Cancer-associated fibroblasts affect breast cancer cell gene expression, invasion and angiogenesis.

PURPOSE: It has been reported that stromal cell features may affect the clinical outcome of breast cancer patients. Cancer associated fibroblasts (CAFs) represent one of the most abundant cell types within the breast cancer stroma. Here, we aimed to explore the influence of CAFs on breast cancer gene expression, as well as on invasion and angiogenesis. METHODS: qRT-PCR was used to evaluate the expression of several cancer progression related genes (S100A4, TGFß, FGF2, FGF7, PDGFA, PDGFB, VEGFA, IL-6, IL-8, uPA, MMP2, MMP9, MMP11 and TIMP1) in the human breast cancer-derived cell lines MCF-7 and MDA-MB-231, before and after co-culture with CAFs. Stromal mononuclear inflammatory cell (MIC) MMP11 expression was used to stratify primary tumors. In addition, we assessed the in vitro effects of CAFs on both MDA-MB-231 breast cancer cell invasion and endothelial cell (HUVEC) tube formation. RESULTS: We found that the expression levels of most of the genes tested were significantly increased in both breast cancer-derived cell lines after co-culture with CAFs from either MMP11+ or MMP11- MIC tumors. IL-6 and IL-8 showed an increased expression in both cancer-derived cell lines after co-culture with CAFs from MMP11+ MIC tumors. We also found that the invasive and angiogenic capacities of, respectively, MDA-MB-231 and HUVEC cells were increased after co-culture with CAFs, especially those from MMP11+ MIC tumors. CONCLUSIONS: Our data indicate that tumor-derived CAFs can induce up-regulation of genes involved in breast cancer progression. Our data additionally indicate that CAFs, especially those derived from MMP11+ MIC tumors, can promote breast cancer cell invasion and angiogenesis.

Stromal factors involved in human prostate cancer development, progression and castration resistance.

PURPOSE: To detect new predictive markers from the prostate cancer tissue, to study the expression by cultured cancer-associated fibroblasts (CAFs) of stromal factors implicated in prostate carcinogenesis, and to compare their expressions in localized, metastatic, castration-sensitive (CSCP), castration-resistant prostate tumors (CRCP) as well as in fibroblasts from benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: The genomic expression of 20 stroma-derived factors, including the androgen receptor (AR), growth factors (FGF2, FGF7, FGF10, HGF, TGFß, PDGFB), protein implicated in invasion (MMP-2, MMP-9 and MMP-11), inflammation (IL-6, IL-17, STAT-3 and NFκB), stroma/epithelium interaction (CDH11, FAP, CXCL12 and CXCL14) and chaperones (HPA1A and HSF1), was evaluated in cultured fibroblasts both from BHP and prostate carcinomas (PCa). After isolation and culture of fibroblasts by biopsy specimens, RNA was isolated and genomic studies performed. RESULTS: Finally, 5 BPH and 37 PCa specimens were selected: clinically localized (19), metastatic (5), CSCP (7) and CRPC (6). Interleukin-17 receptor (IL-17RB) was highly expressed in CAFs compared with fibroblasts from BPH. However, metalloproteinase-2 and chemokine ligand 14 (CXCL14) were expressed at higher levels by fibroblasts from BPH. The fibroblastic growth factor-7 was highly expressed by CAFs from localized tumors, but metalloproteinase-11 in metastatic tumors. MMP-11, androgen receptor (AR) and heat-shock-70kda-protein-1A (HSPA1A) expressions were significantly higher in CAFs from CRPC. CONCLUSIONS: These results demonstrate a CAFs heterogeneity among prostate carcinomas with regard to some molecular profile expressions that may be relevant in tumor development (IL-17RB), progression (MMP-11) and castration resistance (AR, MMP-11 and HSPA1A).

Prognostic significance of inflammatory factors expression by stroma from breast carcinomas.

