate. In the present study, we tested whether induction of a thermoregulatory-mediated increase in tissue blood flow, induced by exposure of mice to mild environmental heat stress, could influence IFP and other vascular parameters within tumors. Using several murine tumor models, we found that heating results in a sustained reduction in tumor IFP correlating with increased tumor vascular perfusion (measured by fluorescent imaging of perfused vessels, laser Doppler flowmetry, and MRI) as well as a sustained reduction in tumor hypoxia. Furthermore, when radiation therapy was administered 24 hours postheating, we observed a significant improvement in efficacy that may be a result of the sustained reduction in tumor hypoxia. These data suggest, for the first time, that environmental manipulation of normal vasomotor function is capable of achieving therapeutically beneficial changes in IFP and microvascular function in the tumor microenvironment.

Methylselenocysteine: a promising antiangiogenic agent for overcoming drug delivery barriers in solid malignancies for therapeutic synergy with anticancer drugs

INTRODUCTION

Despite progress, chemotherapeutic response in solid malignancies has remained limited. Although initial results of the use of antiangiogenic agents in combination chemotherapy indicated an enhanced therapeutic response, recent data indicate that the surviving cancer is not only able to surmount therapy, but also actually able to adapt a more aggressive metastatic phenotype. Thus, selecting an antiangiogenic agent that is less likely to lead to tumor resurgence is a key to future therapeutic success of antiangiogenic agents in a combinatorial setting.

AREAS COVERED

Against the broad spectrum of antiangiogenic agents used at present in the clinic, the putative benefits of the use of organoselenium compounds, such as methylselenocysteine (MSC), are discussed in this review.

EXPERT OPINION

MSC, being part of the mammalian physiology, is a well-tolerated, versatile and economical antiangiogenic agent. It downregulates multiple key upstream tumor survival markers, and enhances tumor drug delivery, at a given systemic dose of an anticancer agent, while protecting normal tissue from cytotoxic adverse effects. Further clinical trials, especially in poorly differentiated cancers, are warranted.

Double immunohistochemical staining method for HIF-1alpha and its regulators PHD2 and PHD3 in formalin-fixed paraffin-embedded tissues

Hypoxia-inducible factor (HIF-1alpha) is expressed in the nuclei of tumor cells under hypoxic conditions, and is regulated, in part, by cytoplasmic prolyl hydroxylases (PHDs). As HIF-1alpha is selectively expressed in tumor cells, inhibitors are being developed for cancer therapy. Although methods for the detection of HIF-1alpha and PHDs are available, an immunohistochemical double staining method for these markers in individual tumor cells is not available. For method development a human squamous cell carcinoma (SCC) xenograft, A253, was used as a known positive control tissue for HIF-1alpha in well-differentiated areas without microvessels. This laboratory showed that tumor cells in these areas are strongly positive for hypoxia markers. Another human, poorly differentiated SCC xenograft, FaDu, without hypoxic areas, was used as a negative control. PHD2 and 3 immunostaining was optimized individually using the human kidney. To optimize HIF-1alpha detection the pressure cooker time for antigen retrieval, concentration of the primary antibody, amplification reagent, and DAB development time were decreased. Casein blocking further decreased the background. Double staining resulted in brown nuclei for HIF-1alpha (DAB), and pink cytoplasmic staining for PHD2, 3 (fast red). The isotype-matched controls were negative. Normal human tissues had no detectable HIF-1alpha, but expressed PHD2, 3. The potential use of this new and improved method was confirmed by analyzing 15 surgical biopsies of oropharyngeal SCC of which 6 were positive for HIF-1alpha. This new method defined the optimal conditions for detection of HIF-1alpha and PHDs in individual tumor cells and could have a diagnostic and therapeutic potential.

Architectural heterogeneity in tumors caused by differentiation alters intratumoral drug distribution and affects therapeutic synergy of antiangiogenic organoselenium compound

Tumor differentiation enhances morphologic and microvascular heterogeneity fostering hypoxia that retards intratumoral drug delivery, distribution, and compromise therapeutic efficacy. In this study, the influence of tumor biologic heterogeneity on the interaction between cytotoxic chemotherapy and selenium was examined using a panel of human tumor xenografts representing cancers of the head and neck and lung along with tissue microarray analysis of human surgical samples. Tumor differentiation status, microvessel density, interstitial fluid pressure, vascular phenotype, and drug delivery were correlated with the degree of enhancement of chemotherapeutic efficacy by selenium. Marked potentiation of antitumor activity was observed in H69 tumors that exhibited a well-vascularized, poorly differentiated phenotype. In comparison, modulation of chemotherapeutic efficacy by antiangiogenic selenium was generally lower or absent in well-differentiated tumors with multiple avascular hypoxic, differentiated regions. Tumor histomorphologic heterogeneity was found prevalent in the clinical samples studied and represents a primary and critical physiological barrier to chemotherapy.

