CD44 expression in the tumor periphery predicts the responsiveness to bevacizumab in the treatment of recurrent glioblastoma

Abstract Anti-angiogenic therapy with bevacizumab (Bev), a monoclonal antibody targeting vascular endothelial growth factor (VEGF), is a common treatment for recurrent glioblastoma (GBM), but its survival benefit is limited. Resistance to Bev is thought to be a major cause of ineffectiveness on Bev therapy. To optimize Bev therapy, identification of a predictive biomarker for responsiveness to Bev is required. Based on our previous study, we focused on the expression and functions of CD44 and VEGF in the Bev therapy. Here, we analyze a relationship between CD44 expression and responsiveness to Bev and elucidate the role of CD44 in anti-VEGF therapy. CD44 and VEGF expression in the tumor core and periphery of 22 GBMs was examined, and the relationship between expression of these molecules and progression-free time on Bev therapy was analyzed. The degree of CD44 expression in the tumor periphery was evaluated by the ratio of the mRNA expression in the tumor periphery to that in the tumor core (P/C ratio). VEGF expression was evaluated by the amount of the mRNA expression in the tumor periphery. To elucidate the roles of CD44 in the Bev therapy, in vitro and in vivo studies were performed using glioma stem-like cells (GSCs) and a GSC-transplanted mouse xenograft model, respectively. GBMs expressing high P/C ratio of CD44 were much more refractory to Bev than those expressing low P/C ratio of CD44, and the survival time of the former was much shorter than that of the latter. In vitro inhibition of VEGF with siRNA or Bev activated CD44 expression and increased invasion of GSCs. Bev showed no anti-tumor effects in mice transplanted with CD44-overexpressing GSCs. The P/C ratio of CD44 expression may become a useful biomarker predicting responsiveness to Bev in GBM. CD44 reduces the anti-tumor effect of Bev, resulting in much more highly invasive tumors.

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CBMS-04 SIGNIFICANT ROLE OF HYPOXIA IN THE EXPRESSION AND FUNCTION OF OSTEOPONTIN IN CD44-HIGHLY EXPRESSED GLIOMA STEM-LIKE CELLS IN TUMOR PROGRESSION OF GLIOBLASTOMA

Neuro-Oncology Advances ◽

10.1093/noajnl/vdz039.024 ◽

2019 ◽

Vol 1 (Supplement_2) ◽

pp. ii5-ii5

Author(s):

Masahiro Nishikawa ◽

Akihiro Inoue ◽

Yoshihiro Ohtsuka ◽

Saya Ozaki ◽

Shirabe Matsumoto ◽

...

Keyword(s):

Tumor Progression ◽

Hypoxia Inducible Factor ◽

Tumor Resection ◽

Signal Pathways ◽

Moderate Hypoxia ◽

Cd44 Expression ◽

Hypoxic Conditions ◽

Tumor Periphery ◽

Tumor Tissues ◽

And Function

Abstract The poor prognosis of glioblastoma multiforme (GBM) may be due to the surviving glioma stem-like cells (GSCs) in the tumor periphery after tumor resection. We demonstrated that CD44-expressed GSCs existed much more in the tumor periphery of high invasive (HI) type GBM than low invasive (LI) type GBM. The HI type was significantly associated with worse outcome, but how GSCs with high CD44 expression relate to tumor progression remains unknown. In this study, we investigated effects of hypoxia on CD44-directed signal pathways, leading to tumor invasion and proliferation in GBM. We focused on the CD44 ligand osteopontin (OPN) because it is known hypoxia affects the interaction of CD44 and OPN which promotes stemness and proliferation of cancer stem cells. We examined mRNA expressions of hypoxia inducible factor (HIF)-1a, HIF-2a, CD44 and OPN in tumor tissues of GBM and investigated effects of hypoxia (1%O2:severe or 5%O2:moderate) on the expression of these molecules using cultured GSCs that were established from tumor tissues showing high CD44 expression in the periphery of GBMs. In addition, we analyzed the effects of OPN on invasive, migratory and proliferative activities of GSCs under the hypoxic conditions. OPN was much higher expressed in the tumor periphery of LI type GBM than HI type GBM. Severe hypoxia significantly increased the expressions of HIF-1a and CD44 but did not OPN. On the other hands, moderate hypoxia promoted the expressions of HIF-2a and OPN. Knockdown of HIF-2a significantly inhibited OPN expression. In addition, the more OPN was expressed in the cultured GSCs under moderate hypoxia, the more the GSCs proliferated and decreased their invasive and migratory activities. In conclusion, GSCs existing in the tumor periphery of GBM can migrate or proliferate by changing CD44-directed signal pathways. Moderate hypoxia promoted HIF-2a/OPN/CD44 pathway, resulting in phenotypic transition to high proliferative tumors.

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Glioblastoma CUSA Fluid Protein Profiling: A Comparative Investigation of the Core and Peripheral Tumor Zones

Cancers ◽

10.3390/cancers13010030 ◽

2020 ◽

Vol 13 (1) ◽

pp. 30

Author(s):

Giuseppe La Rocca ◽

Giorgia Antonia Simboli ◽

Federica Vincenzoni ◽

Diana Valeria Rossetti ◽

Andrea Urbani ◽

...

Keyword(s):

Aminolevulinic Acid ◽

Recurrent Glioblastoma ◽

Protein Profiling ◽

Normal Brain ◽

Newly Diagnosed ◽

The Core ◽

Molecular Features ◽

Proteomic Approach ◽

Tumor Periphery ◽

Newly Diagnosed Glioblastoma

The present investigation aimed to characterize the protein profile of cavitating ultrasound aspirator fluid of newly diagnosed and recurrent glioblastoma comparing diverse zones of collection, i.e., tumor core and tumor periphery, with the aid of 5-aminolevulinic acid fluorescence. The samples were pooled and analyzed in triplicate by LC-MS following the shotgun proteomic approach. The identified proteins were then grouped to disclose elements exclusive and common to the tumor state or tumor zones and submitted to gene ontology classification and pathway overrepresentation analysis. The proteins common to the distinct zones were further investigated by relative quantitation, following a label free approach, to disclose possible differences of expression. Nine proteins, i.e., tubulin 2B chain, CD59, far upstream element-binding, CD44, histone H1.4, caldesmon, osteopontin, tropomyosin chain and metallothionein-2, marked the core of newly diagnosed glioblastoma with respect to tumor periphery. Considering the tumor zone, including the core and the fluorescence positive periphery, the serine glycine biosynthesis, pentose phosphate, 5-hydroxytryptamine degredation, de novo purine biosynthesis and huntington disease pathways resulted statistically significantly overrepresented with respect to the human genome of reference. The fluorescence negative zone shared several protein elements with the tumor zone, possibly indicating the presence of pathological aspects of glioblastoma rather than of normal brain parenchyma. On the other hand, its exclusive protein elements were considered to represent the healthy zone and, accordingly, exhibiting no pathways overrepresentation. On the contrary to newly diagnosed glioblastoma, pathway overrepresentation was recognized only in the healthy zone of recurrent glioblastoma. The TGFβ signaling pathway, exclusively classified in the fluorescence negative periphery in newly diagnosed glioblastoma, was instead the exclusive pathway classified in the tumor core of recurrent glioblastoma. These results, preliminary obtained on sample pools, demonstrated the potential of cavitron ultrasonic surgical aspirate fluid for proteomic profiling of glioblastoma able to distinguish molecular features specific of the diverse tumor zones and tumor states, possibly contributing to the understanding of the highly infiltrative capability and recurrent rate of this aggressive brain tumor and opening to potential clinical applications to be further investigated.

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