The aim of this work was to evaluate the expression and clinical relevance of some cytokines in breast carcinomas. An immunohistochemical study using tissue arrays and specific antibodies against interleukin 1ß (IL-1ß), IL-6, IL-10, IL-17, interferon ß (IFNß) and nuclear factor kappa B (NFκB) was performed in 108 breast carcinomas. Most studied cytokines were mainly expressed by cancer cells but also by stromal cells as cancer-associated fibroblasts (CAFs) or mononuclear inflammatory cells (MICs). Global expression (score) of IL-1ß and IL-17 was positively associated with histological grade; human epidermal growth factor receptor 2-positive tumors showed a higher global expression of IFNß but a lower global expression of NFκB; and node-negative tumors showed a higher global expression of IL-6. High score of IL-6 was significantly associated with both longer relapse free-survival (RFS) and overall survival (OS). Moreover, the expression of IL-1ß by each stromal cells (CAFs and MICs) was significantly associated with both longer RFS and OS, whereas the expression of IL-10 by these cells was significantly associated with both shorter RFS and OS. However, the combination of IL-1ß, IL-6 and IL-10 expression by MICs reached an important association with prognosis and improved our previously reported prognostic signification based on the matrix metalloprotease 11 status by MICs. The combination of IL-1ß, IL-6 and IL-10 expression by MICs was significant and independently associated with distant RFS in a multivariate analysis. Therefore, the combination of the expression of IL-1ß, IL-6 and IL-10 may serve as promising biomarkers of MICs with prognostic significance, contributing to a better characterization of breast carcinomas microenvironment.

Gene expression profile of normal and cancer-associated fibroblasts according to intratumoral inflammatory cells phenotype from breast cancer tissue.

The biological heterogeneity of breast cancer leads to the need for finding new approaches to understand the mechanisms implicated in breast cancer progression. The tumor stroma appears as a key in the progression of solid tumors towards a malignant phenotype. Cancer associated fibroblasts (CAFs) may orchestrate a functional "corrupted" stroma which in turn helps metastatic spread. In this study, we investigated by real-time PCR, the expression of 19 factors by normal breast-associated fibroblasts (NAFs) and CAFs, which were implicated in several actions promoting tumor growth, such as extracellular matrix remodeling, inflammation and invasion. Also, we explored the influence of inflammatory cells phenotypes (MMP11 status) and breast cancer cell lines (MCF-7 and MDA-MB-231) on the molecular profile of CAFs. If we consider that one of the major sources of CAFs are resident NAFs, the transition of NAFs into CAFs is associated with molecular changes involving the overexpression of some molecular factors of biological importance in tumor progression. In addition, the characterization of the tumor stroma regarding to the MMP11 status by MICs reflects a type of fibroblasts which contribute even more to tumor progression. Moreover, different patterns in the induction of the expression of factors by CAFs were observed, depending on the tumor cell line which they were co-cultured with. Furthermore, CAFs influence TGFß expression in both cancer cell lines. Therefore, this study can help to a better characterization of tumor stroma in order to improve the prognostic evaluation, as well as to define the different populations of CAFs as potential therapeutic targets in breast cancer. © 2015 Wiley Periodicals, Inc.

A phenotype from tumor stroma based on the expression of metalloproteases and their inhibitors, associated with prognosis in breast cancer.

The objective of the present work was to evaluate the impact of the phenotype of both mononuclear inflammatory cells (MICs) and cancer-associated fibroblast (CAFs) in early breast cancer patients, specifically assessed as to their expression of MMP/TIMP relative to their position within the tumor (i.e., localization at the tumor center or invasive front) and the occurrence of distant metastases.. An immunohistochemical study was performed using tissue arrays and specific antibodies against matrix metalloproteinase (MMP)-1, -2, -7, -9, -11, -13 and -14, tissue inhibitors of metalloproteinase (TIMP)-1, -2 and -3, both at tumor center and at invasive front, in 107 patients with primary ductal invasive breast tumors. Data were analyzed by unsupervised hierarchical clustering analysis. Our results indicated that MMP-11 expression by MICs, and TIMP-2 expression by CAFs at either the tumor center or the invasive front, were the most potent independent prognostic factors for predicting the clinical outcome of patients. Using the unsupervised hierarchical clustering analysis, we found well-defined clusters of cases identifying subgroups of tumors showing a high molecular profile of MMPs/TIMPs expression by stromal cells (CAFs and MICs), both at the tumor center and at the invasive front, which were strongly associated with a higher prevalence of distant metastasis. In addition, we found combinations of these clusters defining subpopulations of breast carcinomas differing widely in their clinical outcome. The results presented here identify biologic markers useful to categorize patients into different subgroups based on their tumor stroma, which may contribute to improved understanding of the prognosis of breast cancer patients.