Se-methylselenocysteine sensitizes hypoxic tumor cells to irinotecan by targeting hypoxia-inducible factor 1alpha

PURPOSE

Hypoxic tumor cells overexpressing hypoxia-inducible factor 1alpha (HIF-1alpha) are generally resistant to chemo/radiotherapy. We have reported that Se-methylselenocysteine (MSC) therapeutically enhances the efficacy and selectivity of irinotecan against human tumor xenografts. The aim of this study was to delineate the mechanism responsible for the observed efficacy targeting on HIF-1alpha and its transcriptionally regulated genes VEGF and CAIX.

METHODS

We investigated the mechanism of HIF-1alpha inhibition by MSC and its critical role in the therapeutic outcome by generating HIF-1alpha stable knockdown (KD) human head and neck squamous cell carcinoma, FaDu by transfecting HIF-1alpha short hairpin RNA.

RESULTS

While cytotoxic efficacy in combination with methylselenic acid (MSA) with SN-38 (active metabolites of MSC and irinotecan) could not be confirmed in vitro against normoxic tumor cells, the hypoxic tumor cells were more sensitive to the combination. Reduction in HIF-1alpha either by MSA or shRNA knockdown resulted in significant increase in cytotoxicity of SN38 in vitro against hypoxic, but not the normoxic tumor cells. Similarly, in vivo, either MSC in combination with irinotecan treatment of parental xenografts or HIF-1alpha KD tumors treated with irinotecan alone resulted in comparable therapeutic response and increase in the long-term survival of mice bearing FaDu xenografts.

CONCLUSIONS

Our results show that HIF-1alpha is a critical target for MSC and its inhibition was associated with enhanced antitumor activity of irinotecan. Inhibition of HIF-1alpha appeared to be mediated through stabilization of PHD2, 3 and downregulation of ROS by MSC. Thus, our findings support the development of MSC as a HIF-1alpha inhibitor in combination chemotherapy.

Inhibition of colon cancer growth by methylselenocysteine-induced angiogenic chemomodulation is influenced by histologic characteristics of the tumor

Despite an armamentarium that is wide in range, scope of action, and target, chemotherapy has limited success in colorectal cancer (CRC). Novel approaches are needed to overcome tumor barriers to chemotherapy that includes an abnormal tumor vasculature constituting a poor drug delivery system. We have previously shown that 5-methylselenocysteine (MSC) enhances therapeutic efficacy of irinotecan in various human tumor xenografts. We have recently demonstrated that MSC through vascular normalization leads to better tumor vascular function in vivo. In this study, we examined the role of MSC on tumor vasculature, interstitial fluid pressure (IFP) and drug delivery in 2 histologically distinct CRC xenografts, HCT-8 (uniformly poorly differentiated) and HT-29 (moderately differentiated tumor with avascular glandular regions). The presence of specific histologic structures as a barrier to therapy in these xenografts and their clinical relevance was studied using tissue microarray of human surgical samples of CRC. MSC led to a significant tumor growth inhibition, a reduced microvessel density, and a more normalized vasculature in both colorectal xenografts. While IFP was found to be significantly improved in HCT-8, an improved intratumoral doxorubicin delivery seen in both xenografts could explain the observed increase in therapeutic efficacy. Differentiated, glandular, avascular and hypoxic regions that contribute to tumor heterogeneity in HT-29 were also evident in the majority of surgical samples of CRC. Such regions constitute a physical barrier to chemotherapy and can confer drug resistance. Our results indicate that MSC could enhance chemotherapeutic efficacy in human CRC, especially in CRC with few or no hypoxic regions.

Hypoxia-specific drug tirapazamine does not abrogate hypoxic tumor cells in combination therapy with irinotecan and methylselenocysteine in well-differentiated human head and neck squamous cell carcinoma a253 xenografts

Well-differentiated hypoxic regions in head and neck squamous cell carcinoma like in A253 xenografts are avascular and, therefore, hinder drug delivery leading to drug resistance and tumor regrowth. Methylselenocysteine (MSC, 0.2 mg/mouse per day per oral for 35 days starting 7 days before the first irinotecan (CPT-11)) has been found to increase efficacy of a wide variety of chemotherapeutic agents including CPT-11 (100 mg/kg per week x 4 intravenously). Whereas CPT-11 leads to a 10% complete response (CR) in A253 xenografts, the combination of MSC and CPT-11 increased the CR to 70%. Surviving tumors were found to consist largely of avascular hypoxic regions. Here, we investigated the combination of tirapazamine (TPZ, 70 mg/kg per week intraperitoneal x 4 administered 3 or 72 hours before CPT-11), a bioreductive drug in clinical trial with selective toxicity for hypoxic cells, with MSC and CPT-11 in further enhancing the cure rates. Tumor response, change in tumor hypoxic regions, and DNA damage were monitored in vivo. Tirapazamine administered 3 hours before CPT-11 in combination with MSC + CPT-11 led to a lower tumor burden. Tirapazamine did not increase cure rate beyond that of MSC + CPT-11 combination and was instead found to decrease cures with no evidence of an increased DNA damage or a significant reduction in avascular hypoxic tumor regions. CD31 immunostaining in A253 demonstrated disruption of tumor vessels by TPZ that could lower cytotoxic drug delivery to carbonic anhydrase IX-positive hypoxic tumor cells and may explain at least partially these unexpected results.

Tumor vascular maturation and improved drug delivery induced by methylselenocysteine leads to therapeutic synergy with anticancer drugs

PURPOSE

Our previously reported therapeutic synergy between naturally occurring seleno-amino acid methylselenocysteine (MSC) and anticancer drugs could not be shown in vitro. Studies were carried out to investigate the potential role of MSC-induced tumor vascular maturation and increased drug delivery in the observed therapeutic synergy in vivo.

EXPERIMENTAL DESIGN

Mice bearing s.c. FaDu human head and neck squamous cell carcinoma xenografts were treated with MSC (0.2 mg/d x 14 days orally). Changes in microvessel density (CD31), vascular maturation (CD31/alpha-smooth muscle actin), perfusion (Hoechst 33342/DiOC7), and permeability (dynamic contrast-enhanced magnetic resonance imaging) were determined at the end of the 14-day treatment period. Additionally, the effect of MSC on drug delivery was investigated by determining intratumoral concentration of doxorubicin using high-performance liquid chromatography and fluorescence microscopy.

RESULTS

Double immunostaining of tumor sections revealed a marked reduction ( approximately 40%) in microvessel density accompanying tumor growth inhibition following MSC treatment along with a concomitant increase in the vascular maturation index ( approximately 30% > control) indicative of increased pericyte coverage of microvessels. Hoechst 33342/DiOC7 staining showed improved vessel functionality, and dynamic contrast-enhanced magnetic resonance imaging using the intravascular contrast agent, albumin-GdDTPA, revealed a significant reduction in vascular permeability following MSC treatment. Consistent with these observations, a 4-fold increase in intratumoral doxorubicin levels was observed with MSC pretreatment compared with administration of doxorubicin alone.

CONCLUSION

These results show, for the first time, the antiangiogenic effects of MSC results in tumor growth inhibition, vascular maturation in vivo, and enhanced anticancer drug delivery that are associated with the observed therapeutic synergy in vivo.

Advances in methods for assessing tumor hypoxia in vivo: implications for treatment planning

Tumor hypoxia and its downstream effects have remained of considerable interest for decades due to its negative impact on response to various cancer therapies and promotion of metastasis. Diagnosing hypoxia non-invasively can provide a significant advancement in cancer treatment and is the dire necessity for implementing specific targeted therapies now emerging to treat different aspects of cancer. A variety of techniques are being proposed to do so. However, none of them has yet been established in the clinical arena. This review summarizes the methods currently available to assess tumor hypoxia in vivo and their respective advantages and shortcomings. It also points out the impedances that need to be overcome to establish any particular method in the clinic, along with a broad overview of requirements for further advancement in this sphere of cancer research.