Analysis of the expression of interleukins, interferon ß, and nuclear factor-κ B in prostate cancer and their relationship with biochemical recurrence.

There are accumulating epidemiological, experimental, and genetic data supporting that prostate inflammation may contribute to prostate carcinogenesis, and several inflammatory-related molecules have been linked to tumorigenesis and prognosis in several tumors. The aim of this study was to evaluate tumor expression of inflammatory-related factors in prostate carcinomas and their possible relationship with biochemical recurrence (elevation of prostate-specific antigen serum levels). An immunohistochemical study was conducted using tissue microarrays and specific antibodies against interleukin-1ß (IL-1ß), IL-6, IL-10, IL-17, interferon ß (IFNß), and nuclear factor-κ B (NF-κB). Determinations in cancer specimens from 118 patients with primary prostate cancer (78 without and 40 with recurrence during the follow-up period) were performed. Immunostaining for all the studied proteins was localized both in tumor cells and in stromal cells in the majority of tumors. High-score values for IL-1ß or low-score values for IFNß were significantly associated with biochemical recurrence. The analysis defined a score value of 160 for IL-1ß and of 170 for IFNß as the optimal cutoff points that identified 32.7% and 73.2% of patients, respectively, having high probability of biochemical recurrence. Multivariate analysis according to a Cox model indicated that the cutoff point 170 for IFNß (P=0.035) was an independent factor associated with biochemical recurrence in patients with prostate cancer. Both IL-1ß and IFNß may be new biomarkers to distinguish high-risk/low-risk patients with prostate cancer, and to select appropriate therapeutic approaches.

Structure-based design of new KSP-Eg5 inhibitors assisted by a targeted multicomponent reaction.

An integrated multidisciplinary approach that combined structure-based drug design, multicomponent reaction synthetic approaches and functional characterization in enzymatic and cell assays led to the discovery of new kinesin spindle protein (KSP) inhibitors with antiproliferative activity. A focused library of new benzimidazoles obtained by a Ugi+Boc removal/cyclization reaction sequence generated low-micromolar-range KSP inhibitors as promising anticancer prototypes. The design and functional studies of the new chemotypes were assessed by computational modeling and molecular biology techniques. The most active compounds-20 (IC50 =1.49 µM, EC50 =3.63 µM) and 22 (IC50 =1.37 µM, EC50 =6.90 µM)-were synthesized with high efficiency by taking advantage of the multicomponent reactions.

Clinical significance of toll-like receptor 3, 4, and 9 in gastric cancer.

Toll-like receptors (TLRs) have raised an extraordinary interest in cancer research due to their role in tumor progression. By activating the production of several biological factors, TLRs drive an inflammatory response and activate the adaptive immune system. The aim of this study was to investigate the expression and clinical relevance of TLR3, TLR4, and TLR9 in gastric cancer. For this purpose, an immunohistochemical study on cancer specimens from 106 patients with gastric cancer was performed using tissue arrays and specific antibodies against TLR3, TLR4, and TLR9. The results indicate that gastric carcinomas samples show high expression of TLR3, TLR4, and TLR9 by cancer cells. The expression of TLR3 by cancer cells was significantly associated with a poor overall survival in patients with resectable tumors. Moreover, in patients with resectable tumors and lymph node invasion, a high TLR3 expression defines a population with even worse prognosis. Therefore, TLR3 may have clinical interest as indicator of tumor aggressiveness and as a prognostic indicator in gastric cancer.

Expression and prognostic significance of fibronectin and matrix metalloproteases in breast cancer metastasis.

AIMS: Fibronectin (FN) has attracted interest in cancer research, owing to its role in tumour progression. The aims of this study were to investigate the expression and clinical relevance of FN in breast cancer, and to explore its relationship with the expression of matrix metalloproteases (MMPs) and their inhibitors (TIMPs). METHODS AND RESULTS: An immunohistochemical study was performed using tumours from 110 breast cancer patients, with tissue arrays and specific antibodies against FN, MMP-7, MMP-9, MMP-11, TIMP-1, and TIMP-2. The results indicated that FN expression was related to tumour size, histological grade, and MMP-9 expression. Tumours with high FN expression by tumour cells were significantly associated with a higher probability of metastasis, poorer overall survival, and expression of MMP-7, MMP-9, MMP-11, TIMP-1 and TIMP-2 by mononuclear inflammatory cells (MICs). In addition, the combination of FN expression by tumour cells and MMP-11 by MICs was strongly associated with distant metastasis development. CONCLUSIONS: Breast carcinomas with distant metastasis frequently have tumour cells expressing intracellular FN. There is a strong association between FN expression by tumour cells and MMP or TIMP expression by stromal MICs, and this may represent crosstalk that is of prognostic relevance in breast cancer.