In vivo evaluation of a new polymer-lipid hybrid nanoparticle (PLN) formulation of doxorubicin in a murine solid tumor model

The purpose of this study is to evaluate the in vivo efficacy, unwanted toxicity and loco-regional distribution of a doxorubicin-loaded polymer-lipid hybrid nanoparticle (Dox-PLN) formulation in a murine solid tumor model after intratumoral injection. Dox-PLN were prepared by dispersing Dox in stearic acid and tristearin, with subsequent addition of a novel anionic polymer HPESO (hydrolyzed polymer of epoxidized soybean oil) to enhance the drug incorporation in the lipids. Solid tumors were obtained by injecting EMT6 mouse mammary cancer cells intramuscularly into the hind legs of BALB/c mice. Dox-PLN, blank PLN or surfactant formulations were injected intratumorally (IT) when tumors reached approximately 0.3 g. In vivo efficacy of treatment was measured by tumor growth delay (TGD), defined as the delay in time for the tumor to grow to 1.13 g relative to the untreated control. Signs of unwanted drug toxicity, the histology and morphology of tumor and heart tissues, and the IT distribution of Dox-PLN after IT treatment were examined or monitored. IT-administered Dox-PLN resulted in 70% and 100% TGD (p<0.01) for Dox doses of 0.1 and 0.2 mg, respectively. Dox-PLN treated tumors developed substantially larger central necrotic regions than the untreated tumors, with Dox-PLN residues extensively distributed among the dead cell debris, suggesting that the anticancer effect of Dox-PLN was mainly a combined result of IT nanoparticle distribution and short-ranged, sustained drug release. Except for two of fifteen mice receiving the higher 0.2 mg Dox dose showing transient fur-roughing, all Dox-PLN treated mice showed no signs of toxicity. The present study demonstrates that Dox-PLN possess significant in vivo cytotoxic activity against solid tumors with minimal systemic toxicity. IT administered Dox-PLN have the potential to improve the therapeutic index of loco-regional solid tumor chemotherapy.

High mobility group A2 is a target for miRNA-98 in head and neck squamous cell carcinoma

BACKGROUND

HMGA2 expression has been shown to be associated with enhanced selective chemosensitivity towards the topoisomerase (topo) II inhibitor, doxorubicin, in cancer cells. Although the roles of signaling cascades and proteins as regulatory factors in development, neoplasia and adaptation to the environment are becoming well established, evidence for the involvement of regulatory small RNA molecules, such as microRNAs (miRNAs) as important regulators of both transcriptional and posttranscriptional gene silencing is presently mounting.

RESULTS

Here we report that HMGA2 expression in head and neck squamous cell carcinoma (HNSCC) cells is regulated in part by miRNA-98 (miR-98). Albeit HMGA2 is associated with enhanced selective chemosensitivity towards topoisomerase (topo) II inhibitor, doxorubicin in HNSCC, the expression of HMGA2 is thwarted by hypoxia. This is accompanied by enhanced expression of miRNA-98 and other miRNAs, which predictably target HMGA2. Moreover, we show that transfection of pre-miR-98trade mark during normoxia diminishes HMGA2 and potentiates resistance to doxorubicin and cisplatin. These findings implicate the role of a miRNA as a key element in modulating tumors in variable microenvironments.

CONCLUSION

These studies validate the observation that HMGA2 plays a prominent role in governing genotoxic responses. However, this may only represent cells growing under normal oxygen tensions. The demonstration that miRNA profiles are altered during hypoxia and repress a genotoxic response indicates that changes in microenvironment in eukaryotes mimic those of lower species and plants, where, for example, abiotic stresses regulate the expression of thousands of genes in plants at both transcriptional and posttranscriptional levels through a number of miRNAs and other small regulatory RNAs.

High mobility group A2 is a target for miRNA-98 in head and neck squamous cell carcinoma

BACKGROUND

HMGA2 expression has been shown to be associated with enhanced selective chemosensitivity towards the topoisomerase (topo) II inhibitor, doxorubicin, in cancer cells. Although the roles of signaling cascades and proteins as regulatory factors in development, neoplasia and adaptation to the environment are becoming well established, evidence for the involvement of regulatory small RNA molecules, such as microRNAs (miRNAs) as important regulators of both transcriptional and posttranscriptional gene silencing is presently mounting.