Toll-like receptors 3, 4 and 9 in hepatocellular carcinoma: Relationship with clinicopathological characteristics and prognosis.

AIM: Hepatocellular carcinoma (HCC) is in the 10 leading cancer types, being difficult to detect as most of patients who develop this tumor have no symptoms other than those related to their long-standing liver disease. The liver is constantly exposed to bacterial products, viral infection, alcohol or other products, which may be the cause of chronic liver damage, and thus an increasing risk for HCC. Toll-like receptors (TLR) have gained an extraordinary interest in cancer research due to their role in several biological processes such as innate immune responses, the induction of adaptive immune responses, regulation of inflammation, would healing and carcinogenesis. Therefore, the aim of this study was to investigate the expression and clinical relevance of TLR3, 4 and 9 in HCC. METHODS: The expression levels of TLR3, TLR4 and TLR9 were analyzed in tumors from 30 patients with HCC. The analysis was performed by immunohistochemistry. Results were correlated with various clinicopathological findings and with overall survival. RESULTS: TLR3 was significantly high in large tumors (>4 cm in diameter) compared with small tumors (P < 0.05). Our results demonstrated that patients whose tumors showed both TLR4 and TLR9 positive immunostaining had poor prognosis. In addition, TLR9 expression by fibroblast-like cells was significantly associated with a shortened overall survival (P = 0.015). CONCLUSION: The results demonstrated an association between TLR3, TLR4 and TLR9 expression and tumor aggressiveness and poor prognosis in HCC.

A TRAF2 binding independent region of TNFR2 is responsible for TRAF2 depletion and enhancement of cytotoxicity driven by TNFR1.

Tumor Necrosis Factor (TNF) interacts with two receptors known as TNFR1 and TNFR2. TNFR1 activation may result in either cell proliferation or cell death. TNFR2 activates Nuclear Factor-kappaB (NF-kB) and c-Jun N-terminal kinase (JNK) which lead to transcriptional activation of genes related to cell proliferation and survival. This depends on the binding of TNF Receptor Associated Factor 2 (TRAF2) to the receptor. TNFR2 also induces TRAF2 degradation. In this work we have investigated the structural features of TNFR2 responsible for inducing TRAF2 degradation and have studied the biological consequences of this activity. We show that when TNFR1 and TNFR2 are co-expressed, TRAF2 depletion leads to an enhanced TNFR1 cytotoxicity which correlates with the inhibition of NF-kB. NF-kB activation and TRAF2 degradation depend of different regions of the receptor since TNFR2 mutants at amino acids 343-349 fail to induce TRAF2 degradation and have lost their ability to enhance TNFR1-mediated cell death but are still able to activate NF-kB. Moreover, whereas NF-kB activation requires TRAF2 binding to the receptor, TRAF2 degradation appears independent of TRAF2 binding. Thus, TNFR2 mutants unable to bind TRAF2 are still able to induce its degradation and to enhance TNFR1-mediated cytotoxicity. To test further this receptor crosstalk we have developed a system stably expressing in cells carrying only endogenous TNFR1 the chimeric receptor RANK-TNFR2, formed by the extracellular region of RANK (Receptor activator of NF-kB) and the intracellular region of TNFR2.This has made possible to study independently the signals triggered by TNFR1 and TNFR2. In these cells TNFR1 is selectively activated by soluble TNF (sTNF) while RANK-TNFR2 is selectively activated by RANKL. Treatment of these cells with sTNF and RANKL leads to an enhanced cytotoxicity.

Toll-like receptor-4 expression by stromal fibroblasts is associated with poor prognosis in colorectal cancer.

Because of the important role in inflammation and tissue regeneration, toll-like receptors (TLR) are likely candidates to mediate effects of the innate immune system on tumorigenesis. The aim of this study was to investigate the expression and clinical relevance of TLR in colorectal cancer (CRC). The expressions of TLR3, TLR4, TLR7, and TLR9 were analyzed in 104 patients with resectable CRC by immunohistochemistry. The evaluation of the expression consisted on measuring the overall level of TLR expression and by each cell type. The results showed a direct association between the histologic grade of tumor and TLR9 expression by tumor cells. TLR4 expression by tumor cells was significantly associated with a lower rate of tumor recurrence, whereas the expression by fibroblasts was significant and independently associated with a high rate of tumor recurrence and with a shortened overall survival in patients; particularly in tumors from left colon and rectum. Therefore, TLR4 expression by fibroblasts could be a useful prognostic marker in CRC.

Cytokines related to MMP-11 expression by inflammatory cells and breast cancer metastasis.

Breast tumors infiltrated by matrix metalloprotease 11 (MMP-11)+ mononuclear inflammatory cells are prone to form metastases; express high levels of interleukin (IL)-1, IL-5, IL-6, IL-17, interferon ß (IFNß) and NFκB; and exhibit an increased CD68+/(CD3+CD20+) cell ratio at their invasive front. These factors, which are implicated in the crosstalk between tumors and their inflammatory microenvironment, may emerge as attractive prognostic factors and therapeutic targets.

Prediction of metastatic breast cancer in non-sentinel lymph nodes based on metalloprotease-1 expression by the sentinel lymph node.

AIMS: Sentinel lymph node (SLN) biopsy is the current standard axillary approach for patients with clinically node-negative breast cancer. If the SLN is positive, is still also standard in most centres to proceed with a complete axillary dissection to predict the remaining nodes affectation, despite of SLN is the only positive lymph node in 50-68% of cases. If we could identify them, these patients could be spared a complete axillary dissection. METHODS: Elevated expression of specific matrix metalloproteases (MMPs) and their inhibitors (TIMPs) by stromal mononuclear inflammatory cells (MICs) of primary tumours is significantly associated with distant metastasis development in breast cancer. In the present study we first identified candidate MMPs/TIMPs associated with axillary metastasis in a preliminary group (n=50), and subsequently examined the potential of their expression in the SLN for predicting the status of the remaining nodes, in 105 patients with intraoperative SLN-assessment. RESULTS: MMP-1 expression by MICs from SLNs was significantly associated with metastatic spread to non-SLNs. Moreover, in all cases with negative MMP-1 expression by MICs from SLNs, the remaining non-SLNs were not affected (p<0.0001). Therefore, we demonstrate that MMP-1 expression by MICs from SLNs had 100% sensitivity, 100% negative-predictive value and 61.5% specificity to predict non-SLNs status. CONCLUSION: This is the first time that tumour spread to the remaining axillary nodes has been predicted from molecular features of the SLN(s). If confirmed in larger studies, patients could be spared the morbidity associated with an unnecessary complete lymphadenectomy.

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.

Relationship between the inflammatory molecular profile of breast carcinomas and distant metastasis development.

Inflammatory conditions may promote tumor progression and aggressiveness. In previous reports, we found a group of breast cancer tumors characterized by metalloprotease-11 (MMP-11) expression by intratumoral mononuclear inflammatory cells (MICs), which was associated with distant metastasis development. Thus, in the present study we evaluated the relationship between MMP-11 expression by MICs, distant metastasis development, and a wide panel of inflammatory factors in breast carcinoma. In an initial approach, we analyzed 65 factors associated with tumor progression and inflammation, in a tumor population classified in good or bad prognosis, based on MMP-11 expression by intratumoral MICs. The most differentially expressed factors were then analyzed in a wider tumor population classified according to MMP-11 expression by MICs and also according to metastasis development. These analyses were carried out by Real-time PCR. The results showed that of the 65 starting factors analyzed, those related with MMP-11 expression by MICs were: IL-1, -5, -6, -8, -17, -18, MMP-1, TIMP-1, ADAM-8, -10, -15, -23, ADAMTS-1, -2, -15, Annexin A2, IFNß, Claudin-3, CCL-3, MyD88, IRAK-4 and NFκB. Of them, factors more differentially expressed between both groups of tumors were IL-1, IL-5, IL-6, IL-17, IFNß and NFκB. Thereafter, we confirmed in the wider tumor population, that there is a higher expression of those factors in tumors infiltrated by MMP-11 positive MICs. Altogether these results indicate that tumors developing worse prognosis and identified by MMP-11 expression by intratumoral MICs, shows an up-regulation of inflammatory-related genes.