RESULTS

Here we report that HMGA2 expression in head and neck squamous cell carcinoma (HNSCC) cells is regulated in part by miRNA-98 (miR-98). Albeit HMGA2 is associated with enhanced selective chemosensitivity towards topoisomerase (topo) II inhibitor, doxorubicin in HNSCC, the expression of HMGA2 is thwarted by hypoxia. This is accompanied by enhanced expression of miRNA-98 and other miRNAs, which predictably target HMGA2. Moreover, we show that transfection of pre-miR-98trade mark during normoxia diminishes HMGA2 and potentiates resistance to doxorubicin and cisplatin. These findings implicate the role of a miRNA as a key element in modulating tumors in variable microenvironments.

CONCLUSION

These studies validate the observation that HMGA2 plays a prominent role in governing genotoxic responses. However, this may only represent cells growing under normal oxygen tensions. The demonstration that miRNA profiles are altered during hypoxia and repress a genotoxic response indicates that changes in microenvironment in eukaryotes mimic those of lower species and plants, where, for example, abiotic stresses regulate the expression of thousands of genes in plants at both transcriptional and posttranscriptional levels through a number of miRNAs and other small regulatory RNAs.

ALK5 promotes tumor angiogenesis by upregulating matrix metalloproteinase-9 in tumor cells

Transforming growth factor beta 1 (TGF-beta1) is a potent tumor suppressor but, paradoxically, TGF-beta1 enhances tumor growth and metastasis in the late stages of cancer progression. This study investigated the role of TGF-beta type I receptor, ALK5, and three mitogen-activated protein kinases (MAPKs) in metastasis by breast cancer cell line MDA-MB-231. We show that autocrine TGF-beta signaling in MDA-MB-231 cells is required for tumor cell invasion and tumor angiogenesis. Expression of kinase-inactive ALK5 reduces tumor invasion and formation of new blood vessels within the tumor orthotopic xenografts in severe combined immunodeficiency (SCID) mice. In contrast, constitutively active ALK5-T204D enhances tumor invasion and angiogenesis by stimulating expression of matrix metalloproteinase MMP-9/gelatinase-B. Ablation of MMP-9 in ALK5-T204D cells by RNA interference (RNAi) reduces tumor invasion and tumor growth. Importantly, RNAi-MMP-9 reduces tumor neovasculature and increases tumor cell death. Induction of MMP-9 by TGF-beta-ALK5 signaling requires MEK-ERK but not JNK, p38 MAPK or Smad4. Dominant-negative MEK blocks and constitutively active MEK1 enhances MMP-9 expression. However, all three MAPK cascades (ERK, JNK and p38 MAPK) are required for TGF-beta-mediated cell migration. Collectively, our results show that TGF-beta-ALK5-MAPK signaling in tumor cells promotes tumor angiogenesis and MMP-9 is an important component of this program.

Oxygen-dependent differentiation of human keratinocytes

Oxygen is an essential micronutrient. Unlike many internal tissues, human epidermis obtains much of its oxygen supply from the atmosphere (21% oxygen), and it ordinarily experiences higher oxygen levels than internal tissues (estimated approximately 5%). To test whether epidermal cell growth and differentiation depend upon this higher oxygen level, keratinocyte cultures were studied at 21, 5, and 2% oxygen concentrations. Compared to 21% oxygen, culture in 5% had little effect on growth but led to profound suppression of the differentiation program as assessed by expression of differentiation markers and formation of squames in the superficial layers. Culture in 2% oxygen reduced the growth rate as well as stratification and differentiation. In low-oxygen conditions, the cells exhibited increased colony-forming ability, consistent with a lower proportion of differentiated cells, and increased expression of vascular endothelial growth factor and cyclooxygenase-2. Growth in 21% oxygen led to higher levels of glutathione and expression of oxidant-responsive genes. Electrophoretic mobility supershift assay using an involucrin activator protein 1 (AP1) response element sequence revealed altered binding by proteins of the Jun and Fos families in nuclear extracts. The present data thus demonstrate oxygen-dependent differentiation in human keratinocytes, to which altered utilization of AP1 transcriptional response elements may contribute.

Activity of the vascular-disrupting agent 5,6-dimethylxanthenone-4-acetic acid against human head and neck carcinoma xenografts

Head and neck squamous cell carcinomas (HNSCC) constitute a majority of the tumors of the upper aerodigestive tract and continue to present a significant therapeutic challenge. To explore the potential of vascular-targeted therapy in HNSCC, we investigated the antivascular, antitumor activity of the potent vascular-disrupting agent (VDA) 5,6-dimethylxanthenone-4-acetic acid (DMXAA) against two HNSCC xenografts with markedly different morphologic and vascular characteristics. Athymic nude mice bearing subcutaneous FaDu (human pharyngeal squamous cell carcinoma) and A253 (human submaxillary gland epidermoid carcinoma) tumors were administered a single dose of DMXAA (30 mg/kg, i.p). Changes in vascular function were evaluated 24 hours after treatment using contrast-enhanced magnetic resonance imaging (MRI) and immunohistochemistry (CD31). Signal enhancement (E) and change in longitudinal relaxation rates (deltaR1) were calculated to measure alterations in vascular perfusion. MRI showed a 78% and 49% reduction in vascular perfusion in FaDu and A253 xenografts, respectively. CD31-immunostaining of tumor sections revealed three-fold (FaDu) and two-fold (A253) reductions in microvessel density (MVD) 24 hours after treatment. DMXAA was equally effective against both xenografts, with significant tumor growth inhibition observed 30 days after treatment. These results indicate that DMXAA may be clinically beneficial in the management of head and neck cancers, alone or in combination with other treatments.

Irinotecan, oxaliplatin and raltitrexed for the treatment of advanced colorectal cancer

Out of every 17-18 individuals in the US, one develops colorectal cancer (CRC) in their lifetime. Of individuals diagnosed with CRC, > 50% present or develop metastatic disease, which, if untreated, is associated with 6-9 months median survival. Although surgical resection is the primary treatment modality for CRC, chemotherapy is the mainstay of treatment for metastatic or unresectable disease. For nearly three decades, 5-fluorouracil (5-FU) has been the chemotherapy of choice for treatment of CRC. However, the response rates to single 5-FU therapy have been suboptimal with an objective tumour response of 10-20%. Attempts have been made to improve the efficacy of 5-FU by either schedule alteration (protracted infusion versus intravenous push) or biochemical modulation with leucovorin (LV). Continuous infusion induced more tumour regression and prolonged the time-to-disease progression with some significant impact on survival (11.3 versus 12.1 months; p < 0.04). 5-FU/LV resulted in a significant increase in overall response rates and in the prolongation of disease-free survival in the adjuvant setting, although severe toxicities represent a major clinical problem. The last 10 years have seen the addition of several new agents such as irinotecan, oxaliplatin, raltitrexed, bevacizumab and cetuximab. The prognosis has significantly improved with the addition of these agents, with median survivals now > 20 months. This review paper focuses on irinotecan, oxaliplatin and raltitrexed when used alone and in combination.

Potentiation of irinotecan sensitivity by Se-methylselenocysteine in an in vivo tumor model is associated with downregulation of cyclooxygenase-2, inducible nitric oxide synthase, and hypoxia-inducible factor 1alpha expression, resulting in reduced angiogenesis

Until recently, the use of Se-methylselenocysteine (MSC) as selective modulator of the antitumor activity and selectivity of anticancer drugs including irinotecan, a topoisomerase I poison, had not been evaluated. Therapeutic synergy between MSC and irinotecan was demonstrated by our laboratory in mice bearing human squamous cell carcinoma of the head and neck tumors. In FaDu xenografts, a poorly differentiated tumor-expressing mutant p53, the cure rate was increased from 30% with irinotecan alone to 100% with the combination of irinotecan and MSC. Cellular exposure to cytotoxic concentration of SN-38, the active metabolite of irinotecan (0.1 microM) alone and in combination with noncytotoxic concentration of MSC (10 microM) did not result in additional enhancement of chk2 phosphorylation and downregulation of specific DNA replication-associated proteins, cdc6, MCM2, cdc25A, nor increase in PARP cleavage, caspase activation and the 30-300 kb DNA fragmentation induced by SN-38 treatment. MSC did not alter significantly markers associated with apoptosis, nor potentiate irinotecan-induced apoptosis. These results indicate that apoptosis is unlikely to be one of the main mechanism associated with the observed in vivo therapeutic synergy. In contrast, significant downregulation of cyclooxygenase-2 (COX-2) expression and activity was observed in the cells exposed to SN-38 in combination with MSC compared to SN-38 alone. Moreover, the inhibition of PGE(2) production was also observed in the cells treated with the combination as compared with SN-38 alone. Analysis of tumor tissues at 24 h after treatment with synergistic modality of irinotecan and MSC revealed significant downregulation of COX-2, inducible nitric oxide synthase (iNOS) and hypoxia-induced factor-1alpha expression (HIF 1alpha). Moreover, decreased microvessel density was observed after irinotecan treatment with the addition of MSC. These results suggest that observed therapeutic synergy correlates with the inhibition of neoangiogenesis through the downregulation of COX-2, iNOS and HIF-1alpha expression.