Nuclear envelope-associated dynein drives prophase centrosome separation and enables Eg5-independent bipolar spindle formation.

The microtubule motor protein kinesin-5 (Eg5) provides an outward force on centrosomes, which drives bipolar spindle assembly. Acute inhibition of Eg5 blocks centrosome separation and causes mitotic arrest in human cells, making Eg5 an attractive target for anti-cancer therapy. Using in vitro directed evolution, we show that human cells treated with Eg5 inhibitors can rapidly acquire the ability to divide in the complete absence of Eg5 activity. We have used these Eg5-independent cells to study alternative mechanisms of centrosome separation. We uncovered a pathway involving nuclear envelope (NE)-associated dynein that drives centrosome separation in prophase. This NE-dynein pathway is essential for bipolar spindle assembly in the absence of Eg5, but also functions in the presence of full Eg5 activity, where it pulls individual centrosomes along the NE and acts in concert with Eg5-dependent outward pushing forces to coordinate prophase centrosome separation. Together, these results reveal how the forces are produced to drive prophase centrosome separation and identify a novel mechanism of resistance to kinesin-5 inhibitors.

Impact of CD68/(CD3+CD20) ratio at the invasive front of primary tumors on distant metastasis development in breast cancer.

Tumors are infiltrated by macrophages, T and B-lymphocytes, which may favor tumor development by promoting angiogenesis, growth and invasion. The aim of this study was to investigate the clinical relevance of the relative amount of macrophages (CD68⁺), T-cells (CD3⁺ and B-cells (CD20⁺) at the invasive front of breast carcinomas, and the expression of matrix metalloproteases (MMPs) and their inhibitors (TIMPs) either at the invasive front or at the tumor center. We performed an immunohistochemical study counting CD3, CD20 and CD68 positive cells at the invasive front, in 102 breast carcinomas. Also, tissue sections were stained with MMP-2, -9, -11, -14 and TIMP-2 antibodies, and immunoreactivity location, percentage of reactive area and intensity were determined at the invasive front and at the tumor center. The results showed that an increased CD68 count and CD68/(CD3+CD20) ratio were directly associated with both MMP-11 and TIMP-2 expression by mononuclear inflammatory cells at the tumor center (p = 0.041 and p = 0.025 for CD68 count and p = 0.001 and p = 0.045 for ratio, respectively for MMP-11 and TIMP-2). In addition, a high CD68/(CD3+CD20) ratio (>0.05) was directly associated with a higher probability of shortened relapse-free survival. Multivariate analysis revealed that CD68/(CD3+CD20) ratio was an independent factor associated with distant relapse-free survival (RR: 2.54, CI: (1.23-5.24), p<0.01). Therefore, CD68/(CD3+CD20) ratio at the invasive front could be used as an important prognostic marker.

Proteomic analysis of annexin A2 phosphorylation induced by microtubule interfering agents and kinesin spindle protein inhibitors.

Microtubule interfering agents (MIAs) are antitumor drugs that inhibit microtubule dynamics, while kinesin spindle protein (KSP) inhibitors are substances that block the formation of the bipolar spindle during mitosis. All these compounds cause the accumulation of mitotic cells and subsequently cell death. We used two-dimensional gel electrophoresis (2DE) followed by MALDI-MS analysis to demonstrate that the MIAs vinblastine (Velban) and paclitaxel (Taxol), as well as the KSP inhibitor S-tritil-L-cysteine, induce the phosphorylation of annexin A2 in human lung carcinoma A549 cells. Further tandem mass spectrometry analysis using a combination of peptide fragmentation methods (CID and ETD) and multiple reaction monitoring (MRM) analysis determined that this modification occurs mainly at threonine 19. We show that MIAs and KSP inhibitors only induce this phosphorylation in cells capable of reaching the M phase. Furthermore, we demonstrate that CDK activity is required for the phosphorylation of annexin A2 induced by MIAs and KSP inhibitors. Finally, we have used double thymidine block synchronization to demonstrate that annexin A2 is not phosphorylated during a normal mitosis, indicating that this phosphorylation of annexin A2 is a specific response to these drugs.