Computer-Assisted Analysis of Biopsy Specimen Microvessels Predicts the Outcome of Esophageal Cancers Treated with Chemoradiotherapy

PURPOSE

A computer-assisted microvessel analysis system was developed to evaluate correlations between the architecture of biopsy specimen microvessels and the outcome for patients with esophageal cancer treated with chemoradiotherapy.

EXPERIMENTAL DESIGN

Biopsy specimens from 51 patients with esophageal cancer (T(2-3), any N, M0) treated with chemoradiotherapy were immunostained with an anti-CD31 antibody and quantified using computerized image analysis. We evaluated the association of several microvessel factors with overall survival, including the ratio of total microvessel perimeter to total tumor area (TP/TA), the tumor hypoxic ratio, and the ratio of total microvessel number to total tumor area (TN/TA). Results from traditional manual microvessel density (MVD) hotspot count and computerized hotspot count were compared and the relation between hotspot MVD count and survival rate was evaluated.

RESULTS

The median follow-up time was 32 months. Both univariate and multivariate analyses revealed that computer-counted hotspot MVD and TN/TA and TP/TA ratios correlated significantly with the outcome of chemoradiotherapy. Kaplan-Meier survival curves showed that patients with high computer-counted hotspot MVDs and high TN/TA and TP/TA ratios had better overall survival rate than patients with low MVDs or ratios (P = 0.025, 0.008, and 0.031, respectively). Combining computer-counted MVD or TN/TA ratio with TP/TA ratio proved more predictive than any single factor. Two researcher-counted hotspot MVDs had no significant relation with outcome.

CONCLUSION

Computer-assisted tumor microvessel analysis is a powerful tool in predicting the outcome for patients with esophageal cancer treated with chemoradiotherapy because intraobserver and interobserver variability is minimized.

What the clinician wants to know: surgical perspective and ultrasound for lymph node imaging of the neck

Imaging of lymph node metastases in the neck can have two major indications: (1) prognosis and assisting with choice of treatment; (2) staging and detection of clinically occult metastases in different levels of the neck. Both indications are discussed. The role and limitations of US and US-guided fine-needle aspiration cytology are also reviewed.

Irinotecan pharmacokinetic and pharmacogenomic alterations induced by methylselenocysteine in human head and neck xenograft tumors

The combination of methylselenocysteine and irinotecan (CPT-11) is synergistic against FaDu and A253 xenografts. Methylselenocysteine/CPT-11 increased tumor cure rate to 100% in FaDu and to 60% in A253. In this study, the effect of methylselenocysteine on pharmacokinetic and pharmacogenetic profiles of genes relevant to CPT-11 metabolic pathway was evaluated to identify possible mechanisms associated with the observed combinational synergy. Nude mice bearing tumors (FaDu and A253) were treated with methylselenocysteine, CPT-11, and a combination of methylselenocysteine/CPT-11. Samples were collected and analyzed for plasma and intratumor concentration of CPT-11 and 7-ethyl-10-hydroxyl-camptothecin (SN-38) by high-performance liquid chromatography. The intratumor relative expression of genes related to the CPT-11 metabolic pathway was measured by real-time PCR. After methylselenocysteine treatment, the intratumor area under the concentration-time curve of SN-38 increased to a significantly higher level in A253 than in FaDu and was associated with increased expression of CES1 in both tumors. Methylselenocysteine/CPT-11 treatment, compared with CPT-11 alone, resulted in a significant decrease in levels of ABCC1 and DRG1 in FaDu tumors and an increase in levels of CYP3A5 and TNFSF6 in A253 tumors. No statistically significant changes induced by methylselenocysteine/CPT-11 were observed in the levels of other investigated variables. In conclusion, the significant increase in the cure rate after methylselenocysteine/CPT-11 could be related to increased drug delivery into both tumors (CES1), reduced resistance to SN-38 (ABCC1 and DRG1) in FaDu, and induced Fas ligand apoptosis (TNFSF6) in A253. No correlation was observed between cure rate and other investigated variables (transporters, degradation enzymes, DNA repair, and cell survival/death genes) in either tumor.